Warm and moist air continued to overrun surface cold air and a light snowpack, causing areas of dense fog to develop during the early morning hours of the 24th.
Every event with a place to put it; 9 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.
Warm and moist air continued to overrun surface cold air and a light snowpack, causing areas of dense fog to develop during the early morning hours of the 24th.
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 Jan 24, 2:56 AM EST, 1 hour 57 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
256 AM EST TUE JAN 24 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION EARLY THIS MORNING...AND HIGH
PRESSURE WILL BUILD BEHIND THIS SYSTEM THROUGH WEDNESDAY. A LOW
PRESSURE SYSTEM WILL IMPACT THE AREA LATE IN THE WEEK. HIGH
PRESSURE IS EXPECTED TO RETURN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
CDFNT ALONG WRN SLOPES OF APLCNS WILL MOVE SLOWLY EWD ACRS FCST
AREA LATE TNGT. MSTR AHD OF THE BNDRY HAS REMAINED TRAPPED BLW
LOW-LVL INVERSION...LEADING TO DENSE FOG ACRS N-CNTRL AND WRN MD
AND THE WV PNHDL. UNTIL LOW-LVL DRY AIR ARRIVES...FOG XPCD TO BE
MAINTAINED...SPCLY WHERE ADZY IS IN EFFECT UNTIL 24/13Z.
CI WILL HAVE MOVED EWD BY MRNG...WHICH WILL FOSTER EROSION OF
STAGNANT LOW-LVL CLDS THROUGH MIXING. MOSTLY SUNNY SKIES XPCD MUCH
OF TDA EXCEPT ON WRN SLOPES...WHERE CLDS MAY DVLP IN UPSLP FLOW.
MAXIMA WILL BE IN THE LWR-UPR 50S...SVRL DEG F ABV NRML.
PRES SURGE TNGT XPCD TO SHIFT WINDS TO NWLY AS SFC HIPRES BUILDS
INTO THE RGN. LGT WINDS...GENLY CLR SKIES AND DRY LOW-LVL AMS WILL
PROMOTE RADIATIONAL COOLING. EXCEPT IN WASHINGTON AND BALTIMORE...
MINIMA WILL BE IN THE MID 20S-LWR 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
HIPRES RMNS OVHD WED...WITH MAXIMA MAINLY IN 40S. INCRG CLOUDS LATE
WED AS M/ULVL SWLY FLOW ADVECTS MOISTURE AND WARM AIR INTO MID-ATLC.
ISENTROPIC LIFT MAY BE SUFFICIENT TO INDUCE PRECIP ACRS SWRN ZONES
AS EARLY AS MIDNIGHT...WITH CHC POPS SPREADING NEWD TWD MRNG. PTYPE
MAY BE AN ISSUE ERY WED...ESPECIALLY ACRS NRN ZONES...AS THERMAL
PROFILES AT PCPN ONSET TIME SHOW LLVLS COLD ENUF FOR SN/IP...AND SFC
TEMPS AOB FRZG. CNTR OF SFC HIPRES MAY STILL BE OVR INTERIOR NEW
ENGLAND...AND UNTIL IT MOVES OFFSHORE LATER WED MRNG...COLD SFC AIR
WILL BE SLOW TO ERODE. EXPECT BULK OF QPF TO HOLD OFF UNTIL LATER
THU/THU NGT AS NRN STREAM SHRTWV TROF AND ASSOCIATED SFC CDFNT
APPROACH MID-ATLC. TEMPS DURG THIS PERIOD SHUD BE WELL ABV FRZG...
IN U30S/L40S...AND ONLY RAIN IS XPCD. FRONT MOVES THRU ERY FRI...
WITH POPS GRADUALLY DIMINISHING BEHIND IT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
EXTDD FCST DEPENDENT ON WHICH NRN STREAM SHRTWV TROF LIFTS AND
ABSORBS CLOSED ULVL LOPRES ACRS SRN PLAINS/LWR MS VLY. LATEST
GUIDANCE SUGGESTS LOW WILL BE PULLED INTO AFOREMENTIONED SYSTEM AND
PASS S OF RGN THU/FRI. IN THIS MORE LIKELY SCENARIO...HIPRES BUILDS
INTO MID-ATLC FOR WKEND. IF SRN UPR LOW RMNS IN PLACE UNTIL
SECONDARY SHRTWV TROF THAT WILL DIVE FROM GREAT LAKES INTO NERN
CONUS SAT...THEN SFC CYCLOGENESIS NEAR COAST S OF MID-ATLC COULD
IMPACT PORTIONS OF CWA. WILL HANDLE THIS POSSIBILITY WITH LOW CHC
POPS RN/SN MIX FRI NGT/SAT.
SAT NGT...CLIPPER FRONT MOVES THRU AS SHRTWV TROF PASSES N OF RGN.
COLDER AIR WILL BE USHERED IN ON NW FLOW SUN...WITH HIPRES BUILDING
IN ERY NEXT WK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
PRES SURGE AHD OF APRCHG CDFNT HAS PROMOTED AN EROSION OF FOG IN
MANY AREAS. WINDS XPCD TO SUBSIDE AGAIN OVNGT...WHICH SHOULD ALLOW
FOG TO DVLP WITH MSTR TRAPPED BLW LOW-LVL INVERSION. DENSE FOG
XPCD AT KMRB...WITH IFR-MVFR FOG AND CIGS PSBL ELSEWHERE.
FOG WILL ERODE DURG THE MRNG...WITH VFR CONDS XPCD ALL TERMINALS
BY MID-MRNG. VFR CONDS WILL RMN THRU TNGT AS LGT WINDS BCM NWLY IN
WAKE OF CDFNT PASSAGE.
VFR CONDS THRU LATE WED EVE...THOUGH CLOUDS INCR AND CIGS LWR THRU
PERIOD. SUB-VFR CIGS AND EVENTUALLY VSBYS LIKELY TO DVLP BY THU MRNG
AND CONT THRU AT LEAST THU NGT. CDFNT MOVES THRU THU NGT. HIPRES
LIKELY TO BUILD IN SAT...BUT WILL MONITOR POTENTIAL LOPRES S OF RGN.
&&
.MARINE...
PRES SURGE AHD OF APRCHG CDFNT HAS INVIGORATED GUSTS IN EXCESS OF
20 KT ON THE WATERS. SMALL CRAFT ADZY WAS ISSUED THRU TNGT FOR
PORTIONS OF MD CHSPK BAY AND TIDAL POTOMAC RVR TO HIGHLIGHT THESE
GUSTS. WINDS XPCD TO GUST 10-15 KT BY LATE THIS MRNG...BUT SHOULD
RMN BLW SMALL CRAFT ADZY THRESHOLDS. LGT NWLY WINDS XPCD TNGT.
NW FLOW AROUND 10 KTS WED BCMG LGT WED NGT/THU AS HIPRES RESIDES OVR
WATERS. MOISTURE OVERRIDING THIS HIPRES LIKELY WILL LEAD TO SHWRS
THU/THU NGT. IN ADVANCE OF FRI FROPA...SLY FLOW MAY NEAR SCA
THRESHOLDS THU NGT. NWLY FLOW BEHIND THE CDFNT AND SECONDARY FRONT
SAT NGT MAY CAUSE PERIODS WHERE AOA 20 KT GUSTS ARE FREQUENT THRU
WKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR MDZ003>005-
502.
VA...NONE.
WV...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR WVZ050>053-
504.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
ANZ532>534-536-537-540>543.
&&
KRAMAR/SBKHAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 135 AM EST TUE JAN 24 2012 ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057- 241045- 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- 135 AM EST TUE JAN 24 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 SMALL CRAFT ADVISORY IS IN EFFECT TONIGHT FOR THE TIDAL POTOMAC RIVER FROM INDIAN HEAD TO SMITH POINT AND FOR THE MARYLAND CHESAPEAKE BAY FROM SANDY POINT TO SMITH POINT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A SMALL CRAFT ADVISORY MAY BE NEEDED FRIDAY THROUGH THE WEEKEND FOR PORTIONS OF THE WATERS. .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>506-241045- 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- 135 AM EST TUE JAN 24 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 A DENSE FOG ADVISORY IS IN EFFECT TONIGHT FOR MUCH OF WESTERN AND NORTH-CENTRAL MARYLAND AND PORTIONS OF THE EASTERN WEST VIRGINIA PANHANDLE. REFER TO THE LATEST HAZARD MESSAGE /NPWLWX/ FOR DETAILS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A DENSE FOG ADVISORY IS IN EFFECT UNTIL 8 AM TUESDAY FOR PORTIONS OF THE OUTLOOK AREA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. KRAMAR
The national radar mosaic for the moment the first event began.
11 dense fog. Local standard time, as filed.
Visibility was estimated to be around one quarter mile across portions of the county.
Visibility was estimated to be around one quarter mile across portions of the county.
Visibility was reported to be around one quarter mile at the Charlottesville Airport.
Visibility was estimated to be around one quarter mile across portions of the county.
Visibility was estimated to be around one quarter mile across portions of the county.
Visibility was estimated to be around one quarter mile across portions of the county.
Visibility was reported to be around one quarter mile at Dulles Airport.
Visibility was estimated to be around one quarter mile across northern portions of the county.
Visibility was reported to be around one quarter mile at Culpeper.
Visibility was reported to be around one quarter mile at Warrenton.
Visibility was reported to be around one quarter mile at Manassas.
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, January 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: 362239, 362241, 362245, 362242, 362243, 362240, 362246, 362244, 362247, 362248, 362249.