Area Forecast Discussion
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000 FXUS61 KPBZ 312238 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 638 PM EDT FRI OCT 31 2014 .SYNOPSIS... LOW PRESSURE WILL CROSS THE REGION THROUGH SATURDAY WITH UNSETTLED WEATHER. HIGH PRESSURE RETURNS EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY NIGHT/... WITH 515PM UPDATE...MADE LITTLE CHANGE EXCEPT FOR UPDATING HOURLY TEMPERATURE TRENDS THROUGH THE EVENING...AS TEMPERATURES DID NOT REACH AS HIGH AS EXPECTED TODAY. CHANGES WERE MINIMAL ENOUGH THAT THIS SHOULD NOT AFFECT PRECIPITATION TYPE FORECASTS. PREVIOUS DISCUSSION FOLLOWS. WAVE OF LGT RAIN IS MOVG ACRS NRN WV PNHDL AND WRN PA ATTM. HIGH POP LOW QPF SITUATION HAS BEEN ADJUSTED IN GRIDS TO REFLECT THIS EARLY PCPN. PRIMARY PCPN XPCD LATER THIS AFTN. STRONG H5 TROF WILL CLOSE OFF AND DIG SEWD THIS AFTN AND EVE FROM GRTLKS TO TN. WDSPRD MDT SHWRS ARE EVIDENT ON RADAR IN ASSOCIATION WITH THIS STRENGTHENING WAVE...AND THESE SHWRS WILL CONT TO MOVE EWD INTO FCST AREA THIS AFTN. EWD EXTENT OF THE PCPN WILL BE DICTATED IN LARGE PART BY UPPER WAVE...AS SEWD TRAJECTORY WILL MOST FAVOR WRN HALF OF FCST AREA FOR GREATER PCPN TOTALS...WHICH STILL WILL REMAIN BLW 0.2 INCH. SFC LOW WILL CROSS FCST AREA TNGT AND WILL DRAW CDFNT SEWD ACRS THE RGN BY SAT MRNG. COLDER...DRIER AIR WILL FILTER INTO THE RGN IN THE WAKE OF THE BNDRY...PROMOTING AN INCR IN LAKE-ENHANCED PCPN FOR NRN ZONES AS FLOW BCMS NNWLY. A FURTHER SHIFT TO NWLY FLOW WILL SUPPORT INCRD POPS FOR THE RDGS SAT AFTN AND EVE. AIR COLD ENOUGH TO SUPPORT SNOW WILL BE HARD TO COME BY FOR MUCH OF THE FCST AREA WITH THE EXCEPTION OF THE RDGS. THERE MAY BE A BRIEF WINDOW WHERE SNOWFLAKES ARE SEEN TWD THE END OF THE LAKE- ENHANCED PCPN PD IN NWRN PA AND ERN OH. WITH TEMPS CONSISTENTLY COLDER AND PCPN ENHANCED BY UPSLP...THERE MAY BE A SLGTLY LONGER PD THAT WOULD SUPPORT SNOW PRODUCTION ON THE RDGS...BUT OMEGA AND INSTBY INTERSECTING THE DENDRITIC GROWTH ZONE ARE MINIMAL...SO ANY ACCUMS XPCD TO BE VERY LGT. AT BEST...1-2 IN AMTS ARE PSBL AT THE HIGHEST ELEVATIONS...WITH MUCH LWR AMTS ELSEWHERE. THERE WILL NOT BE MUCH IN THE WAY OF DIURNAL TEMPERATURE INCRS ON SAT...WITH MAXIMA XPCD TO REACH ONLY THE LWR 40S AT BEST. RDGS LKLY WILL RMN IN MID 30S. WDSPRD FRZG TEMPS XPCD SAT NGT...SGFNT DESPITE HAVING PASSED DATE OF AVG FRZ WITH SVRL CTYS NOT YET HAVING EXPERIENCED A HARD FRZ. CLD CVR WILL HELP SLOW COOLING PROCESS...BUT COLD ADVCTN WILL DOMINATE. KRAMAR && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE DEEP TROUGH PULLS EAST SUNDAY MORNING...WITH SKIES CLEARING AS A MIDLEVEL RIDGE BEGINS TO APPROACH. SUNDAY NIGHT WILL BE MOSTLY CLEAR AND COLD AS THE SURFACE HIGH DRIFTS BY TO OUR SOUTH. AFTER A COLD START TEMPERATURES WILL BEGIN TO MODERATE MONDAY AS SURFACE RIDGE SHIFTS EAST AND SOUTHWEST FLOW RETURNS. ONLY A FEW HIGH CLOUDS INCREASING LATE DAY MONDAY. MID AND HIGH CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AND WILL HELP HOLD TEMPERATURES IN THE MID AND UPPER 30S. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A COLD FRONT CROSSING THE REGION LATER TUESDAY INTO WEDNESDAY WITH A CHANCE FOR SHOWERS. NEXT FRONT AND PUSH OF COLDER AIR TIMED FOR THURSDAY WITH SHOWERS WHICH LOOK TO END AS SNOW SHOWERS IN THE RIDGES FRIDAY MORNING. CLOSE TO WPC PROGS THROUGH THE PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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WDSPRD MVFR CONDS AND SHWRS ARE EXPD INTO SAT MRNG AS A DEEPENING TROF ADVNS ACRS THE GT LKS AND OH VLY RGN. WITH LLVL MOISTURE IN PLACE SOME PTCHY IFR IS ALSO PSBL THIS EVE. DEEP MOISTURE IS PROGGED TO DCR ERLY SAT AS COASTAL SFC LOW PRES DVLPS IN RESPONSE TO THE DIGGING UPR TROF...DCRG THE SHWR COVG. MVFR SC AND SCT SHWRS ARE EXPD TO CONT THRU SAT WITH COLD AIR ALOFT. OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... CIGS RSTRNS ARE EXP INTO SUN MRNG IN COLD NW FLOW. RSTRNS ARE PSBL AGAIN WITH A MID WK CDFNT.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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