Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 212332 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 732 PM EDT MON JUL 21 2014 .SYNOPSIS... WARMER AND MORE HUMID CONDITIONS CAN BE EXPECTED UNTIL THE PASSAGE OF A MIDWEEK COLD FRONT. && .NEAR TERM /THROUGH TUESDAY/... 6PM UPDATE - NOT MANY CHANGES NEEDED. SHRA ARE MOSTLY TIED TO RIDGES...THE ONLY REASONABLE SOURCE OF LIFT TODAY. GRIDS HANDLED THIS WELL OVERALL. DID REMOVE THUNDER...AS TOTAL LIGHTNING DATA SHOWS VIRTUALLY NO IC/CC/CG STRIKES WHATSOEVER ALONG THE APPALACHIANS AND OVERALL INSTABILITY REMAINS WEAK. PREVIOUS DISCUSSION... THE REST OF TODAY AND TOMORROW WILL BE HIGHLIGHTED BY A WARM...HUMID AIRMASS. WHILE THE LATEST MESOANALYSIS AND MODEL SOUNDINGS SUGGEST THE PRESENCE OF MODEST INSTABILITY...THE LACK OF ANY LIFTING MECHANISM WILL KEEP ANY SHOWER OR THUNDERSTORM CHANCES GENERALLY CONFINED TO THE HIGHER TERRAIN WHERE OROGRAPHIC ENHANCEMENT WILL OCCUR. THE MODEL SOUNDINGS ALSO KEEP THE REGION CAPPED AROUND 10KFT EACH AFTERNOON WITH STRENGTHENING WARM AIR ALOFT. THUS...FELT COMFORTABLE WITH CARRYING LOW CHANCE POPS...GENERALLY ESE OF PIT FOR THE REST OF THIS AFTERNOON AND TUESDAY AFTERNOON. TEMPERATURES TONIGHT SHOULD BE CLOSE TO NORMAL...IN THE LOW 60`S WITH DIURNAL CU DISSIPATING. SOME FOG/STRATUS MAY BE POSSIBLE AS WELL. WITH AN UPPER RIDGE BUILDING OVERHEAD...WILL NOT BE SURPRISED IF SOME LOCATIONS GET VERY CLOSE TO 90 DEGREES TOMORROW...WHICH IS ABOUT 5 DEGREES ABOVE AVERAGE. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A COLD FRONT WILL APPROACH THE REGION BY WEDNESDAY AFTERNOON. THE MODELS HAVE SPED UP THE TIMING OF THE FRONTAL PASSAGE AND PRECIP A BIT FROM THE LAST FEW RUNS...WITH THE NAM NOW THE FASTEST. OPTED TO GENERALLY IGNORE THE NAM AND WENT CLOSER TO THE GFS/ECMWF WHICH WERE RELATIVELY CLOSE TO ONE ANOTHER. WITH THESE SLIGHT DIFFERENCES HOWEVER...OPTED TO CARRY LIKELY POPS AND NO HIGHER THROUGH WEDNESDAY NIGHT INTO THURSDAY AS THE COLD FRONT CROSSES. PLENTY OF INSTABILITY OUT AHEAD OF THE FRONT SHOULD PROVIDE FOR THUNDERSTORMS BUT SHEAR VALUES ARE NOT OVERLY IMPRESSIVE AT THIS POINT. POST FRONTAL SHOWERS WILL BE POSSIBLE THROUGH THURSDAY...ESPECIALLY IN THE SOUTHERN HALF OF THE FORECAST AREA BEFORE HIGH PRESSURE BUILDS UNDER A LARGER UPPER TROUGH. THE NE FLOW AND COOLER 850HPA TEMPERATURES SHOULD BRING THE RETURN OF A MORE COMFORTABLE AIRMASS FOR THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... DRY HIGH PRESSURE WILL THEN DOMINATE INTO SATURDAY. BY SUNDAY NEXT SYSTEM WILL APPROACH FROM THE GREAT LAKES WITH INCREASING DEW POINTS AND CHANCE POPS INTO EARLY NEXT WEEK. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
VFR CONDITIONS EXPECTED THROUGH TONIGHT AS DIURNALLY DRIVEN CU FIELD DISSIPATES. CLEAR SKIES AND LIGHT SFC FLOW OVERNIGHT WILL RADIATE TEMPERATURES DOWN NEARING THE DEW POINT BEFORE DAYBREAK TUES. COULD SEE SOME MVFR TO IFR FOG DEVELOP NEAR SUNRISE AND QUICKLY DISSIPATE BY 14Z OR SO BEFORE SCT-BKN CU DEVELOPS AGAIN ON TUESDAY. OUTLOOK.../TUESDAY THROUGH FRIDAY/... A COLD FRONT WILL RESULT IN RESTRICTIONS AT TIMES WEDNESDAY INTO THURSDAY.
-- 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.