Alert archive / Maryland / Flash Flood Warnings in 2011
Flash Flood Warning 21, NWS Baltimore/Washington
NWS Baltimore/Washington issued this flash flood warning at Apr 28, 2011, 7:27 AM EDT for 4 counties in Maryland; Loudoun County, Virginia. It was in force for 5 hr. 5 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Apr 28, 2011, 7:27 AM EDT (11:27 UTC)
- Expired
- Apr 28, 2011, 12:17 PM EDT
- In force
- 5 hr
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
- Flood severity
- None
Counties Carroll County, MD, Frederick County, MD, Howard County, MD, Montgomery County, MD, Loudoun County, VA
The radar
The Sterling radar (KLWX), 60 km from the middle of the area, began a volume at 11:29 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Apr 28, 8:30 AM EDT | FLASH FLOOD | 3 Ese Ballenger Creek, MD | MARYLAND STATE ROUTE 355 FLOODED AND CLOSED AT BALL ROAD NEAR MONOCACY BATTLEFIELD. |
| Apr 28, 8:30 AM EDT | FLASH FLOOD | Libertytown, MD | NORTH AND SOUTH STREETS FLOODED AND CLOSED BETWEEN ROUTE 75 AND TRAMMELS ALLEY. |
| Apr 28, 10:09 AM EDT | FLASH FLOOD | Libertytown, MD | ONE LANE OF ROUTE 26 FLOODED AND CLOSED AT ROUTE 75 IN LIBERTYTOWN. |
| Apr 28, 12:07 PM EDT | FLASH FLOOD | 4 Nne Westminster, MD | BEAR BRANCH CREEK OUT OF ITS BANKS |
| Apr 28, 12:19 PM EDT | FLOOD | 2 Wsw Union Bridge, MD | TWO ROADS CLOSED IN THE UNION BRIDGE AREA. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 00:00Z, 11.5 hours before the alert went out and 61 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
- 1143 J/kg
- Mixed-layer CIN
- -34 J/kg
- Mixed-layer LCL
- 834 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 283 m²/s²
- 0-3 km storm-relative helicity
- 353 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 14.0
The text
As transmitted, in the capitals the NWS used until 2016.
011
WGUS51 KLWX 281127
FFWLWX
MDC013-021-027-031-VAC107-281430-
/O.NEW.KLWX.FF.W.0021.110428T1127Z-110428T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
727 AM EDT THU APR 28 2011
THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A
* FLASH FLOOD WARNING FOR...
CARROLL COUNTY IN NORTH CENTRAL MARYLAND...
FREDERICK COUNTY IN NORTH CENTRAL MARYLAND...
NORTHWESTERN HOWARD COUNTY IN CENTRAL MARYLAND...
NORTHWESTERN MONTGOMERY COUNTY IN CENTRAL MARYLAND...
NORTHEASTERN LOUDOUN COUNTY IN NORTHERN VIRGINIA...
* UNTIL 1030 AM EDT
* AT 721 AM EDT...HEAVY RAIN IS PRODUCING RAPIDLY RISING WATER ACROSS
THE WARNED AREA. THERE ARE SEVERAL REPORTS OF ONE TO TWO INCHES OF
RAIN SINCE MIDNIGHT...AND UP TO AN INCH MORE IS EXPECTED.
* SOME LOCATIONS THAT WILL CONTINUE TO BE AFFECTED BY THE HEAVY RAIN
INCLUDE BALLENGER CREEK...BRADDOCK HEIGHTS...DAMASCUS...
EMMITSBURG...FREDERICK...GREEN VALLEY...HAMPSTEAD...MANCHESTER...
MOUNT AIRY...NEW MARKET...POINT OF ROCKS...TANEYTOWN...THURMONT...
WALKERSVILLE AND WESTMINSTER.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.
&&
LAT...LON 3971 7739 3971 7679 3958 7687 3919 7728
3917 7755 3932 7756
$$3 follow-up statements
381
WGUS71 KLWX 281313
FFSLWX
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
913 AM EDT THU APR 28 2011
MDC013-021-027-031-VAC107-281430-
/O.CON.KLWX.FF.W.0021.000000T0000Z-110428T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CARROLL MD-FREDERICK MD-HOWARD MD-MONTGOMERY MD-LOUDOUN VA-
913 AM EDT THU APR 28 2011
...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1030 AM EDT FOR
NORTHEASTERN LOUDOUN...NORTHWESTERN MONTGOMERY...EXTREME NORTHWESTERN
HOWARD...FREDERICK AND CARROLL COUNTIES...
AT 909 AM EDT...NUMEROUS REPORTS OF FLOODED ROADS HAVE BEEN RECEIVED
IN LUCKETTS IN LOUDOUN COUNTY...THROUGHOUT FREDERICK COUNTY...AND IN
THE NEW WINDSOR AREA IN CARROLL COUNTY. HEAVY RAIN CONTINUES TO FALL
IN MANY OF THESE SAME LOCATIONS. THIS IS A DANGEROUS SITUATION AND
SIGNIFICANT FLASH FLOODING IS LIKELY ALREADY OCCURRING.
LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
WESTMINSTER...WALKERSVILLE...THURMONT...TANEYTOWN...MANCHESTER...
HAMPSTEAD AND EMMITSBURG
PRECAUTIONARY/PREPAREDNESS ACTIONS...
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.
&&
LAT...LON 3971 7739 3971 7679 3958 7688 3919 7728
3917 7755 3932 7756
$$
JE159
WGUS51 KLWX 281405
FFWLWX
MDC013-021-027-031-VAC107-281630-
/O.EXT.KLWX.FF.W.0021.000000T0000Z-110428T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1005 AM EDT THU APR 28 2011
THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS EXTENDED THE
* FLASH FLOOD WARNING FOR...
CARROLL COUNTY IN NORTH CENTRAL MARYLAND...
FREDERICK COUNTY IN NORTH CENTRAL MARYLAND...
NORTHWESTERN HOWARD COUNTY IN CENTRAL MARYLAND...
NORTHWESTERN MONTGOMERY COUNTY IN CENTRAL MARYLAND...
NORTHEASTERN LOUDOUN COUNTY IN NORTHERN VIRGINIA...
* UNTIL 1230 PM EDT
* AT 1000 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
ANOTHER ROUND OF HEAVY RAIN MOVING INTO EASTERN FREDERICK AND
WESTERN CARROLL COUNTIES...AS WELL AS EXTREME NORTHWESTERN
MONTGOMERY COUNTY. WITH RAINFALL OF TWO TO THREE INCHES HAS
ALREADY FALLEN ALONG THE FREDERICK AND MONTGOMERY COUNTY BORDER
AND THE FREDERICK AND CARROLL COUNTY BORDER. NUMEROUS ROADS ARE
ALREADY CLOSED IN THE AREA...AND WATERS ARE LIKELY TO CONTINUE TO
RISE WITH THE NEW ROUND OF RAIN.
* SOME LOCATIONS IN THE WARNING AREA INCLUDE BALLENGER CREEK...
BRADDOCK HEIGHTS...DAMASCUS...EMMITSBURG...FREDERICK...GREEN
VALLEY...HAMPSTEAD...MANCHESTER...MOUNT AIRY...NEW MARKET...POINT
OF ROCKS...TANEYTOWN...THURMONT...WALKERSVILLE AND WESTMINSTER.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.
&&
LAT...LON 3971 7739 3971 7679 3958 7688 3919 7728
3917 7755 3932 7756
$$
JE801
WGUS71 KLWX 281617
FFSLWX
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1217 PM EDT THU APR 28 2011
MDC013-021-027-031-VAC107-281626-
/O.CAN.KLWX.FF.W.0021.000000T0000Z-110428T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CARROLL MD-FREDERICK MD-HOWARD MD-MONTGOMERY MD-LOUDOUN VA-
1217 PM EDT THU APR 28 2011
...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHEASTERN
LOUDOUN...NORTHWESTERN MONTGOMERY...EXTREME NORTHWESTERN HOWARD...
FREDERICK AND CARROLL COUNTIES...
RAIN HAS ENDED ACROSS THE AREA...AND THE POTENTIAL FOR LIFE
THREATENING FLASH FLOODING HAS ALSO ENDED. HOWEVER...SMALL STREAMS
ARE STILL RISING...SO THE FLASH FLOOD WARNING HAS BEEN CANCELLED AND
REPLACED WITH AN AREAL FLOOD WARNING THROUGH EARLY AFTERNOON.
LAT...LON 3971 7739 3971 7679 3958 7688 3919 7728
3917 7755 3932 7756
$$
JEThe office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 27, 8:19 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Montgomery, Washington | 36 min |
| Apr 27, 8:28 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 19 min |
| Apr 27, 8:56 PM EDT | Special Weather Statement | LWX | Frederick | 34 min |
| Apr 27, 10:39 PM EDT | Special Weather Statement | LWX | Allegany | 111 min |
| Apr 28, 12:35 AM EDT | Flash Flood Warning | LWX | Allegany | 5 hr |
| Apr 28, 12:35 AM EDT | Severe Thunderstorm Warning | LWX | Allegany | 70 min |
| Apr 28, 1:18 AM EDT | Tornado Warning | LWX | Allegany | 27 min |
| Apr 28, 1:29 AM EDT | Severe Thunderstorm Warning | LWX | Allegany, Washington | 35 min |
| Apr 28, 1:33 AM EDT | Flash Flood Warning | LWX | Allegany, Washington | 4 hr |
| Apr 28, 2:59 AM EDT | Severe Thunderstorm Warning | LWX | Frederick, Washington | 62 min |
| Apr 28, 3:04 AM EDT | Flash Flood Warning | LWX | Washington | 7 hr |
| Apr 28, 4:24 AM EDT | Tornado Warning | LWX | Carroll, Frederick, Washington | 51 min |
| Apr 28, 5:09 AM EDT | Special Weather Statement | LWX | Frederick | 51 min |
| Apr 28, 5:35 AM EDT | Tornado Warning | LWX | Frederick | 26 min |
| Apr 28, 5:43 AM EDT | Tornado Warning | LWX | Frederick | 18 min |
| Apr 28, 6:06 AM EDT | Special Weather Statement | LWX | Harford | 39 min |
| Apr 28, 6:37 AM EDT | Tornado Warning | LWX | Frederick, Montgomery | 38 min |
| Apr 28, 7:05 AM EDT | Tornado Warning | LWX | Carroll, Frederick, Howard, Montgomery | 25 min |
| Apr 28, 7:17 AM EDT | Tornado Warning | LWX | Carroll, Frederick | 28 min |
| Apr 28, 7:55 AM EDT | Tornado Warning | LWX | Baltimore, Carroll, Frederick | 27 min |
| Apr 28, 8:01 AM EDT | Flash Flood Warning | LWX | Frederick, Washington | 119 min |
| Apr 28, 8:12 AM EDT | Tornado Warning | LWX | Carroll, Frederick | 33 min |
| Apr 28, 8:14 AM EDT | Tornado Warning | LWX | Baltimore, Harford | 11 min |
| Apr 28, 8:45 AM EDT | Tornado Warning | LWX | Baltimore, Carroll | 30 min |
| Apr 28, 9:14 AM EDT | Tornado Warning | LWX | Baltimore, Carroll, Frederick, Howard, Montgomery | 31 min |
| Apr 28, 9:39 AM EDT | Severe Thunderstorm Warning | LWX | Howard, Montgomery | 36 min |
| Apr 28, 9:45 AM EDT | Flash Flood Warning | LWX | Montgomery | 101 min |
| Apr 28, 9:49 AM EDT | Tornado Warning | LWX | Baltimore, Harford | 26 min |
| Apr 28, 9:58 AM EDT | Areal Flood Warning | LWX | Frederick, Washington | 3 hr |
| Apr 28, 10:10 AM EDT | Special Weather Statement | LWX | Carroll, Howard | 50 min |
| Apr 28, 10:36 AM EDT | Flash Flood Warning | LWX | Baltimore, Carroll, Harford | 102 min |
| Apr 28, 10:38 AM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Charles, Prince George's, Saint Mary's | 52 min |
| Apr 28, 10:54 AM EDT | Special Weather Statement | LWX | Calvert, Charles, Prince George's, Saint Mary's | 51 min |
| Apr 28, 10:54 AM EDT | Severe Thunderstorm Warning | LWX | Calvert, Charles, Saint Mary's | 66 min |
| Apr 28, 11:09 AM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Prince George's | 36 min |
| Apr 28, 11:22 AM EDT | Tornado Warning | LWX | Anne Arundel | 14 min |
| Apr 28, 11:26 AM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Charles, Prince George's, Saint Mary's | 18 min |
| Apr 28, 11:38 AM EDT | Coastal Flood Advisory | LWX | Anne Arundel, Baltimore, Calvert, Charles, Prince George's, Saint Mary's and 1 more | 7 hr |
| Apr 28, 12:15 PM EDT | Areal Flood Warning | LWX | Baltimore, Carroll, Frederick, Harford, Montgomery | 3 hr |
| Apr 28, 12:28 PM EDT | River Flood Warning | LWX | Washington | 11 hr |
| Apr 28, 4:40 PM EDT | Special Weather Statement | LWX | Saint Mary's | 50 min |
| Apr 27, 8:02 PM EDT | Special Weather Statement | LWX | Fauquier, Loudoun | 28 min |
| Apr 27, 8:12 PM EDT | Severe Thunderstorm Warning | LWX | Orange, Spotsylvania | 28 min |
| Apr 27, 8:20 PM EDT | Tornado Warning | LWX | Albemarle, City of Charlottesville | 25 min |
| Apr 27, 8:30 PM EDT | Tornado Warning | LWX | Orange, Spotsylvania | 30 min |
| Apr 27, 8:51 PM EDT | Special Weather Statement | LWX | Greene, Madison | 24 min |
| Apr 27, 9:24 PM EDT | Tornado Warning | LWX | Culpeper, Fauquier, Orange, Spotsylvania, Stafford | 18 min |
| Apr 27, 9:40 PM EDT | Tornado Warning | LWX | Culpeper, Madison, Orange | 35 min |
| Apr 27, 10:00 PM EDT | Tornado Warning | LWX | Culpeper, Fauquier | 30 min |
| Apr 27, 10:28 PM EDT | Tornado Warning | LWX | Fauquier, Prince William, City of Manassas, City of Manassas Park | 47 min |
| Apr 28, 12:04 AM EDT | Severe Thunderstorm Warning | LWX | Highland | 71 min |
| Apr 28, 12:05 AM EDT | Flash Flood Warning | LWX | Highland | 5 hr |
| Apr 28, 1:09 AM EDT | Severe Thunderstorm Warning | LWX | Augusta, Highland, Rockingham | 66 min |
| Apr 28, 2:07 AM EDT | Tornado Warning | LWX | Augusta, City of Staunton | 42 min |
| Apr 28, 2:10 AM EDT | Severe Thunderstorm Warning | LWX | Frederick, Page, Rockingham, Shenandoah, Warren | 65 min |
| Apr 28, 2:24 AM EDT | Tornado Warning | LWX | Shenandoah | 25 min |
| Apr 28, 2:53 AM EDT | Tornado Warning | LWX | Page, Rockingham, Shenandoah, City of Harrisonburg | 36 min |
| Apr 28, 3:09 AM EDT | Special Weather Statement | LWX | Augusta | 36 min |
| Apr 28, 3:19 AM EDT | Tornado Warning | LWX | Augusta, City of Staunton | 41 min |
| Apr 28, 3:23 AM EDT | Tornado Warning | LWX | Clarke, Frederick, Page, Shenandoah, Warren | 39 min |
| Apr 28, 3:50 AM EDT | Tornado Warning | LWX | Page, Rockingham, Shenandoah, City of Harrisonburg | 40 min |
| Apr 28, 3:54 AM EDT | Tornado Warning | LWX | Clarke, Frederick, City of Winchester | 34 min |
| Apr 28, 4:26 AM EDT | Tornado Warning | LWX | Fauquier, Page, Rappahannock, Warren | 23 min |
| Apr 28, 4:32 AM EDT | Special Weather Statement | LWX | Albemarle, Greene, Nelson, City of Charlottesville, City of Waynesboro | 28 min |
| Apr 28, 4:44 AM EDT | Severe Thunderstorm Warning | LWX | Albemarle, Culpeper, Greene, Madison, Orange, Rappahannock and 1 more | 46 min |
| Apr 28, 5:50 AM EDT | Tornado Warning | LWX | Culpeper, Fauquier, Prince William, Rappahannock | 40 min |
| Apr 28, 6:05 AM EDT | Special Marine Warning | LWX | 55 min | |
| Apr 28, 8:45 AM EDT | Areal Flood Warning | LWX | Albemarle, Clarke, Culpeper, Fauquier, Greene, Loudoun and 3 more | 6 hr |
| Apr 28, 10:03 AM EDT | Severe Thunderstorm Warning | LWX | King George, Spotsylvania, Stafford, City of Fredericksburg | 42 min |
| Apr 28, 10:06 AM EDT | Special Marine Warning | LWX | 84 min | |
| Apr 28, 10:16 AM EDT | Special Marine Warning | LWX | 59 min | |
| Apr 28, 10:59 AM EDT | Special Marine Warning | LWX | 81 min | |
| Apr 28, 3:34 PM EDT | Small Craft Advisory | LWX | 37 hr | |
| Apr 28, 4:07 PM EDT | Special Marine Warning | LWX | 53 min | |
| Apr 28, 4:15 PM EDT | Special Marine Warning | LWX | 60 min | |
| Apr 28, 4:51 PM EDT | Special Marine Warning | LWX | 36 min |
Nearby
Flash Flood Warnings in Maryland, 2011Flash Flood Warnings in Virginia, 2011Every flash flood 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.