Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 251543
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1043 AM EST WED FEB 25 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE THIS AFTERNOON. LOW PRESSURE OVER
LOUISIANA WILL TRACK ACROSS NORTH CAROLINA TONIGHT AND RAPIDLY
OFFSHORE THURSDAY MORNING. AN UPPER LEVEL TROUGH CROSSES THE
GREAT LAKES THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD THROUGH
SATURDAY NIGHT.

&&

.NEAR TERM /TODAY/...

NO PROBS THIS AFTN W/ HIGH PRES OVR THE AREA. HIGHS XPCTD TO REACH
U30S/L40S.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...

WE BLV WE`LL BE FCSTG ACCUMULATING SNOWFALL FURTHER N W/ THE FAST
MOVG SRN STREAM LOW LATE TNGT/THU MRNG. ATTM ADVISORIES RMN AS
IS...BUT BLV THE PEAK SNOWFALL INTENSITY IN THE I-95 CORRIDOR BTWN
FREDERICKSBURG AND BALT WL BE BTWN ~4AM AND 9AM. THIS WL LKLY LEAD
TO THE ADVSRY BEING XPANDED FURTHER N...ESPCIALLY GIVEN THE LOWER
REQUIREMENTS DURG THE MRNG COMMUTING TIMES. ST. MARYS STILL LOOKS
TO BE RCVG THE HIGHEST TOTALS...AS MUCH AS 4". THE FARTHER N AND W
YOU GO THE LOWER THE TOTALS ARE XPCTD TO BE.

PRVS DSCN...

MAIN CONCERN FOR TONIGHT THROUGH TOMORROW WILL BE AN APPROACHING
LOW PRESSURE TO THE SOUTH. WINTER WEATHER ADVISORIES HAVE BEEN
ISSUED FOR THE SOUTHERN TIER OF THE CWA TO ACCOUNT FOR THE AREA OF
HIGHEST CONFIDENCE OF REACHING AT LEAST 2 INCHES.

AS THE LOW PUSHES OFFSHORE...AND THE UPPER LVL FORCING PIVOTS
ALONG THE EASTERN SEABOARD...HAVE THE PCPN TAPERING OFF OVER THE
WESTERN SECTIONS BY MID MORNING THURS...WITH LINGERING PCPN OVER
THE EASTERN HALF THROUGH THE EARLY PART OF THE AFTN. COULD SEE
SOME SNOW SHOWERS THURS AFTN OVER THE ALLEGHENY FRONT WITH
WESTERLY FLOW COMBINING WITH A DECENT PASSING
SHORTWAVE...RESULTING IN UPSLOPING SHOWERS. HOWEVER...NOT
EXPECTING MUCH MORE THAN HALF AN INCH WITH THESE SHOWERS.

TEMPERATURE GUIDANCE WAS VERY INCONSISTENT FOR HIGHS ON THURSDAY.
HIGH CONFIDENCE LOW TEMPS TONIGHT ALL WELL BELOW FREEZING...SO NOT
EXPECTING A P-TYPE ISSUE. SIDED WITH THE COOLER MET/MAV BLEND ON
TEMPS FOR THURS...KEEPING EVERYWHERE MAINLY IN THE 20S...EXCEPT FAR
SOUTHWESTERN AREAS WHICH COULD SEE THE LOWER 30S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AN INTRUSION OF NRN STREAM ENERGY PROGGED TO IMPACT AREA THU NGT-
FRI. WHILE THERES NOTHING SPECIFICALLY THAT JUMPS OUT...LLVL CAA...
MID LVL PVA...RATHER AMPLE MEAN-LYR MSTR...AND A TAIL OF THE UPR LVL
JET ALL SUGGEST LOTSA CLDS AT A MINIMUM. IF ITEMS ALIGN
APPROPRIATELY...THEN FLURRIES PRBL AND A SHSN OR TWO PSBL. WENT A
LTL MORE AGGRESSIVE ON POPS THU EVE /STILL CHC/...AND SCALED IT BACK
OVNGT INTO FRI MRNG. IN THE BIG PICTURE...BLDG HIPRES SUGGESTS THAT
THE ODDS FOR PCPN WL BE DIMINISHING THRU THE PD...AND WL BE HIGHLY
UNLKLY BY FRI NGT. H8 TEMPS DROPPING INTO THE NEG TEENS /AGAIN/
SUGGEST THAT SHSN WUD BE THE ONLY PTYPE TO CONSIDER. NO CONFIDENCE
WRT ACCUMS. IN A WORST CASE SCENARIO...SUPPOSE ITS PSBL. CERTAINLY
WONT BE ADVERTISING THAT AS A PART OF A DETERMINISTIC FCST.

ARCTIC HIPRES WL BE KEEPING WX QUIET THRU SAT NGT...ALBEIT COLD. NO
BIG CHGS IN TEMP FCSTS. MAXT STRUGGLING TO RISE ABV FRZG...ALTHO SAT
HAS A SLGTLY BETTER CHC. MIN-T DOWN IN THE TEENS AND LWR 20S. RADL
COOLING AND THE CORE OF THE COLD AIR OVER AREA SAT MRNG IMPLY THAT
SINGLE DIGIT OR SUBZERO LOWS PSBL W OF I-95.

DEEP MEAN TROUGH WILL PERSIST OVER THE EASTERN CONUS THROUGH THE
XTNDD PERIOD BUT ABATE SLIGHTLY BY THE MIDDLE OF NEXT WEEK.
MEANWHILE...SUBTROPICAL RIDGING WILL BEGIN TO AMPLIFY OVER THE
SOUTHEASTERN CONUS. THIS WILL SET THE STAGE FOR A COUPLE OF
OVERRUNNING/PERHAPS MIXED P-TYPE EVENTS LATE IN THE WEEKEND INTO
EARLY NEXT WEEK AS MODERATING AIRMASS ALOFT MOVES OVER RESIDUAL
COLD AIR AT THE SURFACE. THE OVERALL PATTERN WILL BE FOR A TREND
IN MODERATING TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK
HOWEVER.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS TODAY.

LOW PRESSURE APPROACHING TONIGHT WILL BRING LIGHT SNOW...WITH SUB-
VFR CONDITIONS EXPECTED. THE HEAVIEST SNOW SHOULD REMAIN TO THE
SOUTH. ALL SITES COULD SEE A PD OF SUB-VFR CONDS...PSBLY APRCHG
IFR AT CHO/DCA.

OUTLOOK...

THU NGT-FRI MRNG...LOW CONFIDENCE. MAY BE SOME FLURRIES...AND WUDNT
OUTRIGHT RULE OUT FLGT RESTRICTIONS DUE TO SHSN.

FRI AFTN-SUN MRNG...VFR. SUN AFTN...MAINLY VFR..ALTHO CIGS SHUD BE
LWRG AS PCPN CHCS INCREASE.

&&

.MARINE...
SUB-SCA CONDITIONS EXPECTED TODAY WITH HIGH PRESSURE. HAVE ISSUED
A SCA LATE TONIGHT THROUGH THURSDAY WITH INCREASING NORTH FLOW AS
LOW PRESSURE PASSES TO THE SOUTH.

N/NWLY FLOW WL PREVAIL THU NGT-FRI. ATTM MIXED LYR DOES NOT APPEAR
TO SUPPORT SCA CONDS. WIND FIELD INCREASES FRI NGT...AND THEN
RELAXES AGN BY SAT AS HIPRES BLDS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
     THURSDAY FOR MDZ017.
     SMALL CRAFT ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR MDZ508.
VA...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST
     THURSDAY FOR VAZ025-036-037-508.
     WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
     THURSDAY FOR VAZ050-056-057.
WV...NONE.
MARINE...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
     THURSDAY FOR ANZ537.
     SMALL CRAFT ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR
     ANZ530>534-537>543.
     SMALL CRAFT ADVISORY FROM 10 AM TO 4 PM EST THURSDAY FOR
     ANZ535-536.

&&

$$
UPDATE...WOODY!
PRVS...APS/HTS


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