FXUS61 KLWX 150056
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
756 PM EST MON DEC 14 2009
.SYNOPSIS...
HIGH PRESSURE OFFSHORE TONIGHT. A COLD FRONT WILL MOVE THROUGH
THE MID ATLANTIC ON TUESDAY...USHERING IN A COLDER AND DRIER
AIRMASS. HIGH PRESSURE WILL BUILD BACK OVER THE REGION FOR THE
REMAINDER OF THE WEEK INTO THE WEEKEND.
&&
.NEAR TERM TONIGHT/...
DID AN EARLY UPDATE - IT'S NOT REALLY APPARENT IN THE WORDING OF
THE ZNS BUT I AM FEELING THE THREAT OF DENSE FOG IS DROPPING
QUICKLY. GOING OUTSIDE TO TAKE OBS I DON'T SEE ANY HZ IN THE
AIR...AND WE ARE LOCATED IN AN LOCATION THAT IS USUALLY AMONG THE
FIRST TO BEGIN FG FORMATION. THERE IS ALSO A NOTICEABLE SRLY BRZ
OUTSIDE...WHICH IS THE RESULT OF THE APRCHG CD FNT. FOR THE TIME
BEING I'VE LEFT FOG IN THE ZNS E OF THE MTNS...BUT REMOVED THE
DENSE FOG QUALIFIER AS WELL AS REMOVE MENTION OF DENSE FOG FM THE
HWO. COMPARING TNGT'S SNDG W/ 24 HRS PRVS SHOWS SIG DIFFERENCES -
S WINDS 25 KT AT 800 FT FOR STARTERS...INVERSION IS WEAKER...AND
LOW LVL MOISTURE IS MUCH MORE SHALLOW AS WELL.
LOPRES OVER THE UPPER MIDWEST MOVES THRU THE GREAT LAKES REGION
TNGT. ASSOCIATED COLD FRONT SHOULD APPROACH THE APPALACHIANS BY
DAYBREAK.
TEMPS GENERALLY IN THE U30S ACROSS NRN MD TO M40S ALONG AND E OF
I-95.
&&
.SHORT TERM /TUESDAY/...
LOPRES WILL TRACK ACROSS NRN NEW ENGLAND...DRAGGING A COLD FRONT
THRU THE REGION. MODEL GUIDANCE CONSISTENT ON KEEPING
MOISTURE/PRECIP HUNG UP ON THE WINDWARD SIDE OF THE MTS...KEEPING
TUE DRY FOR MOST OF THE AREA. BEHIND THE FRONT...UPSLOPE SHOWERS
WILL CHANGE TO SNOW SHOWERS ALONG THE WRN SLOPES OF THE ALLEGHENY
AND POTOMAC HIGHLANDS...WHERE SOME LGT SNOWFALL ACCUMULATIONS ARE
POSSIBLE DURING THE AFTN.
STRONG CAA ALOFT WILL ALLOW FOR GUSTY WNW WINDS TO MIX
DOWN TO THE SFC DURING THE AFTN. DEPENDING ON EXACT TIMING OF
FROPA...TEMPS MAY STRUGGLE TO RISE IN THE AFTN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TUESDAY NIGHT IN THE WAKE
OF A COLD FRONT. UPSLOPE SNOW SHOWERS WILL BE LIKELY IN THE NW FLOW
BEHIND THE SYSTEM...BUT THEY SHOULD CUT OFF EARLY WEDNESDAY. A QUICK
INCH OR TWO OF SNOW IS POSSIBLE OVERNIGHT TUESDAY INTO WEDNESDAY
ALONG THE WESTERN FACING RIDGES. HIGH PRESSURE REMAINS IN CONTROL OF
THE SENSIBLE WEATHER THROUGH THE END OF THE WEEK. A WEAK LOW
PRESSURE SYSTEM MAY MOVE THROUGH THE AREA ON FRIDAY...WHILE A COLD
FRONT IS EXPECTED ON SUNDAY.
HAVE KEPT THE FORECAST DRY FOR THE MID AND LATE WEEK...PRECIP
CHANCES DURING THIS PERIOD LOOK TO SMALL TO MENTION AT THIS TIME.
HOWEVER...HAVE INCLUDED SOME CHANCE POPS IN FOR SUNDAYS FRONTAL
PASSAGE.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
VSBYS MAY XPRNC SOME RESTRICTIONS AFTR MDNGT..BUT DO NOT BLV IT WL
BE AS BAD AS LAST NGT. BWI/MTN/CHO WOULD BE MOST LKLY CANDIDATES
TO SEE IFR CONDS.
NO CIG/VSBY RESTRICTIONS ARE ANTICIPATED THROUGH THE END OF THE
WEEK. HOWEVER...SUB VFR CONDITIONS ARE POSSIBLE SUNDAY INTO EARLY
MONDAY. NW WINDS WILL BE LIKELY THROUGH THE END OF THE WEEK...AND BE
GUSTY AT TIMES.
&&
.MARINE...
SLY CHANNELING TNGT WILL INCREASE WINDS 10-15 KT ACROSS THE CHSPK
BAY BUT GUSTS SHOULD STAY UNDER SCA LVLS. A COLD FRONT MOVES THRU
MIDDAY TUE WITH GUSTS WNW WINDS EXPECTED BEHIND THE FRONT. A SCA
HAS BEEN POSTED FOR ALL MARINE ZONES BEGINNING 18Z TUE.
SMALL CRAFT CONDITIONS WILL LIKELY CONTINUE INTO TUESDAY NIGHT
BEHIND THE COLD FRONT. NW WINDS ARE EXPECTED TO CONTINUE THROUGH THE
END OF THE WEEK...AND REMAIN GUSTY AT TIMES. SMALL CRAFT CONDITIONS
WILL BE POSSIBLE WEDNESDAY INTO THURSDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM TUESDAY TO 7 AM EST WEDNESDAY
FOR ANZ530>543.
&&
$$
UPDATE...WOODY!
PRVS...JRK/NWL
