656
FXUS61 KPBZ 241559
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1059 AM EST TUE NOV 24 2009
SYNOPSIS
RAIN AND SNOW SHOWERS MAY BE EXPECTED DURING THE SECOND HALF OF
THE WEEK AS DEEP LOW PRESSURE DEVELOPS OVER THE GREAT LAKES REGION.
NEAR TERM /THROUGH TONIGHT/
LOW PRESSURE OVER THE PLAINS STATES WILL DEVELOP EASTWARD OVER THE
NEXT 24 HOURS. IN ADVANCE OF THAT FEATURE, SHORTWAVE RIDGE OVER
THE UPPER OHIO VALLEY, WITH DRY MID LEVELS, WILL SUPPORT A
PRECIPITATION FREE FORECAST THROUGH TONIGHT...HOWEVER, ABUNDANT
LOW LEVEL MOISTURE IS EXPECTED TO FUEL CONTINUED CLOUDINESS AND
DRIZZLE FOR MOST AREAS INTO WEDNESDAY MORNING. THAT CLOUD BLANKET WILL
RESTRICT THE TEMPERATURE RANGE, AND OVERNIGHT LOWS ARE EXPECTED TO
BE APPROXIMATELY 10 DEGREES ABOVE THE SEASONAL AVERAGES.
SHORT TERM /WEDNESDAY THROUGH FRIDAY/
STRONG CLOSED LOW ALOFT WILL WORK ACROSS GREAT LAKES THROUGH THE
PERIOD WITH SHOWERS WEDNESDAY FOLLOWED BY COLDER AIR FOR THURSDAY
INTO THE WEEKEND. PRECIP WILL CHANGE TO SNOW SHOWERS THURSDAY
NIGHT AND REMAIN MAINLY SNOW SHOWERS FRIDAY WITH A MIX SOUTH OF
PITTSBURGH FRIDAY AFTERNOON. TEMPERATURES BELOW MEX MOS FRIDAY WHICH
SEEMS TO BE RUNNING WARM BASED ON ECMWF AND GFS THICKNESS AND 850MB
TEMPS. LIGHT COATING OF SNOW POSSIBLE LATER THURSDAY NIGHT AND FRIDAY
NORTH OF PITTSBURGH AND ALONG RIDGES.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
SURFACE LOW WILL BOMB OUT OFFSHORE OF NEW ENGLAND FRIDAY NIGHT
INTO SATURDAY AS CENTER OF CLOSED LOW MOVES ACROSS NEW YORK STATE.
850MB TEMPERATURES FRIDAY NIGHT INTO EARLY SATURDAY FROM -5C TO
-7C AND WITH WELL ALIGNED NORTHWEST FLOW SOME SNOW ACCUMULATION
POSSIBLE MAINLY IN THE RIDGES. UPPER HEIGHTS BEGIN TO RISE
SATURDAY NIGHT WITH SURFACE HIGH PRESSURE ENDING SNOW SHOWERS WITH
A SLIGHT WARMING TREND SUNDAY AND MONDAY.
AVIATION /16Z TUESDAY THROUGH SATURDAY/
CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE TO MVFR CEILINGS AND
UNRESTRICTED VISIBILITY BY THIS AFTERNOON AS SOME DRYING OCCURS
WITH WEAK RIDGING.
PREDOMINATELY MVFR CONDITIONS ARE EXPECTED TO CONTINUE TONIGHT WITH
AREAS OF IFR FOG AND DRIZZLE DEVELOPING LATE. LOW PRESSURE WILL
MOVE INTO THE GREAT LAKES AND SWING A COLD FRONT THROUGH THE
REGION ON WEDNESDAY...BRINGING ADDITIONAL RESTRICTIONS. SOME
IMPROVEMENT COULD OCCUR WEDNESDAY NIGHT BEFORE ANOTHER ROUND OF
PRECIPITATION AND MVFR/IFR RESTRICTIONS OCCURS FOR THE HOLIDAY
WEEKEND AS MOISTURE AND COLDER AIR WRAPS IN BEHIND THE LOW.
PBZ WATCHES/WARNINGS/ADVISORIES
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
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