047
FXUS61 KLWX 072000
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
300 PM EST SAT NOV 7 2009
SYNOPSIS
HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH EARLY NEXT WEEK.
A WEAK PRESSURE TROUGH WILL BRING A WIND SHIFT TO THE AREA
TOMORROW...BUT WILL HAVE LITTLE EFFECT ON TEMPERATURES. THE NEXT
COLD FRONT WILL APPROACH THE REGION LATE TUESDAY INTO WEDNESDAY.
NEAR TERM /THROUGH TONIGHT/
HIPRES CENTERED JUST OFF THE CAROLINA COAST WILL SLOWLY BUILD
SEWD BUT REMAIN IN CONTROL OF THE MID ATLANTIC WX PATTERN. A VERY
WEAK LLVL SHORTWAVE AND SFC PRESSURE TROUGH WILL MOVE THRU THE
REGION LATE TNGT. WLY FLOW ALOFT WILL ADVECT WARMER AIR FROM THE C
CONUS INTO THE REGION...RESULTING IN A FAIRLY STRONG THERMAL
INVERSION IN THE FIRST 3 KFT ABOVE THE GROUND. THIS INVERSION
COMBINED WITH MIXING...ESPECIALLY ACROSS HIGHER ELEVATIONS OF THE
BLUE RIDGE AND POTOMAC HIGHLANDS...WILL RESULT IN MUCH HIGHER MIN
TEMPS COMPARED TO COOLER SHELTERED VALLEYS. FCST LOWS RANGE FROM
AROUND 40F IN LOCATIONS BELOW 1 KFT TO NEAR 50F FOR ELEVATIONS AOA
2 KFT.
SHORT TERM /SUNDAY/
AFOREMENTIONED WEAK SFC PRESSURE TROUGH WILL PUSH THRU BY THE ERY
IN THE PD. SFC FLOW WILL SHIFT NWLY IN WAKE OF TROUGH BUT WILL
BECOME LIGHT AS HIPRES RIDGE SETTLES OVRHD. WITH MSTLY SUNNY SKIES
AND A WARMER AIRMASS IN PLACE...MAX TEMPS WILL GENERALLY BE IN THE
MU60S WITH A FEW SPOTS CLIMBING INTO THE L70S.
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE ACROSS THE
CWFA THROUGH EARLY TUESDAY. A COLD FRONT IS STILL PROGGED TO MOVE
THROUGH THE MID ATLANTIC REGION LATE TUESDAY INTO EARLY WEDNESDAY.
THE GFS IS NOW BRINGING MOISTURE NORTHWARD FROM THE GULF OF MEXICO
AHEAD OF THE FRONT. THERE IS A WIDE SPREAD BETWEEN GUIDANCE NUMBERS
FOR THIS PERIOD...SO WILL OPT TO GO WITH PERSISTENCE AND KEEP THE
SLIGHT CHANCE POPS IN THE FORECAST FOR NOW. HIGH PRESSURE BUILDS
BACK IN FOR THE REMAINDER OF THE WEEK INTO THE EARLY PART OF THE
WEEKEND.
LOOKS LIKE UNTIL THE FROPA LATE TUESDAY/EARLY WEDNESDAY TEMPS IN THE
HIGHER ELEVATIONS COULD REMAIN A BIT HIGHER THAN THE VALLEYS.
ALSO...BREEZY CONDITIONS ARE ANTICIPATED BEHIND THIS FRONT WEDNESDAY
AND EVEN INTO EARLY THURSDAY.
AVIATION /20Z SATURDAY THROUGH THURSDAY/
VFR CONDITIONS TNGT AND SUN. SLY WINDS AROUND 5-10 KT WITH A FEW
GUSTS TO 15 KT WILL RELAX TOWARDS SUNSET. A SUBTLE PRESSURE TROUGH
WILL PUSH THRU OVRNGT...SHIFTING THE WINDS W-NWLY SUN.
NO RESTRICTIONS TO VSBY/CIGS ARE EXPECTED THROUGH EARLY NEXT WEEK. A
COLD FRONT IS EXPECTED LATE TUESDAY/EARLY WEDNESDAY. NOT MUCH
PRECIPITATION CAN IS EXPECTED WITH THIS BOUNDARY...BUT BREEZY
CONDITIONS ARE POSSIBLE WEDNESDAY INTO THURSDAY.
MARINE
SCA HAS BEEN EXTENDED THRU 02Z THIS EVNG IN THE MD CHSPK BAY AND
LOWER TIDAL POTOMAC. SLY CHANNELING WILL PROLONG 20 KT GUST
POTENTIAL THRU THE EVNG BEFORE THE WINDS RELAX LATE THIS EVNG. WINDS
WILL BECOME LGT OVRNGT INTO SUN AS HIPRES SETTLES OVRHD.
SOME CHANNELING UP THE BAY IS POSSIBLE LATER TUESDAY AHEAD OF AN
APPROACHING COLD FRONT...AND GUST POTENTIAL MAY APPROACH SMALL CRAFT
CRITERIA. SMALL CRAFT CONDITIONS ARE LIKELY BEHIND THE FRONT
WEDNESDAY INTO THURSDAY. WILL HAVE TO CONTINUE TO MONITOR...WINDS
ALOFT COULD BE STRONG ENOUGH FOR A BRIEF PERIOD OF GALES DURING THIS
PERIOD.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR
ANZ530>534-537>543.
KLEIN/LISTEMAA
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