Archive for December, 2007

Some Snow for the Year’s End
December 30, 2007

Late Saturday a wave along a cold front in the southeast U.S. is developing into the next storm targeted for the Mid Atlantic region. Unlike the Friday night rainmaker, the developing storm will be moving into a colder air mass and there is a potential for a wintery mix of precipitation across the area.

Most of the significant snow with this storm will be in Pennsylvania, northeastward into New England but minor accumulations are possible with a mix of sleet and snow north & northwest of I-95 in Maryland. All rain is most likely south and east of I-95.

A first guess would allow for trace to one inch accumulations of snow/sleet in the immeditate Baltimore metro area with a potential of up to 2 inches of snow near the Maryland/Pennsylvania line.

John Collins

Christmas In Baltimore
December 24, 2007

Weatherwise, it looks like Christmas in Baltimore this year will be rather quiet. No storms are in the forecast and temperatures will be at or slightly above the seasonal average. At Christmastime high temperatures are generally in the mid 40s and lows in the mid 20s.

Big snows have been snarling Christmas travel in the Midwest but it will not be an issue in Baltimore this year and that is usually the case. Historically, the biggest Baltimore snowfall on Christmas Eve was in 1966 with 8.4 inches. The record Christmas Day snowfall 9.3 inches in 1909.

The 1909 storm started on December 25th and extended into the 26th. National Weather Serevice archives note that Maryland was on the southern edge of the storm. The Upper Eastern Shore received over a foot and a half of snow. A band of 25 inch snowfall stretched from Sudlersville in Queen Annes County to Dover, Delaware. Towson received 16 inches of snow. Baltimore ultimately recorded 10 inches of snow over the two day period.

The previous year, another significant snow hit the area just before Christmas. On December 22 and 23 of 1908, a storm dumped 7.4 inches of snow in Baltimore.

Back in 1839 a pre Christmas blockbuster hit the region. National Weather Service archives show that central and northeast Maryland received a very heavy snowfall on December 22 and 23. Baltimore received 16 inches of snow, mixed with sleet and rain and Frederick was hit with 2 feet of snow. Roads around Baltimore and Washington were blocked for two days.

This year we will have to settle for visions of sugarplums dancing in our heads.

From the weather team at WBAL-TV InstaWeather Plus … have a very, merry Christmas!

Tom Tasselmyer, John Collins, Neal Estano, Sandra Shaw and Jay Kendrick

Wet Not White This Year
December 21, 2007

The storm producing snow from Denver south to Albuquerque with blizzard warnings east into Kansas tonight will actually pump warmer air into the eastern United States by Sunday. The warm-up means we will likely have a wet, not white last weekend before Christmas around Baltimore. So who will have the white Christmases this year? The National Snow Analysis produced by the National Operational Hydrologic Remote Sensing Center, I kid you not, that is the name of this government group (NOHRSC for short), indicates snow in the typically snowy places on the eve. of the winter solstice (1:08 a.m. e.s.t. Saturday): Rocky mountains, upper Midwest, great lakes and New England. Some sample snow depths:

Portland, ME: 16″
Buffalo, NY: 6″
Minneapolis, MN: 5″
Chicago, IL: 2″
Denver, CO: 4″
Boise, ID: 1″
Lake Tahoe, NV: 17″

Once the weekend storm passes, colder air will settle in for the second half of next week, possibly supplying the chill needed to create a couple winter weather threats for Maryland.

Tom Tasselmyer

A Different December…2007 vs. 2006
December 19, 2007

Seeing the record high for the 18th of December listed at 72, set just last year, made me realize what a different December we’re having in 2007 compared to 2006. Through the first 18 days of the month, the contrasts between this December and last December are striking. Here are some statistics that point to the differences (all stats from BWI-Marshall):

Days with temperatures in the 70s:
2006: 2
2007: 0

Days with temperatures in the 60s or higher:
2006: 5
2007: 0

Days with temperatures in the 50s or higher:
2006: 12
2007: 5

Average temperature:
2006: 42.2
2007: 36.4

Snowfall:
2006: Tr.
2007: 4.8″

Total precipitation:
2006: 0.22″
2007: 2.26″

While temperatures may trend upward heading into the weekend, a cold front is expected to move through the area Sunday night, dropping temperatures back to normal or below normal levels heading into the final week of the month. If the forecast holds, this may end up being the first colder than normal month since April.

Tom Tasselmyer

Nor’easter Slams The Northeast
December 18, 2007

The weekend storm exploded, as expected, on its move north from North Carolina to Maine, with the central pressure dropping from 1008 millibars at 11:00 p.m. Saturday evening to 969 millibars by 11:00 p.m. Sunday evening, a 39 millibar drop in 24 hours, qualifying this nor’easter for “bomb” status (a meteorological “bomb” is a storm whose central pressure lowers by at least a millibar per hour for 24 hours). However, with the track of the storm just inland, instead of off the coast, warmer air was able to work farther west, preventing sleet and snow from getting a foothold in central or eastern Maryland. Areas far enough north and west, however, were pummeled with heavy snow and the strong winds created as the storm intensified along the coast of Maine Sunday night reached all the way down the coast to us here in Maryland. As of early Monday morning, reports from the National Weather Service indicate the following extremes of snowfall and wind gusts from the storm:

Snowfall:
Peru, NY: 18.4″
West Topsham, VT: 18.0″
Walden, VT: 16.0″
Saranac Lake, NY: 15.5″
Newark, NY: 15.0″

Wind Gusts:
Mount Washington, NH: 86 mph
Cutler, ME: 68 mph
BWI-Marshall Airport: 61 mph

The huge storm is pulling farther away and high pressure will bring quiet weather for a couple days, but the first big storm of the season is in the books and winter hasn’t even officially started yet! The winter solstice arrives on Dec. 22nd at 1:08 a.m. e.s.t.

Tom Tasselmyer


Developing Nor’easter
December 16, 2007

The weekend storm is developing much as anticipated. The only adjustment to the forecast over the past day or two is a shift in the type of precipitation from an emphasis on snow and ice to an emphasis on freezing rain and rain. Each forecast model run has leaned toward bringing warmer air in ahead of the storm, shifting the forecast toward a wetter solution over the area.

Temperatures Saturday at ground level remained in the mid 30s most of the day but just a few hundred feet up readings hovered at or below freezing. This is a formula for snow or sleet. The upper air sounding at Dulles Airport Saturday evening showed that temperatures are beginning to rise above the freezing point between an altitude of 1-3 kilometers.


SKEWT data courtesy NOAA

Computer models indicate that this trend will continue into Sunday as the storm shifts to the coast and intensifies.

Explosive growth of the storm is expected as it moves north along the coast. This will prove to be more of a problem for New England than the Mid Atlantic region. Interior portions of the Northeast will likely receive a second significant snow in a week’s time.


Map courtesy NOAA

Around the Chesapeake Bay the storm will be more of a rainmaker although freezing rain and sleet may result in some light icing during the predawn hours on Sunday. During the storm’s intensification Sunday, winds will increase but rain chances diminish as the storm pulls north.

John Collins

Hurricane Outlook
December 16, 2007

The first outlook for the 2008 hurricane season is out. The Colorado State University team led by Philip J. Klotzback and professor emeritus William J. Gray have produced their 17th annual forecast and it contains no real suprises.

The Atlantic Basin remains in the middle of a long term statistical cycle of increased tropical storm and hurricane activity. The past two seasons experienced a dip in storm activity but in the long term, climatology points toward an active season.

The forecast ….

Named Storms … 13
Hurricanes … 7
Intense Hurricanes … 3

There are many qualifiers in this long range forecast. They are spelled out in a 28 page report that is available at …

http://hurricane.atmos.colostate.edu/Forecasts

John Collins

Weekend Bombogenesis?
December 13, 2007

The American Meteorological Society’s Glossary of Meteorology defines a meteorological “bomb” as: bomb—An extratropical surface cyclone with a central pressure that falls on the average at least 1 mb per hour for 24 hours. In other words, a rapidly intensifying low pressure system that seems to explode on the weather charts! “Bombs” in the mid Atlantic region are primarily coastal nor’easters that form as cold, polar air and strong upper level winds interact with the warmer, moist air over the ocean. For several computer model cycles, a “bomb” has been forecast to develop this weekend. A look at the forecast maps from NOAA’s Global Forecast System model shows a low pressure system over North Carolina with a central pressure near 1002 mb Saturday night. “Bombogenesis (the creation of bomb) is then forecast with this system as it races up the coast to a position off the coast of Maine with a central pressure of 978 mb late Sunday night. Without a deep arctic air mass in place, the strong northeast winds generated by the intensifying storm will likely pull warmer air farther inland, creating a wind swept rain for many areas along or east of I-95. Farther west, however, this storm may produce some heavy snow. If this track and intensity forecast verify, Baltimore may see a period of snow and sleet before the change to rain Saturday night. Cold air and gusty winds on the backside of the storm could change the rain back to snow Sunday morning. In the mountains of western Maryland this storm could easily dump 15” of snow. Rain or snow, this looks to be the first “Bomb” of the winter of ’07-’08! Stay tuned to WBAL-TV 11 , WeatherPlus on WBAL-DT 11-2 or here no wbaltv.com for updates as the storm approaches.

Tom Tasselmyer

Unsettled Weather Continues
December 12, 2007

A steady stream of moisture and unsettled weather continues to stretch from the Plaines States into the Mid Adlantic and Northeast States. All indications are that this situation will continue into the weekend.

Forecast models have been pointing toward the possibility of a relatively strong storm developing near the Mid Atlantic coast this weekend.



The NOAA maps above show the storm’s anticipated positions for Saturday and Sunday as of Wednesday morning.

The storm will be wedged between warm & cold air masses and is expected to strengthen as it nears the ocean. It is too early to nail down a specific track but some areas of the Mid Atlantic Region could get windy conditions and some ice and snow.

Something to keep an eye on. Check in with WBAL-TV for updates on TV-11, Insta-Weather Plus and wbaltv.com.

John Collins

GOES Satellite Update
December 12, 2007

NOAA has announced that problems with GOES-12, the normal “east satellite”, have been resolved. Final orbit adjustments will be made and the satellite is expected to go back into full service on December 17.

On that date, GOES-10 will be returned to its normal mode with coverage emphasizing South America.

John Collins