Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPBZ 291724 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 124 PM EDT FRI MAY 29 2015 .SYNOPSIS... A WEAK DISTURBANCE THIS AFTERNOON WILL BE FOLLOWED BY A SLOW MOVING COLD FRONT OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... A WEAK SHORTWAVE IN SOUTHWEST FLOW IS PROGGED TO CROSS THE REGION THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP WITH THIS FEATURE...THOUGH PROGGED INSTABILITY IS LIMITED WITH WARM AIR ALOFT. SLOWED ONSET OF PRECIP WITH THE LATE MORNING UPDATE. THIS ACTIVITY SHOULD DECREASE THIS EVENING AS THE WAVE EXITS. MORNING SOUNDINGS SUPPORT HIGHS IN THE LOW TO MID 80S...WITH LOWS TONIGHT REMAINING AROUND 10 DEGREES ABOVE AVERAGE. && .SHORT TERM /SATURDAY THROUGH MONDAY/... WARM SOUTHERLY FLOW WILL CONTINUE INTO SATURDAY WITH THE COLD FRONT STILL WELL TO OUR WEST AND A BROAD ATLANTIC HIGH TO THE EAST. STRONG SURFACE HEATING WILL BOLSTER LOW-LEVEL LAPSE RATES...COMBINING WITH THE MOIST AIRMASS WILL GENERATE PRE-FRONTAL SHOWERS AND THUNDERSTORMS. STRONGER MID- AND UPPER-LEVEL FLOW REMAINS WELL TO OUR NORTH...CLOSER TO THE DEEPER WAVE. STILL...ENOUGH INSTABILITY AND SHEAR EXISTS FOR THUNDERSTORM DEVELOPMENT...ESPECIALLY IN THE LATE EVENING HOURS AS THE BOUNDARY NEARS OUR NORTHWEST AND UPSTREAM THUNDERSTORMS CAN PROGRESS EASTWARD. DEEP UPPER-LOW ADVANCES TO NEAR JAMES BAY CANADA LATE SATURDAY WITH AN ELONGATED DEEP MOISTURE FIELD EXTENDING FROM THE MISSISSIPPI DELTA THROUGH EASTERN QUEBEC. BIGGEST QUESTION REMAINS HOW FAR EAST THAT DEEP MOISTURE PROGRESSES SATURDAY NIGHT INTO SUNDAY. 00Z GFS IS FAST AS IT HAS MODERATE PERPENDICULAR MID-LEVEL FLOW DRIVING THE BOUNDARY AND ASSOCIATED MOISTURE THROUGH PGH BY MIDDAY SUNDAY. THE 00Z NAM AND ECMWF DAMPEN THE MID-LEVEL FLOW AND STALL THE BOUNDARY OVERHEAD...KEEPING AMPLE MOISTURE IN THE AREA. THINKING THE LATTER SOLUTION IS MORE PLAUSIBLE GIVEN THAT THE DRIVER TO THE FRONTS EASTWARD PROGRESSION EXITS WELL TO OUR NORTH AND EAST. WITH THIS IN MIND...WILL KEEP HIGH CHANCE AND LIKELY POPS IN THE FORECAST FOR SUNDAY AFTERNOON AND AGAIN MONDAY AS ANOTHER UPPER-LEVEL WAVE APPROACHES. TEMPERATURES WILL BE WELL-ABOVE AVERAGE SATURDAY AND SATURDAY NIGHT WITH THE WARM SOUTHERLY FLOW. SUNDAYS TEMPS WILL BE SOMEWHAT DEPENDENT ON THE PLACEMENT OF THE FRONT...BUT WITH INCREASED CLOUD COVER...SHOULD BE HELD IN CHECK AND CLOSER TO THE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --
HAVE SLOWED THE ENDING OF SHOWERS A BIT INTO TUESDAY FOR THE SOUTHEAST RIDGES AS MODELS ARE A BIT SLOWER WITH TRYING TO DEVELOP AND SHIFT EAST WAVE OF LOW PRESSURE MOVES ALONG COLD FRONT JUST SOUTH OF REGION. OTHERWISE LITTLE CHANGE FROM WPC PROGS AS DRY SURFACE HIGH PRESSURE BUILDS IN ACROSS THE REGION THROUGH MID WEEK. BY LATE WEEK HEIGHTS RISE ALOFT AND SURFACE RIDGE MOVES OFF THE EAST COAST...ALLOWING FOR WARMER TEMPERATURES AND INCREASING HUMIDITY.
-- End Changed Discussion --
&& .AVIATION /17Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
GENERAL VFR THROUGH THE TAF PERIOD WITH SCATTERED THUNDERSTORMS LATE AFTERNOON AND EVENING. HAVE KEPT A PERIOD OF VCTS AS PROBABILITY OF STORM AT ANY PARTICULAR PORT IS SMALL. NEXT CHANCE FOR MORE WIDESPREAD RESTRICTIONS LOOKS TO BE BEYOND 18Z SATURDAY AS A COLD FRONT APPROACHES. .OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... RESTRICTIONS ARE LIKELY AT TIMES THROUGH SUNDAY.
-- End Changed Discussion --
&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.