Area Forecast Discussion
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000 FXUS61 KPBZ 272008 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 408 PM EDT SUN JUL 27 2014 .SYNOPSIS... SHOWERS AND THUNDERSTORMS...WITH SOME SEVERE...WILL PLAGUE THE UPPER OHIO REGION THROUGH THIS EVENING. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... MULTIPLE MESOSCALE FORCED BOUNDARIES SEEM TO BE LAYING OUT ACROSS THE FORECAST AREA THIS EVENING...AND SEEM TO BE THE MAIN FOCI FOR STORM INITIATION AS OF THIS HOUR. THE FIRST OF THESE SEEMS TO EXTEND GENERALLY FROM NEW PHILADELPHIA EASTWARD...AND HAS A FAIRLY DISCERNIBLE MESOLOW TRACKING DOWN IT ASSISTING WITH ASCENT. ANOTHER NEWER LINEAR FEATURE CAN ALSO BE NOTED ON RADAR ALONG THE SOUTHERN TIER OF THE FORECAST AREA...AND GIVEN RUC/NAM DATA...THIS IS LIKELY THE RADAR MANIFESTATION OF AN AREA OF 850 MB CONVERGENCE THAT SHOULD BE MOVING THROUGH THE SOUTHERN TIER OF THE AREA THIS EVENING. AS SUCH...WIDESPREAD THUNDERSTORMS ARE DEVELOPING IN THESE AREAS...WITH STILL SCATTERED TO NUMEROUS COVERAGE ELSEWHERE GIVEN MODERATE INSTABILITY AND A FAVORABLE SHEAR PROFILE. TRAINING DOWN THESE AREAS OF ENHANCED FOCUSING FOR THUNDERSTORMS IS POSSIBLE THROUGH THE EVENING...SO THE FLASH FLOOD THREAT IS NON- ZERO...PARTICULARLY ACROSS AREAS FROM PITTSBURGH SOUTH AND EAST...WHERE LAST NIGHT`S RAINFALL WAS LOCALLY SIGNIFICANT. OTHERWISE...A FAVORABLE SHEAR PROFILE THROUGH THE EVENING WILL CONTINUE TO MAKE UP FOR A LACK OF SIGNIFICANT INSTABILITY...AND GIVEN CONVERGENCE ALONG THE ESPECIALLY SOUTHERN TIER OF THE FORECAST AREA...THE CHANCE OF ROTATING THUNDERSTORMS IS STILL GOOD. AS IS THE CASE WITH THESE...LARGE HAIL/DAMAGING WINDS/ISOLATED TORNADOES WILL BE POSSIBLE. SPC HAS ISSUED A TORNADO WATCH UNTIL 9 PM FOR THIS. THE MID-LEVEL LOW WILL CONTINUE TO DROP TOWARD THE AREA OVERNIGHT. THIS WILL CONTINUE TO KEEP THE MID-LEVEL UNSTABLE EVEN AS THE LOWER LEVELS BEGIN TO BECOME UNFAVORABLE FOR SURFACE-BASED CONVECTION. WITH STRONG LAPSE RATES ALOFT CONTINUING...HOWEVER...SHOWER AND ISOLATED THUNDERSTORM CHANCES LOOK TO CONTINUE FOR MUCH OF THE NIGHT. FRIES && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... MOISTURE WILL CONTINUE TO WRAP AROUND THE EXITING TROUGH ON MONDAY...KEEPING IN THE RISK FOR SHOWERS. ATMOSPHERE IS NOT SHOWING A GREAT DEAL OF INSTABILITY MONDAY AND WITH LOTS OF CLOUD COVER...STORM THREAT SHOULD BE GREATLY REDUCED. SHOWERS WILL END MONDAY NIGHT...AND MUCH COOLER AIR WILL DIVE SOUTHWARD OVER THE UPPER OHIO VALLEY. TUESDAY SHOULD SEE AN INCREASE IN SUNSHINE...BUT WITH BELOW NORMAL TEMPS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE UNDER UPPER LEVEL TROUGH WILL PROVIDE A COOL AND COMFORTABLE MIDWEEK. ANOTHER WEAK COLD FRONT MAY BRING SHOWERS THURSDAY. HIGH PRESSURE WILL RETURN FRIDAY. WARMER AIR AND THE RISK FOR SHOWERS FOR THE BEGINNING OF THE WEEKEND. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... STG TO SVR TSTMS ARE EXPECTED INTO ERLY EVE WITH ADVNG LOW PRES. TEMPO TSTM MENTIONS HAVE BEEN INCLUDED FOR ALL PORTS. THEREAFTER...EXPECT MVFR TO DEVELOP OVRNGT IN ST/SC AND SHWRS. OUTLOOK.../MONDAY THROUGH THURSDAY/... RSTRNS ARE LIKELY MON AS A CDFNT CROSSES THE RGN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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