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May 31, 2005

Messenger craft snaps Earth's portrait

The MESSENGER spacecraft, en route toward the planet Mercury, has snapped a telephoto portrait of the home planet. The shot, taken May 11 from a distance of more than 18 million miles, shows the Earth and moon in one frame, and enough detail of Earth's sunlit side to reveal the American continents and cloud patterns. Quite a snapshot.

MESSENGER, built and managed by the Johns Hopkins University's Applied Physics Lab, is cruising toward a flyby of the Earth on Aug. 2, one of a series needed to sling it toward its target. Mission managers expect the spacecraft to enter orbit around Mercury in 2011. It will be the first spacecraft form Earth to orbit the nearest planet to the sun.

Posted by Admin at 2:24 PM | | Comments (1) | TrackBacks (1)
Categories: Cool pictures

June arrives with promise of warmer weather

After one of the coolest Mays on record in Baltimore, Marylanders can be forgiven if they look forward to June - which arrives tomorrow - even though summer in these parts usually means some highs in the 90s (or worse) with humidities to match.

For now, the week ahead looks like more springtime weather. The highs will linger in the 70s for a few more days, before the weekend brings us afternoons, at last, in the 80s. That should hit the spot for many. I know my mother-in-law doesn't take off her sweater until the mercury hits the 80s. There's a chance for some showers late Wednesday and Thursday, but the rest of the week looks dry.

In June, the average high temperatures at BWI rise from 79 degrees to 86 degrees by month's end. The average lows climb from 57 to 64 degrees.

The record highs are in the 90s and 100s, with an all-time June record of 105 degrees, set on June 29, 1934. Imagine that day in a Baltimore rowhouse before air conditioning! No wonder they slept in the parks on hot summer nights back then. Anybody remember that? Leave a comment and tell us about it.

The record lows for the month are in the 40s and 50s. The all-time chilly morning in June was a 40-degree surprise on June 11, 1972. That was the same June when the remains of hurricane Agnes (click here and scroll to the bottom of the page that appears) struck Maryland, with disastrous effects. The storm dropped more than 6 inches of rain at the airport on June 21-22. It also contributed to the wettest June on record here - 9.95 inches. (The driest June was in 1954, when the airport recorded barely .15 of an inch of rain.

June also brings the opening of the Atlantic hurricane season. But the peak in hurricane activity is in late summer - from late August through September. The season ends Nov. 30. Dr. William Gray's latest predictions for the season are looking more dire. For the good doctor's latest forecast from Colorado State University, just out today, click here.

Posted by Admin at 11:40 AM | | Comments (0)
Categories: Almanac

May 27, 2005

Rise and see Mars shine

We'll all be trying to sleep in this weekend. But if you can't sleep, or the dog gets you up early, take a minute to see Mars hanging bright over the eastern horizon before dawn.

The red planet is getting bigger and brighter all summer, moving toward opposition and a close encounter with Earth next fall. The best morning to look may be Tuesday, when a crescent moon will share the pre-dawn sky, barely a half-a-degree south of Mars. And we'll all have to get up anyway.

Posted by Admin at 6:10 PM | | Comments (0)
Categories: Sky Watching

Thunderstorms, high tides

The National Weather Service is warning that all this unfamiliar warmth and sunshine is too much of a good thing. It could trigger some thunderstorms this afternoon north of Baltimore, in Pennsylvania and out on the Delmarva Peninsula.

Oh, and those inviting bay waters are misbehaving, too. The continuing influence of "spring" or lunar tides will add a foot or two to the high tides today along the Maryland's western shore.

But does anyone really mind? It's gorgeous out there. And there's a three-day weekend on tap. Priceless.

Posted by Admin at 3:28 PM | | Comments (0)
Categories: Forecasts

Spring comes to Hudson's Bay

And you thought it was a cold May here... For folks living around Hudson's Bay, in northern Quebec, May means the breakup of the winter ice on the Bay. The link will take you there. Count your blessings.

Posted by Admin at 11:30 AM | | Comments (0)
Categories: Events

May 26, 2005

Weekend looks great

Forecasters have pushed the threat of rain from Friday into Saturday. But it's only a "chance" for a passing shower or thunderstorm.

Otherwise, we seem to have emerged from the gloom. Friday should be sunny, with highs around 80 in the Baltimore area. ABOVE normal! Hoo-wah!! Sunday and Monday look good, too, with afternoon highs approaching the seasonal norms - which are now in the upper 70s. The forecasters' discussions hint at a pretty good rainstorm Tuesday. But we'll all be back at work, so who cares?

There's still a chance for coastal flooding later today, thanks to "spring tides" linked to the recent full moon. Look for one to two feet of extra water atop the normal high tides.

And, we're still on track for one of the coldest Mays on record in Baltimore. We're averaging 58.1 degrees through Wednesday. That would rank as the second-coldest May since record-keeping began in 1871. The coldest remains May 1967, when we averaged 57 degrees. (Normal is around 63 degrees.)

This month's average could creep up to 58.9 degrees in the next few days as temps warm, and it would still rank as the second-coldest May. I think the second-place ranking will hold.

Posted by Admin at 10:24 AM | | Comments (0)
Categories: Forecasts

May 25, 2005

Drought threatens millions in Southern Africa

With little rain since January, and public health already threatened by HIV/AIDS, people in southern Africa face a harrowing future. Read more here.

Posted by Admin at 1:54 PM | | Comments (0)
Categories: Drought

Water torture ends, hope springs

Twenty-four hours of off-again, on-again drizzle and spit produced barely a third of an inch from Monday into Tuesday. BWI recorded .38 inches of precipitation. That brought the monthly total to 2.56 inches, still .44 inch below normal for this point in the month of May. And most of the rain came in one splash - 2.04 inches on the 19th and 20th.

The good news is that, except for a "slight" chance of showers and thunderstorms on Friday, the long weekend looks fine. Partly cloudy with highs in the 70s.

That will constitute a major warm-up. High temperatures at this time of year SHOULD be in the mid-to-upper 70s. Yesterday's high of 57 degrees was 19 degrees below normal. The day's average of 55 degrees equals the normal low for the date. And it was the third date in May that never rose above the 50s.

So far this month we have had 17 days with temperatures averaging 1 to 13 degrees below normal, and just 7 days that were warmer than normal. Bring on the sun.

Posted by Admin at 10:36 AM | | Comments (0)
Categories: Forecasts

May 24, 2005

El Salvador dodged Adrian's rain

Satellite imagery has revealed why flood damage from Hurricane Adrian was not as bad as feared in Central America. It turned out that the worst of Adrian's rains fell offshore. Have a look.

Posted by Admin at 6:24 PM | | Comments (0)
Categories: Hurricanes

May coolest since 1967 ... so far

This month still has a week to run. But there's seems little doubt that May 2005 will stack up as one of the coolest on record in Baltimore. At this point the month is averaging 58.4 degrees. That's about 5 degrees below normal (depending on which of the Weather Service's conflicting statistics on the point you accept). Temperatures should warm to near normal by the weekend. That will nudge the average up some. But the month will surely remain among the chillier Mays we've seen.

There have been only five years (since the official Baltimore weather station moved to BWI in 1951) in which May temperatures have averaged less than 60 degrees. The most recent was 2003, when the average was 59.3 degrees. And there has been just one year - 1967 - when May was cooler than 58 degrees.

Here is the full list:

1967: 57.0
2005: 58.4 (through Monday)
1907: 59.0
1917: 59.2
2003: 59.3
1997: 59.5
1973: 59.6
1882: 59.6
1968: 59.7

We've had just three days this month that have averaged above 65 degrees. That comapares with 24 last year. And, we've seen just two days with highs greater than 80 degrees this May. Last year there were 19 days with highs of 80 degrees or more, including two in the 90s.

That translates into just 9 cooling degree-days so far this month, compared with 203 in all of May 2004. So, we've all saved some money in air conditioning expenses.

On the other hand, maybe your furnace has been running some mornings. We've had 156 heating degree-days this month, compared with 49 last May.

Posted by Admin at 4:00 PM | | Comments (0)
Categories: By the numbers

Cool spring, hot summer?

WeatherBlog reader Robert Hartge asks: What do you think about the summer after this? Will it be cool like 2003 and 2004 or much hotter? I think it can go either way, but what are your thoughts on this summer's weather?

I don't have any strong opinion either way. And apparently neither do the climate forecasters. They see an unusually warm summer for the southern tier of states, and dry weather in the Southeast. But they have no strong signals either way for us. Here's how they're calling it.

Posted by Admin at 10:51 AM | | Comments (0)
Categories: Forecasts

Hope for Memorial Day weekend

Okay, so it's drippy, dark and dank now. And tomorrow looks no better. But forecasters say there's hope for the three-day Memorial Day weekend just ahead.

The light rain began this morning after 4 a.m. at BWI, and, as my grandmother used to say, it's been spitting ever since. Irish mist. But only .02 inch had fallen by mid-morning. The forecast calls for more rain tomorrow, then clear and pleasant on Thursday. Friday there's a chance of thunderstorms and showers from 8 a.m. to 8 p.m. But after that, the coast is clear from Saturday through Monday, with partly cloudy skies and pleasant temps in the low 70s.

In the meantime, watch out for more high water at high tides tonight. Onshore winds, combined with a nearly-full moon will mean an extra 1 to 1.5 feet on the tides, especially on the western shore of the Bay.

Posted by Admin at 10:33 AM | | Comments (0)
Categories: Forecasts

May 23, 2005

Lousy spring? Not if you like cool

It looks like more mostly cool, gray, wet weather all week. And it's only more of what we've been seeing for the past four weeks. At least that's the spin from the National Weather Service at Sterling, Va. (It's geared for Washington DC, but worth a read):




True enough. But concentrating the rain in just a few events has left plenty of dry, sunny days with cool but pleasant temperatures. That's not so bad, unless you're a plant. Anyway, back to Sterling:


Ick. Thanks a lot.

Posted by Admin at 3:09 PM | | Comments (3)
Categories: By the numbers

Sterling radar down; parts en route

The big Doppler radar at the National Weather Service's Sterling, Va. forecast station went dark around 2 a.m. Sunday, and was still down at mid afternoon today (Monday). Meteorologist-in-charge Jim Lee reports the problem was a communications circuit board in one of the computers at the base of the radar tower.

"We're doing the best we can," he said. The part was not one that can be expected to fail from time to time, so it had to be ordered from Norman, Oklahoma, and flown to National Airport. It was due to arrive there at 2 p.m. In the meantime, technicians were called in on the midnight shift last night to begin troubleshooting and preparing to get the site up and running again as soon as the part arrives by courier from the airport. (Such midnight shifts for techies is "highly unusual," he said, but in this case "it's warranted."
Officials were hoping to get the radar up and running again by 5 p.m.

In the meantime, there are some thunderstorms crossing western Maryland. Forecasters, and people in their path, can follow them with the radar image from the dish in Pittsburgh.

Posted by Admin at 2:44 PM | | Comments (0)
Categories: Events

Lunar tide, onshore winds mean high water

The National Weather Service is warning of unusually high tides and a chance for minor flooding along Maryland's western shore through Tuesday morning as a full moon and an approaching storm combine to push and trap water in the upper bay.

Not that we're likely to see it tonight, with all these clouds, but the moon is full today - officially, at 4:20 p.m. That means it is directly opposite the sun in the sky, and it will rise in the east as the sun sets in the west. The combined gravitational effects of the sun and a full moon (and also around the time of the new moon) typically produce more extreme high and low tides, called "spring tides."

Today and tomorrow, the spring tide will be amplified by an approaching coastal low pressure system that will produce onshore winds that drive water into the bay and hold it against the western shore until the storm passes.

There will be lots more water falling from the sky, too. There is rain, or a chance of rain, showers or thunderstorms in the forecast all week, except for Thursday. And it will remain cool - way cool for this time of year. Tuesday's predicted high temperature at BWI is only 58 degrees. That's 18 degrees below the normal high for the date, and only 4 degrees warmer than the normal low.

Posted by Admin at 11:05 AM | | Comments (0)
Categories: Forecasts

May 21, 2005

Friday's rain broke a record

Friday's rainstorm in Baltimore broke a 65-year-old rainfall record for the date, according to the National Weather Service. The 1.97 inches recorded at Baltimore-Washington International airport snapped the 1.40 inch mark established in downtown Baltimore on May 20, 1940 (before the airport became the station of record).

It was the second weather record reached so far this month. The first was the 34-degree low on May 3. That tied the record low for the date.
It's also worth noting that Friday's high of just 55 degrees at BWI was only 2 degrees warmer than the normal low for the date.

The heavy rain also brought the month's precipitation to 2.18 inches, but that's still .30 inch short of normal for the date.

Posted by Admin at 12:19 PM | | Comments (0)
Categories: Events

May 20, 2005

High water, fallen trees in storm's wake

Forecasters are warning of high water in creeks and streams, and tides up to 2 feet above normal due to strong onshore winds this evening. The storm is moving off now after dropping more than 2 inches of rain at BWI, and more elsewhere. That takes care of the rainfall deficit for the month.

The high temperatures for the day occurred just after midnight, and they've been 20 degrees below normal all day.

Winds gusted today as high as 40 mph at the airport, bringing down numerous trees and limbs and power lines throughout the region. Rain chances will persist through Monday night.

Posted by Admin at 5:25 PM | | Comments (0)
Categories: Events

Hurricane Adrian weakens

The Pacific storm that blew onto the Salvadoran coast late yesterday has been downgraded to a tropical storm as it moves across central America into Honduras. Tens of thousands of people in both countries have been evacuated from flood-prone areas, mindful of the thousands who died in flooding that followed a Caribbean hurricane - Mitch - in 1998. For more, click here.

Here's the latest - and last - advisory from the National Hurricane Center on Hurricane - now Tropical Storm Adrian.

If the storm regains enough strength after it reaches the Caribbean, it could become the first storm of the Atlantic season. If it reaches tropical storm strength, it would change genders and be re-named Arlene.

Posted by Admin at 11:22 AM | | Comments (0)
Categories: Hurricanes

A Bradford Pear storm

I figure every good storm should have a name. At our house, this morning's rain and wind will live in our memory for - gosh - weeks as The Great Bradford Pear Storm of 2005.

Stepped out the door around 7:30 today and found that about a third of the pear tree in our front yard had split from the main trunk and fallen onto the neighbor's steps. I grabbed a saw, but quickly discovered the truism that Bradford pears are fragile trees. Both broken branches snapped off cleanly.

So I dragged the limbs off the neighbors' property and left the mess 'til later. Driving to work, I saw several other ornamental trees that fared badly during the night. We had allowed our pear tree to grow top-heavy. I liked the way it grew so tall, so fast after the place was built in 1997. It threw more and more shade across the sunny side of the house in summer, so I let it grow, against my wife's objections. But with a heavy load of leaves and branch wood, more than a half-inch of rain during the night on our rain gauge, and gusts (at least at BWI) to 32 mph, it was all too much for the young tree.

The surviving branches still look full enough to justify preserving the tree, though my wife is already suggesting that we have the Bradford removed and replaced with a nice little weeping cherry or some such fussy tree. My sympathies are with our scarred survivor.

The storm, meanwhile, continues to blow. The airport had recorded more than an inch of badly needed rain by 9 a.m., and stiff gusts. Forecasters said the rain had fallen during the night at up to 0.8 inch an hour in some of the heavier rain bands. The creeks are rising, and on the roads, visibility was down, and ponding was contributing to numerous minor accidents, including a tow truck - directly in front of me this morning, that - following too close for conditions - skidded into the rear of a passenger car on York Road in Lutherville. No one was hurt.

So now I'm looking at a wet weekend in which I will have to drag these heavy limbs into the woods. Or, maybe I'll go out and rent a chain saw and cut them up first. A weekend that includes a chain saw is always well-spent.

Posted by Admin at 10:30 AM | | Comments (2)
Categories: Events

May 19, 2005

Hurricane Adrian threatens Central America

Tropical storm Adrian, the first storm of the season for the Eastern Pacific, was upgraded earlier today to hurricane status, with maximum sustained winds of 85 mph. His winds are bad enough, but he is threatening the Central American nations of El Salvador and Honduras with torrential rains, flooding and dangerous mudslides.

It's already raining there, and residents of El Salvador are scrambling to prepare for what would be the first hurricane to strike their country directly since record-keeping began. Most Eastern Pacific hurricanes moves to the north and west, away from the Salvadoran coastline. This one is headed straight for it. The many Central American immigrants in the Washington and Baltimore areas are likely watching this storm closely.

Adrian is expected to weaken as he crosses the Central American landmass, emerging on the Caribbean side as a tropical depression. If the storm regains enough strength, it could reach tropical storm strength again and be renamed Arlene - the first storm of the Atlantic season, which doesn't officially begin until June 1. For now, however, the forecasters at the National Hurricane Center have the storm remaining a depression as it crosses the Caribbean, headed northeast toward drought-stricken Cuba, where they could use the rain.

Posted by Admin at 4:51 PM | | Comments (0)
Categories: Hurricanes

Bob Dylan on weather; (Yes, THAT Bob Dylan)

Alan Robock, an environmental scientist at Rutgers University in New Jersey, has written an admiring essay in the Bulletin of the American Meteorological Society on the poetic weather imagery in Bob Dylan's songs. He writes:

"'Chimes of Freedom' (1964) is the most wonderful, poetic description of a thunderstorm of which I am aware. It begins:

'Far between sundown's finish an' midnight's broken toll
We ducked inside a doorway thunder crashing...
As majestic bells of bolts struck shadows in the sounds
Seeming to be the chimes of freedom flashing.
Flashing for the warriors whose strength is not to fight,
Flashing for the refugees on the unarmed road of flight.
An' for each and ev'ry underdog soldier in the night.
An' we gazed upon the chimes of freedom flashing.'"

There's lots more. You can read it here.

Posted by Admin at 12:44 PM | | Comments (0)
Categories: Cool sites

Rain, minor tidal flooding on tap

The National Weather Service is warning of some potentially (locally) heavy rain with the storm system passing through the region tonight and tomorrow. With southeast winds expected, there could also be some minor flooding on the west shore as Chesapeake Bay water is blown north and west toward the head of the bay and into the creeks.

The rain, at least should be welcomed. We're more than 2 inches short of precipitation so far this month.

Posted by Admin at 11:09 AM | | Comments (0)
Categories: Forecasts

May 17, 2005

Reservoir shrivels in Dakota drought

The multi-year failure of snowfall in the northern Rockies is having a profound effect on Lake Oahe, a reservoir formed by a dam in the Missouri River. Water levels in the reservoir have fallen so far that the segment of the lake north of the North Dakota-South Dakota line has shrunk back into the old, braided Missouri river bed.

The drought is having a serious impact on agriculture, drinking water supplies and tourism in the region. Here is a pair of satellite images that show how much the lake has diminished in the past five years. Enlarge the images and you can see in detail how the lake has been transformed.

Posted by Admin at 1:06 PM | | Comments (0)
Categories: Drought

Don't forget Agnes

I didn't, exactly. In today's front page story about the National Hurricane Center's forecast for the 2005 hurricane season (more active than normal, but similar to last year), I mentioned a number of hurricanes that have hit hard enough here to stick in the memories of many Marylanders - the likes of Hazel, Gloria and, most recently, Isabel.

But I didn't mention Agnes, and we're already getting calls (well, one call) about the omission. In truth, I considered including Agnes, which swept the state in June 1972 with historic flooding. That damage has had a lasting impact on the health of the Chesapeake Bay.

But I left the old girl out mostly because she was not really a hurricane. In fact, it lost that status as it came ashore in the Florida panhandle on June 19. It was very quickly downgraded to a tropical depression and never regained hurricane strength, although it did spin up to tropical storm strength again - briefly - after moving back into the Atlantic off Norfolk on the 21st.

But that's no excuse. Agnes was a big, broad storm, packed with moisture. It drew strength from an unrelated low pressure system, and the resulting rains caused terrible river flooding and huge damages wherever she went. When it was over, Agnes was ranked as the costliest natural disaster in U.S. history.

Agnes killed close to 120 people and caused $2 billion to $3 billion in damage (1972 dollars). In Maryland alone it displaced 3,479 families, destroyed 103 homes and caused major damage to 866 more. More than 80 small businesses were destroyed or severely damaged. (Isabel was worse, in that respect.)

Here's how the National Weather Service summed her up in 1972:

"Regardless of the energy sources and circulation dynamics that caused the floods ... this devastation could not have occurred without the extreme importations of moisture to the area by the depression that had been Hurricane Agnes. Thus, the damage due to river floods, far exceeding the combined losses from Camille in 1969 and Betsy in 1965 - previously the two most destructive storms of history - must be charged to Agnes, the greatest natural disaster of all times in terms of dollars.’’

For a look at that entire report, here's the official Agnes record, reproduced on the National Hurricane Center's site. It's not easy to read - composed of page-by-page facsimiles of the original printed report. But it's an interesting read. Click on each file in order, and on the enlargement button that will appear when you move your cursor over the page.

Finally, the edited version of today's story sliced off the link to the National Hurricane Survival Initiative's Web page. For everything you'll ever need to know to prepare for the hurricane season, click here.

Posted by Admin at 11:02 AM | | Comments (0)
Categories: Hurricanes

May 16, 2005

2005 Hurricane Season forecast is in

The National Hurricane Center is predicting a busy season again this year, along the lines of last year's. Look for 12 to 15 named storms, of which 7 to 9 will grow to be full-fledged hurricanes, and 3 to 5 will reach Category 3 or worse - sustained winds of at least 111 mph.

Here's the full skinny from NOAA.

For a look at how woefully unprepared we are, visit the National Hurricane Survival Initiative.

And here are the storm names planned for the 2005 season (and the next six.)

The season runs from June 1 through Nov. 30.

Posted by Admin at 6:11 PM | | Comments (1)
Categories: Hurricanes

Rain ... please?

There were a few drops on the deck this morning, but hardly enough to wet the geraniums' whistle. So far this month, BWI has recorded barely 15 hundreths of an inch of precipitation. If the month ended here, it would be the driest May on record. Only three Mays (1957, 1964 and 1986) have ended with less than an inch of rain in the gauges.

Of course, some spots have seen more. One St. Paul Street resident tells me his garden got a pretty good soaking last night. Happily, we still have better than two weeks to go in May, and the forecast is calling for a chance of showers and thunderstorms starting Wednesday night. But it's sure been a dry start.

Posted by Admin at 11:17 AM | | Comments (1)
Categories: Drought

Space weather spectacular

A major eruption on the sun on Friday produced some spectacular displays of the aurora borealis - Northern Lights - over the weekend. I haven't seen any reports from Maryland yet, but here are some terrific photos from other parts of the country.

And here's a shot of the solar flare and coronal mass ejection on Friday that caused all the excitement, shot by NASA's Solar and Heliospheric Observatory (SOHO).

Posted by Admin at 10:36 AM | | Comments (0)
Categories: Events

May 13, 2005

Breathing problems? Click here

The summer smog season has begun, and Marylanders sensitive to common air pollutants can anticipate plenty of uncomfortable, unhealthy "bad air days." But this year the Maryland Department of the Environment's "AirWatch" program is making air quality forecasts and warnings easily available to anyone with access to a telephone or an online computer.

MDE Secretary Kendl P. Philbrick, said, "Summertime ground level ozone can be harmful to all of us, especially children, people with respiratory disease such as asthma, and those who work or exercise outdoors. Even at moderate levels, ozone may cause coughing, nose and throat irritation and chest pains. It can make lungs function less efficiently and it can make people more susceptible to respiratory illnesses."

Just call AirWatch at 410 537-3247, or go online to There you can find a graphical display of current air quality readings across the region. You can also sign up to receive faxed or emailed alerts when air quality is deteriorating to unhealthy levels across the region.

"We consider it an early warning system for your lungs," said Thomas C. Snyder, director of MDE's Air & Radiation Management Administration, in a prepared release.

A quick exploration of the state's Website finds that not all its features are up and running yet. But there is plenty of information, and many links to related sites and "hazecams" across the Northeast. Try it. And breathe easier.

Posted by Admin at 5:50 PM | | Comments (0)
Categories: Cool sites

Friday the 13th; so far, so good

Aside from waking up with windows open, 41 degrees at the weather station outside, and heat pump cranking futilely to warm the place up inside, this Friday the 13th has gone OK so far.

Cheer up: It's the only Friday the 13th on tap in 2005. That happens 42 or 44 times per century, according to Guy Ottewell's Astronomical Calendar. Most of the rest of the time there are two. But there can be three Fridays the 13th in non-Leap-Years that begin on a Thursday. That happens 14 or 15 times per century, the next in 2009. When Leap Years start on a Sunday, there are also three Fridays the 13th. That happens next in 2012.

The Friday the 13th that falls in April 2029, may be especially scary, as an asteroid makes what scientists say will be an extraordinarily close - but safe - pass by the Earth. Check it out.

Whatever happens today, there is no avoiding the date. Ottewell says Friday falls on the 13th more often than any other day. So, all you paraskevidekatriaphobics: Be careful out there.

Posted by Admin at 11:26 AM | | Comments (0)
Categories: Events

May 12, 2005

Wednesday's haze, from space

Here's a remarkable shot from orbit of the Chesapeake region, clearly showing the atmospheric haze that stretched along the I-95 corridor. Click on the top-left photo.

And if you liked that, get a look at this image from space, showing the "ship tracks" that ocean-going ships leave when the particulate pollution from their smokestacks causes atmospheric moisture to condense into clouds in their wake. We're all familiar with jet contrails - the cloud trails that form behind jet aircraft when conditions are right. Who knew ships can do much the same thing?

Posted by Admin at 4:19 PM | | Comments (0)
Categories: Cool pictures

We could use some rain

It might put a damper on your outdoor plans, but the rain tentatively predicted for this weekend would be welcomed by many. The forecast calls for at least a chance of showers or thunderstorms on Friday and through the weekend. Area lawns and gardens could use a good soaking, but will likely get much less. Less than 2 inches has fallen at BWI since April 3, and less than a tenth of an inch has been recorded at the airport since May 1.

The weather service has issued a "red flag" warning for parts of eastern Pennsylvania, meaning that dry conditions, low humidity and brisk winds are all ripe for brush fires to develop. The fire risk is also climbing in Maryland, along the Pennsylvania border.

Posted by Admin at 1:57 PM | | Comments (0)
Categories: Drought

May 11, 2005

High of 86 at BWI, 73 in Annapolis

Today's afternoon high at Baltimore-Washington Thurgood Marshall International Airport was 86 degrees, the warmest we've had so far this month. This was only our fourth day in the 80s this year. It's 13 degrees above normal for the date, but well short of the record - 94 degrees, reached on May 11, 1896.

The normal high for the date at BWI is 72 degrees. The record low is 32 degrees.

And while BWI felt like summer, just 20 miles away, down in Annapolis, closer to the Chesapeake and washed in an onshore "bay breeze," the high today was just 73.

Looks like things will be cooling off from here on this week, as cool Canadian air moves in. The forecast for Baltimore calls for a high of just 70 on Thursday and 60 on Friday.

Posted by Admin at 6:18 PM | | Comments (0)
Categories: By the numbers

Moon brings high water; sun creates "bay breeze"

The sun and moon are each playing a significant role in today's forecast. The National Weather Service is predicting water levels around the Chesapeake Bay today 1 to 2 feet above normal. Much of that is being blamed on the lunar cycle.

As we noted yesterday, in an entry about the lovely crescent moon we've enjoyed the last two nights, the moon was "new" on Sunday morning. That means its orbit had carried it to a point directly between the Earth and the sun. With the sun and moon lined up on the same side of the Earth like that, their combined gravitational effect causes unusually high (and low) tides.

Meteorologist Steve Rogowski, out at the forecast office in Sterling, Va., said today that the effect is being enhanced by light south winds across the bay. That is trapping water in the upper end of the bay and its tributaries, preventing it from draining normally to the south and out into the Atlantic.

The situation is expected to ease late tonight as a cold front passes through, with winds shifting to the north, allowing the bay water to retreat.

This afternoon, it will be the sun's turn to write the weather script. Solar heating over the land mass surrounding the bay will push temperatures into the mid- to upper-80s over inland communities. As the heated air rises, it will draw in much cooler air (in the upper 50s) now over the still-chilly bay water.

That produces what forecasters call a "bay breeze." Wherever you are around the bay, the winds will be onshore - from the southeast in Baltimore, and from the southwest on the Eastern Shore. And it will keep communities close to the water in the 70s, while places farther inland will see the thermometer push well into the 80s.

Posted by Admin at 11:46 AM | | Comments (0)
Categories: Forecasts

Ask Mr. WeatherBlogger: Sun pillars

Alert WeatherBlog reader Bob Cantales and his early-rising carpool mates asked this question today:

"During yesterday's sunrise, there appeared to be a golden to orange beam of light similar to a rainbow from the sun at the horizon high into the sky. My carpool members are curious as to what caused this phenomenon?"

From your description, it sounds like what you observed was a "sun pillar." They look like golden search lights beamed straight up into the sky above a rising or setting sun. For those who missed the one Bob saw, here's a good picture. Here's another, from NASA. And, because they're so cool, one more.

Sun pillars are caused by sunlight, reflected off ice crystals in cirrus clouds. Because the crystals in these clouds are falling, they orient themselves, like falling leaves, with their longest dimensions in a horizontal position. That causes the sunlight to reflect toward the observer, creating the horizontal pillar effect.

But while they appear to be rising straight up above the sun, sun pillars are actually being reflected from crystals along a path that is approaching the observer - a bit like the "glitter path," or trail of sunlight or moonlight reflected off the surface of a lake or pond.

The color is produced by the color of the sunlight, which tends to be red or gold at sunset or sunrise. And that's because the low angle of the light sends it on a longer-than-usual path through the thickest layer of the atmosphere, which contains lots of dust. The dust absorbs and filters out most of the light's wavelengths, leaving the reds, oranges and yellows.

This sun pillar was evidently visible from many parts of Maryland. I spotted this message, from Monroe Harden, of Havre de Grace, on a list serve for satellite observers:

"Hello everyone,

"Please pardon the off topic question and cross posting... but I would like to know if anyone happened to see a very large, bright sun pillar before sunrise, at about 0530 EDT, on May 10th, from the east coast of the USA.

"I saw this from my home in northeastern Maryland (Havre de Grace, by the top of the Chesapeake Bay), and it was shown on TV from a tower cam in Baltimore. A member of our local astronomy club said he saw it from the north side of the Washington DC beltway.

"I am curious about how large of an area can see the same sun pillar. If anyone outside of the area I mentioned (ie south of DC or north of Maryland), on or near the US east coast, saw this pillar, please let me know. To avoid list clutter you can email me privately at hardenm at sprynet dot com.

"A couple of photos of the pillar, taken from my back yard (with a Coolpix 4500, so this isn't entirely off topic for digital-astro.....) can be seen here:


Posted by Admin at 11:09 AM | | Comments (0)
Categories: Ask Mr. Weatherblogger

May 10, 2005

One amazing, slender moon

I hope plenty of evening commuters last night got a look at that VERY young crescent moon hanging in the blue western sky at dusk. It was about as slender a slice of moon as you'll ever see, and the clear skies made it all the more dramatic.

The moon was new - directly between the sun and the Earth - at 4:48 a.m. EDT Sunday morning. That means the crescent we saw last evening was barely 40 hours old - shifted eastward in its orbit around the Earth just enough to reveal a sliver of its sunlit side to observers on Earth. Here's an amazing photo of the crescent, as it was being crossed by an airliner.

If skies stay clear this afternoon and evening, we'll have another chance to see a slightly fatter sunlit crescent, just one day older. As darkness grows, look for "Earthshine" on the "dark" side of the moon, which is facing the Earth. Earthshine is the term for sunlight that has bounced off the other side of our plkanet and fallen across the moon, providing a faint illumination that makes the darkened moon faintly visible. It was Leonardo Da Vinci who first explained the phenomenon.

The moon sets tonight in Baltimore at 9:58 p.m.

Posted by Admin at 3:11 PM | | Comments (1)
Categories: Events

May 9, 2005

Offshore storm kept things breezy here

The windy conditions that prevailed in Maryland all weekend were produced by the counter-clockwise flow around the back side of an intense storm off the Middle Atlantic states. NASA's Terra Earth-observing satellite captured a beautiful shot of the storm, and the Eastern U.S., on Saturday. The storm's center has since moved north and east, off Cape Cod.

Posted by Admin at 11:55 AM | | Comments (0)
Categories: Cool pictures

You heard it here first: No snow 'til October

A bold forecast, no? But your WeatherBlogger will never shy away from tough prognostications when there's hard science behind them, or when they contain the word "snow."

Today, you see, is the latest date on record for snowfall in Baltimore - that trace of snow recorded on May 9, 1923. And the earliest date for the return of the dreaded white stuff is Oct. 9, events recorded in 1895 and again in 1903. Those were just traces. The earliest date on record here for measureable snow is Oct. 10, set in 1979.

In the meantime, we've finally popped into more "normal" May weather, after seven straight May days of abnormally cool temperatures. Mother's Day was the best anyone could have ordered up, a great day to take Mom to the racetrack. (Six of the last nine days of April also were unusually cool.)

The forecast for the week ahead calls for highs in the mid-70s, and lows in the 50s. Normal for this time of year is about 72 for the highs and 50 for the overnight lows. There is a threat of showers and thunderstorms Tuesday and Wednesday. But you don't have to shovel rain. So stow the snow shovels and enjoy.

Posted by Admin at 10:58 AM | | Comments (0)
Categories: Forecasts

May 4, 2005

Frost advisory extended to much of Maryland

Better cover the veggies. The National Weather Service has extended tonight's frost advisories from Cecil County, to most of the state north and west of Baltimore and Washington, D.C. Advisories had already been posted for much of Pennsylvania, Delaware and New Jersey, including most of the Pennsylvania counties along the Mason-Dixon Line.

Thursday morning's forecast low for Baltimore is 39 degrees - warmer than the last few days. Westminster's low could reach 36. The day's high in Baltimore should be near 62 - 8 degrees below normal.

Lots of schools have already turned off their furnaces for the season - a bit prematurely, it turns out. I know at least one teacher who's wearing sweaters to work this week. There must be plenty to chilly children, too.

Posted by Admin at 1:50 PM | | Comments (1)
Categories: Watches and warnings

May off to cool start

The merry month of May is sure off to a cool start. Tuesday morning's low of 34 degrees at BWI matched the record low for the date, set in 1986. And the high - a chilly 60 degrees - was 10 degrees below normal. Lots of places around town saw even lower temps. The weather station on my deck in Cockeysville recorded an overnight low of 32 degrees. Thankfully, the flowers we set out there last weekend got through the night with no fatalities.

Normal highs for May in Baltimore start out at 69 degrees and rise through the month to 79 by the 30th. The normal lows rise from 47 to 57 degrees.

But May can bite. On May 9, 1923, the city noted a trace of snow - the latest snowfall ever recorded on the city's official weather records, which began in 1871. The record low for a May day in Baltimore is 32 degrees, set on May 11, 1966. The record high is 98 degrees, recorded on four different dates, most recently on May 30, 1998.

The driest May on record was in 1986, when barely a third of an inch fell. The wettest was in 1989, when the city saw 8.71 inches of rain.

Posted by Admin at 11:14 AM | | Comments (3)
Categories: By the numbers

Satellite documents Brazil's drought

The value of satellite imagery to agricultural interests and emergency management planners is clear in this intriguing image of Brazil from NASA's MODIS instrument (for Moderate Resolution Imaging Spectroradiometer) aboard its Terra Earth-oberserving satellite.

The image compares the health and density of crops during the past southern summer (our winter) with normal values recorded between 2000 and 2004, for the drought-stricken region of southern Brazil. The tan and brown colors reveal where the greatest shortages of rain have been felt, while green colors represent rainfall surpluses. The region has suffered its worst drought in 35 years.

Posted by Admin at 10:40 AM | | Comments (0)
Categories: Cool pictures

May 2, 2005

April exits mild and a bit dry

Two very warm spells during April at BWI allowed the month to make its exit this weekend a bit warmer than the 30-year norms. It was also a bit drier than normal, although local rainfall amounts might differ considerably.

The month started out close to the long-term averages. But the 6th and 7th were unusually warm, with highs of 84 and 76. The overnight low on the 7th never fell below 60 degrees, boosting the day's average temperature to 18 degrees above normal.

There was another warm spell on the 19th and 20th, with highs both days of 86 degrees at BWI. That pushed the days' averages 14 and 17 degrees above normal, respectively. Not even the cold snap on the 24th - with a high of just 49 - was enough to shove the month's averages below normal.

We finished April with an average temperature of 55 degrees - 2 degrees warmer than the 30-year average. The low for the month was 32 degrees, on the 17th. The high was 86, on the 19th and 20th.

Rainfall for the month came to 2.56 inches. That was a third of an inch below normal. Most of that - 2.06 inches - came in the first three days of the month. The rest of April was relatively dry, with just six more days with measurable precipitation. We had two thunderstorms - one on the 2nd, and another on the 23rd.

The skies were clear on 10 days in April, and cloudy on 10 days. And we all enjoyed that long stretch of delightful spring weather at mid-month - 12 straight days, from the 9th to the 20th, with no rain, highs mostly (10 days of the 12) in the 60s, 70s and 80s, and clear skies (8 days of the 12).

Posted by Admin at 1:29 PM | | Comments (0)
Categories: Almanac

Another cold morning

It was a frosty 35 degrees at the weather station on my deck in Cockeysville this morning. And there was actual frost on the roof of my car. All this on May 2!

The official instruments at Baltimore-Washington International Airport registered a low of 39 degrees. That was 8 degrees below the 47-degree norm for the date, but a few degrees short of the record low - 36 degrees - set there in 1978.

Today marks the first day when the normal highs at BWI reach the 70s. The normal lows will hit the 50-degree mark on the 9th. So we're still struggling to warm up to normal.

Other lows overnight included a 36-degree reading at Frederick Airport, 34 degrees at Martinsburg, 39 at Martin State Airport and out at Dulles in northern Virginia, and 47 near the water in Annapolis.

The forecast calls for partial clearing tonight. That will allow radiational cooling to sink the overnight lows to around 38 degrees - still no record for BWI, but plenty cold enough thank you very much. Looks like the whole week will be stuck below normal, despite some welcome sunshine, with highs in the 60s and lows in the 40s.

Posted by Admin at 12:55 PM | | Comments (0)
Categories: By the numbers

Ask Mr. WeatherBlogger: "What are those bright lights?" reader Henry Katz has obviously been watching the night sky lately. He sends this query:

"What planets are visible in the evening sky about 9:00 PM? One in the middle eastern sky and one low in the southwest sky."

Well Henry, the bright light you've been seeing in the eastern sky during the evening hours for the past month or so is the planet Jupiter. Jupiter was at opposition on April 3, which means it was rising in the east as the sun was setting on the "opposite" side of the sky - in the west. It's the time of year when Earth is closest to Jupiter, which is why is has appeared so big and bright in the evening sky.

We're a month past opposition now, which means Jupiter rises a bit earlier, and appears a bit higher each night. It's getting a little smaller and dimmer, too. But it remains the brightest object in that part of the evening sky (except for the moon), and it is easily visible all night, even in the city. On a clear night, with a good pair of binoculars, you can see as many as four of Jupiter's moons, tiny white dots lined up on either side of the planet. Try it.

The bright object you're seeing in the southwest in the evening is probably the bright star Sirius - the "Dog Star." It's the brightest true star in the sky. It's more familiar on late autumn and winter nights, when it follows the constellation Orion, the Hunter, across the sky. Sirius appears bright because it is relatively close to the Earth - "only" 8.8 light years away. (A light year is the distance light travels in a year - almost 5.9 trillion miles.) These days, Sirius is setting in the southwest around 10 p.m.

In the future, when you need to identify a star or planet, a good place to start is Once you have plugged in your location, this Web site can provide you with an interactive sky chart for any hour of any day. It can also tip you off to passes by the International Space Station and other bright satellites.

Keep looking up!

Posted by Admin at 11:44 AM | | Comments (0)
Categories: Ask Mr. Weatherblogger
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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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