Did anyone else see this fireball earlier this week, reported here by Joseph Novotka?  

"I know this is going to sound weird, but just a few nights ago I saw something similar to what is being described above, it was like a large fire ball. It came from the sky traveling from south to north. I was in Rockville, MD and the fire ball appeared to fall in to the Germantown area. I never heard a sound from a landing or explosion. There was nothing in the news about it. So I just said so what! Now that I see that others have seen similar object I decided to chime in. The date was something like Sept 25th or 26th 2007."

If you saw it, leave us a comment here and describe what you saw, where you were, what direction you were looking and anything else you can remember. Maybe we can get a better sense of where it was. I will post all comments as soon as I can, but I may be a bit slow on a weekend.

The link above will take you to a 2006 fireball report to the WeatherBlog, and provide some background on these events. The comments that followed over the next several weeks provided a good sense of where that one was.

For more information on fireballs, and for sighting report forms from the American meteor Society, click here.

Posted by Frank Roylance at 9:53 AM | Permalink | Comments (1)
        

(Briefly) Hurricane Lorenzo has gone ashore in Mexico and has weakened to a tropical depression again after only a few hours at hurricane strength. Tropical Storm Karen, far out in the Atlantic, is also weakening. But hurricane forecasters say yet another area of stormy weather in the far eastern Atlantic has reached tropical depression status, with prospects for becoming the next named storm of the season.

Here is the latest advisory on Lorenzo, now delivering way too much rain in central Mexico. Here is the forecast track and the view from space. And here's some news from CNN on the storm.

Here is the latest on Karen, the forecast track and the view from orbit.

And here is the latest on brand-new Tropical Depression 14, which is expected to encounter cooler water and more wind shear in the coming days, which may weaken it. Here's the view from orbit. Next name on the list: Melissa.

Posted by Frank Roylance at 1:13 PM | Permalink | Comments (0)
Categories: Hurricanes
        

What a beautiful sound that was - the patter and splash of rain, the peals of thunder. Too bad last night's storms didn't have more of an impact on the region's rain totals for the month, which will now end for Baltimore as the fourth-driest September on record.

The rain gauge here on the WeatherDeck in Cockeysville stopped at 0.18 inch after last night's rain. For the month, the total is a mere 0.53 inch.

Out at BWI, where the numbers really count, there was just a trace of rain. That means the month's total will likely halt at 0.35 inch. The totals for last night's storm were a bit better north and west of BWI, but not very impressive:

Inner Harbor:  0.47 inch

Frederick:  0.29 inch

Reagan National:  Trace

Dulles International:  0.59 inch

York (PA) Airport: 0.08 inch

Here's the NWS daily rainfall map, which can be a bit tricky to decipher. Be patient. Hit the "enlarge" arrow button to blow it up, and you'll figure it out.

There's still a chance for a shower this morning, but not much of one. And the forecast for the next week looks beautiful, but dry. 

Posted by Frank Roylance at 7:39 AM | Permalink | Comments (0)
Categories: By the numbers
        

What had been Tropical Depression 13, spinning for days in the Gulf of Mexico off the Mexican coast and going nowhere, has finally gained enough strength to become the 12th named storm of the 2007 Atlantic hurricane season. Tropical Storm Lorenzo is finally moving toward the coast with sustained winds of 70 mph, and higher gusts. It is expected to enter the state of Veracruz early Friday as a minimal hurricane.

UPDATE: 8:10 p.m.:  Lorenzo is now a hurricane, with top sustained winds near 75 mph.

Here's the latest advisory. Here's the forecast storm track, and the view from orbit.

Meanwhile, far at sea, Tropical Storm Karen is weakening, raked by shearing winds from the southwest. Here's the latest advisory, the forecast track (which looks like it may turn more to the west, and Bermuda, in the next few days) and the view from space.  The shear is very visible on the loop. Forecasters say some re-strengthening is possible in a few days as the shear weakens.

Posted by Frank Roylance at 5:42 PM | Permalink | Comments (0)
Categories: Hurricanes
        

Seems like there is plenty of rain on the national map, but it does not look like Maryland will see much of it before the month ends on Sunday night. On the other hand, we can look forward to another terrific weekend - sunny days, clear nights and comfortable temperatures.

First the rain. We need some, obviously. As we've noted here before, September 2007 is currently the fourth-driest on record for Baltimore. And we're running more than 8 inches behind average precipitation since Jan. 1. We haven't had a month with surplus rain since April. The new Drought Monitor map, out this morning, shows that 86 percent of the state is in "moderate" drought, nearly double the amount reported for the past two weeks. And a slice of western Charles County is once again in severe drought.  

The forecast from Sterling says there's a 30 percent chance of some showers this afternoon, and a 50/50 chance for thunderstorms tonight. That may add enough rain to the gauge to knock this month out of the top-five driest Septembers. But it won't deliver the kind of sustained, widespread precipitation we need to bring streamflows back from near-record lows, recharge groundwater, soak the soil and bring the reservoirs back to where we'd like them.

Too bad. There's a low-pressure system in the Ohio Valley, riding along the cold front to our west that might have provided some relief. It appears likely to pass too far to our north toward New England.

At the same time, there's a coastal low that hurricane forecasters are watching for tropical development. That doesn't seem likely, either. But the storm - after brushing the Carolina coast - will head for New England. The convergence of those two storm centers will deliver plenty of rain to the Northeast. But we'll be largely bypassed. Here's how AccuWeather describes it.

And here's how the two storms to our west and east look from space.

The consolation prize? A gorgeous weekend. Highs in the upper 70s - just slightly warmer than the long-term averages for BWI. Overnight lows will be in the 50s - also just about average for late September. So open the windows, shut off the AC and bank these best-of Maryland autumn days.

Posted by Frank Roylance at 11:17 AM | Permalink | Comments (2)
Categories: Forecasts
        

It's not easy to tell from the forecast whether our skies will be hopelessly cloudy around 5:30 a.m. tomorrow, when the International Space Station will be soaring over just north and east of Maryland. It's not too promising.

But on the off-chance the approaching cold front holds off long enough, here are the details of Thursday morning's flyby:

Look for the ISS to come out of the Earth's shadow in the northwestern sky just below the constellation Cassiopeia at 5:33 a.m. EDT. It will look like a bright star, hustling across the sky toward the southeast.

It will reach its highest point, about two-thirds of the way up from the northeastern horizon and the zenith (straight up) at 5:34 a.m. as it crosses central New Jersey.  From there, it will slip out over the Atlantic, pass just south of a brilliant Venus, and disappear over the southeast horizon at 5:37 a.m.

This pass by the ISS will be especially bright - with an apparent magnitude of minus-2.0, brighter than the brightest star, Sirius, which will also be visible low in the southeast to the right of Venus and the ISS, weather permitting.

Once again, if you go out to see it, come back inside and leave a comment.

Posted by Frank Roylance at 5:32 PM | Permalink | Comments (0)
Categories: Sky Watching
        

It may approach 90 degrees here this afternoon, but out in the high Rockies, the snow has already begun to fall. Here is an animation of NOAA's snow-cover map through Sept. 25, based on satellite data. You can see the mountain snows appear in the final frames. You can see the snow cover has also begun to appear at the north end of Hudson's Bay.

But then, that's why we live here in Maryland and not on Hudson's Bay. In the meantime, fall colors are visible on this rather dim satellite image of the Lake Superior region. The leaves have already begun to turn here, too, thanks in part to the persistently dry weather we've had this summer and early fall. Many trees are drought-stressed, and shedding their leaves early.

We may actually pick up a bit of rain tomorrow as this long-anticipated cold front arrives to push this unseasonably warm and muggy weather off the coast.

Posted by Frank Roylance at 10:58 AM | Permalink | Comments (0)
Categories: Winter weather
        

The National Hurricane Center is tracking yet another tropical weather system. Tropical Depression 13 has formed in the southwestern corner of the Gulf of Mexico. The gathering storm is stuck in a region with little wind to steer it, so it is likely to continue to gather strength over very warm water. It  could become a hurricane, and a threat to central Mexico, in as little as three days, according to at least one computer model.

Here is the latest advisory on TD 13. Here is the forecast storm track. And here is the view from space.

Meanwhile, forecasters have issued their final advisory on what was Tropical Storm Jerry, now absorbed by other weather systems in the mid-Atlantic. But they're still watching Tropical Storm Karen, also spinning far out in the Atlantic and not a threat to land.

Posted by Frank Roylance at 6:21 PM | Permalink | Comments (0)
Categories: Hurricanes
        

Tropical Storm Karen, the 11th named storm of the 2007 Atlantic hurricane season, came to life overnight in the central Atlantic Ocean. It does not appear to be any immediate threat to land and its forecast track would seem to keep it at sea.

Here's the latest advisory. Here's the forecast track and here's a view from space. (Karen is at lower right.)

The other stormy area forecasters were watching yesterday has not gotten any better organized, and poses only a rain threat to the Leeward Islands. Here's how the storm's water vapor looks from orbit.

Posted by Frank Roylance at 10:19 AM | Permalink | Comments (0)
Categories: Hurricanes
        

It was a beautiful morning for watching the International Space Station fly over Baltimore and right past a gleaming Venus. But summer resumes this afternoon, with even hotter, muggier weather tomorrow. This early-autumn reprise of summer will be short-lived however.

The big mound of high pressure that's brought us these gorgeous days (which I've enjoyed through the sealed, double-paned windows of the newsroom) will be packing up and heading out to sea shortly. As it departs, Maryland will find itself on the west side of the clockwise circulation around the high. That will bring our air up from the south. Daytime highs today and tomorrow will rise toward 90 degrees and humidities will climb. It's going to feel a whole lot like summer.

As the high moves away, of course, it will be trailed by an approaching cold front and falling barometer. That will bring us increasing clouds and rising chances for rainfall late Wednesday and Thursday. Forecasters out at Sterling have been boosting their estimates. We're looking at 50 to 60 percent rain chances Thursday - showers and even a possible thunderstorm as the front and daytime heating stirs the air. Obviously, we need the rain, so every drop will be welcome. Right now this September ranks as the fourth-driest on record for Baltimore, with just 0.35 inch of rain on the meter at BWI, and 0.42 inch here at Calvert & Centre.

Once the front goes by, pressure will start to rise again Friday and cold air will pour in from the northwest. Skies will clear, and daytime highs will rise only into the mid-70s for the weekend, with sleeping-weather lows in the 50s. That's much more fall-like,  just about exactly in line with the long-term averages for Baltimore at this time of year. 

Posted by Frank Roylance at 9:46 AM | Permalink | Comments (0)
Categories: Hurricane background
        

Tropical storm Jerry, which never threatened anyone except shipping and fish, is fading in the mid-Atlantic. But hurricane forecasters are watching two more storms in the tropical Atlantic, including one that forecasters say looks like the "classic Cape Verdean" storm that can sometimes threaten the U.S. East Coast.

Here's the latest advisory on Jerry, which has been downgraded to a tropical depression. Here's his position. And here's the view from orbit.

Here's a broad view of the Atlantic. There are two storms of interest out there - one nearing the Windward Islands. The other - the one that has impressed forecasters - is on the lower right-hand side of the image. Here's another satellite view.

And here's what the tropical discussion had to say about that Cape Verdean storm:

"A 1007 MB LOW PRESSURE SYSTEM IS LOCATED ABOUT 565 NM SW OF THE
CAPE VERDE ISLANDS NEAR 8.5N31W. THIS LARGE SYSTEM CONTINUES TO
SHOW SIGNS OF ORGANIZATION...AND COULD BECOME A TROPICAL
DEPRESSION DURING THE NEXT DAY OR SO AS IT MOVES
WEST-NORTHWESTWARD NEAR 10-15 KT. A MORE CONCENTRATED AREA OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOW MOSTLY W OF
THE CENTER FROM 8N-11N BETWEEN 31W-37W. ISOLATED CLUSTERS OF
MODERATE CONVECTION ARE ELSEWHERE FROM 5N-12N BETWEEN 29W-38W.
THIS IS ONE OF THE MORE CLASSIC LOOKING CAPE VERDE SYSTEMS WE
HAVE SEEN OVER THE PAST COUPLE OF WEEKS."

Next names on the list: Karen and Lorenzo

Posted by Frank Roylance at 1:44 PM | Permalink | Comments (0)
Categories: Hurricanes
        

Unless you're stuck in a foggy river bottom tomorrow morning, you should have a terrific opportunity to watch the International Space Station fly over Maryland. The forecast is good and, while this will be an early-morning pass, it will occur at a reasonable morning hour as the sky brightens with the approaching dawn.

And we're getting close to another period of evening flybys, beginning next week. More on that in a future post.

Here are the details of Tuesday morning's ISS flyby: Look for the station to appear in the northwest at about 6:18 a.m. as it flys over Lake Michigan. Zipping along at 17,500 mph, it will reach its highest point in sky for Baltimoreans - about two-thirds of the way between the horizon and the zenith (straight up) at 6:21 a.m. as it passes over central New Jersey.

From there, the ISS and its crew of three will head out to sea, passing very close to brilliant Venus in the eastern sky. It will disappear from our view at about 6:24 a.m.

There will be another, very similar morning pass beginning at 5:29 a.m. Thursday, but clouds may obscure the view. I will try to post more on that one if it appears the skies will stay clear for it.

If you get out to watch tomorrow, come back inside and leave a comment. Describe what you saw so we can motivate others to get out and see this stuff. Especially the kids. 

Posted by Frank Roylance at 12:39 PM | Permalink | Comments (2)
Categories: Sky Watching
        

This is so sweet. Highs in the 80s this week with lots of sunshine during the day. Lows in the 50s at night, with plenty of stars. This is a Maryland autumn at its best.

It's actually quite a bit warmer than the averages for this time of year. The average high at BWI for Sept. 24 is 76 degrees. We've already reached that here at Calvert & Centre streets. The average low is 53 degrees. BWI bottomed out this morning at 51 degrees. We were in the high 40s on the WeatherDeck in Cockeysville. Left the bedroom windows open and woke up feeling like were were camping out.

Forecasters believe we're headed for the upper 80s in the next couple of days, crowding 90 on Wednesday with higher humidities as we fall into the return, southerly flow on the west side of the departing high pressure.

By Thursday and Friday there should be a new cold front pushing through the region, with some chance for showers. There's cooler weather behind it. Look for temperatures in the more seasonable 70s by the weekend, and more sunny weather.

Posted by Frank Roylance at 11:31 AM | Permalink | Comments (0)
Categories: Forecasts
        

The National Hurricane Center is reporting that the storm that has been drifting from the Atlantic east of north central Florida, across the peninsula into the Gulf for the last couple of days, has finally strengthen to tropical depression status. It was named Tropical Depression Ten this morning, and could continue to strengthen and become the 10th named tropical storm of the Atlantic season. That would be TS Jerry.

Storm warnings and coastal flood warnings have been issued for parts of the Gulf Coast from the Florida panhandle to Louisiana, including New Orleans. Here is the latest advisory. Here's the forecast storm track. And here's the view from space.

Here's AccuWeather's take.

Posted by Frank Roylance at 11:33 AM | Permalink | Comments (0)
Categories: Hurricanes
        

You sure can't complain about the weather this month. It's been beautiful in Baltimore. A little morning fog, maybe. And those clouds off the Atlantic slipped across much of the region yesterday and grayed things up a bit. But on the whole it's been a spectacular end to a very warm and dry summer.

The only complaint you could make would be about the continuing lack of rainfall. BWI has recorded just 0.35 inch of precipitation in September. That's more than 2 inches below normal for the month so far. And there's not much in the forecast, either, at least not until the middle of next week. And even that's not promising very much.

We still have 10 days to go, of course. And there's always the possibility that a tropical system will send a few showers our way. But here's how our rainfall stacks up so far against other very dry Septembers:

1884:  0.09 inch

1967:  0.21 inch

1906:  0.32 inch

2007:  0.35 inch*

1930:  0.37 inch

1970:  0.46 inch

1941:  0.50 inch

* Through 9/20

And, now that the meteorological summer and is over (and the calendar summer ends on Sunday morning) here is the Summer 2007 issue of the Sterling Reporter, the quarterly newsletter from the NWS Sterling Forecast Office. It has a nifty map of the Harford County tornado damage, and a few features on the forecasters we quote from time to time. Nice to put a face to a name.

Posted by Frank Roylance at 8:05 AM | Permalink | Comments (0)
Categories: By the numbers
        

The 2008 Old Farmer's Almanac is out, and with it comes the eagerly anticipated - if not always reliable - forecast for this winter's weather. The bottom line seems to be this: If you love frigid weather and plenty of snow, this may not be the Baltimore winter of your dreams.

Of course, if you've paid attention to this blog, and to the forecasts from National Weather Service climatologists, you already knew that. This is shaping up to be another La Nina winter, which for us means mild weather without much snow.

The Old Farmer, using his "proprietary" prognostication system, agrees. The Mid-Atlantic region, from Rhode Island, down the coast to South Carolina, is looking at "mild and dry" weather this winter, he said. There will be mild weather, but more snow inland, from the Ohio Valley up the Appalachians into New England. That includes Garrett County and a bit more of far-Western Maryland, but not us down here on the coastal plain.

The Deep South looks to be cool and dry, and most of the rest of the U.S., from the Great Lakes to Texas, the Great Plains and the Northwest, all should be "mild and dry" if the Old Farmer is on the beam.

More specifically, the Almanac predicts the first flurries along the mid-Atlantic coast in mid-December, with "rain and snow, then sunny, very cold" around Christmas. I don't see any mention here of a big storm all the rest of the winter. There's a prediction for bit of snow amid very cold outbreaks in late January and mid-February, but nothing emphatic.

Farther ahead the old boy sees a relatively  "hot, wet" summer, capped by a hurricane in the last week of September.

Snow-lovers might want to head west. The Almanac does forecast "heavy snowfalls" for Appalachian Maryland (from roughly Carroll and Frederick to Allegany counties) in mid-December, mid-to-late January and mid-to-late February.  

Next up: The Hagers-town Town and Country Almanack. Stay tuned.

Posted by Frank Roylance at 2:25 PM | Permalink | Comments (6)
Categories: Winter weather
        

Stargazers! Sure, there's plenty to see in the night sky tonight. But take a break and don't miss "Seeing in the Dark," a beautiful and very mellow PBS exploration of the joys of backyard astronomy. It was written and produced by science writer Timoth Ferris, who wrote the delightful book of the same name, which explored Ferris' own youthful discovery of the night sky.

I got a preview copy of the special, and it's terrific. Accompanied by music from Mark Knopfler and Guy Fletcher, this special is beautifully photographed and paced - like a night out under the stars.

It focuses on amateurs, and the astonishing images and discoveries that have become possible for them thanks to a new generation of (more or less) affordable telescopes, laptop computers and image-processing software. I own a small telescope, and I enjoy poking around among the stars and planets I've learned to identify. I will never own the kind of equipment these folks work with, and I will never get into the hobby as deeply as they have. But I know enough to appreciate their skill and passion. Some are making serious contributions to science.

Mostly, though, I just share their amazement as they gather under a dark sky and marvel at the stars. 

The film airs at 8 p.m. tonight, Wednesday Sept. 19, on PBS, Channels 22 and 26 in Baltimore. Enjoy.

Posted by Frank Roylance at 2:20 PM | Permalink | Comments (1)
Categories: Events
        

It doesn't show much sign of developing into a tropical storm, although that remains a possibility. But the storm brewing over the Atlantic just east of the Florida peninsula is expected to drift westward, bringing heavy rains to the north-central part of the state before it moves into the Gulf of Mexico. Doesn't look like this will benefit us anytime soon. But AccuWeather's Joe Bastardi is looking for it to strengthen in the Gulf and threaten La. and Tex. Here's Joe on video.

Here's the satellite image. And here's the discussion from the National Hurricane Center:

"A WEAK SURFACE LOW PRESSURE AREA AND A UPPER-LEVEL LOW NEAR THE
FLORIDA PENINSULA ARE PRODUCING A LARGE AREA OF DISTURBED
WEATHER OVER THE WESTERN ATLANTIC...NORTHERN BAHAMAS...AND THE
EAST COAST OF FLORIDA. THERE ARE NO SIGNS OF ORGANIZATION AT
THIS TIME. HOWEVER...SURFACE PRESSURES ARE SLOWLY FALLING AND
ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR A SUBTROPICAL OR A
TROPICAL CYCLONE TO FORM OVER THE NEXT DAY OR TWO...AS THE
DISTURBANCE MOVES WESTWARD OVER FLORIDA AND INTO THE GULF OF
MEXICO. REGARDLESS OF DEVELOPMENT...THIS SYSTEM WILL LIKELY
BRING SHOWERS...SQUALLS...AND LOCALLY HEAVY RAINS OVER PORTION
OF FLORIDA DURING THE NEXT DAY OR TWO. MOSAIC DOPPLER RADAR FROM
THE SE US SHOWS SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED
TSTMS ROTATING CYCLONICALLY MAINLY OVER NORTH-CENTRAL FLORIDA.  
SCATTERED SHOWERS ARE ALONG SOUTH FLORIDA EAST COAST."

Posted by Frank Roylance at 10:37 AM | Permalink | Comments (2)
Categories: Hurricanes
        

That big slab of high pressure that's given us all this delightful late-summer weather this week is still in place, stretched from Nova Scotia to Texas. But the clockwise flow around the system's center axis is dragging lots of marine air off the Atlantic and across the Eastern Shore.

Doesn't look too bad out there ATM, however..

Some of that moisture will encourage fog formation late tonight and early tomorrow morning, even in the Baltimore-Washington metro area. But daytime sunshine and warming temperatures should eventually burn it off. And the high pressure will continue to deliver pleasant weather well into next week. There's still no rain in sight. Here's the forecast.

Posted by Frank Roylance at 10:16 AM | Permalink | Comments (0)
Categories: Forecasts
        

Super typhoon Wipha is passing Taiwan and closing in on the southeast Chinese coast, headed for landfall somewhere on the heavily populated coast between Taiwan and Shanghai. Here's the latest image from NASA's Earth Observing Aqua satellite.

Here's an UPDATE.

This is a powerful, Cat. 4 storm, with gusts to 165 mph and a storm surge of 18 feet. And an estimated 1.8 million Chinese are being evacuated from vulnerable areas. Here's the storm track. Looks like North Korea, too, could feel Wipha's effects. 

Posted by Frank Roylance at 4:35 PM | Permalink | Comments (0)
Categories: Hurricanes
        

This feels like weather forecasting for Honolulu. No, actually, this is better than Honolulu. They should be flocking to Baltimore. For as far ahead as forecasters can see (a week, in this case),  Marylanders can expect perfect weather, with sunshine and daytime highs in the upper 70s and low 80s. At night, good sleeping weather and fine stargazing.

OK, as this big high begins to move offshore, we'll get into a return flow with warmer, more humid air from the South. But for outdoor activities, from touch football in the park to gnoshing at a sidewalk cafe, to stargazing, we're looking at very fine weather through the weekend. The only exceptions might be to our south and east, where northeasterly winds have been bringing moist ocean air and clouds onto the beaches, the Eastern Shore and perhaps into far Southern Maryland. You can see it in the satellite imagery. Baltimore and most of the Western Shore should remain in the clear.

Rain? Fuggeddaboudit. We're short - 2 inches this month alone, and seven inches for the year. Half the state is still in moderate drought, and we're going to stay short of moisture for the foreseeable future. The crop damage is already done, but we'll need to start recharging the groundwater and the reservoirs soon if we're to avoid serious water issues next summer. Streamflow in central Maryland is way down.

Posted by Frank Roylance at 10:16 AM | Permalink | Comments (0)
Categories: Forecasts
        

This is the week when the sun rises directly in the middle of Baltimore's east-west street grid, popping up at the eastern end of east-west streets laid out according to the city's original 18th century street plan.

If the streets were built pointing exactly due east and west, this would occur on Sept. 23, the autumnal equinox. But the surveyors used magnetic north rather than true north. That skewed the street grid 3 degrees counterclockwise, according to Baltimore Streetcorner Astronomer Herman Heyn.

As a result, the street-canyon sunrises occur this week, a few days ahead to the equinox. The sunsets will occur late next week, just after the equinox.

It is a time when rush-hour drivers can find themselves heading directly into a blinding sunrise or sunset. But it's a nifty challenge for photographers. If you'd like to take a crack at a dramatic street-canyon sunrise or sunset shot, give it your best, then send the image to me at frank.roylance@baltsun.com and I will post the best ones.

The shot above was made during one of New York City's street-canyon sunsets.

Posted by Frank Roylance at 1:26 PM | Permalink | Comments (0)
Categories: Sky Watching
        

Can't sleep? Dog whining to go out before dawn? Got an impossibly early commute? Well, here's something to adorn the darkness of your early-morning, so-called life. Venus, Earth's sister planet, is up well before dawn this week, and about as bright as she ever gets. The forecast is good.

Look east after 4 a.m. That bright light you see in the sky is not a jetliner looking for BWI. It's the Goddess of Love, shining with sunlight reflected off her thick mantle of noxious clouds. The second planet from the sun will reach its most brilliant on the morning of the 23rd - a "magnitude minus-4.3." That's astronomer-speak for very, very bright. They say it's 19 times brighter than the brightest star. That star would be Sirius, visible low in the southeastern sky at 4:30 a.m., below the familiar winter constellation Orion.

Mars is up there, too. Look about halfway up the southeastern sky after 4:30 a.m., above Orion's head. It's pretty bright now, too, and reddish, of course. Hard to miss. Dust storms on the Red Planet have subsided, and NASA's twin Mars rovers are once again on the move. One has just entered Victoria crater, the biggest either of the robots has yet encountered.

Still asleep before the sunrise? Well, you can satisfy your craving for naked-eye planets in the evening this week, too. Look to the southwest after sunset. That bright "star" - the first to appear as the evening sky darkens - is Jupiter. A good pair of binoculars and a steady place to rest them on a clear night will reveal up to four of the planet's moons - tiny dots of light lined up on either side of the planet's disk. 

Posted by Frank Roylance at 11:14 AM | Permalink | Comments (0)
Categories: Sky Watching
        

What was once Tropical Storm Ingrid has melted away into a cloudy mess in the western Atlantic just east of the Leeward Islands. The ninth named storm of the 2007 Atlantic hurricane season was sliced and diced by wind shear and never got close to becoming a hurricane. The National Weather Service has now issued its final advisory on Ingrid's sad and inconsequential existence.

Here is the final storm track, showing what is now a tropical depression east of the islands of St. Kitts and Nevis, and the French island of Guadeloupe. Here's the satellite loop.

Posted by Frank Roylance at 10:40 AM | Permalink | Comments (0)
Categories: Hurricanes
        

Now THIS feels like fall. It was 42 degrees this morning out here on the WeatherDeck in Cockeysville. The low at BWI was 44 degrees, the coldest morning since May 22. That approached the record for the date, but fell short. The coldest Sept. 16 on record was in 1873, when the mercury stood at 41 degrees in Baltimore.

Night shift forecasters out at Sterling were fretting about whether to post a frost advisory for far northern and western suburbs tonight. Mighty early in the season for that. Check back later today to see what the day shift decides.

Here are some other early-morning readings around the region:

Inner Harbor:  55 degrees

York Airport:  38 degrees

Cumberland:  39 degrees

Morgantown, W. Va.:  39 degrees

Washington-Reagan Arpt.:  51 degrees

Dulles International:  43 degrees

The weather for the week ahead looks fabulous if you don't care about our lack of rain. Clear skies and highs in the 70s or low 80s, with cool nights, right into next weekend as high pressure settles in for a long stay. Expect a slow warming trend by mid-week. But still no need for the AC, and no need for heat. So open the windows, bank those degree-days and enjoy.

Posted by Frank Roylance at 8:39 AM | Permalink | Comments (0)
Categories: By the numbers
        

Tropical Depression Eight showed just enough life late last night to become the eighth named tropical storm of the 2007 Atlantic season - Ingrid. But the poor thing has been having considerable difficulty getting her breath.

Ingrid is drifting slowly in the Atlantic, moving toward the west northwest at 7 mph, hundreds of miles east of the Leeward Islands. Top sustained winds are just barely tropical storm strength at 45 mph, and Ingrid is expected to get weaker. The problem is that she is moving into a region of stronger wind shear, which forecasters this morning described this way:

 "...A DAGGER THROUGH THE HEART.  THEREFORE...A GRADUAL
WEAKENING IS FORECAST. IT IS POSSIBLE THAT INGRID WILL NOT LAST
THROUGH FIVE DAYS.  IN FACT...THE CLOUD PATTERN HAS ALREADY BEGUN
TO DETERIORATE SINCE THIS MORNING'S CLASSIFICATIONS."

Here's the latest advisory. Here's the forecast storm track. And here's a satellite view of the storm's water vapor. Ingrid is the blob at lower right. Looks like a greater threat to Bermuda than the continental U.S.

Posted by Frank Roylance at 11:04 AM | Permalink | Comments (0)
Categories: Hurricanes
        

We'll likely see some gathering clouds today and showers tonight as a cold front approaches from the north and west. But it looks like the remnants of Hurricane Humberto will stay to our south, a disappointment to anyone looking for some significant relief from the summer's drought.

Instead, forecasters out at Sterling are calling for only a "slight" chance of showers after lunch today, then a stronger chance for more showers tonight. But don't expect more than a few tenths of an inch.

If you're worrying about too much rain for the weekend rather than too little, you're in luck. We could still see a few showers Saturday morning, but forecasters say the cold front should work through by noon, bringing us clearing skies, cool temperatures and breezy conditions for the rest of the weekend and into Monday. Great days for the bike trail, or sailing.

Keep a blanket handy. Overnight lows Saturday and Sunday nights will dip into the 40s. We're looking at sunshine and highs in the 70s through mid-week. That's 5 to 10 degrees below the long-term averages for this time of year. Nice.

Posted by Frank Roylance at 10:11 AM | Permalink | Comments (0)
Categories: Forecasts
        

The Northwest Passage - a ship route across northern Canada, from the Atlantic to the Pacific - is now ice-free as the 2007 summer meltdown of the Arctic ice cap continues to set new records. Here's the latest report from the National Snow and Ice Data Center. The melting season is about over, and the region will soon begin to ice over again for the winter.

Posted by Frank Roylance at 1:01 PM | Permalink | Comments (2)
Categories: Events
        

Whatever remains of Hurricane Humberto could provide Maryland with a bit of needed rain late tomorrow. Forecasters out at Sterling say how much we get will depend on timing.

UPDATE: 11:15 a.m.  After less than 10 hours as a hurricane, Humberto was downgraded this morning to a tropical storm.

As the storm moves inland into the Deep South, its moisture will be swept north and east toward the mid-Atlantic. But we're also looking at a cold front that's expected to move across the region tomorrow. That could shove much of Humberto's remnants aside, to our south and east. In that case we'd get our rain primarily from the front itself, without the added tropical moisture.

"Less than a quarter-inch," said Sterling forecaster Calvin Meadows. "Possibly more" if Humberto's rains make it this far. But "I'm not going to hazard an amount, since I'm not sure which is going to get here first."

In either case we'll get some rain. Here's the forecast. Here's the national radar loop showing where the rain is headed now.

It's been a pretty interesting hurricane season, hasn't it? The first two storms of the season, Dean and Felix, both reach Cat. 5, the first time that's happened since they began keeping records. And both remain at Cat. 5 at landfall, also a first. And now, forecasters are surprised when the third hurricane, Humberto, accelerates from a tropical depression to an 85- mph, Cat. 1 hurricane in just a matter of hours.

"To put this development in perspective, no tropical cyclone in the historical record has ever reached this intensity at a faster rate near landfall," Hurricane Center specialist James Franklin told an online discussion group, according to CNN. "It would be nice to know, someday, why this happened."

Very warm water in the Gulf, and Humberto's lingering pace over water might be part of the answer.

Posted by Frank Roylance at 9:44 AM | Permalink | Comments (0)
Categories: Hurricanes
        

The power of the Richter 7.9 earthquake today in Indonesia has been captured on a video of a fishtank  500 miles away in Singapore, and in a groundwater monitoring well  9,000 miles away in Christianburg, Va.

Here's more on the quake from the US Geological Survey. And from BaltimoreSun.com

Posted by Frank Roylance at 3:00 PM | Permalink | Comments (0)
Categories: Events
        

UPDATE: Tropical Depression Nine has been upgraded. It's now Tropical Storm Humberto, threatening Texas, Louisiana and Mississippi with torrential rains. An earlier report follows:

Forecasters at the National Hurricane Center are watching two new tropical depressions that formed today in the western Atlantic and in the Gulf of Mexico just off the Texas coast.

The first is Tropical Depression Eight, gathering strength east of the Windward Islands. Here is the latest advisory. Here is the forecast track, which would seem to take it toward the U.S. Virgin Islands. And here is a view from orbit. If this storm reaches tropical storm strength (sustained winds of 39 mph) first, it would be named Humberto.

The second, and more immediately worrisome, is Tropical Depression Nine, which has boiled up in the Gulf, right on the Texas coast. Tropical Storm warnings and watches have been posted for parts of the Texas and Louisiana coastlines. This storm could dump 5 to 10 inches of rain on parts of the region, with some spots receiving as much as 15 inches as the storm heads inland toward the north and east. (Some places, like Galveston, have already seen several inches of rain.)

That sort of rain could cause devastating floods. But it may also put an end to the severe drought that has been scorching the Deep South, especially Alabama, this summer. New Orleans, mercifully, seems not to be in the bullseye this time.

Here is the latest advisory. Here is the forecast track. And here is the view from space.

If it reaches tropical storm force after TD8, it would be named Ingrid. If they spin up in the reverse order, TD Nine would become Humberto.

Posted by Frank Roylance at 11:40 AM | Permalink | Comments (0)
Categories: Hurricanes
        

Sometimes parking is hard to find. But too often you drive across acres of empty spaces before you settle on a spot. Rain on those empty acres collects pollutants and rushes them into the storm sewers, and on to the Chesapeake Bay.

Purdue University scientists have done some calculating, and they've found that empty spaces in the region they surveyed outnumber actual drivers by three-to-one. Tons of oil and heavy metals are swept off the blacktop when it rains and sluiced into the nearest waterways.  Loads of salt are spread each winter to keep the space free of snow and ice, not to mention the fuel burned to shove the snow aside. The result is a degraded environment and more urban flash flooding. 

I know there are rules about how much parking is needed for each square foot of retail space. But do some builders go overboard? Could we revisit those rules and see if they could be modified under certain circumstances to reduce the amount of impervious, paved surfaces we build? Could we provide a tax credit, or some sort of incentive for retailers to dig up unneeded blacktop and plant something that would absorb more runoff?

Am I dreaming? Does the WalMart out in Hunt Valley really need parking all the way out to the Light Rail station? Do you have an expanse of parking you drive by every day that is never filled? Leave a comment and nominate your favorite overkill-parking lot. Send me a digital photo and I'll post it.    

Posted by Frank Roylance at 1:35 PM | Permalink | Comments (1)
Categories: Flooding
        

Something wet and slippery dripped out of the sky over Maryland late last night and early today. Oldtimers called it rain, the first measureable amounts that have fallen at BWI since Aug. 25, a dry spell of 17 days.

Could this really have been responsible for the terrible traffic backups this morning? Was it really slippery out there because there's been so little rain to wash away the accumulated oils on the road surfaces? Or are we becoming more and more like Los Angelenos, who panic at the sight of rain much as Baltimoreans panic at a whisper of snow? Perhaps...

Anyway, the rain began here at Calvert & Centre streets at about 11:30 last night, according to our rain gauge data. We got a quick 0.2 of an inch, followed by off-and-on drizzle ever since. In all, we've measured just over a quarter-inch (0.27) beside the Sun's executive parking area - the Bigshot Lot.

Out at BWI they've had 0.15 of an inch.

Here's is the rainfall accumulation loop for the event. Here's how the numbers look. Here's a mapped view.

We're still more than an inch short of rain for September. This comes after a very dry summer, with rainfall shortages every month. We haven't had a month with surplus moisture since April, and we're more than 6 inches short for the year. And with a La Nina coming this fall, we're likely to see a continued scarcity of rain for the forseeable future. A brush with a passing tropical storm would be welcome.

Posted by Frank Roylance at 10:27 AM | Permalink | Comments (1)
Categories: Events
        

Today (Sept. 10) marks the statistical peak of the Atlantic hurricane season. From here, the likelihood that tropical storms will form begins to decline. The season runs through November.

That's not to say we can't still have a busy few months. On the chart above, there's an interesting spike in activity in Mid-October. In fact, forecasters expect the backside of this season will be very active.

So far, we've had 7 named storms, 2 of which became hurricanes - both of them (Dean and Felix) making landfall as Category 5 storms. That's never happened before.

National Weather Service forecasters expect a total of 13 to 16 named storms before the season ends, of which 7 to 9 will become hurricanes. If they're right, we have 6 or 7 more named storms (and 5 to 7 hurricanes) to go. Here's the full report.

Phil Klotzbach and William Gray, at Colorado State University, have predicted 15 names storms and 7 hurricanes this season. That would leave 8 named storms and 5 hurricanes to go. Here's their webpage. A link to their latest report is at the upper left hand corner of their main page.

For now, Gabrielle is the only active tropical system on the charts. There is a disturbance in the Atlantic that forecasters are watching. It could become a tropical storm in the next several days. If so, it will be named Humberto.

Posted by Frank Roylance at 2:36 PM | Permalink | Comments (0)
Categories: Hurricane background
        

The persistent heat that jacked the number of 90-degree-plus days at BWI this summer to 39 this weekend, will give way this week, finally, to more seasonable weather. Forecasters say it may feel downright autumnal after we get through this very warm, tropically humid day today. Here's the official forecast.

The 39th day of 90-degree heat at BWI came on Saturday. We reached 91 degrees at BWI for the second day in a row, and for the third day in September. The day averaged 10 degrees above the long-term average for the date. It also tied with the 39 days of 90-plus days we saw in 2006. 

Thankfully, there's a cool front drifting our way from the north and west. It will move in and stall today and tonight, forecasters tell us. Then there's another right behind it, arriving with breezy conditions late tomorrow. And we'll see a third over the weekend. (This is typical of the transition to fall weather.)

Showers are possible with each frontal passage. After the second front passes by us tomorrow, we're promised "much drier air and a more fall-like air mass" for the rest of the week, forecasters say.

"Much of the mid-Atlantic should barely pass the 80-degree mark for daytime highs the rest of the week," they say. That's actually about normal for this time of year at BWI.

Gabrielle, meanwhile, has moved off the Carolina Capes and back into the Gulf Stream. It sure felt tropical out there this morning, and it's tempting to say that was a breath of Gabby's moisture as she turned for the sea. But it's hard to see that in the satellite loops. Looks like the beaches felt her, but our air and clouds and humidity and morning fog appear to be coming up from the southwest. Have a look.  Here's the water vapor loop.

Posted by Frank Roylance at 10:54 AM | Permalink | Comments (0)
Categories: Forecasts
        

Here is the latest on Tropical Storm Gabrielle, now affecting North Carolina's Outer Banks. The wind map above shows the probabilities for where tropical-storm-force winds could be felt along the Mid-Atlantic coast. Looks like Maryland beaches have about a 20 percent chance of feeling winds that strong - about 39 mph or more. And, it appears we'll squeeze in a decent day today after all before the clouds and rain along an approaching cold front overrun the place.

Here's the latest advisory. Here's the forecast track, which is now expected to skirt the Maryland beaches. And here is a nifty view  of the storm's water vapor, from orbit.

Here's our forecast. And here's the forecast for the beaches. And here's how things look for the Outer Banks. And finally, a Duck web cam view of the surf.

Posted by Frank Roylance at 10:44 AM | Permalink | Comments (0)
Categories: Hurricanes
        

UPDATE:  6:00 p.m. Gabrielle is now a tropical storm. A TS Watch has been posted for portions of the Virginia coast and the lower Chesapeake Bay. An earlier post follows. The links should update automatically.  

She's not quite a tropical storm, and may never be a hurricane, but "Subtropical storm" Gabrielle is on her way, the seventh named storm of the 2007 Atlantic hurricane season. Maryland, especially the lower Eastern Shore, may see some of her wind and rain. Watch out for rip currents at the beaches.

But mostly this storm will impact the Carolinas before swerving away from the coast and heading for the open sea. 

Our weather will deteriorate late Sunday, it appears, and we're facing several days next week of gray, wet weather. But that will be due to a stubborn cold front now drifting our way from the north and west. Here's a bit of this morning's discussion from Sterling:

"ONLY EFFECTS GABRIELLE
APPEAR TO HAVE AT THIS TIME WILL BE SOME NUISANCE TO MINOR
COASTAL FLOODING...PLEASE SEE COASTAL FLOOD STATEMENT
FOR MORE INFORMATION.  PRECIP WILL BE DRIVEN BY
FRONTAL BOUNDARY...WHICH MOVES THROUGH EARLY MON.
... AT LEAST A SLIGHT CHANCE PRECIPITATION THROUGH THE
REMAINDER OF THE WEEK AS SURFACE BOUNDARY REMAINS
STALLED TO OUR SOUTH AND DISTURBANCES MOVE ACROSS THE
AREA."

Here's our official forecast.

Here's the latest advisory on Gabrielle. Here's the predicted storm track. And here the view from orbit. 

Posted by Frank Roylance at 8:48 AM | Permalink | Comments (0)
Categories: Hurricanes
        

Ever wonder how accurate the National Weather Service really is? Are the forecasts getting any better? The American Meteorological Society has issued a statement detailing just how good (or bad) the forecasting today is. Here are some highlights:

* The accuracy of daily forecasts beyond eight days is "relatively low."

* The accuracy of monthly and three-month forecasts of average temperature and precipitation has doubled since 1995.

* Five-day forecasts of the location and intensity of major cyclonic storms are as accurate today as three-day forecasts were in the early 1990s.

* In 2006, the average 48-hour hurricane track forecast proved to be off by 111 miles. But that's an improvement over the 336-mile error in 1985.

* 48-hour precipitation forecasts are now as accurate as 24-hour forecasts a decade ago.

Want more? Here is the full report.  

Posted by Frank Roylance at 5:54 PM | Permalink | Comments (0)
Categories: Forecasts
        

That stubborn, rangy-looking little disturbance out in the Atlantic looks ready to spoil your Sunday at the beach. It's out there between the southeast coast of the U.S. and Bermuda, and appears to have gotten better organized overnight. The National Hurricane Center is preparing to send Air Force Reserve Hurricane Hunter Aircraft into it to have a look.

If it holds together, it could become a factor in our weather. Forecasters expect it to turn around and begin drifting westward today. That, coupled with a cold front approaching from the north and west, could bring us some precipitation by late in the weekend or early next week. Here's the crummy beach forecast. We may also see more minor coastal flooding. Watch your feet at the Inner Harbor or City Dock in Annapolis at high tide.

Here's how the NHC described the threat this morning:

"SATELLITE IMAGES INDICATE THAT THE AREA OF LOW PRESSURE LOCATED
BETWEEN BERMUDA AND THE SOUTHEAST U.S. COAST HAS BECOME BETTER
ORGANIZED OVERNIGHT.  UPPER-LEVEL WINDS ARE BECOMING MORE FAVORABLE
FOR ADDITIONAL DEVELOPMENT...AND A TROPICAL DEPRESSION COULD FORM
LATER TODAY.  AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
SCHEDULED TO INVESTIGATE THIS SYSTEM THIS AFTERNOON.  THE LOW IS
FORECAST TO MOVE GENERALLY WESTWARD OR NORTHWESTWARD DURING THE
NEXT COUPLE OF DAYS...AND INTERESTS ALONG THE EAST COAST OF THE
UNITED STATES SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM."

If the storm hits the Gulf Stream and begins to get cranked up, it could become Tropical Storm Gabrielle. Here's the view from outer space.

Here's the view from Sterling:

"LOW PRESSURE LOCATED 350 MILES SOUTH OF BERMUDA MAY STRENGTHEN THIS
WEEKEND...AS IT TRACKS NORTHWEST TOWARD THE MID ATLANTIC SUNDAY
AND MONDAY. AS THE LOW MOVES CLOSER TO THE REGION...EXPECT
INCREASING CLOUDS AND A CHANCE OF SHOWERS AND THUNDERSTORMS SUNDAY
NIGHT THROUGH TUESDAY. TIDAL ANOMALIES WILL CONTINUE TO
INCREASE...MAKING MINOR TIDAL FLOODING POSSIBLE LATE THIS WEEK AND
THIS WEEKEND ALONG THE TIDAL POTOMAC RIVER...THE CHESAPEAKE BAY
AND ITS ESTUARIES. MONITOR NATIONAL HURRICANE CENTER PRODUCTS FOR
MORE INFORMATION."

And here's the forecast for Baltimore. 

Posted by Frank Roylance at 10:54 AM | Permalink | Comments (2)
Categories: Hurricanes
        

This week's Drought Monitor map is out, and it shows the moderate drought conditions confined last week to Southern Maryland and the southern Eastern Shore, have crept north this week.

Arundel and Prince George's counties are now within the zone experiencing moderate drought conditions, as measured by streamflow, rainfall, soil moisture and vegetation damage. So is almost the entire Eastern Shore south of Kent County. The rest of the state is rated "abnormally dry," with the exception of Garrett and extreme western Allegany counties, where conditions are normal.

Overall, the portion of the state experiencing drought conditions has increased this week from 31.2 percent to 47.9 percent - nearly half. Only 8.4 percent enjoys normal moisture, unchanged from last week. 

Here's the national drought map, which shows the continuing severe and extreme conditions in the Southeast.

Posted by Frank Roylance at 12:30 PM | Permalink | Comments (0)
Categories: Drought
        

Federal climatologists say that conditions in the tropical Pacific are shifting toward a full-fledged La Nina event this fall. That could mean a deepening drought in the southwestern United States, and ripening conditions for an active autumn hurricane season.

In a release this morning, the National Oceanic and Atmospheric Administration's Climate Prediction Center said surface waters in the eastern and central Pacific are cooling. The green color in the map, along the equator west of South America show the cooler-than-average sea-surface waters.

"While we can't officially call it a La Nina yet, we expect that this pattern will continue to develop during the next three months, meeting the NOAA definition for a La Nina event later this year," said Mike Halpert, acting deputy director for the Climate Prediction Center, in Camp Springs, Md.

La Nina events typically mean wetter-than-average weather in the Pacific Northwest, and drier-than-average weather in the Southwest. "These conditions also reinforce NOAA's August forecast for an above-normal Atlantic hurricane season," said Gerry Bell, NOAA's lead seasonal hurricane forecaster.

La Nina winters in Baltimore are typically poor snow-producers. But there have been exceptions. Since 1950 there have been 9 winters with moderate-to-strong La Ninas. None produced a storm with 8 inches of snow or more. There were 7 winters with weak La Ninas. They produced only two storms of 8 inches or more. But those were sizable. They included the 22-inch storm in January 1996, and a 15-inch snowfall in January 2000. El Nino winters - when the Pacific is unusually warm - tend to be bigger snow-makers in Baltimore.

La Nina events are declared when average sea surface temperatures in the eastern and central equatorial Pacific, measured over three months, move more than 0.9 degrees Fahrenheit below the average. For months, forecasters have been predicting weak La Nina ocean temperatures for this summer. Those conditions now appear to be developing, with some portions of the east-central Pacific now a degree or two below long-term averages.

Posted by Frank Roylance at 10:12 AM | Permalink | Comments (0)
Categories: Hurricane background
        

The folks out at Sterling have run the numbers on the Summer of 2007. It was a record-breaker at Dulles International Airport, where the records only go back to 1963. But it was less remarkable for Baltimore, with 135 years of data for comparison.

At Dulles, the period from June 1 through Aug. 31 was the warmest on record, and the third driest. If you add in the month of May, it was the driest four-month period in the airport's history.

Here in Baltimore, the three-month summer period was the 48th warmest in 135 years of record-keeping, and the 24th driest. There were 33 days from June through August with temperatures in the 90s or higher. That compares with an average of just 25. 

Here's the full report.

Posted by Frank Roylance at 1:59 PM | Permalink | Comments (0)
Categories: By the numbers
        

Forecasters have their eyes on a disturbance stirring in the Atlantic Ocean, north of the Bahama Islands and east of South Carolina. It's not a threat to the U.S. at the moment, but computer models suggest changes in the wind circulation over the Atlantic that could draw this stormy weather closer to the East Coast by the weekend.

AccuWeather blogger Brett Anderson has the storm growing to hurricane strength off the North Carolina coast by Saturday morning. (It would be named Gabrielle.) That could bring us some badly needed rain.

Models do have the disturbance becoming a tropical cyclone later this week. Here is a bit of this morning's discussion from Sterling:

"NEXT POTENTIAL WEATHER MAKERS CONTINUE TO BE A SLOW MOVING COLDFRONT EXPECTED TO
APPROACH THE AREA EARLY NEXT WEEK AND A DISTURBANCE LOCATED MIDWAY
BETWEEN THE NORTHEAST FLORIDA COAST AND BERMUDA WHICH ALL THE GLOBAL
MODELS HAVE IT BECOMING A TROPICAL CYCLONE BY LATE THU OR FRI.

"IT IS IMPOSSIBLE TO INDICATE AT THE MOMENT WHAT IMPACTS IF ANY THIS POTENTIAL
TROPICAL CYCLONE MAY HAVE IN THE LOCAL AREA.  FORECAST CONTINUES TO
CALL FOR AN INCREASE IN CLOUD COVER AND PRECIPITATION PROBABILITIES BEGINNING SUNDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK DUE TO FRONTAL BOUNDARY EXPECTED TO
STALL OVER THE REGION."

Meanwhile, the National Hurricane Center's discussion includes this about the storm:

"THIS SYSTEM HAS CHANGED LITTLE OVERNIGHT BUT UPPER LEVEL WINDS ARE EXPECTED TO
BECOME MORE FAVORABLE FOR DEVELOPMENT INTO A TROPICAL OR
SUBTROPICAL DEPRESSION THAT COULD DURING THE NEXT FEW DAYS.

"THE LOW LEVEL CENTER IS PARTIALLY EXPOSED WITH SCATTERED
MODERATE/ISOLATED STRONG CONVECTION TO THE E WITHIN 150/180 NM
OF A LINE FROM THE BAHAMAS NEAR 24N76W TO 31N69W WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM ALONG THE E COAST OF
FLORIDA FROM FORT LAUDERDALE TO JACKSONVILLE."

Here's AccuWeather's take on the system. As they say on the editorial page, "this bears watching."
 

Posted by Frank Roylance at 10:48 AM | Permalink | Comments (0)
Categories: Hurricanes
        

Global warming theory and complex computer climate models predict that a warming ocean will increase the intensity of hurricanes. Both of this year's hurricane to date have made landfall at Category 5 on the Safir-Simpson Scale, the first time that's ever been recorded in the Atlantic basin.

Is there a connection here? Maybe. But it's not as clear as you might think, says Chris Landsea, science and operations officer at the National Hurricane Center.

All the numerical models say we should see increased hurricane intensity as the oceans warm. But Landsea notes that the "sensitivity" of that response is not very impressive - on the order of two percent. In other words, for every one-degree increase in global ocean temperatures, we would expect to see a two-percent increase in hurricane intensity.

Since the tropical oceans are about 1 degree warmer now due to global warming, he said, that means a 160-mph hurricane - the hurricane center's estimate of Felix's top sustained winds at landfall - will instead strike land at 162 mph.

On the other hand, it seems to me, that's an average. Some storms will be more dramatically intensified by warmer oceans, some less so. It's the really bad ones that we worry most about. It's like rising temperatures. The global average is one thing, but the impact is expected to be - and already is - more dramatic in the Arctic and Antarctic. And a seemingly modest rise of a few degrees in the average temperature for Baltimore means some summer days (and some winter days) will be dramatically warmer. And the difference between 95 degrees and 105 degrees on a July afternoon can kill people.

In any case, Landsea said the "real driver" behind the busy hurricane seasons of recent years, and the more numerous Category 5 storms, is a long-term natural cycling of ocean surface temperatures and atmospheric conditions that began in 1995 and is expected to continue for another 10 to 30 years. It's a cycle that looks much like another that began in the 1920s and continued into the 1960s.

"In fact," Landsea said, "there is one year we may have had two Category 5's making landfall."

Those were Hurricane Hilda and Hurricane Janet, in 1955. Both followed the same paths Dean and Felix have this season. "Janet we know was a Category 5," he said. Hilda struck in a sparsely populated region of Central America where measurements were scarce. Hurricane hunter aircraft in those days didn't fly through storms that strong, and there were no satellites to estimate central winds. "We don't have any idea how strong it was," Landsea said. "It could have been a 3, 4 or 5."

We do know it crossed the Yucatan and reintensified in the Gulf of Mexico, becoming a borderline Cat. 3 or 4.

We also know that seasons like this one, in the middle of a multi-decadal upswing in hurricane frequency, and La Nina conditions, the season is "not only busy, but long-lasting," Landsea said. "October and November are quite active as well."

Posted by Frank Roylance at 3:59 PM | Permalink | Comments (0)
Categories: Hurricane background
        

A beautiful, long weekend will be followed in Maryland by a sunny and hot week. There is no significant rain in the forecast (and we remain seriously dry across the region).

Here's the official forecast, calling for daytime highs in the 80s to near 90 degrees all week. Wednesday and Thursday will be closer to normal, in the low 80s before we slip back into the upper 80s at week's end. That's not terribly unusual for early September in Baltimore. We'd have to see highs in the upper 90s to threaten any records at BWI. But it is well above the averages for this time of year, which run closer to 80 degrees through the middle of the month.

The clear skies and mild temperatures should provide some pleasant stargazing, however. Jupiter is the very bright "star" in the southwest after sunset. If you're up after midnight, look east. That brightening red dot is Mars. It's even easier to see before dawn, when it is high in the southern sky. Mars is headed for a (relatively) close encounter with Earth in December, so it will be brightening all through the autumn. Early risers can also get a look at a very bright Venus, in the east before sunrise. 

Unfortunately, there will be no worthwhile flyovers by the International Space Station this week. But look for a nice one, just before 6 a.m. on the 11th. More on that here in a few days.

In the meantime, here is a very cool video of a recent ISS transit of the moon. It may take a few seconds to download, but it shows the ghostly image of the station as it flew between the observer's telescope and the moon. You can see very clearly the distorting effect the atmosphere has on our view of the moon. It's like looking at clouds from the bottom of a pool. 

Posted by Frank Roylance at 9:58 AM | Permalink | Comments (0)
Categories: Forecasts
        

Hurricane Felix, the second Cat. 5 hurricane to make landfall in Central America this season, is coming ashore this morning on Nicaragua's Miskito Coast, just south of where Hurricane Dean crossed the Yucatan peninsula last month.

Here is the latest advisory. Here is the predicted storm track. And here is a satellite view. And here's more from the scene.

Top sustained winds are at 160 mph after some overnight strengthening. Storm surges of up to 18 feet are expected and rains in some locations could reach 20 inches. This is likely to cause catastrophic damage and significant loss of life in the coming days as the storm moves inland, across Nicaragua, Honduras, Guatemala and southern Mexico.

This is the first time since record-keeping began in the late 19th century that two hurricanes during the same season have made landfall at Category 5 strength, with sustained winds above 155 mph, according to Dennis Feltgen, public affairs spokesman for the National Hurricane Center in Miami. It's also the first time that the first two hurricanes in an Atlantic season have both reached Cat. 5 strength. And we're not done with this season yet, not by a long shot.

"We certainly can't rule out another Caribbean storm," Feltgen said. "October is a very active month for the northwest Caribbean Sea. So no one anywhere in the Caribbean certainly should let their guard down. Nor would I let my guard down anywhere along the Atlantic Coast. We still have a long way to go, and we still expect an active season."

Posted by Frank Roylance at 7:57 AM | Permalink | Comments (1)
Categories: Hurricanes