A weak cold front moved southward into the Mid Atlantic. A line of showers and thunderstorms formed and moved southward and heavy rain was observed.
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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.
A weak cold front moved southward into the Mid Atlantic. A line of showers and thunderstorms formed and moved southward and heavy rain was observed.
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 Jul 21, 4:15 PM EST, 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 515 PM EDT SUN JUL 21 2013 .SYNOPSIS... A WEAK COLD FRONT IS POSITIONED ALONG THE NEW YORK-PENNSYLVANIA BORDER. THIS IS EXPECTED TO SLOWLY TRACK SOUTH TODAY BEFORE RETURNING NORTH MONDAY. A COLD FRONT MAY APPROACH THE REGION IN THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 21Z...MSAS ANALYSIS INDICATES WEAK BOUNDARY ACROSS SRN MD AND INTO THE VA PIEDMONT...BASED ON LIGHT NORTHERLY FLOW ACROSS MOST OF THE AREA AND A WEAK DEW POINT GRADIENT. SHOWERS AND TSTMS AROUND THE VICINITY OF THE BOUNDARY HAVE REACHED THE I-95 CORRIDOR...AND WILL CONTINUE TO PUSH EASTWARD. WEST OF 95...TRAILING STRATIFORM RAIN PREVAILS ACROSS MOST OF MD...THE ERN WV PANHANDLE...AND NRN VA. ACTIVITY IS EXPECTED TO CONTINUE PUSHING EWD LATE THIS AFTN AND EARLY EVENING. MAIN THREAT FOR TSTM ACTIVITY IS HEAVY RAIN AND LOCALIZED FLASH FLOODING. WIND GUSTS PRIMARILY IN THE 20-35KT RANGE...SO NO DAMAGING GUSTS/SEVERE TSTMS EXPECTED. THE MAIN SURFACE COLD FRONT LOOKS LIKE IT WILL REMAIN OVER PA BEFORE LIFTING BACK TO THE NORTH TONIGHT. XPCT SKIES WL BE M CLDY TNGT. LOWS IN THE 70S E OF THE MTNS..60S W. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... WITH ONLY SUBTLE CHANGES IN THE OVERALL WEATHER PATTERN THE TREND TOWARD DIURNAL SHOWERS AND THUNDERSTORMS IS LIKELY TO CONTINUE. THE GFS HAS A SURGE OF HIGHER THETA-E AIR MOVING UP FROM THE SOUTH AS THE BOUNDARY IN PA LIFTS NORTH MONDAY IN RESPONSE TO A SHORTWAVE MOVING THRU THE GREAT LAKES. HIGH TEMPERATURES WILL RANGE FROM A90 IN THE METRO AREAS TO THE U70S IN THE MOUNTAINS...MAJORITY OF AREA WL TOP OUT IN THE MU80S. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... ITS NOT EASY TO FIGURE OUT WHERE THE FNT WL BE RESIDING TUE. BEST H8 THERMAL PACKING HANGS ACRS NRN NYS/NEW ENGLAND...INSTBY PARAMETERS SURGE NWD TO THE ST. LAWR RIVER VLY...SFC DEWPT GRADIENT SUGGESTS A DIFFUSE SOMEWHERE ACRS PA/NJ...YET THE PRES FIELDS /AND IN SOME MDL GDNC THE NWLY WND TRAJ/ DIP S OF CWFA. H5 HGTS DROP IN RESPONSE TO S/WV ENERGY ROUNDING AN UPR LOW NEAR THE HUDSON STRAIT. REGARDLESS OF THE PRESENCE /OR ABSENCE/ OF A SFC BNDRY...AMS WL BE MOIST AND MDTLY UNSTBL. SHEAR WL BE NEGLIGIBLE...BUT PWAT SHUD BE ARND 2 INCHES /AGAIN/. GIVEN THE LWR HGTS AND FVRBL LLVL CONDS...WL BE KEEPING LKLY POPS...PLACING EMPHASIS ON THE PREFERRED AFTN-EVE HRS WHEN HEATING WL BE BEST. THE UPR TROF DOES SEND A WK SFC BNDRY OUR WAY WED...REINFORCING SFC TROFFING ALONG THE EASTERN SEABOARD. PWATS DROP TO ABT 1.5 INCHES... BUT INSTBY REMAINS. AS SUCH...LKLY POPS WL STAY IN THE GRIDS...ALTHO THE POTL FOR HVY RAINERS MAY BE A LTL BIT LESS. ATM ABT THE SAME THERMALLY AS TUE...AND WL KEEP TEMPS...BOTH MAXT AND MIN-T...NEARLY THE SAME. THE CONUNDRUM WIDENS THU INTO FRI...AS GDNC DIVERGES FROM CLIMO... SLIDING THE SFC FNT/BNDRY EWD TWD THE WRN ATLC. DO BELIEVE THAT LWR POPS REASONABLE. HWVR IF THIS OUTCOME HOLDS TRUE...THE CWFA CUD BE IN FOR A SUNNY/DRY/SEASONABLY WARM PD...SPCLY THU NGT INTO FRI NGT. WL GO ALONG W/ MODIFIED VERSION OF THIS SOLN ATTM...BUT RECENT MDL PERFORMANCE IN SIMLR SITUATIONS SUPPORTS SKEPTICISM. CANT HOLD THE GOOD FORTUNE INTO THE NEW WKND...AS THERE MAY BE ANTHR FNT DROPPING SWD FM THE GRTLKS. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... LN OF RW/TRW NOW TRACKING E OF I-95...WITH TRAILING LIGHT RAIN ACROSS MUCH OF MD...NRN VA AND ERN WV PANHANDLE. RAIN CONTINUES INTO EARLY EVENING AT ALL TAF SITES EXCEPT KCHO...WITH PERIODIC MVFR/IFR POSSIBLE. PRIMARILY VFR THIS EVENING AFTER THE RAIN CLEARS...BUT SOME SHOWERS/TSTMS MAY REDEVELOP. WILL ALSO HAVE TO CONSIDER POSSIBILITY OF LATE NIGHT FOG IN 00Z TAFS BASED ON LOW LEVEL MOISTURE FROM TODAY'S RAIN. OCNL FLGT RESTRICTIONS PSBL TUE INTO WED DUE TO NMRS TSRA. PRIME TIME SHUD BE AFTN-EVE...INCL THE AFTN PUSH. WHILE VFR SHUD PREVAIL OVERALL...BRIEF MVFR-IFR PSBL. THE MRNG PUSH MORE SUSCEPTIBLE TO PATCHY FOG...ALTHO THE LIKELIHOOD OF THAT HAPPENING LWR. && .MARINE... LINE OF SHOWERS/TSTMS OVER THE NRN CHES BAY..AND APPROACHING THE TIDAL POTOMAC AS OF 21Z. THIS ACTIVITY WILL CROSS THE WATERS OVER THE NEXT FEW HRS. MAIN HAZARD IS GUSTY WINDS ABOVE 35KTS ASSOCIATED WITH STORMS. WK FLOW TUE-THU SHUD RESULT IN LGT/VRBL GRADIENT WND CONDS. AM XPCTG NMRS SHRA/TSRA...SPCLY DURING THE AFTN-EVE HRS. LCLLY HIER WNDS/WVS XPCTD INVOF TSRA...POTENTIALLY REQUIRING SPECIAL MARINE WRNGS. .CLIMATE,,, YDA DCA BROKE THE RECORD FOR MOST CONSECUTIVE DAYS/NGTS WHERE THE TEMP DIDN'T DROP BLO 80. RECORD IS NOW 5 ECLIPSING THE PRVS RECORD SENT IN JUL 2011. THIS MRNG DCA SPENT 4 HRS W/ TEMPS IN THE U70S. PRIOR TO 2011 THERE HAD NEVER BEEN A PD OF LONGER THAN 2 NGTS WHEN THE LOW DIDN'T GET BLO 80. ONE LAST "DC 80" FACT - THE EARLIEST RECORDED DATE WHEN THE TEMP DIDN'T DROP BLO 80 IN DC WAS 7/20/1876. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && NEAR TERM/AVIATION/MARINE UPDATE...KCS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 433 PM EDT SUN JUL 21 2013 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 220945- 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- 433 PM EDT SUN JUL 21 2013 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 WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH TONIGHT...PRODUCING SCATTERED THUNDERSTORMS. SOME OF THESE STORMS WILL PRODUCE HEAVY RAIN. LOCALIZED FLASH FLOODING IS POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THUNDERSTORMS REMAIN LIKELY ON MONDAY AND TUESDAY. A FEW OF THESE STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAIN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-220945- 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- 433 PM EDT SUN JUL 21 2013 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 WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH TONIGHT...PRODUCING SCATTERED THUNDERSTORMS. SOME OF THESE STORMS WILL PRODUCE HEAVY RAIN. LOCALIZED FLASH FLOODING IS POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THUNDERSTORMS REMAIN LIKELY ON MONDAY AND TUESDAY. A FEW OF THESE STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAIN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY.
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1131 AM EDT SUN JUL 21 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0835 PM TSTM WND DMG 2 NW CLARKSBURG 39.26N 77.31W
07/20/2013 MONTGOMERY MD 911 CALL CENTER
TREE DOWN NEAR TRUCK WEIGH STATION ON NB I-270
&&
CORRECTED EVENT TIME
EVENT NUMBER LWX1300690
STRONGThe Dover AFB radar (KDOX), 97 km away, was scanning. The volume nearest the first event began at 21:29 UTC.
1 flash flood. Local standard time, as filed.
There were two roads with 6 to 12 inches of flowing water over them. One of the roads had a foot of ponding and one swift water rescue.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2013Every state in 2013This day in weather historyWarnings in Maryland, July 2013
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: 467769.