Abnormally moist atmosphere across the mid-Atlantic allowed showers and thunderstorms to produce exceptional rainfall rates across portions of northern Virginia|as the remnants of Tropical Depression Lee interacted with a nearly stationary boundary near the Mason-Dixon line. Major flooding and flash flooding occurred in numerous areas.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LWX wrote it up.
Abnormally moist atmosphere across the mid-Atlantic allowed showers and thunderstorms to produce exceptional rainfall rates across portions of northern Virginia|as the remnants of Tropical Depression Lee interacted with a nearly stationary boundary near the Mason-Dixon line. Major flooding and flash flooding occurred in numerous areas. The highest rainfall and worst flooding happened in a band from King George County northward into Fairfax County. An AWOS site in Fairfax County measured 13.48 inches of rain.
The local office's own words before the first event, 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 the first event at Sep 7, 3:06 PM EST, 5 hours 39 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
406 PM EDT WED SEP 7 2011
.SYNOPSIS...
LOW PRESSURE WILL REMAIN OVER THE OHIO VALLEY THROUGH THE END OF
THE WEEK. THE INTERACTION OF TROPICAL MOISTURE AND LOW PRESSURE
WILL RESULT IN PERIODS OF HEAVY SHOWERS THROUGH THE END OF THE
WEEK. IMPROVING CONDITIONS ARE EXPECTED OVER THE WEEKEND AS LOW
PRESSURE WEAKENS.
&&
.NEAR TERM /THROUGH THURSDAY/...
NEARLY STACKED LOW PRESSURE WAS SPINNING OVER THE OHIO VALLEY THIS
AFTERNOON. A WARM FRONT THAT HAD BEEN PARALLELING THE CHESAPEAKE BAY
MOST OF THE DAY HAS TILTED BACK TO THE NORTHWEST TOWARD THE
INTERSTATE 95 CORRIDOR THIS AFTERNOON.
TROPICAL MOISTURE PLUME INTERACTED WITH THE WARM FRONTAL BOUNDARY
AND LED TO A HEAVY SOUTH TO NORTH AXIS OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. 12Z NAM WAS TOO FAR WEST WITH THIS AXIS...AND THE
12Z GFS PERFORMED BETTER ITS PLACEMENT. IN TERMS OF HIGH RESOLUTION
GUIDANCE...WRF-ARW HAS BEEN AND REMAINS TOO FAR WEST AND TOO LATE
WITH SHOWERS WHILE THE HRRR HAS A BETTER HANDLE. HRRR KEEPS THE
CURRENT AXIS OF HEAVY RAINFALL POTENTIAL IN PLACE THROUGH TONIGHT.
IT IMPLIES THAT THE FIRST ROUND OF SHOWERS/ISOLATED THUNDERSTORMS
THIS AFTERNOON IS FOLLOWED BY ANOTHER ROUND OF SHOWERS LATER THIS
EVENING. FORECAST REFLECTS THIS.
HAVE TRIMMED THE WESTERN PORTION OF THE FLASH FLOOD WATCH...BUT HAVE
KEPT UP THE METRO AREAS CURRENTLY EXPERIENCING FLASH FLOODING AND
CONSIDERING THE HRRR PREDICTION MORE HEAVY RAINFALL LATER THIS
EVENING.
SEVERE THREAT HAS ALSO WANED THIS AFTERNOON. STILL CANT RULE OUT AN
ISOLATED DAMAGING THUNDERSTORM NEAR THE BAY...OTHERWISE HAVE BACKED
OFF ON SEVERE THREAT.
UPPER LOW REMAINS ACROSS THE OHIO VALLEY ON THURSDAY. IF
ANYTHING...IT RETROGRADES A LITTLE. HIGH PRECIPITABLE WATER
ENVIRONMENT REMAINS OVER THE CWA...AND THERE WILL BE MORE SHOWERS.
AND IT LIKELY WONT TAKE MUCH ACROSS THE WASHINGTON-BALTIMORE METRO
AREA TO EXACERBATE FLOODING PROBLEMS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
THE SURFACE AND UPPER-LEVEL LOWS ASSOCIATED WITH LEE WILL REMAIN
VERTICALLY STACKED OVER THE OHIO VALLEY AND MIDWEST THROUGH FRIDAY.
HURRICANE KATIA WILL PASS BY WELL TO OUR EAST DURING THIS TIME. A
STATIONARY BOUNDARY WILL REMAIN OVER THE REGION DURING THIS TIME
SEPARATING WARM AND HUMID AIR TO ITS NORTH AND EAST FROM DRIER AIR
TO THE SOUTH AND WEST. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE
BOUNDARY DURING THIS TIME. THE BEST CHANCE FOR PRECIPITATION WILL BE
DURING THE EVENING HOURS THURSDAY AND AGAIN FRIDAY AFTERNOON AND
EVENING. LOCALLY HEAVY RAINFALL IS POSSIBLE IN ANY THUNDERSTORMS
THAT DEVELOP...BUT IT WILL NOT BE AS WIDESPREAD AS RECENT DAYS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE TO SHOW A PERSISTENT CLOSED UPPER LEVEL LOW OVER THE
SOUTH CENTRAL CONUS THROUGH THE WEEKEND. THIS WILL CAUSE PREVAILING
SOUTHERLY FLOW THROUGHOUT THE ATMOSPHERE ENTRAINING MOIST AIR FROM
THE GULF OF MEXICO AND ATLANTIC ACROSS THE CWA. THROUGHOUT THE
EXTENDED PERIOD...THERE ARE CHANCES FOR PRECIPITATION EACH DAY.
HOWEVER...BY SUNDAY CANADIAN SURFACE HIGH PRESSURE WILL BEGIN TO
BUILD SOUTHWARD INTO THE MID ATLANTIC. THIS ALONG WITH THE GRADUAL
ZONAL ELONGATION OF THE UPPER LEVEL LOW...WHICH WILL SHIFT FLOW
LARGELY TO THE WEST...WILL HELP TO LOWER PRECIP CHANCES FOR THE
BEGINNING OF THE WORK WEEK. GUIDANCE SHOWS THE WEAKENING STACKED LOW
MOVING OFF THE EASTERN SEABOARD BY MONDAY. MODELS ARE IN FAIR
AGREEMENT THAT A SURFACE LOW PRESSURE SYSTEM WILL TRACK ACROSS NEW
ENGLAND DURING THE BEGINNING OF THE WORK WEEK CREATING THE POTENTIAL
FOR A FRONTAL PASSAGE ACROSS THE REGION. DUE TO THIS...SHOWERS
THROUGH THE DAY WITH AFTERNOON THUNDERSTORMS WILL BE POSSIBLE.
TEMPERATURES WILL REMAIN SEASONABLE THROUGH THE LONG TERM.
DECREASING CLOUD COVER OVER THE WEEKEND WILL ALLOW DAYTIME HIGHS TO
ONCE AGAIN CLIMB INTO THE MID 80S WITH LOWS IN THE LOW TO MID 60S.
AS THE OVERALL SYNOPTIC PATTERN BEGINS TO TRANSITION...DRIER
CONTINENTAL AIR WILL PUSH INTO THE CWA HELPING TO LOWER RH VALUES.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
MAIN THRUST OF HEAVY RAINFALL/LOW VSBYS ASSOCIATED WITH
THUNDERSTORMS HAS MOVED NORTH OF THE DCA/BWI HUBS. HEAVIEST AXIS SET
UP JUST EAST OF IAD. THERE WILL BE ADDITIONAL SHRA/TSRA INTO THIS
EVENING...BUT ACTIVITY MAY WIND UP BEING MORE SCATTERED. WITH
THAT...VSBYS LIKELY WILL BE PREVAILING VFR FOR THE REST OF THE
AFTERNOON AT THE HUBS. CIGS WILL ALSO LIKELY BE ABLE TO IMPROVE FROM
IFR TO MVFR FOR A TIME THIS AFTERNOON ALTHOUGH MRB/CHO WILL HAVE
MORE TROUBLE IMPROVING. HOWEVER...AT THE SITES WHERE SOME AFTERNOON
IMPROVEMENT OCCURS CIGS ARE EXPECTED TO DROP BACK DOWN TO IFR AND
POSSIBLY LIFR THIS EVENING. GUIDANCE INDICATES THAT VSBYS MAY FOLLOW
SUIT OVERNIGHT. SO WIDESPREAD IFR/LIFR CONDITIONS ARE EXPECTED AT
ALL TERMINALS TONIGHT INTO EARLY THURSDAY MORNING BEFORE CONDITIONS
IMPROVE SOME FOR THURSDAY AFTERNOON.
LOW CLOUDS AND FOG WILL REDUCE CIGS AND VSBYS THURSDAY NIGHT INTO
FRIDAY MORNING. SCATTERED TO NUMEROUS SHOWERS AND T-STORMS ARE
ALSO EXPECTED THURSDAY NIGHT THROUGH FRIDAY.
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY OVER THE WEEKEND AND INTO
THE BEGINNING OF THE WORK WEEK COULD OCCASIONALLY LOWER VISIBILITIES
AT AREA TERMINALS. CEILINGS WILL BEGIN TO RISE AS DRIER AIR BECOMES
ENTRAINED ACROSS THE CWA.
&&
.MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 6 PM UP THE BAY FOR
SOUTH/SOUTHEAST WINDS BEING CHANNELING UP THE BAY. WINDS ARE
EXPECTED TO LESSEN THIS EVENING...ALTHOUGH ANY SHOWERS COULD LOCALLY
TRANSPORT HIGHER GUSTS.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS ARE EXPECTED THURSDAY
NIGHT THROUGH FRIDAY AS A STATIONARY BOUNDARY REMAINS NEAR THE
WATERS.
DECREASING SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED OVER THE
WEEKEND. PRIMARILY LIGHT WINDS INCREASING TO ABOUT 10KT IN THE
AFTERNOONS SHOULD LIMIT WAVES TO 2 FT OR LESS.
&&
.HYDROLOGY...
WE HAVE BEEN WAITING FOR A COUPLE DAYS NOW TO SEE WHERE THE PRIMARY
RAINBAND IS GOING TO SET UP. I THINK WE ARE STARTING TO SEE THE
ANSWER...AND IT APPEARS TO BE FARTHER EAST THAN ORIGINALLY PROJECTED
BY COMPUTER MODELS.
THIS HAD PRETTY SIGNIFICANT IMPLICATIONS ON THE RIVER FORECASTS
PRODUCED BY THE MIDDLE ATLANTIC RIVER FORECAST CENTER...WHICH ARE
NOW SHARPLY LOWER IN MANY AREAS.
ADDITIONAL RAINFALL WILL BE VERY LIMITED IN THE UPPER POTOMAC...
PERHAPS LESS THAN A QUARTER INCH. BUT TWO TO FOUR ADDITIONAL INCHES
OF RAINFALL...WITH ISOLATED HIGHER AMOUNTS...REMAINS POSSIBLE IN THE
EASTERN HALF OF THE FORECAST AREA. I STILL SEE SOME RISK OF UPSLOPE
PRECIP AS WELL...WHICH COULD ENHANCE AMOUNTS LOCALLY.
AT THIS TIME...ISSUED NO NEW FLOOD WARNINGS FOR THE RIVERS. ONLY PAW
PAW ON THE POTOMAC...AND A FEW OF THE SMALL TRIBUTARIES...HAVE
WARNINGS AT THIS TIME. SEVERAL RIVER FLOOD WATCHES REMAIN IN EFFECT.
&&
.TIDES/COASTAL FLOODING...
COASTAL FLOOD ADVISORY IS IN EFFECT FOR HIGH TIDE ON THE UPPER
TIDAL POTOMAC STARTING THIS AFTERNOON AND THEN TONIGHT FOR THE
REST OF THE AREA INTO THURSDAY MORNING. ANOMALIES OF 1 TO PERHAPS
2 FEET ARE EXPECTED. WILL NEED TO WATCH SENSITIVE LOCATIONS SUCH
AS ANNAPOLIS AND BOWLEY BAR AS SOLID COASTAL FLOOD ADVISORY
CRITERIA COULD COME CLOSE TO MODERATE THRESHOLD. HAVE KEPT WATCH
UP FOR THE SUBSEQUENT HIGH TIDE CYCLES THROUGH FRIDAY MORNING.
WITH AN EASTERLY WIND...AM WORRIED THAT WATER MAY REMAIN TRAPPED
AND ANOMALIES AT OR ABOVE CURRENT LEVELS WILL BE IN PLACE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR DCZ001.
FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THURSDAY FOR DCZ001.
MD...COASTAL FLOOD WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR MDZ007-011-013-014-016>018.
FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MDZ004>007-
009>011-013-014-016>018.
COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 10 AM EDT
THURSDAY FOR MDZ007-011-014-016>018.
COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THURSDAY FOR MDZ013.
VA...COASTAL FLOOD WATCH FROM THURSDAY MORNING THROUGH FRIDAY
MORNING FOR VAZ052>055-057.
FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VAZ042-
052>055-057.
COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 10 AM EDT
THURSDAY FOR VAZ052-055-057.
COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THURSDAY FOR VAZ053-054.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ530>534-537-538-542-543.
&&
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...BJL
LONG TERM...CJL
AVIATION...BPP/BJL/CJL
MARINE...BPP/BJL/CJL
HYDROLOGY...JCE
TIDES/COASTAL FLOODING...BPPHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 740 PM EDT WED SEP 7 2011 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 081045- 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- 740 PM EDT WED SEP 7 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 A FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE AREA THROUGH THIS EVENING. PLEASE REFER TO THE LATEST HAZARD MESSAGE /FFALWX/ FOR FURTHER DETAILS. A FLOOD WARNING IS IN EFFECT FOR THE AREA THROUGH 1115 PM FOR CREEKS AND STREAMS. SEE FLWLWX FOR MORE DETAILS. A FEW THUNDERSTORMS ARE POSSIBLE THIS EVENING. ISOLATED DAMAGING WIND GUSTS AND PERHAPS EVEN AN ISOLATED TORNADO WILL BE POSSIBLE. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR LOCATIONS ALONG THE UPPER TIDAL POTOMAC RIVER...INCLUDING WASHINGTON DC AND ALEXANDRIA. A COASTAL FLOOD ADVISORY IS ALSO IN EFFECT ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY AND TIDAL POTOMAC RIVER TONIGHT. A SMALL CRAFT ADVISORY IS IN EFFECT FOR PORTIONS OF THE WATERS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE THREAT FOR HEAVY RAIN WILL PERSIST INTO THURSDAY...WITH A CONTINUED RISK OF FLASH FLOODING. THE COASTAL FLOOD ADVISORY FOR THE WESTERN SHORE OF THE CHESAPEAKE BAY AND TIDAL POTOMAC RIVER CONTINUES INTO THURSDAY MORNING...THEN A COASTAL FLOOD WATCH REMAINS IN EFFECT THURSDAY AFTERNOON THROUGH FRIDAY MORNING. MINOR RIVER FLOODING IS EXPECTED ALONG THE LOWER POTOMAC RIVER AND ITS TRIBUTARIES THROUGH FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. PLEASE RELAY REPORTS OF FLOODING AND HEAVY RAINFALL TOTALS TO THE NATIONAL WEATHER SERVICE. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-081045- 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- 740 PM EDT WED SEP 7 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 A FLASH FLOOD WATCH IS IN EFFECT FROM FREDERICK COUNTY MARYLAND SOUTH THROUGH THE WESTERN SUBURBS OF WASHINGTON DC AND TOWARD THE FREDERICKSBURG AREA THROUGH THIS EVENING. PLEASE REFER TO THE LATEST HAZARD MESSAGE /FFALWX/ FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE THREAT FOR HEAVY RAIN WILL PERSIST INTO THURSDAY... WITH A CONTINUED RISK OF FLASH FLOODING MAINLY EAST OF THE BLUE RIDGE. MINOR RIVER FLOODING IS EXPECTED ALONG THE LOWER POTOMAC RIVER AND ITS TRIBUTARIES THROUGH FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. PLEASE RELAY REPORTS OF FLOODING AND HEAVY RAINFALL TOTALS TO THE NATIONAL WEATHER SERVICE.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
612 PM EDT WED SEP 7 2011
MDZ006-010-011-014-072300-
NORTHERN BALTIMORE MD-HOWARD MD-ANNE ARUNDEL MD-SOUTHERN BALTIMORE MD-
612 PM EDT WED SEP 7 2011
...LOCALLY HEAVY SHOWERS TO AFFECT NORTHERN BALTIMORE...HOWARD...ANNE
ARUNDEL AND SOUTHERN BALTIMORE COUNTIES...
A LINE OF SHOWERS HAVE DEVELOPED ACROSS THE WESTERN AND SOUTHERN
SUBURBS OF BALTIMORE. THESE SHOWERS ARE MOVING NORTH AT 30 MPH.
HEAVY DOWNPOURS FROM THESE SHOWERS ARE OCCURRING OVER THE SAME AREA
THAT RECEIVED HEAVY RAINFALL EARLIER TODAY. THIS WILL LIKELY KEEP
WATER LEVELS ELEVATED AND FLOODING MAY REDEVELOP EARLY THIS EVENING.
ADDITIONAL RAINFALL AMOUNTS OF ONE INCH CAN BE EXPECTED THROUGH 7 PM.
LOCATIONS IMPACTED INCLUDE ELLICOTT CITY...COLUMBIA...
REISTERSTOWN...BROOKLYN PARK AND BALTIMORE.
&&
LAT...LON 3963 7657 3961 7664 3957 7655 3953 7651
3950 7644 3924 7646 3920 7649 3925 7655
3926 7660 3917 7647 3904 7648 3918 7685
3955 7686 3966 7682 3961 7666 3964 7658
3972 7663 3972 7662
TIME...MOT...LOC 2206Z 180DEG 27KT 3954 7679 3919 7653
3927 7675
JRKSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
655 PM EDT WED SEP 7 2011
MDZ017-072330-
ST. MARYS MD-
655 PM EDT WED SEP 7 2011
...STRONG THUNDERSTORM TO AFFECT ST. MARYS COUNTY...
AT 655 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 10
MILES SOUTHWEST OF VALLEY LEE...MOVING NORTH AT 30 MPH.
LOCATIONS IMPACTED INCLUDE SAINT MARYS RIVER...SAINT MARYS CITY...
LEONARDTOWN...LEXINGTON PARK...CALIFORNIA...TOWN CREEK...PATUXENT
RIVER NAS AND HOLLYWOOD.
THIS STORM IS PRODUCING FREQUENT CLOUD TO GROUND LIGHTNING. MOVE
INDOORS IMMEDIATELY FOR YOUR SAFETY. IF YOU CAN HEAR THUNDER...YOU
ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.
HEAVY RAIN WITH THIS STORM WILL REDUCE VISIBILITIES TO BELOW ONE
MILE AND POND ON ROADWAYS.
WIND GUSTS OF 30 TO 40 MPH CAN BE EXPECTED WITH THIS STORM. WITH THE
GROUND ALREADY SATURATED...WINDS OF THIS MAGNITUDE COULD BE ENOUGH
TO BRING DOWN TREES.
&&
LAT...LON 3827 7638 3823 7637 3810 7647 3813 7650
3814 7654 3819 7655 3822 7661 3823 7669
3839 7667 3836 7649 3833 7649 3830 7645
3832 7641 3830 7636
TIME...MOT...LOC 2255Z 200DEG 26KT 3809 7659
JRKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
752 PM EDT WED SEP 07 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0740 PM TSTM WND DMG 3 SE LEONARDTOWN 38.27N 76.60W
09/07/2011 ST. MARYS MD TRAINED SPOTTER
APPROX 6-8 TREES DOWN
&&
EVENT NUMBER LWX1101804
HASPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
753 PM EDT WED SEP 07 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0740 PM FUNNEL CLOUD 3 SE LEONARDTOWN 38.27N 76.60W
09/07/2011 ST. MARYS MD TRAINED SPOTTER
&&
EVENT NUMBER LWX1101805
HASSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
834 PM EDT WED SEP 7 2011
MDZ014-018-080100-
ANNE ARUNDEL MD-CALVERT MD-
834 PM EDT WED SEP 7 2011
...STRONG THUNDERSTORM TO AFFECT ANNE ARUNDEL AND CALVERT COUNTIES...
AT 834 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 4 MILES
EAST OF PRINCE FREDERICK...MOVING NORTH AT 25 MPH.
LOCATIONS IMPACTED INCLUDE BREEZY POINT...CHESAPEAKE BEACH AND NORTH
BEACH.
THIS STORM IS PRODUCING VERY HEAVY DOWNPOURS AND FREQUENT CLOUD TO
GROUND LIGHTNING. MOVE INDOORS IMMEDIATELY FOR YOUR SAFETY. IF YOU
CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.
HEAVY RAIN WITH THIS STORM WILL REDUCE VISIBILITIES TO BELOW ONE MILE
AND MAY CAUSE PONDING OF WATER ON ROADWAYS.
WIND GUSTS OF 40 TO 50 MPH CAN BE EXPECTED WITH THIS STORM. WITH THE
GROUND ALREADY SATURATED...WINDS OF THIS MAGNITUDE COULD BE ENOUGH
TO BRING DOWN TREES.
&&
LAT...LON 3856 7651 3852 7650 3851 7651 3852 7659
3881 7661 3882 7649 3875 7652 3868 7651
3866 7652 3862 7650
TIME...MOT...LOC 0034Z 187DEG 21KT 3857 7652
JRKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
853 PM EDT WED SEP 07 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0740 PM TORNADO 2 W CALLAWAY 38.24N 76.56W
09/07/2011 ST. MARYS MD TRAINED SPOTTER
SPOTTER WITNESSED TORNADO SNAPPING SEVERAL TREES WITH
ROARING WIND. DAMAGE WAS IN THE WOODS JUST NORTH OF
ROUTE 5 NEAR THE INTERSECTION WITH LIGHTFOOT WAY.
&&
EVENT NUMBER LWX1101806
STRONGThe Sterling radar (KLWX), 84 km away, was scanning. The volume nearest the first event began at 01:45 UTC.
31 flash flood, 1 flood. Local standard time, as filed.
Poplar Neck Road was closed due to flash flooding. A trained spotter near the event recorded a storm total of 12.30 inches of rain.
Owens Drive at Potomac Drive was closed due to flash flooding. A nearby spotter recorded 8.35 inches of rain.
Route 110 and Interstate 66 Exit Ramp closed at their intersection due to high water. A trained spotter in Arlington recorded 9.90 inches of rainfall.
A high water rescue was performed at Route 50 and Annandale Road. A nearby spotter observed 6.00 inches of rain.
Swift water rescue at Route 123 at the Dulles Toll Road. A storm total rainfall amount near this event was 11.45 inches.
The retention pond at Fair Oaks Mall overtopped its banks and flooded Route 50. A spotter near this location recorded 10.18 inches.
Route 123 near Assembly Drive was closed due to flash flooding.
University Drive near George Mason University was closed due to flash flooding.
A swift water boat rescue was performed at Hunter Mill Road and Lawyers Road as a result of flash flooding. A nearby spotter measured 5.39 inches of rain.
High water rescued being peformed on stranded vehicles at the intersection of Routes 123 and 50. A nearby spotter recorded 7.59 inches of rain.
Hunter Mill Road underpass beneath the Dulles Toll Road was closed due to flash flooding. A nearby spotter recorded 6.84 inches of rain during the event.
Wiehle Avenue was closed at North Shore Drive due to flash flooding.
A swift water rescue was performed near the intersection of Walker Road and Windswept Drive due to flash flooding.
Waples Mill Road was closed at Oakton Road due to flash flooding.
Flash flooding of Accotink Creek forced the closure of numerous roadways, including Route 50 at Rebel Run, Eaton Place, and Draper Drive. Also, Pickett Road was closed at Old Pickett Road and Old Lee Highway was closed at Ridge Drive.
Route 50 closed at Oak Street due to flash flooding.
Intersection of University and Kenmore Drives closed due to flash flooding.
Intersection of Stringfellow Road and Route 50 was closed due to flash flooding.
Flash flooding on Piney Branch Creek near Marcliff Court swept away and drowned a 12 year old male.
Flash flooding on Charles Branch submerged vehicle on Beach Mill Road near Club View Drive. One person was swept away and drowned.
Flash flooding of Accotink Creek stranded cars on Route 1, Fairfax County Parkway, and Telegraph Road. On Accotink Creek Bridge on Telegraph Road, one person was swept away and drowned.
Flash Flooding on Turkey Cock Run closed Edsall Road and submerged a car. A nearby spotter observed 12.56 inches of rain.
Numerous roadways were closed throughout the county, with the most concentrated and significant flash flooding occurring around Dahlgren.
South West Street closed between Poplar Drive and Kennedy Street due to flash flooding.
Southbound Interstate 95 was closed between Telegraph Road and the Eisenhower Road Exit due to flash flooding on Cameron Run.
Sherrow Road was closed due to flash flooding.
South Oak Street was closed due to flash flooding.
Westbound Interstate 66 was closed due to flash flooding at Exit 57.
Virginia Railway Express Trains shut down due to flash flooding on the tracks.
Numerous high water rescues were performed on Cinder Bed Road. A nearby observer recorded 9.94 inches of rain.
River Road was closed due to flash flooding.
Numerous roadways were closed in eastern Spotsylvania County. A sinkhole occurred near the intersection of Windsor Drive and Abbey Lane.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Flash Flood, Fairfax (C) | 2011-09-08 | 12 | Male | Outside/Open Areas | Direct |
| Flash Flood, Fairfax | 2011-09-08 | 67 | Male | Vehicle/Towed Trailer | Direct |
| Flash Flood, Fairfax | 2011-09-08 | 25 | Male | Vehicle/Towed Trailer | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2011Every state in 2011This day in weather historyWarnings in Virginia, September 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 346944, 346945, 346950, 346957, 346962, 346966, 346970, 346972, 346974, 346979, 346981, 346982, 346983, 346984, 347038, 347044, 347045, 347046, 347048, 347052, 347047, 347050, 347053, 347055, 347057, 347058, 347059, 347060, 347061, 347062, 347063, 347064.