Area Forecast Discussion
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000 FXUS61 KPBZ 192350 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 750 PM EDT SUN OCT 19 2014 .SYNOPSIS... BELOW-NORMAL TEMPERATURES CAN BE EXPECTED THROUGH MONDAY...WITH INCREASING CHANCES FOR RAIN ON MONDAY NIGHT. && .NEAR TERM /THROUGH MONDAY NIGHT/... WITH 8PM UPDATE...MINIMAL CHANGES WERE MADE TO SKY AND TEMPERATURE TRENDS THROUGH THE EVENING HOURS. CIRRUS COVERAGE HAS COME IN A BIT MORE QUICKLY THAN EXPECTED...AND THINK THAT THIS MAY SLOW DOWN THE COOLING TREND OVERNIGHT ENOUGH ACROSS SOUTHERN COUNTIES TO PREVENT FROST FROM DEVELOPING. HOWEVER...WILL CONTINUE WITH FROST ADVISORY. PREVIOUS DISCUSSION FOLLOWS. MID- AND UPR-LVL CLDS WILL INCR AHEAD OF APRCHG SHRTWV TROF THAT WILL DIG INTO GRTLKS TNGT. WIND ALREADY HAS BCM LGT AND WILL BACK TO SWLY IN RESPONSE TO APRCHG TROF. WITH LGT WIND...COOL TEMPS AND LMTD THICKNESS TO CI IMPINGING ON SRN ZONES...FROST WILL BE PSBL IN FAR SRN ZONES... WHERE CLD CVR WILL BE SLOWEST TO ARRIVE. FROST ADZY WAS ISSUED FOR MARION/MONONGALIA/WETZEL CTYS FOR LATE TNGT. ELSEWHERE...GROWING SEASON IS OVER OR MINIMA WILL RMN TOO ELEVATED FOR FROST. PREV SHIFT TRENDED SLOWER WITH PCPN ONSET ON MON...WHICH SEEMS LIKE A GOOD CHOICE. THIS TREND WAS CONTD TDA...WITH PCPN ONLY XPCD TO REACH NWRN ZONES BY LATE MON AFTN. TROF AXIS WILL CROSS MON NGT...AND PCPN WILL SHIFT EWD THRU EARLY TUE MRNG. BY END OF MON NGT PD...PCPN SHOULD BE MAINLY FOCUSED IN FAR ERN ZONES IN ASSOCIATION WITH UPR TROF AND ALONG LAKESHORES AS NWLY FLOW BEHIND CDFNT INCRS CVRG OF LAKE-ENHANCED SHWRS. PRIMARY ADJUSTMENT THESE PDS WAS TO INCR POPS TO CATEGORICAL MON NGT AND INTRODUCE SHARPER PCPN GRADIENT BY TUE MRNG. TEMPS ON MON XPCD TO CLIMB INTO MID-UPR 50S AS FILTERED SUNSHINE XPCD IN WARM SECTOR OWING TO SLOWER ARRIVAL OF PCPN. KRAMAR && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... A BRIEF MORNING LULL IN THE SHOWER ACTIVITY TUESDAY MORNING WILL QUICKLY BE REPLACED BY MORE INSTABILITY AND WIDESPREAD SHOWER ACTIVITY BY AFTERNOON AS YET ANOTHER SHORT WAVE TROUGH DIVES DOWN THE BACK SIDE AND INTO THE BASE OF THE LONGER WAVE RESIDENT TROUGH OVER THE REGION. MID-LEVEL TEMPERATURES FALL FAIRLY WELL BY AFTERNOON...IN FACT EVEN ENOUGH THAT SURFACE BASED INSTABILITY CAN BE NOTED ON MODEL SOUNDINGS. WHILE VERY SKINNY CAPE DOES MANAGE TO WORK ITS WAY UP ABOVE THE -20C LEVEL...TOTAL CAPE VALUES OF ROUGHLY 100 J/KG AND MINIMAL SHEAR MAKE ADDING THUNDERSTORMS TO THE FORECAST SEEM LIKE OVERKILL. HOWEVER...IT IS WORTH NOTING THAT THERE MAY BE A ONE STRIKE WONDER AROUND. UNSTABLE NORTHWEST FLOW THEN CONTINUES AS THE UPPER LOW CLOSES OFF...CUTS OFF...AND SLOWLY...BEGRUDINGLY...MEANDERS EASTWARD FROM THE AREA THROUGH MID-WEEK. THIS ALLOWS FOR A PAINSTAKINGLY SLOW WIND DOWN IN POPS AND AN EVEN SLOWER CLEAR OUT OF THE SKIES GOING TOWARD THE LONGER TERM. FRIES && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... SYSTEM FINALLY EJECTS EASTWARD THE SECOND HALF OF THE WEEK. A PERIOD OF DRY AND WARM WEATHER IS EXPECTED FOR THE END OF THE WEEK AND THROUGH THE WEEKEND. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR INTO MONDAY AS ONLY CIRRUS ACROSS THE TERMINALS OVERNIGHT. AN APPROACHING FRONTAL BOUNDARY WILL BRING MID DECK NORTHWEST TO SOUTHEAST MONDAY WITH A FEW LIGHT SHOWERS ACROSS NORTHERN PORTS LATE DAY. .AVIATION /MONDAY THROUGH FRIDAY/... PERIODIC RESTRICTIONS CAN BE EXPECTED TUESDAY THROUGH THURSDAY AS AN UPPER LEVEL LOW STALLS EAST OF THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...FROST ADVISORY FROM 5 AM TO 9 AM EDT MONDAY FOR WVZ012-021-022. && $$

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