Archive for March, 2007

Palm Sunday Snowstorm of 1942
March 28, 2007

Today is the 65th anniversary of Baltimore’s Palm Sunday Snowstorm, a phenomenal storm that highlights the wide range of weather that is possible as the seasons change in the mid Atlantic states. The following description of the storm was found on the web site of the Batlimore-Washington National Weather Service Office:

March 29-30, 1942: The Palm Sunday Snowstorm dumped the state’s heaviest March snow on record in Maryland. The storm began as rain but changed over to a wet heavy snow. The snow stuck to power lines, trees and shrubs damaging them under its weight. Many of the fruit trees had begun to blossom. Over 20 inches fell over northern Anne Arundel, Howard, Southern and western Baltimore County, Carroll County, eastern and northern Frederick County, and north-central Washington County. Maximum amounts reported were 31 inches at Clear Springs (just 12 days earlier the temperature had reached 79�F here), 32 inches at Westminister, 30 to 36 inches at State Sanatorium (Frederick County) and 36 inches at Edgemont (Washington County). Baltimore City received its greatest snow in 20 years with 22 inches measured. Hagerstown and Westminister reported 22 inches in 24 hours. Frederick had 17 inches in 24 hours. Washington, DC received a total of 11.5 inches of snow.

Tom Tasselmyer


Final Week Of March
March 26, 2007

March is a typically unsettled month. Rain, snow, hot and cold are all possible. Historically, the last week of March has had some notable weather locally.

In 1945 on March 28 & 29 record high temperatures were recorded … 87 and 90 respectively. The 90 degree reading stands as the record high for the month so far.

In 1920 on March 29, a storm dumped 31 inches of snow in a 24 hour period at Clear Spring in Western Maryland.

In 1942 on March 29, the Great Palm Sunday Snowstorm hit Baltimore with 22 inches of snow in a 24 hour period, the record for the month and the 5th biggest snow ever recorded in Baltimore.

The coming week doesn’t look quite as extreme as these events but will be interesting. Temperatures should be at or a little above average for the season and there will likely be a couple of opportunities for some rain, possibly even a thunderstorm.

I can’t pass up mentioning this one additional March oddity. Tuesday and Wednesday will be the third anniversay of the “Brazilian Unnamed Hurricane” It struck coastal areas in the states of Santa Catarina and Grande do Sul. Hurricanes are virtually nonexistent in this part of the world and there was some debate as to whether it was indeed tropical in nature. It had a very clearly defined eye with winds estimated by satellite to range between 74 to 95 mph. The storm made landfall on a somewhat remote, coastal area and there were no weather instruments to take direct measurements of the storm. 300 homes were reported destoyed with 40,000 damaged. There were two reported deaths and numerous injuries. The storm was unofficially dubbed “Catarina”.

So goes the month of March.

John Collins

Spring Temperature Swings
March 22, 2007

You know it’s spring in the mid Atlantic when the temperature roller coaster gets moving. The remnants of winter’s chilly air is still draped along the U.S./Canadian border, close enough to make the occasional push south. Meantime, the strengthening sun and lengthening days make for warmer air masses just south of us. As the jet stream buckles, winter cold can collide with spring warmth and wild temperature swings ensue. Take a look at some of the temperatures contrasts measured at BWI-Marshall airport this month:

March 2nd, high: 62 … March 3rd, low: 29

March 15th, high: 75 … March 16th, low: 29 with snow

March 21st, low: 35 … March 22nd, high: 74

Tom Tasselmyer

Neat Snow Picture
March 18, 2007

Now that the skies have cleared the visible satellite imagery clearly shows where the significant snows fell during the Friday storm. The picture is a Sunday morning image. The only clouds are over the ocean, over northern Pennsylvania up into New York plus a few clouds over West Virginia. Ice clearly shows up on portions of Lake Erie. The rest of the white shaded areas in the picture indicate snow on the ground.

Notice that the white areas are brighter northwest and north of Baltimore. The brighter or more solid the white shading, the deeper the snowpack. Darker shading within the white snow areas indicate heavily forested areas. The Susquehanna River also shows up clearly in the Pennsylvania snowfield. Areas north of the Maryland/Pennsylvania line received 6-12 inches of snow and a few reports came in higher than that.

John Collins

Winter’s Last Gasp?
March 18, 2007

Spring arrives late Tuesday and it is going to be hard to crank up another fullblown winter storm before that so it would appear that this late winter storm is the last …. technically. Of course big snow makers can develop in early spring so we’ll just have to watch the pattern and see what develops. Long range models at the moment do point to another stormy & cold phase developing late in the month but there is a lot of uncertainty this far out.

This latest storm produced it’s biggest snows just west of the I-95 corridor, north of the Baltimore area. The Mid Atlantic region was caught in the early stages of the storm and sleet and rain cut down on the actual snow accumulation. On TV Hill we received .8 inches of snow but the liquid total for the two day event was 2.89 inches.

A sampling of snow totals: Frostburg, 6.5″; Pasadena, .5″; Owings Mills, 2.0″; Manchester, 5.5″; Westminster, 3.8″; Sykesville, 2.4″; Frederick, 7.5″; Bel Air Acres, 1.0″; Savage, 1.7″; Ellicott City, 1.0″; Columbia, .8″.

Think spring!

John Collins

Temperature Drop Begins
March 15, 2007

In downtown Baltimore, at the Maryland Science Center, the temperature reached 76F Thursday afternoon at 1:00pm. As of 7:00pm the temperature had dropped to 47F, falling 29 degrees in six hours! The temperatures may continue to steadily drop through Friday afternoon, bringing winter back with a vengeance. Rain increasing on the cold side of the front may change to snow as temperatures fall through the 30s Friday afternoon. At this point it is unclear how much snow will be able to accumulate on ground that has been warmed by two straight days of 75-83 degree air. Areas that have the greatest potential snowfall Friday, perhaps in excess of 4″, are in northern Baltimore, Carroll and Frederick Counties, where the National Weather Service has issued a Winter Storm Watch. Stay tuned!

Here’s the hourly breakdown of the falling temperatures in downtown Baltimore:
1:00 pm 76F
2:00 pm 69F
3:00 pm 61F
4:00 pm 57F
5:00 pm 52F
6:00 pm 49F
7:00 pm 47F

Tom Tasselmyer

Winter To Summer And Back To Winter
March 14, 2007

Spring is less than a week away (8:07 p.m., March 20th) but we jumped right into summer-like warmth today. BWI-Marshall hit 83F at 1:49 p.m. Wednesday afternoon, establishing a new record high for March 14th. The old record of 81F stood for just 17 years. It was the warmest day around here since last September the 18th when the temperature also peaked at 83F. The last day warmer than today was September the 9th of last year when BWI-Marshall hit 84F.

Those balmy southwest winds will continue through the first half of Thursday, after which a cold front is expected to slide south of Baltimore, shifting winds to the north and ushering in a winter chill. With temperatures slowly falling for almost 24 hours, from Thursday afternoon through much of Friday, rain along the front may change over to sleet and snow Friday afternoon or evening. There is even a chance for some wet snow accumulations Friday night! It’s classic mid Atlantic, season-changing weather chaos…record setting 80s to snowy 30s in just 48 hours! Should be fun to watch.

Tom Tasselmyer

March 11, 2007

We have just experienced a couple of days of very “springlike” weather and we are still a little more than a week away from the official start of spring, Tuesday, March 20, 8:07pm to be precise.

March is a seasonal transition month and is subject to some wild swings in weather. The coldest recorded temperature for the month was +5 degrees in 1923 and the warmest , 90 degrees in 1945. More recently it hit a record 77 degrees on March 10th last year. The biggest snow was a 22 incher on March 29, 1942, coincidentally, three years before it hit that 90 degree reading on the same date.

The “Great Superstorm Blizzard of ’93” struck the East Coast with a vengance on March 13. Snowfall ranged from a foot at Birmingham, Alabama to 43 inches at Syracuse, New York. The Baltimore area received about a foot of snow in that storm and temperatures ran 10-20 degrees below normal for about a week following the storm.

The variability in March weather can be laid largely to increasing hours of sunlight that start a shift in the weather pattern. But snowpack, soil temperature and largescale, multiyear patterns like El Nino all throw kinks and curves into the process. It is one of the toughest months of the year to forecast. Additionally, once folks have had a taste of spring they don’t want to let go and a cold snap or winter storm can be depressing.

Our present warm streak should hold into the middle of the week. A storm system at that time is expected to turn things around. It should be a rainmaker but temperatures will be below average by the end of the week. Enjoy the mild conditions while you can.

John Collins

Satellite View Of Snow Cover
March 8, 2007

Take a look at yesterday’s snowfall from space! Mostly clear skies this morning allowed for a great view of the snow cover in Maryland, Pennsylvania and Virginia on the visible light satellite image. A distinct northwest to southeast line can be seen where the snow cut off. North of the line 1-4″ of snow fell, with locally 6-10″ in the mountains. South of the line little, if any, accumulation occured. The snow cover helped temperatures to tank this morning! Salisbury set a record low, dipping to 8F, breaking the old record of 12 set in 1913. The airport in York Co., PA, near Thomasville, dropped to a frigid -9F. The low at BWI-Marshall was 14, not quite down to the record of 10 set in 1960.

Tom Tasselmyer

Another Clipper
March 7, 2007

It seems this has been the winter of the “Clipper” here in Maryland. We’ve had to deal with a few of these fast moving areas of low pressure that zip in from the northwest. Frequently referred to as “Alberta Clippers” since they commonly originate in Alberta, Canada, they don’t produce the very heavy snow of a storm that tracks up the coast, simply because they are coming from drier territories. A look at the 500 millibar upper level weather chart this morning shows the northwest flow of air that is delivering the clipper and the cold. This system should bring a dry, powdery 2-4″ of snow to many areas of central and eastern Maryland before clearing the coast early this evening. As the storm crosses the Appalachian mountains, the extra lift provided when the air rides up the western slopes, will help to squeeze out a couple more inches for those locations. A nice 5-8″ snowfall seems likely for the ridges of western Maryland, West Virginia and southwest Pennsylvania.

Tom Tasselmyer