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000
FXUS61 KPBZ 061644
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1144 AM EST FRI DEC 6 2013

.SYNOPSIS...
RAIN WILL MIX WITH...THEN CHANGE TO SLEET AND SNOW TODAY. ANOTHER
STORM WILL LIKELY BRING A WINTRY MIX ONCE AGAIN ON SUNDAY AND
EARLY MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
QUICK UPDT TO EXPAND ADVY AREA TO THE E AND S. 12Z GUIDANCE
FOCUSING PCPN FURTHER S THAN PREVIOUS RUNS AND THIS LINES UP WITH
CURRENT RADAR/STLT TRENDS. ALSO WITH EXPD QPF...INCRD SNOW TOTALS
TO 4-6 INCHES ROUGHLY IN A CORRIDOR FM ZZV TO PIT. WSW UPDTD...
FCST PRODUCTS TO FOLLOW.

CURRENT LULL IN PCPN SHOULD COME TO AN END THIS AFTN AS THE NEXT
MOISTURE PLUME AND SPPRTG SHRTWV MOVE INTO THE RGN. CRITICAL
THICKNESSES/SOUNDINGS STILL INDICATE A MIX OF SLEET AND SNOW N OF
PIT...WITH RAIN/SLEET PIT SWD...AND ALL RAIN S OF THE PA BORDER.
THIS PCPN WL GRDLY CHG TO ALL SNW FM N-S THIS EVE.
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&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
REPRIEVE IN PCPN IS STILL INDICATED FOR SATURDAY WITH COLD HIGH
PRES SETTLING OVR THE AREA. THAT COLD CORE IS EXPECTED TO
CONTRIBUTE TO MORE PROBLEMS ON SUNDAY THOUGH AS WARM ADVCTN ALOFT
RESUMES WITH THE ADVN OF LOW PRES OUT OF THE LWR MS VALLEY. MDLS
CONT TO SHOW A TRACK WEST OF THE IMMEDIATE AREA...WHICH WL
CONTRIBUTE TO ANOTHER WINTRY MIX SITUATION...HIGHLIGHTED BY
POTENTIAL FREEZING RAIN AS HIGH PRES ENTRENCHED OVR NEW ENGLAND
HOLDS THE COLDER SFC AIR OVR THE REGION.

GIVEN CONSISTENCY OF SOLNS OVR THE PAST CPL DAYS...HAVE INCRSD
POPS TO CATEGORICAL NMBRS...BUT ADJUSTED FOR A SLOWER
WARMUP...ESPECIALLY FOR COUNTIES N AND E OF PIT WHERE ICING
POTENTIAL WOULD PEAK. A HAZARDOUS WEATHER OUTLOOK MENTION WL BE
MAINTAINED AND MONITORING WL CONT WHILE WE DEAL WITH TODAYS ISSUES.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
COLDER AND DRIER AIR WL BE SHUNTED OVR THE UPR OHIO REGION IN THE
WAKE OF THAT SYSTEM. COLD TEMPS AND GENLY PCPN FREE POPS WERE
FORECAST USING A COMBO OF WPC AND MOS GUIDANCE.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
GENL MVFR TO IFR CONDS EXPD THRU THE PD. AFT A BRF LULL IN THE
PCPN THIS MRNG...EXP A WINTRY MIX TO OVERSPREAD THE RGN AGAIN BY
LT MRNG/ERLY AFTN. GENLY EXP SN OR SN/PL N OF I 80...WITH A RA/PL
MIX INVOF A LINE FM ZZV TO PIT. RA IS EXPD S OF PIT THRU THIS
AFTN. ALL PCPN WL CHG TO SNW TNGT WITH THE BULK OF THE ACCUMS FM
PIT NWD. PCPN SHOULD END LT TNGT...ALTHOUGH MVFR CIGS WL CONT.

.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
RSTRNS ARE LIKELY AGAIN SUN AND MON AS LOW PRES BRINGS A WINTRY
MIX TO THE RGN. VFR SHOULD RTN TUE UNDER BLDG HIGH PRES.

&&

.HYDROLOGY...
THE HEAVIER RAINFALL PROGNOSIS WAS EXPANDED EASTWARD OVER THE
CHEAT AND YOUGHIOGHENY RIVER BASINS. THIS WILL RESULT IN SLIGHTLY
HIGHER CRESTS ON SATURDAY. CRESTS ARE STILL EXPECTED TO REMAIN
BELOW FLOOD STAGES, BUT ACTION LEVELS ARE STILL PROJECTED TO BE
REACHED ALONG THE MONONGAHELA AND OHIO RIVERS.

SUMMARY: A RIVER RISE OF 5 TO 9 FEET IS COMING THIS SATURDAY (DEC
7, 2013) ON THE MONONGAHELA AND OHIO RIVERS. AND THEN A SECOND
RISE IS LIKELY MONDAY (DEC 9, 2013).

A GENERAL 5 TO 9 FOOT RISE IS EXPECTED SATURDAY ON THE
MONONGAHELA AND UPPER OHIO RIVERS. AT THIS POINT PROJECTIONS ARE
TO BRING GRAYS LANDING UP 17.9 FEET SATURDAY LATE MORNING AND
PITTSBURGH 20.2 FEET SATURDAY AFTERNOON. THE MON PARKING WHARF
WILL BE AFFECTED STARTING SATURDAY.

RIVER LEVELS SHOULD RECEDE SATURDAY NIGHT AND SUNDAY THEN A
SECOND RISE IS EXPECTED MONDAY THAT COULD CREST AT HIGHER THAN
SATURDAY LEVELS. THE CURRENT PROJECTIONS DO NOT INCLUDE THE
PROJECTED RAINFALL FOR SUNDAY AT THIS POINT.

THE PRECIPITATION OVER THE ALLEGHENY WILL BE MINIMAL AND WILL
LIKELY FALL IN THE FORM OF SNOW.

RIVERS WILL RECEDE TUESDAY AND FOR THE REST OF THE WEEK.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
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MD...NONE.
OH...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
     OHZ039>041-048>050-057>059-068-069.
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
     PAZ007>009-013>016-020>023-029-031-073>076.
WV...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
     WVZ001>004.
-- End Changed Discussion --

&&

$$