Alert archive / West Virginia / Severe Thunderstorm Warnings in 2012
Severe Thunderstorm Warning 317, NWS Baltimore/Washington
NWS Baltimore/Washington issued this severe thunderstorm warning at Sep 8, 2012, 12:02 PM EDT for Clarke County, Frederick County, City of Winchester, Virginia; Washington County, Maryland; 4 counties in West Virginia. It was in force for 43 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
- Sep 8, 2012, 12:02 PM EDT (16:02 UTC)
- Expired
- Sep 8, 2012, 12:45 PM EDT
- In force
- 43 min
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
Counties Washington County, MD, City of Winchester, VA, Clarke County, VA, Frederick County, VA, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Morgan County, WV
The radar
The Sterling radar (KLWX), 69 km from the middle of the area, began a volume at 16:05 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 nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 4.0 hours before the alert went out and 76 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
- 252 J/kg
- Mixed-layer CIN
- -81 J/kg
- Mixed-layer LCL
- 638 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 150 m²/s²
- 0-3 km storm-relative helicity
- 140 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.0
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 Sep 8, 10:17 AM EDT, 1 hour 45 minutes earlier.
Area forecast discussion, Sep 8, 10:17 AM EDT, 1 hour 45 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1017 AM EDT SAT SEP 8 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE MID ATLANTIC THIS AFTERNOON AND
EVENING. STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED IN ADVANCE OF
THIS FRONT. COOLER AND MUCH DRIER AIR WILL MOVE IN SUNDAY AND
REMAIN OVER THE REGION THROUGH AT LEAST MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-FRONTAL BAND OF SHWRS HAS BEEN SLOW TO ENTER WRN CWA THIS
MRNG...AND ACTIVITY HAS BEEN DIMINISHING...THUS POPS ADJUSTED
DOWNWARD FOR NEXT FEW HOURS. SFC CDFNT LAGGING BEHIND INITIAL
PCPN...AND AT 14Z IS LOCATED ACRS WRN WV. CNVTCV BAND DVLPG ALONG
THIS FEATURE...WHICH SHUD RACE AHEAD OF ANY PRE-FRONTAL PCPN BY
THIS AFTN ACRS SHEN VLY. FRONT WILL ENCOUNTER HIGHLY UNSTABLE
ATM...SO TSTMS SHUD INTENSIFY AS THEY PUSH EWD THRU CWA. BULK
SHEAR IS VERY HIGH AND FAVORABLE FOR STRONG WIND GUSTS.
HODOGRAPH/ENVIRONMENTAL SHEAR ARE ORIENTED SUCH THAT ISOLATED
TORNADOES ARE ALSO PSBL...THO DMGG WINDS ARE MOST SIGNIFICANT THREAT.
AMPLE SUN THIS MRNG ALLOWING TEMPS TO RISE WELL INTO 80S BEFORE TSTMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
TRAILING STRATIFORM EXPECTED TO MOVE EAST THROUGH THE
EVENING...WITH DRY/COOL AIR COMING IN FROM THE NW. NWLY FLOW
AROUND 10 MPH WILL LIMIT FOG. MIN TEMPS IN THE 40S IN THE POTOMAC
HIGHLANDS...50S ELSEWHERE /LOW 60S NEAR SHORE AND URBAN AREAS/
WITH SKIES CLEARING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
COLD FRONT WILL BE OFFSHORE BY SUNDAY WITH COOLER AND DRIER HIGH
PRESSURE MOVING IN. TEMPS SHOULD STAY NEAR OR A LITTLE BELOW NORMAL
THROUGH AT LEAST MIDWEEK BEFORE TEMPS RISE A LITTLE AS THE HIGH
SHIFTS OFFSHORE AND WINDS SWAP TO A SOUTHERLY DIRECTION. THE NEXT
SIGNIFICANT WEATHER FEATURE IS A WEAK COLD FRONT APPROACHING BY THE
END OF NEXT WEEK. NO EXPECTED TROPICAL THREATS TO OUR FORECAST AREA
THROUGH NEXT WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SLY FLOW INCREASES THIS MORNING IN ADVANCE OF THE APPROACHING
COLD FRONT. LINE/S/ OF THUNDERSTORMS EXPECTED IN ADVANCE OF THE
FRONT ACROSS THE TERMINALS FROM WEST TO EAST THIS AFTERNOON INTO
THE EVENING. SOME STORMS MAY BE STRONG/SEVERE...WITH DAMAGING WIND
GUSTS.
PCPN ENDS AND CLOUDS GRADUALLY CLR TONIGHT WITH DRY NWLY FLOW AROUND
10 KT LIMITING FOG DEVELOPMENT.
VFR CONDS EXPECTED THRU NEXT WK. NW WINDS 10-20 KTS SUN/MON...
DIMINISHING THEREAFTER AS HIGH PRESSURE MOVES IN.
&&
.MARINE...
GUSTY SLY WINDS TDA AHEAD OF CDFNT. LINE/S/ OF TSTMS EXPECTED LATE
AFTERNOON INTO EVENING ACROSS THE WATERS IN ADVANCE OF THE COLD
FRONT. SPECIAL MARINE WARNINGS EXPECTED SINCE MAIN THREAT WITH THE
WEATHER IS DAMAGING WINDS. NWLY FLOW AFTER THE FRONT CONTINUES SCA
FOR MAIN PORTIONS OF THE WATERS TONIGHT WITH GUSTS AROUND 20 KT.
GUSTY NW WINDS SUNDAY ARE EXPECTED TO REMAIN AROUND 20KTS FOR MUCH
OF THE BAY CHANNEL SOUTH OF BALTIMORE AND LOWER POTOMAC DURING THE
MORNING...REQUIRING A SMALL CRAFT ADVISORY THERE SUNDAY MORNING.
OTHERWISE NO MARINE HAZARDS THROUGH NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES EXPECTED TO REMAIN ABOUT THREE QUARTERS FOOT
ABOVE ASTRONOMICAL PREDICTION INTO SATURDAY EVENING WITH SLY FLOW
IN ADVANCE OF A COLD FRONT. POST FRONT WILL BE NWLY FLOW AND MORE
NORMAL WATER LEVELS. WITH THE PREFERRED TIDE TONIGHT HAVING
PAST...NO COASTAL FLOODING IS EXPECTED.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ531-539>541.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ530-538-542.
SMALL CRAFT ADVISORY UNTIL 3 PM EDT SUNDAY FOR ANZ532>534-537-
543.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ535-
536.
&&
SYNOPSIS...BAJ/CAS
NEAR TERM...KONARIK
SHORT TERM...BAJ/KONARIK
LONG TERM...CAS
AVIATION...BAJ/KONARIK/CAS
MARINE...BAJ/KONARIK/CAS
TIDES/COASTAL FLOODING...BAJHazardous weather outlook, Sep 8, 11:09 AM EDT, 53 minutes before
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</html>In the hours before
Special weather statement, Sep 8, 11:51 AM EDT, 11 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1151 AM EDT SAT SEP 8 2012 VAZ028-031-WVZ050>053-081615- CLARKE VA-MORGAN WV-JEFFERSON WV-HAMPSHIRE WV-BERKELEY WV- FREDERICK VA- 1151 AM EDT SAT SEP 8 2012 ...STRONG THUNDERSTORM TO AFFECT CLARKE...MORGAN...JEFFERSON... HAMPSHIRE...BERKELEY AND FREDERICK COUNTIES... AT 1151 AM EDT...A STRONG THUNDERSTORM WAS LOCATED OVER HIGH VIEW... MOVING EAST AT 35 MPH. LOCATIONS IMPACTED INCLUDE VALLEY HIGH AND INWOOD. STORM INTENSITY IS INCREASING...AND SEVERE WEATHER MAY DEVELOP RAPIDLY. REMAIN ALERT...AND BE PREPARED TO TAKE ACTION IF WARNINGS ARE ISSUED. WIND GUSTS OF 40 TO 50 MPH CAN BE EXPECTED WITH THIS STORM. && LAT...LON 3954 7800 3923 7800 3915 7849 3935 7849 TIME...MOT...LOC 1551Z 248DEG 32KT 3926 7836 HTS
The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 7, 10:42 PM EDT | Small Craft Advisory | LWX | 23 hr | |
| Sep 8, 11:51 AM EDT | Special Weather Statement | LWX | Frederick | 24 min |
| Sep 8, 12:43 PM EDT | Special Weather Statement | LWX | Clarke, Frederick, City of Winchester | 47 min |
| Sep 8, 1:22 PM EDT | Special Weather Statement | LWX | Clarke | 23 min |
| Sep 8, 1:49 PM EDT | Special Weather Statement | LWX | Loudoun | 26 min |
| Sep 8, 1:52 PM EDT | Special Weather Statement | LWX | Clarke, Shenandoah, City of Winchester | 23 min |
| Sep 8, 2:04 PM EDT | Special Weather Statement | LWX | Augusta | 26 min |
| Sep 8, 2:16 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Frederick, Page, Rockingham, Shenandoah, Warren and 1 more | 46 min |
| Sep 8, 2:19 PM EDT | Special Weather Statement | LWX | Loudoun | 26 min |
| Sep 8, 2:28 PM EDT | Tornado Warning | LWX | Frederick, Shenandoah, Warren | 20 min |
| Sep 8, 2:32 PM EDT | Special Weather Statement | LWX | Augusta, Rockingham, City of Harrisonburg, City of Staunton, City of Waynesboro | 28 min |
| Sep 8, 2:47 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Culpeper, Fauquier, Loudoun, Madison, Page and 3 more | 58 min |
| Sep 8, 2:51 PM EDT | Special Weather Statement | LWX | Culpeper, Greene, Madison | 39 min |
| Sep 8, 3:10 PM EDT | Special Marine Warning | LWX | 2 hr | |
| Sep 8, 3:16 PM EDT | Severe Thunderstorm Warning | LWX | Albemarle, City of Charlottesville | 32 min |
| Sep 8, 3:17 PM EDT | Special Weather Statement | LWX | Greene, Madison, Nelson, City of Waynesboro | 28 min |
| Sep 8, 3:18 PM EDT | Special Weather Statement | LWX | Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church, City of Manassas and 1 more | 87 min |
| Sep 8, 3:22 PM EDT | Special Marine Warning | LWX | 98 min | |
| Sep 8, 3:22 PM EDT | Severe Thunderstorm Warning | LWX | Arlington, Culpeper, Fairfax, Fauquier, Loudoun, Prince William and 6 more | 68 min |
| Sep 8, 3:29 PM EDT | Tornado Warning | LWX | Fairfax, City of Fairfax | 20 min |
| Sep 8, 3:44 PM EDT | Tornado Warning | LWX | Arlington, Fairfax, City of Alexandria, City of Falls Church | 15 min |
| Sep 8, 3:55 PM EDT | Special Weather Statement | LWX | Albemarle, Culpeper, Madison, Nelson, Orange, Spotsylvania and 3 more | 80 min |
| Sep 8, 3:58 PM EDT | Severe Thunderstorm Warning | LWX | Arlington, Fairfax, Prince William, Stafford, City of Alexandria, City of Falls Church | 55 min |
| Sep 8, 4:06 PM EDT | Severe Thunderstorm Warning | LWX | Culpeper, Fauquier, Orange, Spotsylvania, Stafford, City of Fredericksburg | 39 min |
| Sep 8, 4:20 PM EDT | Special Marine Warning | LWX | 85 min | |
| Sep 8, 4:47 PM EDT | Special Weather Statement | LWX | King George, Spotsylvania, Stafford, City of Fredericksburg | 28 min |
| Sep 8, 4:56 PM EDT | Special Marine Warning | LWX | 72 min | |
| Sep 8, 5:41 PM EDT | Special Marine Warning | LWX | 67 min | |
| Sep 8, 5:58 PM EDT | Special Marine Warning | LWX | 83 min | |
| Sep 8, 12:22 PM EDT | Special Weather Statement | LWX | Washington | 23 min |
| Sep 8, 12:35 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 40 min |
| Sep 8, 12:47 PM EDT | Tornado Warning | LWX | Washington | 16 min |
| Sep 8, 1:09 PM EDT | Severe Thunderstorm Warning | LWX | Carroll, Frederick, Washington | 66 min |
| Sep 8, 2:02 PM EDT | Special Weather Statement | LWX | Baltimore | 58 min |
| Sep 8, 2:10 PM EDT | Severe Thunderstorm Warning | LWX | Baltimore, Carroll, Frederick, Harford, Howard, Montgomery | 80 min |
| Sep 8, 3:27 PM EDT | Special Weather Statement | LWX | Harford | 33 min |
| Sep 8, 3:53 PM EDT | Tornado Warning | LWX | Montgomery, Prince George's | 15 min |
| Sep 8, 4:06 PM EDT | Tornado Warning | LWX | Anne Arundel, Prince George's | 39 min |
| Sep 8, 4:25 PM EDT | Special Weather Statement | LWX | Kent | 20 min |
| Sep 8, 1:17 PM EDT | Special Weather Statement | LWX | Grant, Pendleton | 43 min |
| Sep 8, 1:38 PM EDT | Special Weather Statement | LWX | Hampshire, Hardy, Morgan | 37 min |
Nearby
Severe Thunderstorm Warnings in West Virginia, 2012Severe Thunderstorm Warnings in Virginia, 2012Severe Thunderstorm Warnings in Maryland, 2012Every severe thunderstorm warning in 2012
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.