000
FXUS61 KPBZ 240212
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
912 PM EST MON NOV 23 2009

.SYNOPSIS...
CLOUDS, DRIZZLE, AND FOG WILL LINGER OVERNIGHT. TEMPERATURES WILL
ONLY FALL A FEW DEGREES. TUESDAY WILL BE DRY WITH MOSTLY CLOUDY
SKIES. NEXT, A STORM SYSTEM WILL MOVE INTO THE GREAT LAKES
WEDNESDAY. AS IT INTENSIFIES, IT WILL PULL COLDER AIR INTO THE
UPPER OHIO RIVER VALLEY LATER THANKSGIVING DAY INTO FRIDAY.

&&

.NEAR TERM /THROUGH TUESDAY/...
AREA OF LIGHT RAIN WILL CROSS THE REGION THIS EVENING AS SHORTWAVE
IN SOUTHWEST FLOW CROSSES THE UPPER OHIO VALLEY. GIVEN ADVANCE OF
DRY SLOT WITH THIS DISTURBANCE, THINK THAT MEASURABLE PRECIP WILL
END BY MIDNIGHT, BUT AREAS OF DRIZZLE AND FOG SHOULD CONTINUE
THROUGH THE NIGHT, ESPECIALLY FOR COUNTIES EAST OF I 79, AS LOW
MOVING UP THE COAST CONTINUES TO THROW LOW LEVEL MOISURE AROUND
ITS WESTERN FLANK.

AMPLE LOW LEVEL MOISTURE SHOULD ALSO LEAD TO AREAS OF FOG
OVERNIGHT...WITH PATCHES OF DENSE FOG POSSIBLE.

BY TUESDAY, SHORTWAVE RIDGE BRINGS SOME DRY WEATHER IN ADVANCE OF
MISSISSIPP VALLEY LOW. THUS, HIGHS SHOULD STAY 5 TO 10 DEGREES
ABOVE NORMAL.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
FOR MID WEEK AND THANKSGIVING...AFORE-MENTIONED MISSISSIPPI VALLEY
LOW IS PROGGED TO DIG TOWARD THE GREAT LAKES AND PHASE WITH
EASTWARD MOVING TROUGH. SCENARIO WILL SEND A COLD FRONT ACROSS
THE UPPER OHIO REGION ON WEDNESDAY EVENING WITH SCATTERED SHOWERS
EXPECTED WITH THE ADVANCE...COVERAGE IS ANTICIPATED TO BE LIMITED
BY MOISTURE SUPPLY. DEEPENING MID/UPPER LEVEL LOW-TROUGH
AXIS/COLD AIR IS CURRENTLY TIMED TO SWEEP OVER THE UPPER OHIO ON
THANKSGIVING EVENING, WITH CHANGEOVER TO SNOW SHOWER DURING THE
NIGHT.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
STRONG UPPER LEVEL LOW OVER THE EASTERN UNITED STATES WILL AID IN 
THE DEVELOPMENT OF A SURFACE LOW ALONG THE EAST COAST. WRAPAROUND 
PRECIPITATION SHOULD ARRIVE THURSDAY NIGHT. AS WRAPAROUND
MOISTURE BEGINS TO DECREASE ON FRIDAY...COLD 850MB TEMPERATURES
AND FLOW OFF LAKE ERIE SHOULD AT THE VERY LEAST ALLOW FOR HIGH
CHANCE POPS TO EXTEND FROM FRIDAY INTO SATURDAY MORNING. WITH WARM
GROUND TEMPERATURES AND LOWS ONLY DROPPING A COUPLE OF DEGREES
BELOW FREEZING THURSDAY AND FRIDAY NIGHTS...STILL FEEL THAT NO
SNOW ACCUMULATION WOULD OCCUR THURSDAY NIGHT...AND ONLY SMALL
ACCUMULATIONS TO THE NORTH FRIDAY NIGHT. AS THE LOW DEVELOPS
FRIDAY AND THEN MOVES TO THE NORTHEAST...A STRONGER PRESSURE
GRADIENT SHOULD ALSO BRING AN INCREASE IN WINDS...UP TO 30 MPH.
PRECIPITATION SHOULD COME TO AN END ON SATURDAY AS FLOW TURNS OUT
OF THE SOUTHWEST WITH HIGH PRESSURE MOVING IN. NEXT SYSTEM IS
EXPECTED TO ARRIVE BY MONDAY...WITH CHANCE POPS ADDED TO THE
FORECAST FOR THAT TIME PERIOD.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
AMPLE LOW LEVEL MOISTURE WILL LEAD TO CONDITIONS DROPPING TO
VLIFR TO IFR TONIGHT...WITH AREAS OF DRIZZLE...LOW CLOUDS AND
PATCHES OF DENSE FOG DEVELOPING. CONDITIONS WILL SLOWLY LIFT TO
VFR TUESDAY AFTERNOON.

MVFR TO VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT BEFORE LOW PRESSURE
MOVES INTO THE GREAT LAKES AND BRINGS A COLD FRONT THROUGH ON
WEDNESDAY...YIELDING ADDITIONAL RESTRICTIONS. ANOTHER LIFTING OF
CONDITIONS COULD OCCUR WEDNESDAY NIGHT BEFORE YET ANOTHER ROUND OF
PRECIPITATION AND RESTRICTIONS OCCURS FOR THE HOLIDAY WEEKEND.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$