Monday, March 2, 2009

Rare, Record-Breaking March Snow Strikes Washington Area

9:30 pm Update: Included final official snowfall amounts for National, Dulles, BWI

PM Update: Storm totals updated at 11:30.

A rare heavy March snowstorm has wound down in the Washington metro area, leaving record daily snowfall amounts for March 2. As the snow was tapering off at 10 am, National Airport was reporting 5" of snow on the ground. The 4.5" falling today was more than enough to break the daily record of 2.1" set in 1994. Other official snowfall amounts were:
Dulles 4.5" (storm total 5.4")
BWI 5.8" (storm total 6.9")
The Dulles amount was slightly short of the daily record of 4.7" in 1994, but BWI broke the 1969 record of 3.7". Blacksburg, VA also set a record with 5.3", surpassing the 0.3" of 2005.

In this outside-the-Beltway location, a total snow depth of 5" was measured. Some storm totals from around the region reported by the National Weather Service as of 11:30 am are listed below.

Image (click to enlarge): NWS snow depth map, via Maryland Weather blog

********************STORM TOTAL SNOWFALL********************

LOCATION STORM TOTAL TIME/DATE COMMENTS
SNOWFALL OF
(INCHES) MEASUREMENT


DISTRICT OF COLUMBIA

...DISTRICT OF COLUMBIA...
NATIONAL ARBORETUM 8.0 900 AM 3/2 COOP
WASHINGTON 7.0 925 AM 3/2 LOGAN CIRCLE AREA
DALECARLIA RESERVIOR 6.0 800 AM 3/2 COOP

MARYLAND

...ALLEGANY COUNTY...
FROSTBURG T 700 AM 3/2 COOP

...ANNE ARUNDEL COUNTY...
LAUREL 2.7 E 8.1 920 AM 3/2
ODENTON 7.5 830 AM 3/2 2.5" IN 90 MINS
LAUREL 7.0 1025 AM 3/2 SPOTTER
PASADENA 7.0 1040 AM 3/2 SPOTTER
ANNAPOLIS 5.8 700 AM 3/2
BALTO/WASH INTL 5.1 835 AM 3/2
DAVIDSONVILLE 4.0 530 AM 3/2
RIVERA BEACH 3.0 600 AM 3/2 COOP
PASADENA 1.5 545 AM 3/2

...BALTIMORE COUNTY...
HUNT VALLEY 6.5 945 AM 3/2 TV METEOROLOGIST
OWINGS MILLS 5.8 854 AM 3/2 SPOTTER
ESSEX 5.5 900 AM 3/2 SPOTTER
RANDALLSTOWN 5.5 800 AM 3/2 SPOTTER
CATONSVILLE 3.0 715 AM 3/2 SPOTTER
BALTIMORE 2.8 700 AM 3/2
TIMONIUM 2.5 700 AM 3/2
TOWSON 2.5 850 AM 3/2 SPOTTER

...CALVERT COUNTY...
PORT REPUBLIC 12.0 830 AM 3/2
PORT REPUBLIC 11.0 925 AM 3/2 SPOTTER
PRINCE FREDERICK 1.4 10.0 700 AM 3/2 COCORAHS
HUNTINGTOWN 9.2 745 AM 3/2 NWS RETIREE
CHESAPEAKE BEACH 8.0 900 AM 3/2 NCEP EMPLOYEE
NORTH BEACH 6.2 1040 AM 3/2 COOP
NORTH BEACH 6.0 840 AM 3/2 SPOTTER

...CARROLL COUNTY...
SYKESVILLE 6.5 1020 AM 3/2
MILLERS 5.5 1000 AM 3/2 COOP
SYKESVILLE 5.0 915 AM 3/2 SPOTTER
TANEYTOWN 4.8 830 AM 3/2 SPOTTER
WESTMINSTER 1N 4.0 800 AM 3/2 0.26 LIQ EQUIV
WESTMINSTER 3.8 1040 AM 3/2 SPOTTER

...CHARLES COUNTY...
WALDORF 9.0 900 AM 3/2 NCEP EMPLOYEE
LA PLATA 7.8 1000 AM 3/2 SPOTTER
WHITE PLAINS 5.6 630 AM 3/2 SPOTTER

...CITY OF BALTIMORE...
BALTIMORE 3.5 800 AM 3/2 CLYBURN ARBORETUM
BALTIMORE 2.5 700 AM 3/2 SPOTTER
BALTIMORE-HAMPDEN 2.1 500 AM 3/2

...FREDERICK COUNTY...
NEW MARKET 6.8 1000 AM 3/2 SPOTTER

...HARFORD COUNTY...
NORRISVILLE 0.2W 6.0 600 AM 3/2 COCORAHS

...HOWARD COUNTY...
COLUMBIA 7.7 900 AM 3/2 3.1" IN 90 MINS-SPOTTER
LAUREL 7.3 1030 AM 3/2 SPOTTER 0.48" LIQ EQUIV
COLUMBIA 6.7 1030 AM 3/2 SPOTTER
COLUMBIA 4.5 720 AM 3/2 NCEP EMPLOYEE
ELLICOTT CITY 3.5 700 AM 3/2 1 MI SOUTH OF US29/US40
COLUMBIA 2.7 500 AM 3/2
ELLICOT CITY 1.4 545 AM 3/2

...MONTGOMERY COUNTY...
DAMASCUS 2.8 SW 6.5 700 AM 3/2 COCORAHS
DAMASCUS 3SSW 6.0 1100 AM 3/2
NORBECK 6.0 755 AM 3/2 2.2" IN 1 HOUR-SPOTTER
OLNEY 6.0 1030 AM 3/2 COOP
SILVER SPRING 5.5 700 AM 3/2 1 N SILVER SPRING
KENSINGTON 5.0 1015 AM 3/2 SPOTTER
MONTGOMERY VILLAGE 4.5 815 AM 3/2 COCORAHS
DAMASCUS 4.2 700 AM 3/2 2.5" IN 2 HRS
SILVER SPRING 3.0 531 AM 3/2

...PRINCE GEORGE`S COUNTY...
OXON HILL 8.5 900 AM 3/2 SPOTTER
BOWIE 8.0 839 AM 3/2 SPOTTER
LAUREL 6.5 800 AM 3/2 SPOTTER
BRANDYWINE 6.4 700 AM 3/2 7 ESE BRANDYWINE
COLLEGE PARK 3.5 730 AM 3/2 SPOTTER

...ST. MARY`S COUNTY...
LEONARDTOWN 11.0 900 AM 3/2 1 NE LEONARDTOWN
HOLLYWOOD 1N 10.5 1120 AM 3/2
RIDGE 9.2 900 AM 3/2 SPOTTER

...WASHINGTON COUNTY...
SMITHSBURG 3.0 730 AM 3/2
SHARPSBURG 5S 0.4 700 AM 3/2 COOP

VIRGINIA

...ALBEMARLE COUNTY...
BLENHEIM 5.0 950 AM 3/2 3 MI SOUTH
CHARLOTTESVILLE 4.0 800 AM 3/2 COOP
EARLYSVILLE 4.0 600 AM 3/2 COOP
CROZET 2.5 815 AM 3/2 15 MI WSW CHO

...ARLINGTON COUNTY...
ARLINGTON 8.0 844 AM 3/2 SPOTTER
ARLINGTON 8.0 730 AM 3/2 SPOTTER
REAGAN NATIONAL 5.1 950 AM 3/2 REAGAN NATIONAL AIRPORT

...AUGUSTA COUNTY...
STUARTS DRAFT 9.3 820 AM 3/2 SPOTTER
SWOOPE 4.5 620 AM 3/2 SPOTTER
VERONA 3.0 500 AM 3/2

...CITY OF ALEXANDRIA...
ALEXANDRIA 8.2 1025 AM 3/2 NWS EMPLOYEE
ALEXANDRIA 1.8 S 5.0 700 AM 3/2 COCORAHS
ALEXANDRIA 4.5 800 AM 3/2 SPOTTER

...CITY OF CHARLOTTESVILLE...
CHARLOTTESVILLE 4.5 830 AM 3/2 TV METEOROLOGIST

...CITY OF FREDERICKSBURG...
FREDERICKSBURG 6.0 725 AM 3/2 SPOTTER

...CITY OF HARRISONBURG...
HARRISONBURG 3.5 405 AM 3/2

...CITY OF MANASSAS...
MANASSAS 5.0 739 AM 3/2 COOP
MANASSAS 4.0 1000 AM 3/2

...CITY OF STAUNTON...
STAUNTON 5.5 800 AM 3/2 MEDIA

...CITY OF WINCHESTER...
WINCHESTER 0.4 700 AM 3/2 COOP

...CLARKE COUNTY...
BERRYVILLE 0.5 940 AM 3/2 SPOTTER

...CULPEPER COUNTY...
BOSTON 3.5 731 AM 3/2 COOP

...FAIRFAX COUNTY...
DUNN LORING 7.0 800 AM 3/2 COOP
RESTON 7.0 850 AM 3/2 SPOTTER
BURKE 6.5 1000 AM 3/2
CENTREVILLE 6.5 755 AM 3/2
NORTH SPRINGFIELD 6.5 930 AM 3/2 NWS RETIREE
HERNDON 6.3 920 AM 3/2 NWS EMPLOYEE
MERRIFIELD 6.0 1045 AM 3/2 NWS EMPLOYEE
HERNDON 4.8 830 AM 3/2 NWS EMPLOYEE
IDYLWOOD 2.5 530 AM 3/2 NWS EMPLOYEE

...FAUQUIER COUNTY...
REMINGTON 5.5 NNE 5.0 750 AM 3/2 COCORAHS
WARRENTON 5.0 800 AM 3/2 COOP

...KING GEORGE COUNTY...
KING GEORGE 8.2 830 AM 3/2 SPOTTER

...LOUDOUN COUNTY...
ASHBURN 5.0 630 AM 3/2 NWS EMPLOYEE
STERLING NWS/WFO 5.0 1040 AM 3/2 NWS STERLING WFO
ASHBURN 4.0 645 AM 3/2 1 NE
DULLES AIRPORT 3.7 900 AM 3/2
BLUEMONT 3.0 800 AM 3/2 NWS RETIREE
MIDDLEBURG 0.5 558 AM 3/2

...MADISON COUNTY...
HAYWOOD 3.8 645 AM 3/2 COOP

...NELSON COUNTY...
FABER 9.0 800 AM 3/2 SPOTTER
LOVINGSTON 7.6 800 AM 3/2 SPOTTER

...ORANGE COUNTY...
ORANGE 4.6 800 AM 3/2 COOP

...PAGE COUNTY...
LURAY 2.0 700 AM 3/2 COOP

...PRINCE WILLIAM COUNTY...
HAYMARKET 2.8 730 AM 3/2 SPOTTER

...RAPPAHANNOCK COUNTY...
CASTLETON 1.5 703 AM 3/2 COOP

...ROCKINGHAM COUNTY...
ELKTON 5.0 545 AM 3/2
DALE ENTERPRISE 2.0 700 AM 3/2 COOP

...SHENANDOAH COUNTY...
EDINBURG 1.5 700 AM 3/2 COOP
WOODSTOCK 1.3 700 AM 3/2 COOP

...SPOTSYLVANIA COUNTY...
SPOTSYLVANIA 6.0 800 AM 3/2

...STAFFORD COUNTY...
STAFFORD 9.5 1000 AM 3/2 SPOTTER

...WARREN COUNTY...
FRONT ROYAL 2.0 600 AM 3/2 COOP

WEST VIRGINIA

...GRANT COUNTY...
BAYARD T 645 AM 3/2 COOP

Sunday, March 1, 2009

Virtual Snow Machine

With the winter winding down, many snow fanboys in the Washington metro area are bitterly disappointed as what was advertised to be a major snowstorm today appears to be seriously underperforming, especially west of the I-95 corridor. If you're feeling cheated by the ongoing snow drought, or if you just want to learn more about the precipitation process, Steve Ackerman and Tom Whittaker of the University of Wisconsin have a very slick Java applet for teaching precipitation types based on the distribution of temperature and humidity. Drag around the temperature (green line) and dew point (yellow line) and see how that affects the type and amount of precipitation, if any, reaching the ground. See if you can produce all 7 possible precipitation types. If you thought precipitation forecasting was just watching radar blobs move around, this tool shows there is much more going on in the third dimension.

Image (click to enlarge): Example from precipitation type applet by University of Wisconsin

This Just In: Irony Not Dead
Blog Reports Winter Not Yet Over!

A coalition of 90 environmental groups has called for a demonstration called Capitol Climate Action on Monday to protest the coal-fired Capitol Hill power plant in Washington. (This event is not affiliated with CapitalClimate; note the subtle spelling difference.) The cold-weather blog, where all the news is numb and number, has wasted no time in pointing out that the region is under a Winter Storm Watch calling for as much as 8" of snow. While March snows are rare in the Nation's Capital (4" or more on a single day occurring about once a decade), the March daily record of 11.5" was set as late as the 29th of the month in 1942.

Clearly, any specific weather event is not indicative of a trend, and a rare event is even less indicative. Any Fellow of the American Meteorological Society should know better than that. As far as temperatures are concerned, here are the Washington monthly average temperatures for this winter relative to the long-term "normal":
December +0.8°
January -3.3°
February +1.7°
For the country as a whole (only about 3% of the earth's surface), the last 90 days have averaged predominantly above normal. (Note that the map projection exaggerates the area of the northern regions.)

Image (click to enlarge): 90-day temperatures and departures from average, from Climate Prediction Center/NWS/NOAA

New February Precipitation Records in Washington, Baltimore

With only 0.04" of precipitation falling as light snow and sleet in the last few hours before midnight, the February total of 0.35" is a new record low for the month in Washington, DC. The old record since records began in 1871 was 0.42" in 1978. The chart shows the 10 driest Februaries since 1871. The monthly total has been below 1" only 3 additional times, 1872, 1974, and 1925.

At Dulles Airport, the 0.36" for February was above the 0.25" of 1978. However, the 0.01" before midnight at BWI Airport brought the monthly total to 0.26", breaking the previous Baltimore record of 0.36" in 2002.

Image (click to enlarge): CapitalClimate chart from NWS data, background photo © Kevin Ambrose

Seasonal Outlook

Latest seasonal forecast: Click here.


Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.