Alert archive / Maryland / Severe Thunderstorm Warnings in 2011
Severe Thunderstorm Warning 285, NWS Baltimore/Washington
NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 11, 2011, 7:42 PM EDT for Fairfax County, Loudoun County, Virginia; Frederick County, Howard County, Montgomery County, Maryland. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jul 11, 2011, 7:42 PM EDT (23:42 UTC)
- Expired
- Jul 11, 2011, 8:30 PM EDT
- In force
- 48 min
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
Counties Frederick County, MD, Howard County, MD, Montgomery County, MD, Fairfax County, VA, Loudoun County, VA
The radar
The Sterling radar (KLWX), 26 km from the middle of the area, began a volume at 23:45 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jul 11, 5:47 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 11.7 hours before the alert went out and 25 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 6 J/kg
- Mixed-layer CIN
- -140 J/kg
- Mixed-layer LCL
- 1061 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 130 m²/s²
- 0-3 km storm-relative helicity
- 135 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 11, 7:30 PM EDT, 12 minutes earlier.
Area forecast discussion, Jul 11, 7:30 PM EDT, 12 minutes before
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</html>Hazardous weather outlook, Jul 11, 7:05 PM EDT, 37 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 705 PM EDT MON JUL 11 2011 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 121200- CHESAPEAKE BAY NORTH OF POOLES ISLAND MD- CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT MD- CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH MD- CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT MD- CHESAPEAKE BAY FROM DRUM POINT MD TO SMITH POINT VA- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD MD- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND MD- TIDAL POTOMAC FROM COBB ISLAND MD TO SMITH POINT VA- PATAPSCO RIVER INCLUDING BALTIMORE HARBOR- CHESTER RIVER TO QUEENSTOWN MD-EASTERN BAY- CHOPTANK RIVER TO CAMBRIDGE MD AND THE LITTLE CHOPTANK RIVER- PATUXENT RIVER TO BROOMES ISLAND MD- TANGIER SOUND AND THE INLAND WATERS SURROUNDING BLOODSWORTH ISLAND-DISTRICT OF COLUMBIA-NORTHERN BALTIMORE-HARFORD- SOUTHERN BALTIMORE-PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS- CALVERT-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX- ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA- KING GEORGE- 705 PM EDT MON JUL 11 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MARYLAND PORTION OF THE CHESAPEAKE BAY...TIDAL POTOMAC RIVER...AND ADJACENT COUNTIES IN CENTRAL MARYLAND AND NORTHERN VIRGINIA AS WELL AS THE DISTRICT OF COLUMBIA. .DAY ONE...TONIGHT SEVERE THUNDERSTORM WATCH 631 HAS BEEN EXTENDED TO INCLUDE THE MARYLAND COUNTIES EAST OF THE CATOCTINS...AND NORTHERN VIRGINIA EAST OF THE BLUE RIDGE...UNTIL 11 PM. A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH TONIGHT FOR THE LOWER TIDAL POTOMAC RIVER AND FOR THE MARYLAND CHESAPEAKE BAY SOUTH OF POOLES ISLAND. LARGE HAIL AND DAMAGING WINDS THE MAIN THREAT WITH THIS ACTIVITY. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A HEAT ADVISORY IS IN EFFECT TUESDAY FROM NOON UNTIL 8PM. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-121200- WASHINGTON-FREDERICK MD-CARROLL-MONTGOMERY-HOWARD- EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA- ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON- ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER- NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND- EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY- WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL- WESTERN PENDLETON-EASTERN PENDLETON- 705 PM EDT MON JUL 11 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN WEST VIRGINIA... NORTHERN AND CENTRAL VIRGINIA...AND CENTRAL AND WESTERN MARYLAND WITH THE EXCEPTION OF GARRETT COUNTY. .DAY ONE...TONIGHT SEVERE THUNDERSTORM WATCH 631 IS IN EFFECT FOR AREAS WEST OF THE BLUE RIDGE AND MARYLAND CATOCTINS...INCLUDING MUCH OF THE SHENANDOAH VALLEY AND THE POTOMAC HIGHLAND UNTIL 11 PM. LARGE HAIL AND DAMAGING WINDS THE MAIN THREAT WITH THIS ACTIVITY. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A HEAT ADVISORY IS IN EFFECT TUESDAY FROM NOON TO 8PM FOR PORTIONS OF CENTRAL MARYLAND AND NORTHERN VIRGINIA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
In the hours before
Special weather statement, Jul 11, 6:45 PM EDT, 57 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
645 PM EDT MON JUL 11 2011
MDZ003-502-VAZ026>028-WVZ050-051-055-502-504>506-112315-
WASHINGTON MD-SHENANDOAH VA-EASTERN PENDLETON WV-HARDY WV-
HAMPSHIRE WV-MORGAN WV-EASTERN GRANT WV-
CENTRAL AND EASTERN ALLEGANY MD-EASTERN MINERAL WV-ROCKINGHAM VA-
FREDERICK VA-WESTERN PENDLETON WV-
645 PM EDT MON JUL 11 2011
...STRONG THUNDERSTORMS TO AFFECT WASHINGTON...SHENANDOAH...EASTERN
PENDLETON...HARDY...HAMPSHIRE...MORGAN...EASTERN GRANT...CENTRAL AND
EASTERN ALLEGANY...EASTERN MINERAL...ROCKINGHAM...FREDERICK AND
WESTERN PENDLETON COUNTIES...
AT 644 PM EDT...DOPPLER RADAR INDICATED STRONG OUTFLOW FROM
THUNDERSTORMS LOCATED ALONG A LINE EXTENDING FROM CUMBERLAND TO 3
MILES NORTH OF MCNEILL TO ROUGH RUN TO 10 MILES SOUTHWEST OF
FRANKLIN...MOVING EAST AT 45 MPH.
LOCATIONS IMPACTED INCLUDE ROMNEY...MATHIAS...TIMBER RIDGE...
LARGENT...FISHERS BRIDGE...VALLEY VIEW...ROCK GAP AND RIDGE.
BRIEF WIND GUSTS OF 40 TO 50 MPH CAN BE EXPECTED WITH THESE STORMS.
A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THE AREA UNTIL 11 PM
EDT.
&&
LAT...LON 3918 7833 3889 7854 3847 7905 3858 7957
3889 7919 3919 7899 3972 7877 3973 7818
TIME...MOT...LOC 2244Z 270DEG 39KT 3964 7869 3919 7888
3890 7907 3858 7946
SMZSpecial weather statement, Jul 11, 6:58 PM EDT, 44 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
658 PM EDT MON JUL 11 2011
MDZ003>005-112330-
WASHINGTON MD-CARROLL MD-FREDERICK MD-
658 PM EDT MON JUL 11 2011
...STRONG THUNDERSTORMS TO AFFECT WASHINGTON...CARROLL AND FREDERICK
COUNTIES...
AT 658 PM EDT...DOPPLER RADAR INDICATED STRONG THUNDERSTORMS ALONG A
LINE EXTENDING FROM 3 MILES SOUTH OF SABILLASVILLE TO 3 MILES
NORTHWEST OF PLEASANT WALK...MOVING EAST AT 35 MPH.
LOCATIONS IMPACTED INCLUDE THURMONT...EMMITSBURG...WALKERSVILLE AND
TANEYTOWN.
STORM INTENSITY IS INCREASING...AND SEVERE WEATHER MAY DEVELOP
RAPIDLY. REMAIN ALERT...AND BE PREPARED TO TAKE ACTION IF WARNINGS
ARE ISSUED.
WIND GUSTS IN EXCESS OF 50 MPH ARE EXPECTED WITH THESE STORMS. WINDS
THIS STRONG CAN BRING DOWN LARGE TREE BRANCHES. TAKE SHELTER UNTIL
THE STORMS HAVE PASSED.
STAY ALERT IN CASE WARNINGS ARE ISSUED.
&&
LAT...LON 3945 7724 3952 7779 3970 7765 3973 7742
3973 7703
TIME...MOT...LOC 2258Z 260DEG 32KT 3966 7743 3958 7758
SMZLocal storm report, Jul 11, 7:01 PM EDT, 41 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
701 PM EDT MON JUL 11 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0648 PM HAIL 1 S MIDDLEWAY 39.28N 77.99W
07/11/2011 E1.00 INCH JEFFERSON WV TRAINED SPOTTER
4 INCH TREE SNAPPED. OTHER SMALL TREE UPROOTED.
0648 PM TSTM WND DMG 1 S MIDDLEWAY 39.28N 77.99W
07/11/2011 JEFFERSON WV TRAINED SPOTTER
4 INCH TREE SNAPPED. OTHER SMALL TREE UPROOTED.
&&
EVENT NUMBER LWX1101154
EVENT NUMBER LWX1101155
KLWLocal storm report, Jul 11, 7:04 PM EDT, 38 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
704 PM EDT MON JUL 11 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0648 PM TSTM WND DMG MIDDLEWAY 39.30N 77.98W
07/11/2011 JEFFERSON WV EMERGENCY MNGR
SEVERAL TREES DOWN. ONE ON A VEHICLE.
&&
EVENT NUMBER LWX1101156
KLWLocal storm report, Jul 11, 7:34 PM EDT, 8 minutes before
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</html>Local storm report, Jul 11, 7:41 PM EDT, 1 minute before
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</html>The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 11, 1:31 PM EDT | Heat Advisory | LWX | Arlington, Culpeper, Fairfax, Fauquier, King George, Nelson and 8 more | 23 hr |
| Jul 11, 6:01 PM EDT | Special Weather Statement | LWX | Frederick, City of Winchester | 29 min |
| Jul 11, 6:05 PM EDT | Special Weather Statement | LWX | Warren | 25 min |
| Jul 11, 6:35 PM EDT | Special Weather Statement | LWX | City of Winchester | 25 min |
| Jul 11, 6:40 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Loudoun | 35 min |
| Jul 11, 6:54 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Rockingham, Shenandoah | 37 min |
| Jul 11, 7:10 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Loudoun | 35 min |
| Jul 11, 7:47 PM EDT | Special Weather Statement | LWX | Clarke | 28 min |
| Jul 11, 7:52 PM EDT | Special Weather Statement | LWX | Prince William | 23 min |
| Jul 11, 7:53 PM EDT | Special Marine Warning | LWX | 97 min | |
| Jul 11, 7:57 PM EDT | Severe Thunderstorm Warning | LWX | Culpeper, Fauquier, Prince William, Spotsylvania, Stafford, City of Fredericksburg | 48 min |
| Jul 11, 6:45 PM EDT | Special Weather Statement | LWX | Allegany | 30 min |
| Jul 11, 6:58 PM EDT | Special Weather Statement | LWX | Frederick | 32 min |
| Jul 11, 7:05 PM EDT | Severe Thunderstorm Warning | LWX | Carroll, Frederick, Washington | 40 min |
| Jul 11, 7:34 PM EDT | Severe Thunderstorm Warning | LWX | Baltimore, Carroll, Frederick | 41 min |
Nearby
Severe Thunderstorm Warnings in Maryland, 2011Severe Thunderstorm Warnings in Virginia, 2011Every severe thunderstorm warning in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.