FXUS61 KPBZ 251249
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
749 AM EST WED NOV 25 2009
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL BRING A CHANCE OF SHOWERS TODAY THROUGH
THURSDAY. THE COLD AIR IN THE WAKE OF THE FRONT WILL SUPPORT A
CHANGE OF RAIN SHOWERS TO SNOW SHOWERS FOR THE LAST COUPLE DAYS OF
THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A COLD FRONT WILL PUSH SLOWLY ACROSS THE UPPER OHIO VALLEY TODAY
BRINGING CLOUDS AND SHOWERS. A DRY SLOT BEHIND THE FRONT WILL
BRING A BREAK IN THE SHOWERS TONIGHT.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
A DEEP CLOSED LOW WILL DEVELOP OVER OHIO THURSDAY MOVING SLOWLY
EAST INTO PA THURSDAY NIGHT. SHOWERS WILL RETURN THURSDAY AS THE
UPPER LOW MOVES EAST. A STRONG SECONDARY COLD FRONT WILL PUSH
ACROSS THE REGION THURSDAY AFTERNOON AND MUCH COLDER TEMPERATURES
WILL MOVING IN BEHIND THE FRONT THURSDAY NIGHT. RAIN SHOWERS WILL
CHANGE TO SNOW SHOWERS THURSDAY NIGHT. SOME SNOW ACCUMULATION IS
POSSIBLE LATE THURSDAY NIGHT AND FRIDAY NORTH OF PITTSBURGH AND
ESPECIALLY ALONG THE RIDGES...WHERE COUPLE INCHES MAY SPAWN A
WINTER WEATHER ADVISORY. ACCUMULATION IS EXPECTED TO BE QUICKLY
LIMITED ON FRIDAY AS SUBSIDENCE INVERSION LOWERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
BUILDING HIGH PRESSURE FRIDAY NIGHT WILL RELAX THE NORTHWEST FLOW
AND DIMINISH THE LAKE EFFECT SNOW SHOWERS FRIDAY NIGHT INTO
SATURDAY MORNING. THE HIGH PRESSURE WILL PROVIDE DRY CONDITIONS
LATE SATURDAY AND SUNDAY.
THEN A DEEP UPPER TROUGH MOVING EASTWARD OUT OF THE ROCKIES WILL
HELP DEVELOP A BROAD LOW PRESSURE SYSTEM OVER THE PLAINS AND
MISSISSIPPI VALLEY THAT WILL MOVE EASTWARD INTO THE UPPER OHIO
VALLEY MONDAY AND TUESDAY. SOUTHERLY WIND PRECEDING THIS SYSTEM
WILL HELP TEMPERATURES REBOUND TOWARD NORMAL. SO THE DOMINANT
PRECIPITATION TYPE MONDAY AND TUESDAY SHOULD BE RAIN.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR CEILINGS 3000 TO 5000 FEET TO REMAIN OVER THE
REGION THROUGH THE TAF PERIOD. CONDITIONS COULD BRIEFLY LOWER TO
MVFR IN RAIN SHOWERS PRECEDING AN OCCLUDED FRONT THIS MORNING.
LOW PRESSURE WILL MOVE SLOWLY EAST ACROSS THE GREAT LAKES WITH A
SECONDARY SURFACE FRONT MOVING ACROSS THE REGION THURSDAY. SCATTERED
SHOWERS WILL CAUSE MVFR RESTRICTIONS DURING THE DAY THURSDAY.
INTERMITTENT DETERIORATION TO IFR IS POSSIBLE WITH SNOW SHOWERS FOR
THANKSGIVING NIGHT THROUGH FRIDAY NIGHT AS COLDER AIR PUSHES IN WITH
NORTHWEST FLOW.
SURFACE HIGH PRESSURE SHOULD BRING A RETURN TO VFR ACROSS THE UPPER
OHIO VALLEY SATURDAY AND SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
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