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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 131916
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
316 PM EDT MON MAY 13 2013

.SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL BUILD IN TONIGHT AND BRING CLEARING SKIES WITH
A FROST OR FREEZE. A WARM FRONT WILL MOVE THROUGH THE REGION BY
WEDNESDAY WITH WARMER TEMPERATURES INTO LATE WEEK.
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&&

.NEAR TERM /THROUGH TUESDAY/...
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LAST OF THE SHOWERS WILL BE DISSIPATING ACROSS THE RIDGES EARLY
EVENING AS SURFACE RIDGE ACROSS OHIO AND MICHIGAN BUILDS ACROSS
REGION.

AS THE EVENING PROGRESSES SKIES WILL CLEAR OUT AND WITH WINDS
GOING NEAR CALM OVERNIGHT EXPECT ANOTHER FROST/FREEZE ACROSS MUCH
OF THE REGION. HEADLINES FOR A FREEZE WARNING FROM COLUMBIANA
COUNTY AND WV PANHANDLE EASTWARD. FROST ADVISORY FOR REST OF
EASTERN OHIO AS INCREASING HIGH CLOUDS BEFORE DAWN SHOULD LIMIT
TEMPERATURE FALL THERE.

ON TUESDAY HIGH PRESSURE WILL EXIT EAST WITH WARM ADVECTION
BEGINNING ACROSS REGION WITH A GOOD DEAL OF CLOUDS AND A LOW
CHANCE FOR A SHOWER. TEMPERATURES WERE A BLEND OF MODEL MOS.
-- End Changed Discussion --


&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
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WARM FRONT WILL PUSH NORTH ACROSS REGION TUESDAY NIGHT INTO
WEDNESDAY BRINGING A CHANCE OF SHOWERS OR THUNDERSTORMS. LOW
PRESSURE SYSTEM ASSOCIATED WITH CLOSED UPPER LOW MOVING ACROSS
EASTERN CANADA WILL THEN PULL A WEAK FRONT SOUTH ACROSS REGION
LATER WEDNESDAY INTO THURSDAY. MODELS HAVE SOME TIMING
DISAGREEMENTS WITH WHETHER FRONT WILL HANG UP NEAR THE MASON DIXON
LINE OR PUSH SOUTH. HAVE LEFT CHANCE POPS FOR SHOWERS AND STORMS
FOR NOW BUT EXPECT A PERIOD OF HIGHER POPS WILL BE NEEDED...ONCE
TIMING OF FROPA CAN BE BETTER EVALUATED. A GENERAL BLEND OF MODEL
MOS WHICH WILL GIVE ABOVE AVERAGE TEMPERATURES...ESPECIALLY BEHIND
WARM FRONT WEDNESDAY.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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THE MODELS AGREE IN A LOW AMPLITUDE RIDGE REMAINING OVER THE
CENTRAL CONUS THROUGH AT LEAST SUNDAY BEFORE A DEEPENING TROUGH
AMPLIFIES THE RIDGE AND MOVES IT EASTWARD FOR THE BEGINNING OF NEXT
WEEK. HOWEVER...THERE ARE INHERENT DIFFERENCES IN THE TIMING AND
STRENGTH OF A SERIES OF SHORTWAVES AS THEY MOVE THROUGH THE
FLOW...DECREASING CONFIDENCE THROUGH THE PERIOD. THUS...OPTED TO
KEEP NO HIGHER THAN CHANCE POPS THROUGH MUCH OF THE PERIOD...WHICH
IS RIGHT IN LINE WITH BOTH HPC/MEX GUIDANCE. BOTH THE ECMWF AND GFS
GRADUALLY WARM TEMPERATURES THROUGH THE PERIOD KEEPING TEMPERATURES
5-10 DEGREES ABOVE SEASONAL AVERAGES THROUGH THE PERIOD.
-- End Changed Discussion --

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
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COLD NORTHWEST FLOW AND A CROSSING SHORTWAVE WILL CONTINUE TO
PROVIDE ENOUGH INSTABILITY FOR WIDESPREAD CU AND SOME SCATTERED
SHOWERS THROUGH THE AFTERNOON. HOWEVER...CONDITIONS ARE GENERALLY
EXPECTED TO REMAIN VFR AS DRIER AIR ASSOCIATED WITH HIGH PRESSURE
BUILDS EASTWARD TONIGHT. DIURNAL CUMULUS AND SHOWERS WILL DISSIPATE
OVERNIGHT LEADING TO CLEAR VFR CONDITIONS THROUGH THE PERIOD.

GUSTY W-NW WINDS WILL SHIFT TO SW TOMORROW AND SHOULD REMAIN 10KTS
OR LOWER.

.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE PERIOD.
HOWEVER...RESTRICTIONS COULD BE POSSIBLE IN SCATTERED SHOWERS AND
STORMS THURSDAY THROUGH SATURDAY ALONG A STATIONARY FRONT.
-- End Changed Discussion --

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR OHZ039-040-
     048>050-057>059-068-069.
     FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR OHZ041.
PA...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR PAZ007>009-
     013>016-020>023-029-031-073>076.
WV...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR WVZ001>004-
     012-021>023.

&&

$$