Area Forecast Discussion
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000 FXUS61 KPBZ 191750 AAD AFDPBZ AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 150 PM EDT SAT JUL 19 2014 .SYNOPSIS... WEAK LOW PRESSURE WILL GENERATE SHOWERS TODAY. WARMER AND MORE HUMID WEATHER CAN BE EXPECTED INTO MID WEEK. && .NEAR TERM /THROUGH SUNDAY/... LATEST RADAR IMAGERY AND SAT PICS SHOW SHOWERS TRANSITIONING EASTWARD WITH MAIN UPPER LEVEL WAVE. MODELS HAVING A LITTLE BIT OF TROUBLE DECIPHERING ALL THE WAVES ROTATING AROUND OPENING 500MB LOW WHICH IS MOVING ACROSS LAKE ERIE. THE AFOREMENTIONED WAVE PROBLEM IS ALSO LEADING TO AN OVERPLAY OF SHOWER COVERAGE. THE MAIN SOUTHERN WAVE WILL CONTINUE EASTWARD INTO THE MID-ATLANTIC WHILE THE 500MB LOW...OR WHATS LEFT OF IT...LIFTS NORTHWARD INTO SOUTHERN CANADA BY THIS EVENING. AS THIS ENERGY DEPARTS...ANOTHER SHORTWAVE TROUGH WILL SLOWLY MOVE THROUGH OHIO. THE AREA WILL QUICKLY LOSE THE MOISTURE ALOFT...BUT HOLD ONTO SATURATION IN THE MID AND LOWER LEVELS THROUGH THE REST OF THE EVENING AND OVERNIGHT. WILL CONTINUE WITH THE PROCESS OF LOWERING POPS FROM WEST TO EAST THIS AFTERNOON AND THROUGH THE EVENING HOURS. TEMPTED TO GO WITH A DRY FORECAST OVERNIGHT...BUT WITH SHORTWAVE MOVING THROUGH AND SOME WEAK CONVERGENCE AT 850MB...ITS POSSIBLE A SHOWER COULD DEVELOP LATE TONIGHT. FOR THE OVERNIGHT WILL GO WITH SCHC/LOW CHC POPS TO COVER THE RISK FOR SHOWERS. NOT MUCH OF A DECREASE IN CLOUD COVER EXPECTED OVERNIGHT. ON SUNDAY...WEAK SHORTWAVE TROUGH WILL SWING EASTWARD AND INVERTED SURFACE TROUGH WILL REMAIN STALLED OVER WESTERN HALF OF THE AREA. MODEL SOUNDING ARE SHOWING AN OVERALL DRYING TREND... HOWEVER IF WE CAN DISPERSE THE CLOUD COVER WOULD EXPECT CU TO QUICKLY DEVELOP IN THE AFTERNOON AS ATMOSPHERE WILL DESTABILIZE. OVERALL... ATMOSPHERIC FORCING WILL BE WEAK...BUT THERE MAY BE ENOUGH INSTABILITY TO SPARK AND ISO SHOWER OR STORM IN THE AFTERNOON. TEMPS WILL BE WARMER SUNDAY AND HUMIDITY LEVELS WILL CONTINUE TO SLOWLY INCREASE. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... ISOLD TO SCT...DIURNALLY SPPRTED CONVECTION WITH SEASONAL TEMPS AND HUMIDITY UNDR A WEAK...BUT PESKY MID/UPR TROF ARE ANTICIPATED FOR THE START OF THE NEW WEEK. BY TUESDAY...THE EXPANSION OF THE WRN CONUS RIDGE...WITH AXIS PROGGED ACRS THE GREAT LAKES...SHOULD SUPPRESS PCPN CHCS AND DRIVE TEMPS ABOVE THE SEASONAL AVGS. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... THAT EXPANSION IS FORECAST TO BE HALTED VIA SHRTWV ENERGY DIGGING OVR THE LAKES BY WEDNESDAY. THAT DISTURBANCE IS EXPECTED TO DRIVE ANOTHER STRONG CDFNT ACRS THE REGION DURING THE LATTER HALF OF THE WEEK...AND DROP TEMPS BACK UNDR THE AVGS. GIVEN THE CHANGEABLE NATURE OF THE LONG TERM PROGNOSIS...HAVE USED TWEAKED HPC GUIDANCE WHICH REPRESENTS A MDL BLEND. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... A CROSSING SHRTWV WL BRING SHWRS AND WDSPRD MVFR CONDS TO THE RGN INTO ERLY AFTN. PTCHY IFR IS ALSO EXPD ESP FM PIT WWD THRU 15Z. THE RAIN SHOULD TAPER TO SCT SHWRS BY MID AFTN WITH CONDS SLOWLY RTNG TO VFR. MVFR VSBY IS EXPD TO DVLP AGAIN TNGT WITH LLVL MOISTURE IN PLACE. .OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RSTRNS ARE PSBL SUN WITH AN EXITING DISTURBANCE. THE NXT CHC FOR WDSPRD RSTRNS WL BE WITH A LT WED CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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