Area Forecast Discussion
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000 FXUS61 KPBZ 292339 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 739 PM EDT MON SEP 29 2014 .SYNOPSIS... WEAK LOW PRESSURE WILL CROSS THE REGION TUESDAY. WARM AND DRY CONDITIONS WILL FOLLOW UNTIL THE PASSAGE OF A FRIDAY COLD FRONT. && .NEAR TERM /THROUGH TUESDAY/... DRY WEA IS EXPD TNGT AS A WK MID/UPR TROF EXITS. THE NXT ADVNG SHRTWV WL MOVE ACRS THE GT LKS RGN TUE WITH SCT SHWRS. LACK OF DEEP MOISTURE AND THE RECENT DRY PATTERN SHOULD HELP LMT PCPN COVG...SO MAINTAINED ONLY CHC POPS ATTM. LATEST MDL PROGS SHOW VRY LTL INSTBY SO REMOVED TSTM MENTION FM THE FCST. TEMPS WL CONT A FEW DEG ABV SEASONAL LVLS. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... MODELS MORE OR LESS AGREE ON FRONTAL TIMING TUESDAY NIGHT...WITH THE BOUNDARY NEAR OR THROUGH PIT BY 00Z. WITH CONTINUING FROPA...WILL KEEP FADING CHANCE POPS IN THE FORECAST WITH THE LIMITED MOISTURE...LIKELY TOO LITTLE TO TAKE MUCH ADVANTAGE OF THE ARRIVAL OF UPPER CLOSED LOW DURING THE NIGHT. HAVE DRY POPS BY SUNRISE ON WEDNESDAY. COULD SEE SOME PATCHES OF LOW CLOUD FORM UP DURING THE NIGHT...WHICH WOULD KEEP TEMPERATURES UP. BLENDED MOS GUIDANCE INTO PREVIOUS MIN TEMP GRID TO NUDGE VALUES UP A DEGREE OR TWO. AS HINTED AT BY PREVIOUS SHIFT...WENT AHEAD AND ADDED A MINIMAL POP FOR SHRA TO THE EASTERN RIDGES FOR WEDNESDAY AFTERNOON. UPPER LOW ALONG WITH ITS COLD POOL ALOFT WILL STILL BE EXITING DURING TIME OF PEAK HEATING. WHILE THERE IS ENOUGH MIDLEVEL WARM AIR TO PREVENT SHRA FORMATION FROM PIT ON WEST...BUFKIT SOUNDINGS SHOW A BIT MORE FAVORABLE CAPE PROFILE FOR LOCATIONS LIKE DUJ AND LBE. TO THE WEST...ANY MORNING LOW CLOUDS WOULD LIFT INTO SCT CU ONLY. USED NAM H850 TEMPS TO CONSTRUCT MAX TEMP GRID...ENDING UP WITH VALUES CLOSE TO MOS. ONCE UPPER LOW EXITS...WEAK SURFACE HIGH PRESSURE AND H500 RIDGING BUILD IN...GIVING US DRY WEATHER FOR WEDNESDAY NIGHT AND THURSDAY. MAY SEE A FEW MORE CLOUDS ALONG THE EASTERN RIDGES THAN THE WEST GIVEN SOME LIGHT EAST/SOUTHEAST FLOW. TEMPERATURES WILL CONTINUE TO RUN ABOVE NORMAL. && .LONG TERM /FRIDAY THROUGH MONDAY/... ECMWF COMING A LITTLE MORE IN LINE WITH GFS AND ENSEMBLES ON TIMING OF MORE SIGNIFICANT FROPA ON FRIDAY. GIVEN INCREASED CONFIDENCE...BUMPED POPS UP TO LIKELY AND ALSO INSERTED A CHANCE OF THUNDER WITH THE VIGOROUS NATURE OF THE SYSTEM. SOME DISAGREEMENT THEREAFTER WHETHER ANOTHER CLOSED LOW SINKS IN BEHIND THE FRONT. WILL RIDE WITH THE PREVIOUS FORECAST FROM SATURDAY ON FOR NOW. IN ANY CASE...MUCH COOLER AIR ARRIVES FOR THE WEEKEND. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THE ONLY BLEMISH ON VFR CONDITIONS THROUGH DAYBREAK TUESDAY IS EXPECTED TO COME FROM FM SHALLOW PREDAWN FOG. SHOULD MID LVL CLDINESS DVLP A FEW HRS QUICKER THAN ANTICIPATED WITH THE ADVN OF THE AFOREMENTIONED SHRTWV...THAT RESTRICTION POTENTIAL WL BE PRECLUDED. OTHERWISE...SCT SHWRS ARE EXPECTED TO DVLP WITH THE DISTURBANCE...BUT RESTRICTION POSSIBILITY LKS TO BE LTD TO SOME MVFR VSBYS. OUTLOOK.../TUESDAY THROUGH FRIDAY/... THE NXT CHC FOR WIDESPREAD RESTRICTION WL COME WITH A FRIDAY CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 07/15

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