High pressure stretched along the entire eastern seaboard overnight and into the morning. Fog formed in areas of calm winds and temperatures near freezing in the MD/VA Piedmont and valleys west of the Allegheny Front.
Every event with a place to put it; 4 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.
High pressure stretched along the entire eastern seaboard overnight and into the morning. Fog formed in areas of calm winds and temperatures near freezing in the MD/VA Piedmont and valleys west of the Allegheny Front.
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 Nov 20, 9:08 PM EST, 4 hours 52 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
908 PM EST TUE NOV 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THURSDAY WHILE A
STORM SYSTEM REMAINS WELL OFF THE EAST COAST. A COLD FRONT WILL
MOVE THROUGH THE AREA FRIDAY NIGHT. HIGH PRESSURE WILL RETURN FOR
THE WEEKEND BEFORE LOW PRESSURE POSSIBLY IMPACTS THE AREA MONDAY
NIGHT INTO THE MIDDLE PORTION OF NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
JUST ABOUT IN THE CLEAR AS THE DRY SLOT FOR THIS LARGE BUT WEAK
UPPER LEVEL WAVE SLIDES BY TO THE NORTH. THE WEAK BUT LARGE WARM
SECTOR REGION THAT GAVE US A CLOUDY AFTN HAS NOW STARTED TO MOVE
OFF THE MID ATLC COAST. BEHIND IT WILL BE A BRIEF PERIOD OF
CLEARING BUT THEN SOME OF THE UPPER DEBRIS FROM THE BACKSIDE OF
THE SYSTEM - COMING DOWN FROM THE GREAT LAKES - WILL MOVE MAKE ITS
WAY OVER THE AREA TONIGHT. THE LOW LEVELS HAVE BEEN TOO DRY FOR
ANY PRECIP TO REACH THE GROUND FROM EARLIER ACTIVITY THAT MOVED
THRU THIS AFTN.
SIMILAR OVERNIGHT LOWS TO LAST NIGHT. PERIODIC HIGH CLOUDS WILL
KEEP TEMPS ROUGHLY AROUND OR JUST ABOVE FREEZING ALL NIGHT...AS
WILL THE DEWPOINTS IN THE M30S.
AN POSITIVELY TILTED UPPER WAVE WILL CONTINUE DIGGING DOWN THE ERN
SEABOARD ON WED...WHICH MEANS LITTLE FOR THE MID ATLC SINCE IT
WILL BE MOVING FURTHER EAST AS IT DEEPENS. THIS DOES MEAN A
REDEVELOPMENT AND INTENSIFICATION OF A SECOND COASTAL STORM SYSTEM
OFF THE NC COAST...WHICH WILL TAKE THE REMAINDER OF THE WEEK TO
MOVE COMPLETELY AWAY FROM THE ATLC COAST.
A RIDGE OF HIGH PRESSURE WILL BE THE RESULT BACK ACROSS THE EAST
COAST STATES...AS THE RIDGE AXIS SLIDES OVER THE APLCN CHAIN. THIS
MEANS A COUPLE MORE DAYS OF QUIET CONDITIONS AND NEAR-AVERAGE
TEMPS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL REMAIN OVER THE REGION WHILE A STORM SYSTEM
REMAINS WELL OFF THE COAST. DRY AND SEASONABLE CONDITIONS ARE
EXPECTED DURING THIS TIME.
RADIATIONAL COOLING WILL CAUSE MIN TEMPS TO DROP INTO THE UPPER 20S
AND LOWER 30S ACROSS THE COLDER VALLEYS AND RURAL AREAS BOTH
WEDNESDAY AND THURSDAY NIGHTS. MAX TEMPS UNDER PLENTY OF SUNSHINE
WILL BE IN THE 50S AND LOWER 60S ACROSS MOST AREAS THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A POTENT COLD FRONT WILL PASS THROUGH THE AREA LATE FRIDAY AND
FRIDAY NIGHT. LITTLE MOISTURE WILL BE ASSOCIATED WITH THE FRONT SO
ANY SHOWERS WILL BE LIGHT AND ISOLATED. BLUSTERY AND CHILLY
CONDITIONS ARE EXPECTED BEHIND THE BOUNDARY OVERNIGHT FRIDAY
THROUGH SATURDAY. MAX TEMPS SATURDAY WILL RANGE FROM NEAR 30 ALONG
THE ALLEGHENY FRONT TO THE MID AND UPPER 40S NEAR WASHINGTON AND
BALTIMORE. A TIGHT PRESSURE GRADIENT BETWEEN THE DEPARTING
BOUNDARY AND HIGH PRESSURE OVER THE CENTRAL CONUS WILL CAUSE
NORTHWEST WINDS TO GUST AROUND 30 TO 35 MPH SATURDAY.
HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY NIGHT AND SUNDAY. WINDS
WILL NOT BE AS STRONG...BUT IT WILL REMAIN CHILLY. HIGH PRESSURE
WILL MOVE OFF THE COAST MONDAY AND LOW PRESSURE MAY IMPACT THE
REGION MONDAY NIGHT INTO THE MIDDLE PORTION OF NEXT WEEK.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS EXPECTED THROUGH THE VALID TAF PERIOD...ASIDE FROM
POSSIBLE BRIEF MVFR BR AT MRB EARLY WEDNESDAY MORNING. WITH SURFACE
HIGH PRESSURE RESIDING OVER THE AREA...LIGHT WINDS WILL PREVAIL MUCH
OF THE TIME.
VFR CONDITIONS ARE EXPECTED WEDNESDAY NIGHT THROUGH THE WEEKEND. A
COLD FRONT WILL PASS THROUGH THE TERMINALS LATE FRIDAY. GUSTY
NORTHWEST WINDS AROUND 25 TO 30 KNOTS ARE EXPECTED BEHIND THE
FRONT SATURDAY.
&&
.MARINE...
WEAK SURFACE GRADIENT WILL KEEP WINDS BELOW SCA THRESHOLDS THROUGH
WEDNESDAY.
HIGH PRESSURE WILL REMAIN NEAR THE WATERS THROUGH THURSDAY WHILE
A STORM SYSTEM INTENSIFIES WELL OFF THE COAST. A STRONGER PRESSURE
GRADIENT WILL CAUSE NORTHERLY WINDS TO GUST AROUND 20 KNOTS
WEDNESDAY NIGHT/THURSDAY FOR THE MARYLAND CHESAPEAKE BAY FROM DRUM
POINT TO SMITH POINT AND FOR THE LOWER TIDAL POTOMAC RIVER FROM
COBB ISLAND TO SMITH POINT. A SMALL CRAFT ADVISORY IS IN EFFECT
FOR THESE AREAS.
A COLD FRONT WILL PASS THROUGH THE WATERS LATE FRIDAY. GUSTY
NORTHWEST WINDS ARE EXPECTED BEHIND THE FRONT FOR THE WEEKEND. A
GALE WARNING MAY BE NEEDED FOR PORTIONS OF THE WATERS SATURDAY.
&&
.FIRE WEATHER...
DRY CONDITIONS WILL CONTINUE THROUGH THURSDAY NIGHT. A COLD FRONT
WILL PASS THROUGH THE AREA LATE FRIDAY. ANY SHOWERS WILL BE LIGHT
AND ISOLATED AHEAD OF THE FRONT LATE FRIDAY AFTERNOON AND NIGHT.
GUSTY NORTHWEST WINDS AND MUCH DRIER AIR IS EXPECTED BEHIND THE
FRONT SATURDAY. NORTHWEST WINDS WILL GUST AROUND 30 TO 35 MPH. THE
COMBINATION OF GUSTY WINDS...LOW RELATIVE HUMIDITY AND LOW FUEL
MOISTURE MAY ENHANCE THE THREAT FOR WILDFIRES SATURDAY AFTERNOON FOR
LOCATIONS EAST OF THE ALLEGHENY FRONT.
DRY AND BREEZY CONDITIONS ARE EXPECTED SUNDAY. WINDS WILL DIMINISH
SUNDAY NIGHT AND LOW PRESSURE MAY BRING PRECIPITATION MONDAY NIGHT
INTO THE MIDDLE PORTION OF NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
COASTAL FLOOD ADZY REMAINS IN EFFECT FOR THE MD BAY SHORE AND
TIDAL POTOMAC RVR COUNTIES INTO THE EARLY MRNG HRS. CURRENTLY
HEADING INTO THE HIGH TIDE CYCLE FOR THE MID BAY...AND UPPER TP
RVR. POSITIVE ANOMALIES HAVE LEVELED OFF THEIR INCREASE BUT REMAIN
AROUND 1.5 FT ABOVE NORMAL. NOT MUCH CHANGE EXPECTED SINCE WINDS
WILL REMAIN ABOUT THE SAME...THE BEST REASON FOR SUBSIDING WOULD BE
THE COASTAL LOW MOVING FURTHER FROM THE COAST. THIS WILL HAPPEN ON
WED...BUT ANOTHER COASTAL LOW WILL FORM IN ROUGHLY THE SAME
AREA...KEEPING THE POTENTIAL FOR PERIODIC MINOR CF AT HIGH TIDE
THRU THE END OF THE WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL 4 AM EST WEDNESDAY FOR DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ007-011-
013-014-016>018.
VA...COASTAL FLOOD ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ052>055-
057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 3 PM EST THURSDAY
FOR ANZ534-537-543.
&&
UPDATE...GMS
PREV DISCUSSION...BPP/BJLHAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 106 AM EST WED NOV 21 2012 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 211015- 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- 106 AM EST WED NOV 21 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...TONIGHT A COASTAL FLOOD ADVISORY IS IN EFFECT UNTIL 4 AM FOR MINOR COASTAL FLOODING AT SENSITIVE SITES ON THE UPPER TIDAL POTOMAC AROUND HIGH TIDE TONIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY A SMALL CRAFT ADVISORY IS IN EFFECT WEDNESDAY NIGHT AND THURSDAY FOR THE MARYLAND CHESAPEAKE BAY FROM DRUM POINT TO SMITH POINT AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH POINT. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS OVERNIGHT FRIDAY THROUGH SUNDAY. A GALE WARNING MAY BE NEEDED FOR PORTIONS OF THE WATERS SATURDAY. GUSTY WINDS...LOW RELATIVE HUMIDITY AND LOW FUEL MOISTURE WILL LEAD TO AN ENHANCED THREAT FOR THE SPREAD OF WILDFIRES SATURDAY AFTERNOON. .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>506-211015- 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- 106 AM EST WED NOV 21 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...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY GUSTY WINDS...LOW RELATIVE HUMIDITY AND LOW FUEL MOISTURE WILL LEAD TO AN ENHANCED THREAT FOR THE SPREAD OF WILDFIRES EAST OF THE ALLEGHENY FRONT SATURDAY AFTERNOON. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The national radar mosaic for the moment the first event began.
4 dense fog. Local standard time, as filed.
Visibility was reported to be around one quarter mile at Luray Airport and by satellite.
Visibility was reported to be around one quarter mile at Shenandoah Airport and by satellite.
Visibility was reported to be around one quarter mile at Shenandoah Airport and by satellite.
Visibility was reported to be around one quarter mile at Luray Airport and by satellite.
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, November 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: 419375, 419376, 419377, 419374.