FXUS61 KLWX 290751
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
251 AM EST SUN NOV 29 2009
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE EAST COAST THROUGH TONIGHT. A
COLD FRONT WILL PASS THROUGH MONDAY...BRINGING A GOOD CHANCE FOR
SHOWERS. HIGH PRESSURE WILL RETURN TUESDAY...BUT LOW PRESSURE WILL
IMPACT THE REGION WEDNESDAY INTO THURSDAY. CANADIAN HIGH PRESSURE
WILL BUILD OVERHEAD LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
A CLOSED LOW HAS CUT OFF FROM STRONG UPR FLOW ACRS NRN CONUS AND
IS FOUND IN SWRN CONUS EARLY THIS MRNG. SHRTWV TROF IN FASTER NRN
STREAM FLOW MOVG ESE ACRS NRN PLNS.
WATER VAPOR IMAGERY SHOWS PLENTIFUL MSTR ADVCTD NWD INTO SRN PLNS
AHEAD OF CUTOFF LOW...WITH SOME OF THIS MSTR BEING DRAWN AHEAD OF
NRN STREAM SHRTWV TROF.
SFC LOPRES XPCD TO ORGANIZE OVER GRTLKS THIS AFTN AS ASSOCIATED
CDFNT MOVES INTO MS RVR VLY. LOPRES WILL BUILD INTO WRN NY LATE TDA.
AFTER A SUNNY...DRY AND COLD START...MID- AND UPR- LVL MSTR IN
ADVANCE OF APRCHG SHRTWV TROF WILL PROMOTE INCRG CLD CVR LATE THIS
AFTN. DEEP SWLY FLOW WILL ADVCT WARMER AMS INTO RGN...WITH MAXIMA
UPR 50S-MID 60S XPCD.
&&
.SHORT TERM /TONIGHT/...
SFC LOPRES MOVES INTO NRN NEW ENGLAND BY LATE TNGT. BKN-OVC MID-
LVL CLDS WILL INCR QUICKLY THIS EVE. HAVE INCRD CLD CVR SLGTLY
FROM PREV FCST...WHICH DEPICTED TREND WELL BUT WAS NOT QUITE AS
AGGRESSIVE.
PCPN XPCD TO BE ONGOING ALONG CDFNT THIS EVE...PRIMARILY OHVLY AND
WRN WV. AS WAVE APRCHS...PCPN WILL SPREAD INTO WRN ZONES AS CDFNT
ARRIVAL FOSTERS UPSLP FLOW ALONG WRN SLOPES. HAVE INCRD POPS TO
LKLY LATE TNGT FOR WRN SLOPES OF ALLEGHENY FRONT. NEVERTHELESS...
PCPN AMOUNTS WILL BE LIGHT. LIGHT PCPN MAY BGN TO SPREAD ACRS NRN
MD AND WV PNHDL LATE TNGT.
COOLING TNGT WILL BE HAMPERED BY INCRG LOW-LVL CLDS AND HIGHER
MSTR CONTENT. THEREFORE...FCST MINIMA IN UPR 30S-MID 40S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
A COLD FRONT WILL PASS THROUGH THE REGION MONDAY. DESPITE LIMITED
MOISTURE WITH THIS SYSTEM...THERE WILL BE ENOUGH LIFT FOR SHOWERS
ALONG AND JUST BEHIND THE COLD FRONT. QPF AMOUNTS WILL BE AROUND
ONE TENTH OF AN INCH ACROSS THE NORTHERN AND EASTERN CWA...WITH
LIGHTER AMOUNTS ACROSS CENTRAL VIRGINIA. UPSLOPE SNOW SHOWERS
BEHIND THE FRONT WILL IMPACT THE POTOMAC HIGHLANDS MONDAY
AFTERNOON/NIGHT. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE...ESPECIALLY
MONDAY NIGHT.
HIGH PRESSURE WILL BUILD OVER THE REGION TUESDAY...BRINGING DRY AND
SEASONABLE CONDITIONS. HIGH PRESSURE WILL MOVE OFF THE COAST
TUESDAY NIGHT INTO WEDNESDAY WHILE LOW PRESSURE TRACKS ALONG THE
GULF COAST. THIS LOW WILL TRACK UP THE TENNESSEE VALLEY WEDNESDAY
NIGHT BEFORE TRANSFERRING ITS ENERGY TO A SECONDARY LOW OFF THE
MID-ATLANTIC COAST. THIS SECONDARY LOW WILL TRACK TOWARD NEW
ENGLAND THURSDAY AS IT INTENSIFIES. DESPITE A LACK OF CERTAINTY IN
THE EXACT TRACK OF THIS SYSTEM...IT DOES APPEAR THAT CLOUDS AND
RAIN WILL OVERSPREAD THE REGION FROM SOUTH TO NORTH LATER
WEDNESDAY INTO WEDNESDAY NIGHT. RAIN WILL HANG AROUND OVERNIGHT
WEDNESDAY AND PROBABLY INTO THURSDAY BEFORE DRIER AIR MOVES INTO
THE REGION ON THE BACKSIDE OF THE LOW LATER THURSDAY/THURSDAY NIGHT.
COLDER AIR WILL WORK ITS WAY INTO THE REGION FRIDAY AND SATURDAY
BEHIND THE STORM SYSTEM AND AHEAD OF CANADIAN HIGH PRESSURE.
NORTHWEST FLOW WILL BRING UPSLOPE SNOW SHOWERS TO THE POTOMAC
HIGHLANDS DURING THIS TIME.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
LIGHT WINDS THIS MRNG BCM SWLY DURG THE AFTN AS LOPRES ORGANIZES
ACRS WRN NEW ENGLAND. MOSTLY SUNNY SKIES THRU MUCH OF TDA WITH
INCRG CLDS LATE THIS AFTN. BKN-OVC SKIES BY MID-EVE WITH CIGS AT
4.0 KFT XPCD LATE TNGT.
A COLD FRONT WILL PASS THROUGH THE TERMINALS MONDAY...BRINGING A
GOOD CHANCE FOR SHOWERS ALONG WITH SUBVFR VSBYS/CIGS. MAINLY MVFR
CONDITIONS ARE EXPECTED WITH THIS SYSTEM...BUT BRIEF PERIODS OF
IFR CIGS/VSBYS ARE POSSIBLE IN SHOWERS. THE BEST CHANCE FOR
SHOWERS WILL BE DURING THE MORNING AND MIDDAY HOURS. NORTHWEST
WIND GUSTS AROUND 20 KNOTS ARE EXPECTED BEHIND THE FRONT MONDAY
AFTERNOON INTO EARLY MONDAY EVENING.
HIGH PRESSURE WILL BRING VFR CONDITIONS MONDAY NIGHT THROUGH
TUESDAY. LOW PRESSURE WILL TRACK TOWARD THE TERMINALS WEDNESDAY...
BRINGING INCREASING CLOUDS ALONG WITH A CHANCE OF RAIN DURING THE
AFTERNOON. A SECONDARY LOW WILL DEVELOP OFF THE MID-ATLANTIC COAST
WEDNESDAY NIGHT BEFORE TRACKING TOWARD NEW ENGLAND THURSDAY. RAIN
WILL IMPACT THE TERMINALS WEDNESDAY NIGHT INTO THURSDAY. SUBVFR
CIGS AND VSBYS ARE EXPECTED DURING THIS TIME.
&&
.MARINE...
LIGHT WINDS ACRS CHSPK BAY AND TIDAL POTOMAC THIS MRNG. AS LOPRES
ORGANIZES ACRS WRN NY THIS AFTN...SLY WINDS WILL INCR. WINDS SHUD
RMN BLW SMALL CRAFT ADZY THRESHOLDS TDA...BUT GUSTS TO 20 KT WILL
SPREAD NWD TNGT INTO CNTRL PORTIONS OF THE MD CHSPK BAY AND LWR
TIDAL POTOMAC. SMALL CRAFT ADZY ISSUED TNGT FOR THESE ZONES.
A COLD FRONT WILL PASS THROUGH THE WATERS MONDAY. SCA WINDS ARE
EXPECTED AHEAD OF THE FRONT ACROSS THE MIDDLE PORTION OF THE BAY AND
LOWER TIDAL POTOMAC MONDAY MORNING...AND ACROSS ALL OF THE WATERS
MONDAY AFTERNOON INTO MONDAY EVENING. THE GRADIENT BEHIND THE FRONT
WILL REMAIN STRONG ENOUGH FOR SCA WIND GUSTS OVER THE CHESAPEAKE BAY
AND LOWER TIDAL POTOMAC MONDAY NIGHT.
SCA WINDS ARE POSSIBLE TUESDAY AHEAD OF APPROACHING HIGH PRESSURE
OVER THE CHESAPEAKE BAY AND LOWER TIDAL POTOMAC. WINDS WILL DIMINISH
TUESDAY NIGHT AS HIGH PRESSURE BUILDS OVERHEAD.
LOW PRESSURE WILL APPROACH THE WATERS WEDNESDAY BEFORE PASSING
THROUGH WEDNESDAY NIGHT AND EVENTUALLY HEADING TOWARD NEW ENGLAND
THURSDAY. SCA WINDS ARE LIKELY WEDNESDAY NIGHT INTO FRIDAY BEHIND
THE LOW.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EST TUESDAY FOR
ANZ530-531-538-539.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
TUESDAY FOR ANZ532>534-537-540>543.
SMALL CRAFT ADVISORY FROM NOON TO 8 PM EST MONDAY FOR ANZ535-
536.
&&
$$
KRAMAR/LASORSA
