A decaying meso-scale convective system moved across the Mid Atlantic in the afternoon and thunderstorms developed on the southern edge of the system across Southern Maryland and Central Virginia.
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The episode as NWS LWX wrote it up.
A decaying meso-scale convective system moved across the Mid Atlantic in the afternoon and thunderstorms developed on the southern edge of the system across Southern Maryland and Central Virginia.
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 May 12, 8:54 AM EST, 4 hours 51 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 954 AM EDT MON MAY 12 2014 .SYNOPSIS... HIGH PRESSURE OFF THE SOUTH CAROLINA COAST WILL LEAD TO WARM CONDITIONS FOR THE FIRST PART OF THE WEEK. A COLD FRONT WILL MOVE INTO THE REGION WEDNESDAY AND REMAIN OVER THE AREA THROUGH THE END OF THE WEEK. HIGH PRESSURE IS EXPECTED TO RETURN TO THE MID ATLANTIC STATES FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK SURFACE PRESSURE PATTERN RESIDES OVER THE MID-ATLANTIC TODAY. ALOFT...RIDGE IS IN PLACE ACROSS THE WESTERN ATLANTIC AND SOUTHERN STATES. MID-ATLANTIC LIES ON THE NORTHERN EDGE OR PERIPHERY OF THE RIDGE AND A WEAKENING CONVECTIVE SYSTEM WAS RIDING ALONG THIS NORTHERN FRINGE OVER CENTRAL/EASTERN WV. THIS WEAKENING SYSTEM WILL BRING SOME SHOWERS AND ISOLATED THUNDERSTORMS THIS MORNING ACROSS THE HIGHLANDS. THERE IS THE POSSIBILITY THAT THE SOUTHERN TAIL OF THIS SYSTEM REINVIGORATES SOME DURING THE MIDDAY AND AFTERNOON HOURS...AFFECTING THE NORTH CENTRAL VA PIEDMONT AND PERHAPS LOWER SOUTHERN MARYLAND. HOWEVER LOOKING AT THE 12Z KIAD AND FORECAST MODEL SOUNDINGS...BOTH LOW LEVEL SURFACE INSTABILITY AND SHEAR ARE FORECAST TO BE ON THE WEAK SIDE AN NO SEVERE WX IS EXPECTED. BEHIND THE CONVECTIVE SYSTEM...ADDITIONAL CONVECTION DEVELOPMENT MAY OCCUR THIS AFTERNOON. NO SUBSTANTIAL WIND SHIFT OR DRYING OCCURS BEHIND IT...AND THUS EXPECT ISOLATED TO SCATTERED THUNDERSTORMS OVER THE HIGHER TERRAIN THIS AFTERNOON. THESE MAY PROPAGATE EASTWARD INTO THE EARLY EVENING BEFORE DISSIPATING. REPOPULATED TEMPS BASED ON LATEST MAV/MET BLEND...STAYING WITH THE FLAVOR OF ABOVE NORMAL BY 10 OR MORE DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... ANY CNVCTN THAT DVLPS DURG THE AFTN SHOULD BE ON THE WANE DURG THE EVE HRS...AGN WIND FIELD THRU 20K FT IS VERY WEAK. ALTHO IT'S PRBLY STILL TOO ERLY TO USE THE WORD "SULTRY" TO DESCRIBE TNGT'S WX...IT WL BE RLTVLY WARM. DID A CHECK OF THE WARMEST MIN TEMPS TO SEE IF THIS COULD BE THE WARMEST OVRNGT SO FAR THIS YR: AIRPORT FCST LOW HIGHEST MIN IN 2014 SO FAR DCA 68 67 (5/10) BWI 65 62 (4/14) IAD 64 63 (4/14) MAJORITY OF AREA WL DROP INTO THE LM60S. IN TERMS OF CONVECTIVE INSTABILITY OVER A MULTI-DAY PERIOD...THE NEXT FEW DAYS WILL BE THE MOST UNSTABLE FOR OUR REGION SO FAR THIS YEAR. THE PASSAGE OF ANY ORGANIZED SYNOPTIC-SCALE FEATURE WILL BE A SLOW BOIL HOWEVER...W/ EACH DAY FOR THE UPCOMING WORK WEEK HAVING THE POTENTIAL FOR SOME WEAK CONVERGENCE/DIURNAL CONVECTION. AN OFFSHORE HIGH WILL SUPPLY THE MUCH-ABOVE AVG TEMPS AND MOISTURE. A DEEPENING UPPER TROUGH TO OUR WEST WILL SUPPLY THE GRADUALLY ENVIRONMENT FOR STEEPER LAPSE RATES. DESPITE THESE MORE FAVORABLE CONVECTIVE CONDITIONS...ONLY LOCAL-SCALE AND/OR WEAK CONVERGENCE ZONES WILL HELP DEVELOP OUR SHOWER/TSTM CHANCES FOR THE NEXT FEW DAYS. AFTER SOME SCATTERED/ISOLATED TSTMS ON MON-MON EVE...CONDITIONS WILL SETTLE DOWN AGAIN W/ A WARM OVERNIGHT THAT WILL SET US UP FOR ANOTHER HOT DAY ON TUE. WHILE MIDWEST AND MS VLY ARE UNDER THE CONVECTIVE CROSSHAIRS MON-TUE...A NEARBY WARM FRONT AND SOME WEAK LEE TROUGH ACTIVITY WILL HELP DEVELOP TSTMS OVER THE MID ATLC ON TUE AFTN. GIVEN SOME CONVECTION INITIATION...THERE WILL BE AMPLE INSTABILITY FOR INDIVIDUAL CELLS TO PRODUCE STRONG-SEVERE WX IN ISOLATED AREAS. WE'LL BE EXPERIENCING SOME OF THE HIGHEST DEWPOINTS OF THE YEAR SO FAR ON TUE AFTN. COUPLE THAT W/ TEMPS ON DOORSTEP OF THE 90F MARK AND WE'LL SEE SOME OF THE WARMEST HEAT INDICES OF THE YEAR...POTENTIALLY IN THE M90S. THE FRONTAL SYSTEM CAUSING LIKELY WIDESPREAD CONVECTION A COUPLE OF STATES TO OUR WEST ON TUE WILL BREAK OFF FROM ANOTHER UPPER WAVE OVER THE SRN PLAINS AND TAKE OFF TO THE NE - WELL AWAY FROM OUR AREA. THE COLD FRONT WON'T EVEN PASS OVER OUR AREA AS THE SRN PLAINS UPPER WAVE GEARS-UP TO DEVELOP IT'S OWN LOW PRESSURE SYSTEM. A SFC HIGH WILL DEVELOP OFF THE NEW ENGLAND COASTLINE LATE TUE INTO WED...SETTING-UP AN ONSHORE ELY FLOW OVER THE MID ATLC - ADDING SOME STABILITY AND COOLER CONDITIONS FOR AREAS E OF THE BLUE RIDGE ON WED. TEMPS WILL TAKE A BREAK FROM THE U80S ON WED...LIKELY STRUGGLING TO REACH THE L80S - OUTSIDE OF THE LOWER SHEN VLY/VA PIEDMONT. TSTMS WILL STILL BE POSSIBLE ACROSS THE AREA LATER IN THE DAY AS THE ONSHORE FLOW SUBSIDES AND SOME HEATING PUSHES THRU THE MARINE LAYER. A FAIRLY WEAK BUT STILL INFLUENTIAL SFC LOW PRESSURE SYSTEM WILL MOVE UP OVER THE LENGTH OF THE APLCNS FROM WED AFTN INTO THU. THE MARINE AIR WILL STILL BE IN PLACE OVER THE MD BAY/NEAR I-95 AS THE WARM FRONT OF THE LOW PRES SYSTEM APPROACHES. THE MARINE LAYER WILL DO ITS PART TO KEEP THESE AREAS STABLE...WHILE AREAS FURTHER WEST WILL RECEIVE AT LEAST SOME RESIDUAL ACTIVITY FROM THE WINDWARD SIDE OF THE APLCNS. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AFTER THE WARM FRONT MOVES THRU ON THU MRNG...WIPING AWAY AND MIXING OUT THE MARINE LAYER - SLY WINDS WILL GRADUALLY INCREASE TEMPS BACK INTO 70S. PRECIP WILL LARGELY CLEAR OUT FOR THE REST OF THE MRNG...WHILE A LARGE/THIN CORRIDOR OF MOISTURE GETS TRANSPORTED UP FROM THE GULF COAST TO THE GREAT LAKES. THIS NORTH-SOUTH ORIENTED SECTION OF MOISTURE WILL BE SLOWLY PUSHED EWD TOWARD THE APLCNS CHAIN. THIS CORRIDOR WILL EVENTUALLY REACH THE EASTERN SEABOARD TOWARD THE SECOND HALF OF THE DAY...W/ STEADY BATCHES OF MODERATE TO HEAVY PRECIP SLIDING OVER THE AREA FROM THE WEST THROUGHOUT THE EVE/NIGHTTIME HRS. AS MORE AND HEAVIER BATCHES OF PRECIP SLIDE OVER THE AREA OVERNIGHT/EARLY FRI...AREAL AND LOCALIZED FLOODING WILL BECOME A CONCERN. LONG RANGE MODEL QPFS AVERAGE IN THE 1-2" RANGE FOR MUCH OF OUR AREA...BUT 4-5 DAYS OUT - THERE IS STILL UNCERTAINTY IN TIMING AND AREAS OF OUR REGION EXPECTING THE MOST PRECIP. THE COLUMN WILL SATURATE WELL AS THE UPPER TROUGH APPROACHES. THIS WILL EFFECTIVELY EAT-UP THE RESIDUAL INSTABILITY...ALLOWING FOR ONLY A SMALL AMOUNT OF ELEVATED CAPE FOR CONVECTIVE INTENSITY AS THE PRECIP ARRIVES. LACK OF INSTABILITY WILL BE MORE THAN COMPENSATED FOR W/ THE INCREASE IN LOW LEVEL SHEAR AND HELICITY. THE UPPER TROUGH WILL STRETCH ALL THE WAY FROM SRN CANADA TO THE GULF COAST...BUT SMALLER-SCALE REGIONS ALONG THE LENGTH OF THE UPPER WAVE WILL BE INFLUENCED BY EMBEDDED VORTS SLIDING INTO IT FROM THE BACK SIDE. LATE THU INTO FRI...THIS TRANSITION PHASE WILL HELP BRING SOME OF THE HEAVIER BATCHES OF PRECIP ACROSS OUR REGION BUT WILL ALSO EVENTUALLY PUSH THIS ACTIVITY OFF THE COAST LATE IN THE DAY ON FRI. THE LATEST (00Z) GFS AND EURO RUNS ARE FAIRLY SIMILAR IN THEIR PASSAGE DEPICTIONS...TAKING THE PRECIP OFF THE COAST LATE FRI INTO EARLY SAT. THE MAIN CONTINUING DIFFERENCE IS THAT THE EURO MAKES THE MAIN DRIVER A CLOSED AND ANOMALOUSLY COLD UPPER LOW...WHILE THE GFS MAINTAINS AN OPEN UPPER WAVE THAT HAVE LESS PRECIP PUSHING-IN ONCE THE SUBSIDENCE REGION ARRIVES HEADING INTO THE WEEKEND. JUST AS W/ MOST UPPER LEVEL LOWS...SAT INTO SUN - WE'LL HAVE THE UPPER COLD AIR REGION MOVING ACROSS THE AREA. A FEW SHOWERS COULD MOVE OVER THE AREA W/ AN EMBEDDED UPPER WAVE BUT DRIER WX WILL LARGELY SPREAD OVER THE AREA THIS WEEKEND. DURING THE LATTER HALF OF THIS WEEK...THE APPROACH...PASSAGE...AND EXITING OF UPPER LEVEL FEATURE WILL MARK A GOOD DECREASE IN TEMPS...KEEPING THEM MUCH CLOSER TO AVG FOR THIS TIME OF YEAR. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... COMPLEX OF SHRA/ISOLATED TSRA OVER WV SHOULD CONTINUE TO WEAKEN OVER THE NEXT FEW HOURS BUT THERE IS SOME UNCERTAINTY HOW LONG IT HOLDS TOGETHER. ADDITIONAL CONVECTION MAY ALSO FIRE BEHIND IT THIS AFTERNOON OVER THE MTNS. CURRENTLY HAVE VCTS AT THE HUBS COINCIDING WITH SCATTERED THUNDERSTORMS IN GRIDDED DATABASE BUT CONVECTION COULD APPROACH THE TERMINALS SOONER THAN THIS DEPENDING ON PROGRESSION OF AFOREMENTIONED COMPLEX. OUTSIDE OF ANY CONVECTION...PREVAILING VFR WITH SOUTHERLY WINDS MAINLY UNDER 10 KT. DAYTIME HEATING WILL PROVIDE THE SET-UP FOR CONVECTIVE POTENTIAL THROUGH MID WEEK BUT THE TRIGGER FOR DEVELOPING SHOWERS AND TSTMS WILL BE LIMITED. A WARM FRONT WILL GRADUALLY MOVE FROM SOUTH-TO- NORTH LATE WED THRU THE WEEKEND. BRIEF HEAVY RAINS POSSIBLE...ALONG W/ SOME ELEVATED TSTMS THU INTO FRI AS A BULK OF THE SYSTEM ARRIVES AND SLOWLY MOVES ACROSS THE REGION. THIS FEATURE WILL THEN MOVE OFF THE COAST W/ ANOTHER HIGH PRES RIDGE BUILDING IN THRU THE WEEKEND. && .MARINE... WINDS XPCTD TO RMN BLO SCA VALUES TDA AND TNGT IN A WEAK PRESSURE PATTERN HOWEVER IF WINDS REMAIN SOUTHERLY TONIGHT THEY MAY CHANNEL UP THE BAY FOR 10 TO 15 KT. IT IS PSBL THAT A TSTM COULD IMPACT THE WATERS IN THE AFTERNOON OR ERLY EVE HRS. HIGH PRESSURE WILL BE IN PLACE FOR THE FIRST HALF OF THE WEEK... KEEPING THE WATERS RELATIVELY QUIET. SOME SLY CHANNELING LATE MON INTO TUE...W/ THE MAIN THREATS BEING POTENTIAL TSTMS EACH AFTN/EVE THRU MID WEEK. BRIEF AND SCA CONDITIONS POSSIBLE WED NIGHT INTO THU...AS THE COLD ARRIVES FROM THE WEST. GULF MOISTURE WILL RIDE UP ACROSS THE ERN SEABOARD THU INTO FRI...BRINGING PERIODS OF HEAVY RAIN AND GUSTY WINDS TO THE BAY/TP REGION W/ QUIETER CONDITIONS FOR THE COMING WEEKEND. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && BPP/WOODY!/GMS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1113 AM EDT MON MAY 12 2014 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 131000- 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- 1113 AM EDT MON MAY 12 2014 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...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY HEAVY RAINFALL IS POSSIBLE THURSDAY NIGHT WHICH COULD LEAD TO FLOODING. ISOLATED SEVERE THUNDERSTORMS MAY ALSO BE POSSIBLE THURSDAY AND THURSDAY NIGHT. A SMALL CRAFT ADVISORY IS POSSIBLE THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-131000- 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- 1113 AM EDT MON MAY 12 2014 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...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY HEAVY RAINFALL IS POSSIBLE THURSDAY AND THURSDAY NIGHT WHICH COULD LEAD TO FLOODING. ISOLATED SEVERE THUNDERSTORMS MAY ALSO BE POSSIBLE THURSDAY AND THURSDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The Sterling radar (KLWX), 141 km away, was scanning. The volume nearest the first event began at 18:44 UTC.
1 thunderstorm wind. Local standard time, as filed.
There was a tree on a mobile home in Southwood Estates Mobile Home Park.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2014Every state in 2014This day in weather historyWarnings in Virginia, May 2014
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: 520199.