Archive for April, 2007

Chilly April
April 29, 2007

April is drawing to a close and 2007 will go down in the record books as a chilly one but not a record breaker. A survey of National Weather Service records for Baltimore from April 1-27 shows that this April is the 15th coolest on record with an average temperature of 50.2 degrees.

With the exception of April 2, when it hit 80 degrees and April 3 when it hit 69 degrees, daily high temperatures at BWI-Marshall Airport were were stuck in the 40s and 50s through April 19. This was followed by a six day spell of above average temperatures with highs in the 70s and 80s. It looks like we will finish out the month with temperatures at or a bit above average.

Spring has gotten off to a slow start but with longer days and higher sun angles, it can’t help but warm up from this point on … at least in theory.

John Collins


The Flip-Flopping Weather of ’07
April 28, 2007

In just three days the first 1/3rd of 2007 will be in the record books and so far it has been a year of weather flip-flopping. The year started with an unusually warm January which was followed by a an unusually cold February. In fact, the two months perfectly balanced each other with January 6.4F warmer than normal and February 6.4F colder than normal. March then flipped back to the warm side and April, so far, has been a bit cooler than normal. Here’s the scoop on average temperatures for each month of 2007 so far:

January: 38.7F 6.4F above normal
February: 29.1F 6.4F below normal
March: 45.1F 1.4F above normal
April: 49.9F 2.7F below normal (through 4/27)

So, will May keep the pattern going? The official 30 day outlook for May 2007 from the Climate Prediction Center shows an equal chance of warm or cold weather around here.

Tom Tasselmyer

One More Day!
April 23, 2007

Looks like we get one more day of really fine weather before changes move in. Friday and Saturday highs in the 70s brought some relief from 40 and 50 degree high temperatures that have dominated the April weather scene. Sunday we broke into the 80s, only the second time to do that this month.

Changes are on the way though. A cool front will slip into the area Tuesday morning. Rain chances are low with it but the problem is that it will stall out over the region for a few days. It will allow for a wide range of temperatures from Pennsylvania to Southern Maryland and will serve as a focal point for weather disturbances moving in from the west. Forecasting the details of the weather, especially Wednesday through Friday, will be challenging. Timing of impulses and the position of the wavering front will be critical in temperature and rainfall forecasts. Suffice it to say that it will be cooler and cloudier by mid week with a couple of periods of rain likely for the second half of the week.

The first part of April was unusually chilly but the weather we expect this week is fairly typical of the variability that April weather delivers.

John Collins

Unprecedented April Chill
April 19, 2007

A month into spring and the chill has been hard to shake in the mid Atlantic states. In fact, the National Weather Service reports the period from April 5th through the 17th was the coldest on record for Baltimore. The average temperature of 42.2F for the period was more than a degree colder than the previous record of 43.7F set back in 1907.

For the month, as a whole, it has been cloudy, cold and wet. The average temperature so far is running 6 degrees below normal with precipitation 2.64″ above normal. Only 2 of the first 19 days this month have been sunny.

A big change is on the way for the weekend. As high pressure builds into the region Friday, clearing skies and warmer temperatures will arrive in time for the weekend.

Tom Tasselmyer

Spring Nor’easters
April 14, 2007

Another big storm is headed this way for the weekend, which will only add to the chilly, windy and wet April we’ve had so far. The storm, as shown on this water vapor image, is coming from the south and west and is expected to intensify on the mid Atlantic coast as a full blown April nor’easter by Sunday. It may seem strange to have a major nor’easter track through the area this late in the season, but a look back through the history books, as detailed on the web site of the Baltimore-Washington National Weather Service Office, shows spring nor’easters have made some big headlines around here in years past. Here’s a rundown of the notable nor’easters that brought winter-like conditions to Maryland in April and May:

May 4, 1774: George Washington records snow showers at Mt. Vernon in Virginia, likely occuring in Maryland too.

May 8, 1803: Snow reported in Washington, D.C.

April 9, 1884: Snowfall of 8″ reported in Baltimore.

April 10-12, 1894: Nor’easter dumps heavy snow on Maryland: Fallston: 24″, Baltimore: 5″

April 3, 1915: Big nor’easter produces heavy snow on the eastern shore: Sudlersville: 15″, Salisbury: 10″. West of the bay Baltimore records 4.5″. Winds of 30-35 mph produce near blizzard conditions.

April 8-9, 1916: Second year in a row with a major April snowstorm in Maryland. Darlington: 12″, Towson: 9″, Laurel: 8″, Union Bridge: 8″, Baltimore: 5″, Rockville: 4″

May 9, 1923: Latest snow ever officially recorded in Baltimore: trace. 2-3″ fall in Garrett Co.

April 1, 1924: Nor’easter produces heavy April Fool’s snowfall…Westminster: 10″, Freeland: 10″, Frederick: 10″, Baltimore: 9.5″, College Park: 9″, Aberdeen: 8″

April 27-28, 1928: Incredible heavy mountain spring snowfall: 25-30″ in the Allegany mountains with 16″ reported at Oakland, MD.

May 23, 1931: Very late season cold snap produces flurries in the mountains.

The weekend’s storm will likely produce mainly rain and wind around Baltimore through Sunday, but as the storm is moving up toward New England, colder air sweeping in might produce some wet snow showers. In the higher elevations to our north and west, some significant late season snow is possible. We’ll have to wait and see if this storm rates among the notable spring nor’easters listed above.

Tom Tasselmyer

Stormy Outlook
April 12, 2007

A big spring storm will be pulling away from the Mid Atlantic region on Thursday while another storm develops out west. It is the second storm that could get interesting. Computer model indications point to the development of a ‘noreaster this weekend.

As the storm develops over the next couple of days out west, snow could be an issue in parts of Colorado, Kansas and Nebraska with the potential for up to a foot. This would be unusual for so late in the season.

The storm is expected to hit the Mid Atlantic coast Sunday and deepen rapidly. High pressure over eastern Canada will likely hold the storm off shore through Monday before it can finally pull away. There will be plenty of cold air behind the storm and snow is likely in interior portions of New England and the Great Lakes. Higher elevations northwest of Baltimore may even get a few wet snow flakes mix with rain.

Of course the storm is a couple of days away and a lot can happen to change the outcome so check in with Tom, Neal & Domenica for the latest updates the rest of this week. I’ll be here this weekend to track whatever comes through.

John Collins

Record Broken
April 10, 2007

After five days of temperatures running 10-20 degrees below the seasonal average a record low temperature was finally broken at BWI-Marshall Airport.

The temperature dropped to 26 degrees in the 6:00am hour on Monday, breaking the previous record low of 28 degrees set in 1917. The high temperature Monday was held to only 47 degrees due to the continuous NW flow of air out of Canada and a sun blocking cloud deck.

It appears we are turning the corner though. A more zonal (west to east) pattern is setting up and that should moderate the temperatures in the days ahead. Readings will still be on the chilly side of normal but be much closer to that magic number than we have been in the past several days.

John Collins

April Snow
April 8, 2007

Snowfall in April is not exactly rare but it is a bit unusual. The Saturday morning snowfall was generated by a “clipper-type” system that is more common in January or February. Clippers generally don’t carry much moisture and this most recent storm was no exception. The ground was relatively warm and much of the snow melted on contact but a few areas experienced a rate of snow that outstripped the effect of melting.

A sampling of area snow totals: BWI/Marshall, .2″; Crofton, .4″; Kingsville, .2″; Lusby, 2″; La Plata, 1.5″; Jessup, .5″; Columbia, .4″; Elkridge, .4″; Takoma Park, .8″; Olney, .5″; Greenbelt, .5″; Bowie, .3″; Leonardtown, 4″; Patuxent River NAS, 3″; Salisbury, 1″.

National Weather Service records show that snow has been measured on April 7 only one other time in Baltimore since records have been kept with .2″ in 1972. That means that Saturday’s snowfall tied the record for the date. The all-time record snow in April fell in 1924, on the first and measured 9.4″. The records also show that at least a trace of snow has been measured on all but seven days in the month.

John Collins

Arctic Air in April
April 5, 2007

Low pressure consolidating over Quebec and New England will combine with high pressure moving south from the polar regions of northern Canada to bring an arctic blast into the mid Atlantic states just in time for Easter weekend. Spring break for many students in the area will feel more like winter as brisk west to northwest winds create wind chills in the teens and twenties. This will likely be the coldest April air in 4 or 5 years. The lowest temperatures at BWI-Marshall over the last few Aprils:

2006: 33F on April 10th
2005: 32F on April 17th
2004: 29F on April 6th
2003: 27F on April 1st
2002: 26F on April 7th

Record lows may also be threatened through the weekend. Here are the record lows for the next few days and the year they were established:

April 6th: 26F in 1878
April 7th: 22F in 1982
April 8th: 26F in 1982
April 9th: 28F in 1917

Along with the cold, snow flurries are expected to move through the area from time to time. A weather disturbance in the upper atmosphere will track south of Maryland Friday night and it might be strong enough to produce widespread snow showers Friday night into Saturday. The last time we had snow accumulations in April was in 2000 when 0.2″ was measured at BWI-Marshall.

Bundle up! Temperatures should start to moderate by about the middle of next week.

Tom Tasselmyer

Worst Tornado Outbreak in U.S. History
April 3, 2007

Thirty three years ago the worst tornado outbreak in U.S. history exploded across 13 states and Ontario Canada. In terms of the number of tornadoes, combined path length and damage, the April 3-4, 1974 outbreak was the worst on record. The 148 tornadoes touched down and traveled across some 2,500 miles killing 330 people and injuring 5,477 others. One particularly hard hit town was Xenia, Ohio where the tornado pictured here struck on April 3, 1974 destroying more than 1000 homes, killing 30 people and injuring 1,100. The widespread outbreak saw tornadoes touch down from near the gulf coast, north to Canada and from Virginia, west to Illinois with 48 of them producing fatalities. There were 7 tornadoes rated F5, the top of the Fujita Damage Scale, and 23 more were rated F4. According to the National Weather Service’s Storm Prediction Center, this was one of only two outbreaks with over 100 confirmed tornadoes, the other being with Hurricane Beulah in 1967 (115 tornadoes). The Public Affairs Office of the National Oceanic and Atmospheric Administration has a website with more information on this historic outbreak: April 3-4, 1974 Tornado Outbreak

Tom Tasselmyer