Upper-level high provided subsidence over the area while a southerly flow around high pressure over the Atlantic caused high humidity. Hot and humid conditions caused high heat index values during the 6th.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Upper-level high provided subsidence over the area while a southerly flow around high pressure over the Atlantic caused high humidity. Hot and humid conditions caused high heat index values during the 6th.
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 6, 8:45 AM EST, 5 hours 15 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
945 AM EDT FRI JUL 6 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH SATURDAY. A WEAK
COLD FRONT IS EXPECTED TO CROSS THE REGION SUNDAY AFTERNOON AND
EVENING...PROVIDING A FOCUS FOR SHOWERS AND THUNDERSTORMS. UPPER-
LEVEL LOW PRESSURE WILL STRENGTHEN OVER QUEBEC NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
ZONALLY-ELONGATED UPR HIPRES OVER CNTRL CONUS WILL NOSE EWD TDA.
ONGOING SHWRS IN FAR SWRN ZONES WILL CONT THEIR SWD MVMT...BUT
ADDITIONAL DVLPMT N OF THIS CLUSTER DOES NOT SEEM VERY LKLY. POPS
THIS AFTN WERE CONFINED TO SWRN ZONES.
GIVEN CURRENT TEMPS AND STRONG INSOLATION...MAXIMA TDA WERE INCRD
SLGTLY. WITH INVERSION HAVING BROKEN...TEMPS WILL BE SLOWER TO
CLIMB...BUT STILL SEEM LKLY TO APRCH 100F MANY LOCATIONS. HEAT
ADZY WAS EXPANDED TO INCLUDE ADDITIONAL CTYS IN SHENANDOAH VLY...
ERN WV PNHDL AND NRN VA.
SUBSIDENCE ASSOCIATED WITH HIPRES WILL SUPPRESS CNVCTN TNGT.
ALTHOUGH RADIATIONAL COOLING CONDS WILL BE PRIME...CONTD HIGH HEAT
DURG THE DAY AND VERY HIGH BNDRY LYR MSTR CONTENT WILL SLOW OVNGT
COOLING.
PRESENCE OF UPR RDG ON SAT WILL LMT CNVCTV POTENTIAL OWING TO
MODEST CAP AND MINIMAL SOURCE OF LIFT. ISOLD TSTMS ON HIGHER
TERRAIN CANNOT BE RULED OUT ENTIRELY BUT DOES NOT APPEAR LKLY.
HOWEVER...TSTMS XPCD TO DVLP ALONG SAGGING CDFNT IN CNTRL PA.
THESE MAY APRCH FAR NRN ZONES LATE SAT AFTN...BUT LKLY WILL HOLD
OFF UNTIL SAT EVE.
WITH H8 TEMPS OF 23-24C...TEMPS ON SAT XPCD TO BE THE HIGHEST OF
THE WK AS THEY CLIMB TO THE LWR 100S IN MOST AREAS. PREV RECORDS
MAY BE BKN AT SVRL CLIMATE SITES. EXCESSIVE HEAT WATCH RMNS IN
EFFECT...WITH HEAT ADZY LKLY NEEDED FOR MOST OTHER ZONES.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
SOME TSTMS FORMING ALONG CDFNT IN CNTRL PA COULD IMPACT NRN TIER
OF FCST AREA SAT NGT. COLD FRONT BEGINS TO SAG SOUTHWARD ACROSS
THE CWFA ON SUNDAY. ATMOS WILL BE UNSTABLE...AND ANY MID LEVEL
ENERGY/WEAK FORCING ALONG THE FRONT SHOULD HELP OVERCOME ANY WEAK
CAP IN PLACE. FORECAST MODEL SOUNDINGS SHOW ANY SURFACE
INVERSIONS/CAPPING ERODING BY THE EARLY AFTERNOON WITH DEEP
INVERTED V PROFILES. MID LEVEL LAPSE RATES WILL ALSO BE FAIRLY
STEEP...SO LARGE HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE
WITH ANY OF THE SEVERE THUNDERSTORMS THAT DEVELOP.
FRONT WILL CONTINUE TO SAG SOUTHWARD SATURDAY NIGHT. WILL KEEP
HIGHEST POPS ALONG THE FRONTAL BOUNDARY.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
FRONT SHOULD MOVE SOUTH OF THE CWFA BY EARLY MONDAY...PROVIDING FOR
A COOLER AIRMASS TO SETTLE ACROSS THE MID ATLANTIC. MID LEVEL
SHORTWAVE ENERGY AND LOW LEVEL MOISTURE IN PLACE WILL AID SHOWER AND
THUNDERSTORM DEVELOPMENT EACH DAY.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
STRONG INSOLATION AND DP MIXING WILL MAINTAIN VFR CONDS AT ALL
TERMINALS THRU SAT. BAY BRZ LKLY WILL DVLP TDA AND TMW AFTN AND
WILL GENERATE SELY WIND AT KMTN. SLOW DIURNAL COOLING TNGT SHOULD
PREVENT FOG DVLPMT AT TERMINALS DESPITE HIGH DEWPT TEMPS.
A FRONT WILL DROP SOUTH ACROSS THE MID ATLANTIC ON SUNDAY...
PROVIDING A FOCUS FOR SHOWERS AND THUNDERSTORMS DURING THE
AFTERNOON AND EVEN INTO THE OVERNIGHT HOURS. THUNDERSTORMS WILL
HAVE THE POTENTIAL TO BECOME SEVERE...PRODUCING DAMAGING WIND
GUSTS AND LARGE HAIL.
ISOLD/SCT CONVECTION WILL CONTINUE POSSIBLE INTO THE FIRST OF THE
WEEK EACH DAY.
&&
.MARINE...
LGT WINDS XPCD THRU SAT. DAILY LAND INTRUSIONS OF BAY/RVR BRZ SEEM
PROBABLE OWING TO GENL LGT WIND. SLY CHANNELING MAY ENSUE OVNGT BUT
SHOULD RMN BLW THRESHOLD FOR SMALL CRAFT ADZY.
CDFNT WILL MOVE SWD ACRS WATERS ON SUN. SVR TSTMS ARE XPCD...AND
SPCL MARINE WRNGS LKLY WILL BE NEEDED.
&&
.CLIMATE...
DAILY RECORD MAXIMA AND HIGH MINIMA MAY BE REACHED TODAY AND THIS
WEEKEND. BELOW ARE THE DETAILS...
DAILY MAXIMA
SITE.....DATE....RECORD...YEAR...FORECAST
DCA FRI JUL 6 103 1999 101F
SAT JUL 7 102 2010 102F
SUN JUL 8 100 1993 97F
BWI FRI JUL 6 105 2010 100F
SAT JUL 7 101 2010 103F
SUN JUL 8 100 1993 96F
IAD FRI JUL 6 102 1993 100F
SAT JUL 7 101 2010 102F
SUN JUL 8 100 1993 97F
DAILY MINIMA
SITE.....DATE....RECORD...YEAR...FORECAST
DCA SAT JUL 7 80 2010 80F
SUN JUL 8 80 2010 81F
BWI SAT JUL 7 79 2010 77F
SUN JUL 8 79 1986 79F
IAD SAT JUL 7 73 2010 75F
SUN JUL 8 78 2010 78F
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DCZ001.
EXCESSIVE HEAT WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR DCZ001.
MD...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MDZ009-011-013-
014-016>018.
EXCESSIVE HEAT WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MDZ003>007-009>011-013-014-016>018.
VA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR VAZ027>031-
036>040-042-050>057-501-502.
EXCESSIVE HEAT WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR VAZ025>031-036>040-042-050>057-501-502.
WV...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ051>053.
EXCESSIVE HEAT WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR WVZ052-053.
MARINE...NONE.
&&
UPDATE...KRAMAR
PREV DISCUSSION...KONARIK/LISTEMAAHAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 220 PM EDT FRI JUL 6 2012 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 071000- 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- 220 PM EDT FRI JUL 6 2012 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 A HEAT ADVISORY IS IN EFFECT TODAY FOR A PORTION OF THE OUTLOOK AREA FOR HEAT INDICES AROUND 105 DEGREES. REFER TO THE LATEST HAZARD MESSAGE /NPWLWX/ FOR DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY AN EXCESSIVE HEAT WARNING IS IN EFFECT SATURDAY FOR THE OUTLOOK AREA FOR HEAT INDICES AROUND 110 DEGREES. REFER TO THE LATEST HAZARD MESSAGE /NPWLWX/ FOR DETAILS. SEVERE THUNDERSTORMS WILL FORM ON SUNDAY ALONG AN APPROACHING COLD FRONT. SOME STORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WIND GUSTS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION LIKELY WILL BE NEEDED SUNDAY. MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504- WVZ050>053-055-501>506-071000- 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- 220 PM EDT FRI JUL 6 2012 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 A HEAT ADVISORY IS IN EFFECT FOR A PORTION OF THE OUTLOOK AREA FOR HEAT INDICES AROUND 105 DEGREES. REFER TO THE LATEST HAZARD MESSAGE /NPWLWX/ FOR DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY AN EXCESSIVE HEAT WARNING AND HEAT ADVISORY ARE IN EFFECT SATURDAY FOR A LARGE PORTION OF THE OUTLOOK AREA FOR HEAT INDICES OF 105 TO AROUND 110 DEGREES. REFER TO THE LATEST HAZARD MESSAGE /NPWLWX/ FOR DETAILS. SEVERE THUNDERSTORMS WILL FORM ON SUNDAY ALONG AN APPROACHING COLD FRONT. SOME STORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION LIKELY WILL BE NEEDED SUNDAY. KRAMAR
The national radar mosaic for the moment the first event began.
3 heat. Local standard time, as filed.
Heat indices were between 105 and 107 degrees at the Charlottesville Airport.
Heat indices were between 105 and 107 degrees at Orange.
Heat indices around 105 degrees were estimated based on observations nearby.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2012Every state in 2012This day in weather historyWarnings in Virginia, July 2012
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: 405469, 405470, 405471.