Windiest weather in Washington since Superstorm Sandy: Why?


Strong winds take down newspaper containers in the District Wednesday night (Angela N via Flickr) .

Since Wednesday afternoon, winds in Washington, D.C. metro region have raged, gusting consistently over 30 mph, with peak gusts in the 50-60 mph range. These punishing winds have ripped off roof shingles, torn off siding, knocked down fences, signs and garbage cans, downed trees, and led to thousands of power outages (at peak over 50,000).

Link: Local storm reports (National Weather Service)

These are strongest winds to lash the area since Superstorm Sandy in late October, 2012. The explanation for this wind storm is simple: the atmospheric pressure has been changing dramatically due to the approach and passage of a vigorous March storm – the same storm which dumped over a foot of snow in the interior Northeast and brought blizzard conditions to Buffalo.


Snowfall totals from storm. (National Weather Service)

Wind is created by pressure differences in the atmosphere. It will escalate both when the pressure is rapidly falling ahead of a storm and rising in its wake.

At Dulles Airport, wind gusts ramped up abruptly as pressures began to tank Wednesday afternoon as the intensifying storm raced towards the region. The first strong gust – clocked at 48 mph – occurred at 1 p.m. yesterday afternoon when the rate of atmospheric pressure falls increased from 1 to 2 millibars per hour.


Dulles wind gusts – noon Wednesday to 10 a.m. Thursday
Weather map at 5 p.m. Wednesday when low pressure was making closest approach to D.C. region and winds diminished briefly (National Weather Service)
Weather map at 5 p.m. Wednesday when low pressure was making closest approach to D.C. region and winds diminished briefly (National Weather Service)

As the storm center drew close in the evening and the pressure plateaued – around 7 p.m., the winds died down a bit – similar to what happens in the eye of a hurricane. Not coincidentally, the minimum pressures measured in the region were in the 983-984 mb range – which is similar to that of a category 1 hurricane. By comparison, superstorm Sandy’s minimimum pressure measured locally was around 965 mb (964 mb in Baltimore – lowest on record there)

After the storm center zipped off to the northeast and its trailing cold front passed, pressures rose at an astonishing rate of 3 to 4 mb per hour, between around 8 and 11 p.m. It was during this time window that the “wall of wind” battered the region, with those howling, window-rattling 50-60 mph gusts.


Pressure changes over 3-hour period ending at 10 p.m. Wednesday night. Red and magenta areas show large increases, coincident with “wall of wind”. (Unisys Weather)
Weather map at 8 a.m. Thursday morning shows low pressure exiting offshore New England, with high pressure in the Midwest building east. The difference in pressure between these two weather systems is resulting in strong winds over the eastern U.S. (National Weather Service)
Weather map at 8 a.m. Thursday morning shows low pressure exiting offshore New England, with high pressure in the Midwest building east. The difference in pressure between these two weather systems is resulting in strong winds over the eastern U.S. (National Weather Service)

Overnight and into this morning, the rate of the increase in pressure has stabilized. Nevertheless, there remains a strong pressure gradient – or difference in pressure over small geographic area – which is sustaining gusts in the 35-50 mph range. The weather map to the right shows this pressure gradient – with very low pressure associated with the storm off the coast of New England contrasting with the strong high pressure system over the Midwest building east.  Whenever you see the brown lines – known as isobars (lines of equal pressure) – tightly packed together, that means pressures are changing markedly over a small distance and indicative of strong winds.

Once the Midwest high pressure system nears the East Coast, winds will diminish from west to east – starting this evening. Until then, hold onto your hats. The worst of the winds are over, but 30 mph+ gusts will stick around through the afternoon. As of 11 a.m., Dulles’ winds have been gusting over 30 mph for 15 straight hours. (Note: I see the National Weather Service has discontinued the wind advisory — progress).

List of peak winds from the National Weather Service

***********************PEAK WIND GUST***********************

LOCATION             MAX WIND     TIME/DATE   COMMENTS
                        GUST            OF
                         MPH    MEASUREMENT

DISTRICT OF COLUMBIA

...DISTRICT OF COLUMBIA...
   1 NE REAGAN NATIONAL    49   818 PM  3/12  BUOY

MARYLAND

...ANNE ARUNDEL COUNTY...
   1 N BALT-WASH INTL A    53   823 PM  3/12  ASOS
   2 NE LAKE SHORE         49   824 PM  3/12  MESONET
   2 N NORTH BEACH         49   830 PM  3/12  BUOY
   1 NW SHADY SIDE         47   833 PM  3/12  MESONET
   2 SW FORT MEADE         45   845 PM  3/12  AWOS
   4 SE UPPER MARLBORO     40   930 PM  3/12  NERRS STATION

...ANZ531...
   4 S MIDDLE RIVER        51   821 PM  3/12  BUOY
   9 SE MIDDLE RIVER       47   306 AM  3/13  BUOY

...ANZ532...
   1 E BAY RIDGE           49   316 AM  3/13  BUOY
   1 SE EASTPORT           46   303 AM  3/13  BUOY

...ANZ533...
   3 E CALVERT CLIFFS      46   918 PM  3/12  BUOY

...ANZ537...
   2 WSW PINEY POINT       53   636 AM  3/13  BUOY
   1 WSW POINT LOOKOUT     47   340 AM  3/13  BUOY

...ANZ538...
   3 W SPARROWS POINT      51   354 AM  3/13  BUOY
   1 S FELLS POINT         44   848 PM  3/12  BUOY

...ANZ543...
   13 SE FISHING CREEK     56   535 AM  3/13  BUOY

...BALTIMORE COUNTY...
   1 N BALTIMORE MARTIN    52  1115 PM  3/12  AWOS
   1 NW REISTERSTOWN       46   805 PM  3/12  CO-OP OBSERVER
   1 WSW GLYNDON           46   810 PM  3/12  TRAINED SPOTTER

...BALTIMORE CITY...
   GWYNN OAK               51   804 PM  3/12  MESONET
   1 NNE CARROLL           46   249 PM  3/12  MESONET

...CARROLL COUNTY...
   4 NE MILLERS            57   822 PM  3/12  CO-OP OBSERVER
   2 N WESTMINSTER         46   735 PM  3/12  AWOS
   3 NNW GAITHER           44   714 PM  3/12  COCORAHS

...FREDERICK COUNTY...
   2 SW FLINT              66   750 PM  3/12  KRSP AWOS
   2 ESE FREDERICK         43  1035 PM  3/12  AWOS

...MONTGOMERY COUNTY...
   2 N GERMANTOWN          54   124 PM  3/12  MESONET
   1 W LANGLEY PARK        53   759 PM  3/12  MESONET
   2 ESE MONTGOMERY VIL    51   755 PM  3/12  AWOS
   1 ENE WASHINGTON GRO    46   124 PM  3/12  MESONET

...PRINCE GEORGES COUNTY...
   1 E MORNINGSIDE         55  1058 PM  3/12  AWOS
   1 SSW BERWYN HEIGHTS    45   755 PM  3/12  AWOS

...ST. MARYS COUNTY...
   2 W SAINT INIGOES       50  1055 PM  3/12  AWOS
   2 ENE PATUXENT RIVER    47   401 AM  3/13  AWOS

...WASHINGTON COUNTY...
   1 E HAGERSTOWN          54   749 PM  3/12  MESONET
   1 NE MAUGANSVILLE       50   726 PM  3/12  ASOS

VIRGINIA

...ALBEMARLE COUNTY...
   1 NNW HOLLYMEAD         48   925 PM  3/12  ASOS

...ANZ536...
   2 SE DAHLGREN           56  1235 AM  3/13  BUOY

...ANZ543...
   8 E SMITH ISLAND        55   433 AM  3/13  BUOY
   1 WNW SMITH ISLAND      47   518 AM  3/13  BUOY

...ARLINGTON COUNTY...
   1 S REAGAN NATIONAL     52   912 PM  3/12  ASOS

...AUGUSTA COUNTY...
   3 NNW GREENWOOD         54  1013 PM  3/12  SAWMILL RIDGE RAWS
   3 WSW MOSCOW            52   540 PM  3/12  MESONET

...CITY OF ALEXANDRIA...
   1 SE BAILEYS CROSSRO    54   749 PM  3/12  MESONET
   1 W ALEXANDRIA          42   908 PM  3/12  TRAINED SPOTTER

...CITY OF MANASSAS...
   3 SW MANASSAS           46   915 PM  3/12  AWOS

...FAIRFAX COUNTY...
   1 ESE NEWINGTON         54   911 PM  3/12  AWOS

...FAUQUIER COUNTY...
   1 SE MIDLAND            46  1015 PM  3/12  AWOS

...FREDERICK COUNTY...
   2 SE WINCHESTER         53   635 PM  3/12  AWOS
   2 E STEPHENS CITY       50   609 PM  3/12  TRAINED SPOTTER

...LOUDOUN COUNTY...
   1 NNE DULLES INTERNA    61   912 PM  3/12  ASOS
   ASHBURN                 55   911 PM  3/12  NWS EMPLOYEE
   2 ENE LOVETTSVILLE      54   758 PM  3/12  MESONET
   2 SSW LEESBURG          53   815 PM  3/12  AWOS
   2 WSW LOVETTSVILLE      53   711 PM  3/12  MESONET
   PURCELLVILLE            50   635 PM  3/12  TRAINED SPOTTER

...ORANGE COUNTY...
   1 WSW NASONS            46   557 PM  3/12  AWOS

...PAGE COUNTY...
   2 ESE HONEYVILLE        45   635 PM  3/12  MESONET

...PRINCE WILLIAM COUNTY...
   1 SW QUANTICO           52   540 PM  3/12  AWOS

...SPOTSYLVANIA COUNTY...
   3 SE FREDERICKSBURG     45   815 PM  3/12  AWOS

...STAFFORD COUNTY...
   2 SSE RAMOTH            44  1055 PM  3/12  AWOS

WEST VIRGINIA

...BERKELEY COUNTY...
   1 N MARTINSBURG ARPT    61   555 PM  3/12  ASOS

...GRANT COUNTY...
   1 S PETERSBURG          49   455 PM  3/12  AWOS

...JEFFERSON COUNTY...
   2 NE SHENANDOAH JUNC    50   851 PM  3/12  TRAINED SPOTTER
   2 NNE HALLTOWN          48   314 AM  3/13  MESONET

...MINERAL COUNTY...
   2 SSW KEYSER            61   811 PM  3/12  CO-OP OBSERVER
   1 E WILEY FORD          47   547 PM  3/12  AWOS

...PENDLETON COUNTY...
   2 SW BRUSHY RUN         53   617 PM  3/12  MESONET
Jason is currently the Washington Post’s weather editor. A native Washingtonian, Jason has been a weather enthusiast since age 10.
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