Alert archive / Maryland / Tornado Warnings in 2009
Tornado Warning 11, NWS Baltimore/Washington
NWS Baltimore/Washington issued this tornado warning at Aug 19, 2009, 4:35 PM EDT for Saint Mary's County, Maryland. It was in force for 40 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
- Aug 19, 2009, 4:35 PM EDT (20:35 UTC)
- Expired
- Aug 19, 2009, 5:15 PM EDT
- In force
- 40 min
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
County Saint Mary's County, MD
The radar
The Dover AFB radar (KDOX), 116 km from the middle of the area, began a volume at 20:38 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
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.6 hours before the alert went out and 144 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
- 277 J/kg
- Mixed-layer CIN
- -81 J/kg
- Mixed-layer LCL
- 953 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
What forecasters said that day
The local office's own words before this tornado 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 tornado warning went out at Aug 19, 2:56 PM EDT, 1 hour 39 minutes earlier.
Area forecast discussion, Aug 19, 2:56 PM EDT, 1 hour 39 minutes before
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</html>Hazardous weather outlook, Aug 19, 2:42 PM EDT, 1 hour 53 minutes before
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</html>In the hours before
Special weather statement, Aug 19, 3:17 PM EDT, 1 hour 18 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 317 PM EDT WED AUG 19 2009 MDZ013-016-VAZ052-053-192045- PRINCE GEORGES MD-CHARLES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA- FAIRFAX VA- 317 PM EDT WED AUG 19 2009 ...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT PRINCE GEORGES... CHARLES...PRINCE WILLIAM/MANASSAS/MANASSAS PARK AND FAIRFAX COUNTIES... AT 316 PM EDT...DOPPLER RADAR INDICATED A CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN OVER WOODBRIDGE AND LORTON...MOVING EAST AT 15 MPH. LOCATIONS THAT WILL LIKELY BE AFFECTED BY THESE STORMS INCLUDE MASON NECK...POTOMAC HEIGHTS...BRYANS ROAD...ACCOKEEK...NORTHWOOD...WALDORF AND BADEN. RAINFALL OF ONE TO TWO INCHES WILL BE POSSIBLE IN AN HOUR. HEAVY DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND CAUSE PONDING OF WATER ON ROADWAYS. HTS
Special weather statement, Aug 19, 3:21 PM EDT, 1 hour 14 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 321 PM EDT WED AUG 19 2009 VAZ037-192045- ALBEMARLE VA- 321 PM EDT WED AUG 19 2009 ...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT ALBEMARLE COUNTY... AT 319 PM EDT...DOPPLER RADAR INDICATED A THUNDERSTORM WITH HEAVY RAIN OVER NORTH GARDEN...MOVING EAST AT 15 MPH. LOCATIONS THAT WILL LIKELY BE AFFECTED BY THIS STORM INCLUDE OVERTON...MONTICELLO...SHADWELL...BOYD TAVERN...KESWICK AND CAMPBELL. RAINFALL OF AN INCH TO AN INCH AND A HALF WILL BE POSSIBLE IN AN HOUR OR LESS. HEAVY DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND CAUSE PONDING OF WATER ON ROADWAYS. HTS
Special weather statement, Aug 19, 3:45 PM EDT, 50 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 345 PM EDT WED AUG 19 2009 VAZ056-192030- SPOTSYLVANIA VA- 345 PM EDT WED AUG 19 2009 ...THUNDERSTORMS WITH HEAVY RAIN TO AFFECT SPOTSYLVANIA COUNTY... AT 343 PM EDT...DOPPLER RADAR INDICATED SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN 3 MILES WEST OF GATEWOOD...MOVING EAST AT 20 MPH. LOCATIONS THAT WILL LIKELY BE AFFECTED BY THIS STORM INCLUDE MASSAPONAX AND PARTLOW. HEAVY DOWNPOURS MAY REDUCE VISIBILITY BELOW A MILE AND CAUSE PONDING OF WATER ON ROADWAYS. BJL
The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 8:25 PM EDT | Special Marine Warning | LWX | 65 min | |
| Aug 19, 4:30 PM EDT | Special Marine Warning | LWX | 2 hr | |
| Aug 19, 5:45 PM EDT | Special Marine Warning | LWX | 90 min | |
| Aug 19, 4:19 PM EDT | Severe Thunderstorm Warning | LWX | Saint Mary's | 41 min |
| Aug 19, 5:15 PM EDT | Severe Thunderstorm Warning | LWX | Saint Mary's | 45 min |
| Aug 19, 7:10 PM EDT | Flash Flood Warning | LWX | Morgan | 3 hr |
Nearby
Tornado Warnings in Maryland, 2009Every tornado warning in 2009Tornadoes in 2009
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.