Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 011549
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1049 AM EST SUN FEB 1 2015

.SYNOPSIS...
LOW PRESSURE MOVES THROUGH THE REGION THROUGH MONDAY. HIGH PRESSURE
WILL RETURN FOR THE FIRST HALF OF THE WEEK. A COLD FRONT IS
EXPECTED TO MOVE INTO THE REGION WEDNESDAY NIGHT.

&&

.NEAR TERM /THIS AFTERNOON/...

RDR SHOWING LGT RETURNS OVR W.V. BUT NO OBS THERE ARE REPORTING
ANY PCPN. STILL - AS THE ECHOES TRACK INTO WRN MD THERE IS THE
PSBLTY OF SOME LGT SNOW...BUT AM NOT XPCTG ANY ACCUM W/ THIS.

12Z NAM IS IN...GFS JUST BEGINNING...ONE OF THE QSTNS W/ THE
APRCHG SYSTEM IS "HOW COLD IS THE AIR MASS?" NAM SHOWS 850-1000
SUB 130 DM LN FLICKERING ACROSS MD THRU 06Z...THEN PUSHING INTO
PA. IT`S GETTING HARDER FOR ME TO THINK THERE`S GOING TO BE MUCH
IN THE WAY OF SNOW WHEN THE MAIN AREA OF PCPN ARRIVES HERE TNGT.
HV RMVD IT FM THE FCST AFTR 03Z. THIS LVS IP AND FZRA AS THE
CONCERNS.

AIR TEMPS ARE ANOTHER CONCERN - WE ARE ALREADY AOA FRZG IN A LARGE
PART OF THE FCST AREA. MESONET OBS STILL SHOWING 31-32 IN CENTRAL
MD...A FEW 29`S ALONG THE MD/PA BRDR. ALTHO CLDS HV GRTLY REDUCED
INSOLATION THE LO LVL SWRLY WINDS WL SURELY HELP TO WARM THE AIR A
FEW DEGS...AND IN MD ROAD TEMPS ARE IN THE 35-40 DEG RNG.

WE HV AN ADVSRY IN EFFECT ACROSS XTRM NRN VA...ERN WV..AND CENTRAL
MD. DO NOT FEEL THE NEED TO XPAND UPON THIS. BIGGEST WORRY IS THAT
LOW LYING AREAS WL HV DIFFICULTY SCOURING OUT COLD AIR...AS WELL
AS EVAP COOLING THAT COULD OCCUR AT PCPN ONSET WHICH COULD CAUSE
RAIN TO FRZ.

&&

.SHORT TERM /TONIGHT THROUGH  MONDAY/...

WITH MULTIPLE SHORTWAVES WORKING THROUGH TONIGHT AS THE SFC LOW
PASSES OVER THE MID- ATLANTIC...CAN EXPECT PERIODS OF MODERATE TO
HEAVY PCPN.

THE SFC LOW PUSHES OFF THE NJ COAST BY MIDDAY MONDAY...WHILE THE
STRONG UPPER LEVEL TROUGH FINALLY SWINGS THROUGH THE REGION MONDAY
AFTN. CONTINUED POPS EVERYWHERE FOR MONDAY MORNING...THEN TAPERED
OFF FROM WEST TO EAST...WITH THE THINKING ALL PCPN SHOULD CLEAR THE
AREA BY MONDAY EVENING EXCEPT WITH THE CHC FOR UPSLOPE SNOW SHOWERS.
STRONG SURGE OF CAA WITH THE NW FLOW ON THE BACKSIDE OF THE LOW WILL
INCREASE WINDS BY MONDAY AFTN...WITH GUSTS INTO THE 20S. THIS WILL
ALSO RESULT IN A NON-DIURNAL TEMP TREND...MAINLY FOR WESTERN AREAS
AS THEY WILL SEE THEIR DAYTIME HIGHS IN THE MORNING. OVER THE
EASTERN AREAS...BEFORE THE CAA MOVES IN...COULD SEE HIGHS IN THE
UPPER 40S.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...

STRONG NW FLOW KICKS IN MON EVENING AS CSTL LOW BOMBS OUT OFF CAPE
COD. THE COMBO OF A TIGHTENING P-GRAD AND GOOD MIXING FM CAA WL
EASILY PROVIDE MEAN MIXED LYR WINDS GREATER THAN 30 KT. THIS
GRADIENT WL BE SUBSIDING/DCPLG SLIGHTLY THRU THE EVNG...BUT IT WL
STILL BE A BRZY /AND CHILLY/ NGT. SCT LINGERING UPSLP SHSN AT START
OF PD WL DIMINISH AS HIPRES BLDS. WL HV PT-MOCLDY INTHE MTNS BUT CLR
ELSW. TEMP GDNC NOT QUITE AS COLD AS PRVS RUNS. WL LEAN ON THE
COOLER SIDE OF LTST DATA. WIND CHILLS NOT TO ADVY LVL...BUT SINGLE
DIGITS SHUD BE COMMON.

HIPRES WL BE NEARBY TUE...W/ RETURN FLOW BGNG TUE NGT. H8 THERMAL
TROF STILL AN INFLUENCE TUE /-10 TO -12C/. MAXT ADJUSTMENTS
MINIMAL...MAYBE A DEGF OR TWO HIER ACRS MD/NRN VA. CENTRL VA THE
ONLY PLACE THAT SAFELY WL GET ABV FRZG. MIN-T TUE NGT WONT BE QUITE
AS HARSH...DUE PARTLY TO A BLDG MID CLD DECK.

LOPRES IN THE NRN STREAM DROPS FM S-CENTRAL CNDA ACRS NEW ENGLAND
WED-WED NGT. ITS NOT EXACTLY CLEAR HOW MUCH MSTR WL BE ASSOCD W/
IT...BUT FOR THE MID ATLC ITS OUTPACING ANY UPA SUPPORT. THEREFORE
WL BE BANKING ON A SYSTEM THAT WL BE STRUGGLING TO PRODUCE PCPN ON
ITS OWN. AFTER A RELATIVELY MILD DAY WED...WL BE KEEPING SCHC SNW
CONFINED TO THE MTNS WED NGT.

TEMPS WL BE DROPPING THU /15 DEGF COOLER THAN MAXT WED/...WHICH CUD
PROVIDE AN ENVIRONMENT FOR DIURNAL SHSN. TOO FAR OUT TO PINPOINT
CVRG...BUT IT WUD BE A SITUATION FOR BRIEF...MINIMAL ACCUM /IF
ANY/...BUT SUDDEN ONSET SHSN. WL HV MID-RANGE CLDS AND LOW END POPS.

HIPRES SHUD CLOSE OUT THE WEEK. NO OTHER HAZARDS ANTICIPATED ATTM.
TEMPS GRADUALLY MODERATING TWD CLIMO...BUT NOT SURE IF WE WL GET
THERE.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS INTO THE AFTN. CONDITIONS DIMINISH AS THE PCPN MOVES
IN...WITH IFR BCMG LIKELY BY SUN NIGHT WITH THE HEAVIEST PCPN.
INITIAL PCPN -SN/PL/RA MIX...BCMG ALL RAIN TONIGHT EVERYWHERE.
TRANSITION TIMING IN TAFS COULD BE +/- 2 HOURS. ANY SNOW ACCUMS AT
THE TERMINALS TODAY WOULD BE LESS THAN ONE INCH.

S WINDS LESS THAN 10 KTS TODAY/TONIGHT WILL SHIFT TO THE NW MONDAY
AND INCREASE...WITH GUSTS MIXING IN BY MONDAY AFTN. VFR CONDITIONS
AS WELL BY MONDAY AFTN AS THE PCPN EXITS THE REGION.

VFR SHUD PREVAIL MON NGT THRU AT LEAST WED. BIGGEST IMPACT WL BE THE
WINDS MON NGT...WHICH WL BE FM THE NW AND MAY GUST UP TO 35-40 KT
DURING THE EVNG PUSH.

ANOTHER CDFNT WL CROSS LT WED. MAY HV WIDELY SCT SHSN REDUCING VSBY
ON THU...ALONG W/ MORE GUSTY WINDS.

&&

.MARINE...
SUB-SCA CONDITIONS ON ALL THE WATERS THROUGH 06Z TONIGHT. HAVE
ISSUED A SCA OVER THE CENTRAL CHESAPEAKE BAY AND THE LOWER UPPER
TIDAL POTOMAC TO ACCOUNT FOR INCREASING SOUTHERLY FLOW LATE
TONIGHT...AND THEN NW FLOW BY TOMORROW AFTN. PSBL LULL IN THE SCA
GUSTS AS THE WINDS SHIFT...BUT THIS WILL BE SHORT LIVED.

AS CSTL LOPRES STRENGTHENS LT MON...IT WL INCREASE THE P-GRAD.
COMBINED W/ DEEPENING FVRBL MIXING IN CAA...WINDS SHUD EXHIBIT A
MARKED INCREASE LATE MON AFTN INTO MON NGT. WL HV MEAN 35-40 KT W/IN
THE MIXED LYR. HV RAISED GLW FOR THE 2ND HALF OF THE AFTN INTO THE
EVNG. SCA CONDS WL CONT THEREAFTER...AND MAY LEAK INTO TUE. BLDG
HIPRES WL GRDLY RESULT IN DIMINISHING WINDS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR MDZ003-501-
     502.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EST
     MONDAY FOR MDZ004>006-503-505-507-508.
VA...WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR VAZ028-031.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EST
     MONDAY FOR VAZ505.
WV...WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR WVZ050>053-
     503-504.
MARINE...GALE WARNING FROM 3 PM MONDAY TO 1 AM EST TUESDAY FOR
     ANZ530>543.
     SMALL CRAFT ADVISORY FROM 1 AM TO 3 PM EST MONDAY FOR ANZ533-
     534-537-542-543.

&&

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







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