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March 30, 2007

Chamber of Commerce weather

Not a lot to write about when the weather is like this. Sunny, in the 60s, with trees in blossom Clearsky everywhere. Thought you'd like to see what a beautiful day in Maryland looks like from the other side of the atmosphere. Here's a shot (click on the photo at right), snapped at midday Thursday by NASA's Terra Earth Observing Satellite, showing the eastern United States from orbit. Clear skies prevailed over Maryland. Looks like a bit of ice remaining in Lake Erie. Clouds to our south and west. You can even see the spring green-up moving our way from the South. For a closer look, click here, and then on the image. Rest your cursor over the picture when it pops up, then click on the enlarger button that appears at lower right.

The forecast shows some showers moving in for much of the weekend. The barometer has been falling sharply since late this morning. But temperatures will remain pleasant.

Forecasters looking ahead well into next week, however, see a new invasion of cold air from the Canadian arctic. That's got a few prognosticators watching computer models that suggest a storm system running along the edge of that cold air could bring an Easter snow to the Midwest, or Tennessee, the Appalachians or the Middle Atlantic states. Here's AccuWeather's Henry "Always-Ready-to-Predict-Snow-for-the-East-Coast" Margusity on the prospects. But all that's a long way off. Lots can change.

On the other hand, if you think snow is impossible in Maryland in April, here's something from the NWS you should read:

"April 27-28, 1928:  A late season heavy snow storm struck western Maryland. A nor'easter brought heavy snow, sleet and rain to Frederick, Washington, and Allegany Counties with rain and gale force winds east of there. The Allegheny Mountain highlands received 25 to 30 inches of snow. Oakland reported 16 inches. It all melted within two to three days causing the upper Potomac River to flood. Telegraph, telephone and electric services were completely knocked out. Damages to these services were estimated at $200,000 (1928) dollars. High winds accompanied the storm. In Middletown, Frederick County, a number of houses were unroofed and many trees were uprooted, signs and outbuildings blown down, and the baseball park grandstand was demolished. In Baltimore, the press stand at the stadium was unroofed, several plate glass store windows blown in, signs and billboards blown down, and trees were uprooted."

Posted by Frank Roylance at 3:04 PM | | Comments (0)
Categories: Cool pictures
        

March 29, 2007

The finger of God

Ever wonder about the difference between a tornado and a dust devil?  Well, as we've seen on TV and in The Sun this morning, tornadoes are much larger and more destructive, and they arise from entirely different weather phenomena.

For a taste of what they're like up close, check out this mesmerizing YouTube video of tornadoes. And compare it with this video, my favorite shots of an amazing dust devil in Japan.

Posted by Frank Roylance at 11:10 AM | | Comments (0)
Categories: Cool pictures
        

Brush fire hazard on Shore

Dry air and stiff winds have spurred the National Weather Service forecast office in Mt. Holly, N.J. to issue "red flag warnings" for northeastern Maryland and Delaware. That means conditions are ripe for the spread of brush fires. The warnings extend well beyond the Eastern Shore, north into New Jersey and eastern Pennsylvania.  So if you're in that area - or anywhere else for that matter - be careful with outdoor fires, and snuff your cigarettes in the ashtray. Here's our official forecast, from Sterling.

Ever wonder why much of Maryland's Eastern Shore gets its weather forecasts from a forecast office in New Jersey? Me too. It turns out that Maryland - one of the nation's smallest states - was carved up and parceled out to no fewer than four regional weather forecast offices, all located in other states. Here in Central Maryland, we're covered from the Sterling, Va. office. Garrett County, in far Western Maryland, gets its forecasts from the Pittsburgh office. Northeastern Maryland is handled from Mt. Holly, N.J.  And the Southern Shore, including Ocean City, is covered by forecasters in Wakefield, Va., west of Norfolk.

Go figure.

Posted by Frank Roylance at 8:39 AM | | Comments (0)
Categories: Watches and warnings
        

March 28, 2007

Weird hexagon on Saturn

There's no life as we know it on Saturn. The giant, ringed planet doesn't even have a surface. It's composed almost entirely of gas. Hexacassini But NASA's Cassini spacecraft has spied a strange geometric shape at Saturn's north pole. It's a hexagon, and a big one - twice as wide as the Earth. It has formed in the planet's atmosphere surrounding the pole. Here's the story on SpaceWeather.com

It's been spotted before. The Voyager spacecraft sent back photos of the same phenomenon back in 1980. HexagonHere's the Voyager image (left), alongside a Hubble photo (right).  But the thing still has scientists baffled. It could be some sort of polar vortex, like Earth's. Except that ours is a circle. The best explanation so far relates the hexagon to a phenomenon noticed in spinning buckets of water. Spin them fast enough, and the water sloshes to the sides of the bucket, leaving an air space in the center which, at increasing speeds, assumes a regular geometric shape.

Just how that relates to Saturn's spinning atmosphere isn't clear yet, but it seems like they ought to be related somehow. Starfort One thing seems safe to say: It's not a Saturnian star fort.

Posted by Frank Roylance at 12:21 PM | | Comments (0)
Categories: Cool pictures
        

Dust or El Nino: What killed the 2006 hurricane season?

Even the nation's top hurricane forecasters were caught off-guard when last year's hurricane season - forecast to be another active one - fizzled. The early explanation was that the development of El Nino Mitch conditions in the central and eastern tropical Pacific Ocean stifled hurricane development in the Atlantic. But some scientists are arguing that dust storms blowing off North Africa were to blame.

As the theory goes, that dust wafts off the desert and out over the eastern Atlantic where many hurricanes are born. It absorbed solar heat and cooled the ocean waters beneath it, cutting off the energy needed to spawn new storms.

Not everyone agrees, of course. This is science, after all. Some say El Nino was a bigger factor. Some say it was mostly the dust. You can read about it for yourself. Just click here.

The 2007 Atlantic hurricane season starts June 1, and the El Nino conditions have ended, so forecasters expect a busier season this time around. The National Hurricane Center's official forecast comes out later this spring. Here's the December prediction from Colorado State University's hurricane forecasting team.

Posted by Frank Roylance at 11:07 AM | | Comments (0)
Categories: Hurricane background
        

March 27, 2007

Flash! Boom! Summer's gone

So much for the 80-degree weather for this week. That little thunderstorm this evening dropped temperatures here at The Sun from 81 degrees at 6:30 p.m. to 71 degrees at 7 p.m. We clocked just .15 inch of rain, but it sure fell in a hurry, peaking briefly at a rate of more than 3 inches an hour.

Our high at Calvert & Centre streets was 83 degrees. The airport saw a high today of 81 degrees The rest of the week will be cooler.

Posted by Frank Roylance at 7:29 PM | | Comments (1)
Categories: Events
        

Following GPS into the drink

GPS is a very cool technology. If I had had the dough, I would have ordered my Prius with it. But there is always a need for a functioning human brain to provide backup. A British woman could have used more cranial software recently. The GPS in her Mercedes said there was a road ahead, so she plunged ahead, despite data entering her eyeballs that told her brain the road was under water, submerged by heavy rains.

The water grabbed the L96,000 (that's $188,000; is that even possible?) SL500 and tossed it downstream. The woman managed to escape, was rescued, and ... well, you can read about it here. Take-home lesson: If the road ahead is flooded, turn around, don't drown, no matter what your GPS tells you.

Posted by Frank Roylance at 10:50 AM | | Comments (1)
Categories: Flooding
        

March showers, April flowers

Forecasters say we're headed for the upper 70s today. I'd guess that with enough sunshine between the clouds, we could top 80. It's already 72 degrees at 10 a.m. at The Sun. It wouldn't be the first time this month. BWI reached 83 degrees back on March 14. The month thus far is running a tad (0.3 degrees) above normal after a couple of days that averaged 20 degrees above normal.

Expect a few scattered showers along the way for the next couple of days as we fall beneath a weak, slow-moving cold front. And this afternoon will likely be the warm point for the week. Nights will be cold - in the 30s after tonight - but not freezing. Days will be mild - upper 50s to mid-60s, forecasters say.

Here's the Northeast radar loop.

Any showers we see will only add to the surplus we've accumulated this month. It's the first wet month we've seen since November. And we're still short of moisture since Jan. 1. The 4.13 inches at BWI for March thus far has made up only 42 percent of the deficit since New Year's Day. The last really wet month we've had was November, when 6.25 inches fell at the airport. That was more than 3 inches above the long-term average for the month.

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

March 23, 2007

Purple haze

Marchhaze On Thursday morning, NASA's Terra Earth Observing Satellite captured this nice shot of Maryland the the other mid-Atlantic states as we basked in 70-degree weather under hazy skies. You can see today's rainy weather, headed this way, from the west. But notice the gray haze of tiny airborne particles called aerosols smeared across Maryland and the rest of the Piedmont.

Rainfall today, tonight and tomorrow will clear the air. Here's the Northeast radar loop. We're stuck under a stalled cold front, but it should move on Saturday night. We'll see a nice Sunday, and a better week ahead. Look for a very chilly Monday, followed by rapid warming as the week unfolds.

Posted by Frank Roylance at 5:50 PM | | Comments (0)
Categories: Cool pictures
        

Brits forecast busy hurricane season

A British forecaster has joined other hurricane experts who are expecting another busy Atlantic hurricane season this year. He's talking about nine hurricanes - 50 percent more than in the average season. The disappearance of the El Nino influence over the winter is again cited as a key reason why we won't get the same calm weather we had in 2006. Click here to link to the story.

Posted by Frank Roylance at 3:26 PM | | Comments (0)
Categories: Hurricanes
        

March 22, 2007

We hit 76

UPDATE: Ample sunshine drove the highs to 76 degrees today here at the Sun, the second-warmest day this year. It was 74 at BWI. Nice.

EARLIER: Forecasters out at Sterling had been predicting highs today in the 70s in Baltimore, thanks to a rush of warm air from the south ahead of a cold front. But they've backed off that number this morning, looking now for a high of 67 degrees at best.

A bigger dose of sunshine could still push the mercury a bit higher. That's what they're calling for to our south, in D.C. and Southern Maryland. But for now, the coolest highs today are expected in the Baltimore region. Diningout You want lunch in the 70s at a sidewalk cafe? Head for Washington.

The rain, at least, should hold off until the evening. The approaching cold front (the blue line draped beneath the Great Lakes in this map) is bringing fitful showers with it as it shoves this mild, wet air aside. The greatest chances for rain will come Friday during the day, with breezes off the ocean. But showers will continue to hang around through the day on Saturday, especially in the northern counties along the Mason-Dixon line.

You want sunshine? Best bet for the weekend will be Sunday, after the cold front moves through. A good day to clean up around the yard, or back in the alley. The highs will stick around 60 degrees, but the sun will be warm and it will smell like spring. That's my olfactory forecast. The auditory forecast is for birdsong by day, changing to spring peepers by night.

Here's a photo bonus - a shot of Monday's partial solar eclipse, taken in Goa, India. Wow!

Posted by Frank Roylance at 10:16 AM | | Comments (1)
Categories: Forecasts
        

March 21, 2007

Cool movie from the sun

Hinode Japan's new Hinode ("Sunrise") solar observatory - sometimes called a Hubble for the sun - is sending back some spectacular, and scientifically important movies of action in the sun's chromosphere. Click here to go to the NASA page that links to the movie. Click once on the photo on the NASA page, then be patient. It took about 30 seconds for it to load on my home computer (DSL).

Posted by Frank Roylance at 6:57 PM | | Comments (0)
Categories: Cool pictures
        

Cheap, but at what cost?

Sure the stuff we buy from China is cheap. Low wage rates, plentiful labor, skimpy benefits and rudimentary environmental controls keep prices down. But look at the environmental costs. This is a satellite image, taken this week, of the haze over a part of China on the Yellow Sea. Much of the haze is industrial pollution. You may have lost your union job to a Chinese factory. But at least you don't have to breathe this stuff en route to your job at Wal-Mart. At least, not until their air drifts over here.

Posted by Frank Roylance at 6:31 PM | | Comments (0)
Categories: Cool pictures
        

An unsettled week

A pile of cold, dry air on top of us is keeping temperatures today well below normal for this time of year. It's still 37 degrees at Calvert & Centre as I write this, up - barely - from the overnight low of 36 degrees. That's just about the normal low for a March 21 in Baltimore (35 degrees). But today's forecast high of 45 degrees would be more than 10 degrees short of the normal high of 56 degrees for this date at BWI.

But the high pressure will be moving away shortly, opening the door to an influx of warm, moist Atlantic air. That will mean a slight chance for showers tomorrow, along with a forecast high of 67 degrees (10 degrees ABOVE the norm). Thursday night's overnight low won't drop much below the normal HIGH for the date. And Friday should see the mercury top 70 degrees, before another cold front brings cooler air and showers. If you have weekend plans outdoors, make them for Sunday: Sunny and 60s.

Until then we won't see any of the clear skies we've enjoyed for the past few days. Crescentmoon Last night's cloudless view provided a grand spectacle in the evening as the thin crescent moon settled down toward the western horizon after sunset, with a brilliant Venus hanging just above and to the left. For more crescent moon images like the one at left, click here.

Speaking of wonderful views of the moon, here's one shot by astronauts aboard the International Space Station, showing the crescent moon hanging above the Earth's clouds below. Wow. 

Posted by Frank Roylance at 11:16 AM | | Comments (0)
Categories: Forecasts
        

March 20, 2007

Testing

This is a test post

Posted by baltimoresun.com at 2:23 PM | | Comments (0)
        

March 18, 2007

Snow vanishes, spring nears

So far, so good. The snow and ice that made the commute so slick on Friday evening has vanished from the streets this weekend, leaving only some nasty-looking remnant heaps. Here's a tally of accumulations from Friday's storm.

Now we're looking for a little warm-up as the week unfolds. The forecast is calling for 50s for the first part of the week, and 60s by the end, with a bit of rain in between. Those spring peepers sure got a surprise Friday, but I expect they'll be singing again in the evenings this week.

The first official day of spring arrives Tuesday, Mar. 20, when the sun reaches the Vernal Equinox at 8:07 p.m. EDT.

Posted by Frank Roylance at 9:33 PM | | Comments (0)
Categories: Forecasts
        

March 16, 2007

Streams rising, snow coming

Today's rains have pushed many streams across Central Maryland to near-record flows for this date. Here is a link to real-time streamflow measurements from the U.S. Geological Survey. The black dots represent streams flowing at more than 90 percent of record flows for a March 16. Run your cursor over the dots to details. Here's more real-time river flow data.

We've measured 1.18 inches of rain so far here at The Sun today. Since the rain began yesterday afternoon we've seen 1.64 inches. Here's the radar loop. Here are some rain totals from around the region. (You can ignore the Caroline Street gauge, which may be located under a Fells Point beer tap. It's been over-reporting for years and no one seems interested in fixing it.)

UPDATE: Rainfall at BWI has topped 1.2 inches, setting a new rain record for the date. The previous wettest March 16 was in 1876, when 1.14 inches were recorded. That topples the oldest March rainfall record on the books for Baltimore.

And the rain is only about half over if you believe the forecasters. Flood warnings have been posted for most of the region. Here's the storm's rainfall accumulation radar loop. And here's today's Sun story about this miserable weather, and the more wintry stuff that's due. Three to 8 inches of snow is forecast tonight for parts of the region north and west of Baltimore. Here's the winter storm warning.

Posted by Frank Roylance at 3:12 PM | | Comments (0)
Categories: Forecasts
        

Small brain warnings

OK. Somebody please tell me why the good folks who operate the Solomons Island Sailing Club down in Calvert County had a dozen young sailors - inexperienced boaters in their teens - out on the Chesapeake yesterday afternoon in "daysailors."

In case you hadn't heard, five of the six boats capsized in strong winds at around 4:30 p.m., pitching the kids into the frigid water. All were saved, thanks to life vests, wet suits and quick action by rescuers. But everybody was danged lucky.

In The Sun's story today, the youth sailing organizer for the Southern Maryland Sailing Association described the boats as "small dinghies ... they capsize all the time."

That's fine in the summer. With life jackets on, a little dunking when the boat goes over is fine. Fun, even. A learning experience.

But the water temperatures in the bay are still in the 40s.

And more to the point, the National Weather Service had posted small craft advisories for the Chesapeake at 11:10 a.m. There was a strong cold front surging across the region during the afternoon, forecast to shift the winds from south to north, and increase their speeds to 15 to 20 knots or higher. (That's 17 to 23 mph.)

At the Patuxent Naval Air Station, just across the river from Solomons, weather data show that the winds shifted from south to north between 4 and 5 p.m., and jumped from 9 mph to 25 mph, with gusts to 35 mph. Just about the time the boats keeled over.

So why would any (presumably) adult send student sailors onto the bay - in "dinghies" - under small craft advisories? Sure, it was balmy through the noon hour yesterday. But wasn't anyone watching the forecast? Checking the watches and warnings?  Someone needs to go back to sailing school.

Posted by Frank Roylance at 11:01 AM | | Comments (5)
Categories: Events
        

March 15, 2007

Winter was warmest ever

Winter0607 The National Oceanic and Atmospheric Administration says the northern winter just ending was the warmest since record-keeping began in 1880, though it was only average for the United States. Read all about it here.

Posted by Frank Roylance at 11:02 PM | | Comments (0)
Categories: Climate change
        

Man the pumps

It's going to be a wet couple of days ahead. And maybe snowy, too. (And you thought spring had arrived...) The interior northeast appears headed for a big late-season snowstorm. Temperatures, which reached 75 degrees here at The Sun building around 1 p.m., have already dropped to just 50 degrees - 25 degrees lopped off in just four hours.

The National Weather Service has issued flood watches for most of Maryland as showers behind a passing cold front tonight morph into heavy rains as a coastal low-pressure system forms - a rainy nor'easter - off the coast. Here's the official forecast for BWI.

Here's the watch:

"SHOWERS BEHIND A COLD FRONT WILL BRING LIGHT TO MODERATE RAIN
  TONIGHT. HOWEVER...AS A COASTAL STORM DEVELOPS OFFSHORE ON
  FRIDAY...RAIN WILL INTENSIFY. MODERATE TO HEAVY RAIN IS EXPECTED
  FRIDAY.
ONE TO THREE INCHES IS EXPECTED DURING THE ENTIRE
  COURSE OF THIS EVENT...WITH MUCH OF THAT OCCURRING DURING THE
  DAY AND EVENING ON FRIDAY."

As if that  weren't enough, dropping temperatures behind the front could turn the rain to some sort of frozen precipitation. Hence, the winter storm watch issued today for Maryland north and west of the I-95 corridor. Here's the bulk of the statement:

"AS THE LOW NEARS...WIDESPREAD PRECIPITATION WILL DEVELOP LATE
TONIGHT AND CONTINUE ALL DAY FRIDAY. NEAR FREEZING SURFACE
TEMPERATURES COULD RESULT IN POTENTIAL FOR SIGNIFICANT WINTER
PRECIPITATION TO FALL ACROSS PARTS OF THE REGION.

FOR TONIGHT...MIXED RAIN SNOW AND SLEET IS EXPECTED TO DEVELOP AS
EARLY 7 PM TONIGHT ACROSS THE WESTERN MOUNTAIN AREAS. THIS WINTRY
MIX WILL SPREAD EAST ACROSS THE POTOMAC HIGHLANDS AND THE NORTHERN
SHENANDOAH VALLEY OVERNIGHT.

ON FRIDAY...A RAIN AND SNOW MIX IS EXPECTED ACROSS THE POTOMAC
HIGHLANDS AND THE NORTHERN SHENANDOAH VALLEY DURING THE LATE MORNING
HOURS AND WILL CONTINUE THROUGH THE AFTERNOON. AT TIMES MORE SNOW
THAN RAIN COULD OCCUR. AT HIGHER ELEVATIONS ABOVE 3000 FEET
FREEZING RAIN IS ALSO POSSIBLE.

FURTHER EAST ON FRIDAY...ACROSS EXTREME NORTHERN VIRGINIA AND
NORTH CENTRAL MARYLAND...RAIN WILL BECOME MIXED WITH SNOW IN THE
AFTERNOON.
AT TIMES MORE SNOW THAN RAIN WILL OCCUR.

BY FRIDAY NIGHT...AS THE LOW MOVES UP THE COAST...PRECIPITATION
WILL CHANGE TO MOSTLY ALL SNOW DURING THE EVENING
...BEFORE THE
PRECIPITATION ENDS LATE FRIDAY NIGHT.

Accuweathersnowmap UNCERTAINTY STILL EXISTS AS TO THE EXACT AMOUNT AND TYPE OF WINTER
PRECIPITATION BUT THE POTENTIAL EXISTS FOR 5 OR MORE INCHES OF
SNOW IN THE WATCH AREA
. CONTINUE TO MONITOR THE LATEST FORECASTS
FOR UPDATES ON THIS POTENTIAL WINTER STORM."

Here's AccuWeather's snow map. Here's AccuWeather's take on the storm.

Posted by Frank Roylance at 5:18 PM | | Comments (0)
Categories: Forecasts
        

March 14, 2007

Spring peepers are back

The spring peepers - the tiny frogs that emerge from the muck in early spring to peep their way to love and Peeper procreation - are back. Or at least tonight was the first night of the season that I've heard them from the WeatherDeck in Cockeysville. Anybody else hear them? It's always a welcome sound after a long winter, and a good indication that somebody's wetlands are still healthy enough to support the little amphibians.

Here's what they look like. Be sure to click on the "Listen" button for some recordings of their songs. A breath of spring.

Posted by Frank Roylance at 10:40 PM | | Comments (4)
Categories: Events
        

Record heat today, snow Saturday

UPDATE: It was 83 degrees at BWI this afternoon, 84 at the Inner Harbor and 81 at The Sun. The 83-degree mark at BWI breaks the prior record for a March 14 at BWI - 81 degrees, set in 1990.

EARLIER: It's the crazy season again. As the hot-and-cold forces of springtime clash around us, forecasters at Sterling are calling for highs in the 70s today and tomorrow as warm air continues to flow into the region from the south and southwest, drawn north by that high spinning clockwise off the coast. We may even get some thunderstorms in the mix.

But all this spring-like weather comes ahead of another cold front that promises lows in the 20s by Saturday, with chances for rain and, yes, snow showers late Saturday and Saturday night. Here's AccuWeather's take on it all.

We made it to 73 degrees yesterday at BWI. (The record for the date is 85 degrees, set in 1990.) It was cooler here at Calvert & Centre streets. The Sun's instruments made it only to 66 degrees around 5 p.m. Then the mercury fell to an overnight low of 51 degrees just before sunrise. That's close to the normal HIGH for the date. Balmy weather indeed.

Evidently, it was enough to rouse the urge to migrate among a flock of maybe 80 honking Canada geese, spotted this morning high over Timonium, in a grand "V", headed north.

Likewise, the forecast inspired a gaggle of Cockeysville teenagers to dress for May this morning, despite morning readings of 43 degrees. They were spotted in my neighborhood, waiting for the school bus dressed in very mini-skirts, and bitty short sleeves. And shivering in the gray dawn light. What's that about, Mom?

Posted by Frank Roylance at 10:32 AM | | Comments (0)
Categories: Forecasts
        

March 13, 2007

May tomorrow, then February

That high-pressure system spinning off the coast will continue to pump warm air in from the South and Southwest for the next couple of days, warming us into a May-like reverie. The highs tomorrow and Thursday will be the warmest since - well, since January 6, when we hit 71 degrees at BWI. How quickly we forget.

Forecasters out at Sterling are looking for highs in the low-to-mid 70s for Wednesday and Thursday. That's the sort of high we normally expect here in mid-May. Then a cold front pushes through, bringing showers on Thursday into Friday, with highs dropping to the mid-40s on Friday. That's where the norms are in mid-February.

The weekend will stay in the 40s - cooler than the averages for this time of year in Baltimore, which are creeping up through the 50s. But skies will clear, and we'll have cool, dry air, excellent for stargazing.   

In the meantime, the thaw is threatening to flood Vermont's capital, Montpelier, where a stubborn ice jam is backing up the Winooski River. Here's some local TV video.

Posted by Frank Roylance at 12:43 PM | | Comments (0)
Categories: Forecasts
        

March 12, 2007

A 10-hour day on Jupiter

And you thought adjusting to an hour's time change was tough? Imagine adjusting to a day that lasted just 10 hours - five hours from sunrise to sunset, and just five hours of darkness.

That's life on Jupiter, if there is any. And now NASA's New Horizon's spacecraft has photographed a single day in the life of the solar system's largest planet. The animation was assembled by scientists working for the $700 million mission, using a series of stills taken as the spacecraft approached the gas giant this winter. It shows one full rotation. (Click on the image to set it spinning. If it's sort of jerky, let it play out, then run it a second time. It should smooth out, depending on your Internet connection speed. Be patient during the download.)

New Horizons is on its way toward a 2015 rendezvous with the dwarf planet Pluto, and last month passed within 1.4 million miles of Jupiter's center. The flyby gave it a gavitational speed boost needed to trim three years from the journey.

Jupiter's diameter is 11 times that of Earth, but its 10-hour rotation is less than half as long as Earth's 24-hour day.

The New Horizons mission is being managed by the Johns Hopkins University's applied Physics Lab near Laurel, and the spacecraft itself is being controlled from the Mission Operations Center at APL.

Posted by Frank Roylance at 8:44 PM | | Comments (0)
Categories: Cool pictures
        

Feels like Spring

Now THIS is more like it. After reaching single-digit lows in many spots last week (18 at BWI), we're looking for highs above 70 degrees on Tuesday and Wednesday at BWI. That's well above the long-term average for this time of year, which are now moving into the mid-50s. (Record highs are in the 80s.)

Daffodil We can thank a high-pressure system that has settled in along the mid-Atlantic coast, spinning clockwise and drawing warm air up from the southwest along the high's western flank.

The seagulls are happily sunning themselves this morning on the roof of the new Catholic Charities center, on the Fallsway alongside Supermax. And soon we can expect the usual photos of Hopkins students sunbathing on the greensward at lawn at Homewood. (Our flower photo is from 2006.)

After three days of mild, sunny weather, there are some showers ahead, followed by clear weather again for the weekend, if current forecasts hold up. We're looking for a clear morning Sunday for a bright flyover by the International Space Station. More on that later in the week.

Posted by Frank Roylance at 10:38 AM | | Comments (0)
Categories: Forecasts
        

March 9, 2007

Volcanic spectacle

The Maryland-built and Hopkins-operated New Horizons spacecraft snapped a spectacular photo of the Tvashtar volcano last week as it soared past Io, the innermost of Jupiter's Gallilean moons. It Tvashtar1 caught the Texas-sized volcano in the middle of a huge eruption, shooting debris more than 150 miles into space. The material - much of it sulfur - from Io's volcanic eruptions coats the little moon. Some of it flies off into space, orbiting Jupiter, falling into its atmosphere and creating aurorae, or getting swept up by the solar wind.

To read more, click here. For a New Horizons photo gallery, click here.

New Horizons, launched in January 2006, is en route to the (dwarf) planet Pluto in 2015, and then off into the icy Kuiper Belt beyond. The $700 million mission is mankind's first to Pluto. It is being managed by the Johns Hopkins University's Applied Physics Laboratory near Laurel.

Posted by Frank Roylance at 3:30 PM | | Comments (0)
Categories: Cool pictures
        

Rushing the season ?

By now everyone has to be aware that most residents of the United States will be moving their clocks ahead one hour this Sunday morning, making the switch to Daylight Saving Time. The changeover comes three weeks ahead of the more familiar first Sunday in April. That's the work of the U.S. Congress, which hopes to save Americans some energy and cash by providing an extra hour of daylight in the evening.

Clock I'm not sure how the math on that works out. After all, we will need the lights for an extra hour every morning. But it will be nice to drive home from work each day with some light in the sky.

So what, exactly, can we expect Sunday morning in Baltimore as a result of the time change?

Well, according to the U.S. Naval Observatory's sunrise and sunset tables, the sun will rise over the city on Sunday morning at 7:25 a.m. EDT, instead of 6:25 a.m. EST.

That means, as the days grow longer this spring and the sunrise continues to get a bit earlier each day, we won't get back to a 6:25 a.m. (EDT) sunrise until April 18. That's a good thing if you like to sleep late in the dark; a bad thing if you like to wake to daylight.

On the other hand, the sun will set Sunday evening in Baltimore at 7:09 p.m. EDT, instead of 6:09 p.m. EST. The change thus buys us three weeks of later sunsets. But on April 1, when the time change would have occurred under the old law, the advantage is lost. The sun will set that evening at 7:30 p.m. EDT.

So what do you think? Does it makes sense to start Daylight Saving Time in winter?  Will we really save any energy, or money? Is it a problem that it will be darker when kids and commuters head out in the morning? Does it make any difference at all? Leave us a comment.

Posted by Frank Roylance at 10:44 AM | | Comments (8)
Categories: By the numbers
        

March 8, 2007

Freezing fog a rarity

This morning's bitter cold came with forecasts for "freezing fog" in Frederick and Washington counties. It's a weather phenomenon that plenty of people were unfamiliar with, and we've had several questions about it here.

We'll address it on the Weather Page on Sunday for non-blog readers. But it occurs when fog is "supercooled" to temperatures between freezing and about 14 degrees Fahrenheit. By themselves, the water droplets in fog won't freeze at those temperatures because they need airborne dust particles or solid objects to attach to in order to trigger the crystallization needed to freeze.

Fzgfg But when they come into contact with solid objects, the droplets do freeze, forming feathery crystals called "rime."  Often the rime forms on the windward side of poles and wires and such. It also forms in trees, coating every twig and making quite a beautiful scene.

Speaking of cold and wintry weather, here is the snow map for yesterday's snowfall in Maryland.

Posted by Frank Roylance at 1:21 PM | | Comments (0)
Categories: Winter weather
        

Yikes! That's cold!

The mercury is climbing now, but we hit some pretty impressive lows around the region overnight as the arctic cold dug in and skies cleared. It was 5 degrees on the WeatherDeck in Cockeysville at daybreak today, the lowest of the winter so far. Here are some other overnight low readings from around the region. Feel free to leave us a comment and report your own lows.

BWI:  14 degrees

Martin Airport:  18 degrees

Frederick Airport:  1 degree

Martinsburg, W. Va.:  6 degrees

Reagan National Airport: 20 degrees

Dulles International Airport:  11 degrees

York, Pa. Airport:  minus-7 degrees

Mt. Washington, N.H.: minus-17 degrees. Winds gusting to 79 mph. Wind chill minus-58 degrees.

We're already at 9 degrees on the WeatherDeck as I write. Forecasters expect we'll reach the upper 30s today at BWI. The real warm-up comes this weekend, with highs in the 50s, with showers. Monday could approach 60 degrees, with highs well into the 60s for later in the week. Here's the official forecast.

Posted by Frank Roylance at 8:14 AM | | Comments (2)
Categories: Winter weather
        

March 7, 2007

After snow, sun, warming

It's not much snow, but I have to admit to sliding around on it a bit as I left the neighborhood this morning. Maybe the school systems got it right this time. Although, back in the day, an inch of snow 3707snow wouldn't have slowed us down much. My wife and I lived in New Hampshire for a while after we were married, and schools never closed for snow. The school buses might stop running, but the kids were expected to make it in - on skis if necessary. And most of them did. But that's New Hampshire. This is Baltimore.

Here, we're looking at a few inches of snow on the ground and all area school systems closed except for the city. We'll have light snow off and on for the rest of the day, with temperatures stuck below freezing. The next few days will get sunny and a bit warmer - breaking into the 30s, but still very cold at night and below normal for this time of year.

More seasonable temperatures, reaching back into the 50s will follow, along with some rain late in the weekend, if the forecasters are right.

Posted by Frank Roylance at 10:08 AM | | Comments (0)
Categories: Forecasts
        

March 6, 2007

A snowy Wednesday

The National Weather Service has posted snow advisories for most of Maryland on Wednesday. We can expect a few inches, with snow on the roads and limited visibility at times. It doesn't seem like a big wup, but I've stopped predicting how much snow it takes for school officials to throw in the towel. Here's the advisory:

"A STRONG CLIPPER SYSTEM ... OVER THE GREAT LAKES WILL CROSS THE
REGION WEDNESDAY. SNOW WILL BEGIN NEAR THE MORNING DRIVE. A BAND
OF SNOW WILL FALL NORTH OF THE TRACK OF THE LOW. AROUND 2 TO 4
INCHES OF SNOW CAN BE EXPECTED IN THIS BAND...WITH ONE TO TWO
INCHES ON THE SOUTHERN FRINGE OF THE PRECIPITATION. SNOWFALL WILL
END BY DARK.

"A SNOW ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE PRIMARILY
TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED ROADS AND
LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING."

Wedssnomap Where, exactly will the 4 inches of snow fall? Nobody really knows. But here is AccuWeather's snow map.

Posted by Frank Roylance at 3:46 PM | | Comments (0)
Categories: Winter weather
        

Do we do negative dew?

Weather instruments here at The Sun as I write are showing 23 degrees, with a crispy 32 percent relative humidity. That works out to a dew point of minus-3. Here's the reading at BWI. A negative dew-point reading prompted this message from Dennis Harrington:

"Today’s dew point is negative 5. How can dew be negative?? – thanks, Dennis"

Fair question. But it's more easily understood when we remember that dew point readings are actually temperatures. Specifically, it's the temperature at which the air - with a given moisture content - could no longer hold that water vapor in a gaseous state. The vapor would condense and form dew (or some other form of liquid or frozen precipitation)..

In short, this morning's readings mean the arctic air that blasted in here yesterday and overnight is very dry, and the temperature would have to cool to minus-3 degrees F before it would become saturated, and its moisture would condense into liquid form. Remember, cold air can't hold as much moisture as warm air. So when we cool air, without changing its moisture content, we eventually hit the dew point, and the vapor condenses. (That's what produces the dripping water under an air conditioner in summer, or the fog on the cold bathroom window pane when we shower.)

As wetter air moves in later today and tomorrow, we'll watch relative humidities rise, lifting dew points at the same time. When actual temperature and dew point meet (in the clouds if not on the surface), we get condensation and a precipitation event - in this case snow, the inch or two expected tonight and tomorrow. Garrett County could get 8 inches or more.

Posted by Frank Roylance at 10:29 AM | | Comments (0)
Categories: Forecasts
        

March 5, 2007

Snow due Tuesday/Wednesday

Snow chances with the little "clipper" system headed this way tomorrow night are now pegged at 70 percent. Northern tier counties could see two inches as the storm sweeps down from the Great Lakes to the mid-Atlantic coast.

Just a dusting, but a reminder that winter isn't over 'til it's over. Snowmap_1 Here's Henry Margusity's snow map.

Of more consequence may be the stiff wind, falling tempertaures and low wind-chills over the next few days. The Sun's instruments have been recording winds of 10 or 12 mph, gusting to 30 mpg this afternoon. Temperatures are headed for the low 20s, even the teens in some spots for the next two nights.

Posted by Frank Roylance at 5:39 PM | | Comments (0)
Categories: Winter weather
        

Not spring yet

So here it is, March 5 in Baltimore, and the long-term average high temperatures are at 50 degrees at BWI. And yet we're looking at a forecast for highs in the 30s tomorrow and Wednesday, with a chance of rain or SNOW Wednesday night. We are most definitely not out of the wintry woods just yet.

The official forecast calls for a high today of 46 degrees, falling to the low 20s over night with stiff winds making it feel even colder if you're stuck outside. Tomorrow may get no warmer than the mid 30s, with even colder temperatures Tuesday night into Wednesday as the cold Canadian air mass builds in from the north.

Another Alberta Clipper - a stormy patch in the jet stream - is due late Wednesday. But it will be moving very quickly and won't hold much moisture. So they're looking for some snow, mixing with rain by late morning. Here's AccuWeather's Henry Margusity on the subject.

And here's a bit of this morning's discussion from Sterling:

"MARCH SEEMS TO WANT TO KEEP WINTER AROUND FOR A
WHILE LONGER. LOW LEVEL TEMPERATURE PROFILES ARE SHOWING SNOW
BEGINNING LATE TUESDAY NIGHT IN THE NORTHWEST AND SPREADING
SOUTHEAST WEDNESDAY MORNING. EXPECT ENOUGH WARMING WEDNESDAY
AFTERNOON TO HAVE A CHANGEOVER FROM SNOW TO RAIN. TIMING HAS BEEN
DIFFICULT OVER THE PAST FEW STORMS. WILL BE MORE PESSIMISTIC WITH
THIS ONE AND MENTION SNOW IN THE MORNING ACROSS THE SOUTH CHANGING
TO RAIN BY AFTERNOON. THIS GOES ALONG WITH (COMPUTER MODEL) THINKING...
SHOWS AROUND 2 INCHES ALONG THE NORTHERN TIER OF COUNTIES...WITH AN
INCH FOR DC AND NORTH."

Sounds lousy. And to think it was 83 degrees here on this date back in 1976.

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

March 4, 2007

Some saw eclipse

Last night's lunar eclipse was a total washout for me. We were driving down the NJ Turnpike as it began, with lots of low clouds on the eastern horizon. As it got darker, I could see Venus fairly high in the southwest. But that was it. We pulled over at a rest stop for a look from the parking lot. Nothing. As we arrived back home after the end of the eclipse - at about 8:20 p.m. - there was the moon, high in the east, too late, and blurred by thin clouds. Too bad.

Here's to better luck in August, when the full moon will set in full eclipse. We get to see the beginning of the event this time - assuming clear skies. Next chance after that is in February 2008.

Eclipse Fortunately, the eclipse was witnessed by lots of people in other, more fortunate locations. Here are a few images from them.

An animation of images from the start of the eclipse from Britain.

Stills from the end of the eclipse, from Alabama.

And a magnificent gallery of images from all over, including the one posted above, from Ulrich Beinart, in Germany.

Here's CNN's account.

Posted by Frank Roylance at 9:09 AM | | Comments (1)
Categories: Sky Watching
        

March 2, 2007

Flooding on the Gunpowder

The National Weather Service has posted flood warnings for parts of Baltimore, Carroll and Frederick counties. Flooding is reported in the Gunpowder valley. Here's the warning.

The storm is moving past our region this morning. The barometer appears to have bottomed out, and flood threats should ease. Here's the latest forecast. In the meantime, if you can do it safely, we'd love to see your photos of flooding in the region. Just register and upload your digital images to our Readers Photos page.

Posted by Frank Roylance at 8:23 AM | | Comments (0)
Categories: Flooding
        

Clouds may cover eclipse

The first total eclipse of the moon visible over Maryland since October 2004 will begin at moonrise Saturday, around 6 p.m. But the weather forecast is not promising. The Sun ran a story in the Health and Science section of Friday's print editions. If you missed that, here's a site that will explain it all.

Eclipselunar Here's the latest forecast, which does not look good.

If we are clouded out here, there are several sites where you can watch the eclipse on line. Here are a few. From NorwayNetherlands. Italy.

Or, you can always wait for the next one, in August. Here are the particulars.

Posted by Frank Roylance at 7:27 AM | | Comments (0)
Categories: Sky Watching
        

March 1, 2007

Wind, moon mean high tides

Coastal residents in Maryland should watch the water at their shores tonight as the approaching storm brings strong southeast winds, blowing water up the bay and holding it there. That, plus an approaching full moon, will mean high tides running two to three feet above predicted highs tonight. Here is the coastal flood watch issued today.

You can watch the tide gauges here. Just click on "MD" and pick your gauge.

Here are the high tide times, from the flood watch:

TIMES OF HIGH TIDES FOR THE FOLLOWING SITES EARLY FRIDAY MORNING...
HAVRE DE GRACE...8:24 AM.
BOWLEY BAR...6:04 AM.
FORT MCHENRY BALTIMORE...5:13 AM.
NAVAL ACADEMY ANNAPOLIS...3:35 AM.
COVE POINT...1:08 AM.
POINT LOOKOUT...11:47 PM THIS EVENING.
LEANARDTOWN...1:06 AM.
GOOSE BAY...2:36 AM.
MOUNT VERNON...6:39 AM.
ALEXANDRIA...7:04 AM.
KEY BRIDGE WASHINGTON DC...7:21 AM.

Posted by Frank Roylance at 3:14 PM | | Comments (0)
Categories: Forecasts
        

Hubble guide to March night sky

Saturn_1 Each month, the Space Telescope Science Institute in Baltimore provides an on-line video guide to the night sky for that month, including prominent constellations, planets and sky events to watch for during the following weeks. Here's the March guide. Get yourself outdoors on any clear evening and enjoy.

Posted by Frank Roylance at 10:06 AM | | Comments (0)
Categories: Sky Watching
        
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About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff
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