Area Forecast Discussion
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000 FXUS61 KPBZ 081033 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 633 AM EDT TUE JUL 8 2014 .SYNOPSIS...
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SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TODAY. SOME STORMS MAY BECOME SEVERE. SHOWERS AND THUNDERSTORMS WILL DEVELOP AGAIN ON WEDNESDAY...EXITING THE REGION BY EARLY WEDNESDAY EVENING. HIGH PRESSURE WILL THEN RESULT IN DRIER WEATHER FOR THE REST OF THE WEEK.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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QUICK UPDATE TO INCLUDE SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS OVER SOUTHEASTERN OHIO AND WESTERN PA SEVERAL HOURS EARLIER THIS MORNING BASED ON LATEST RADAR TRENDS AND GUIDANCE...BUT OTHERWISE NO CHANGES NEEDED. ALTHOUGH THE POTENTIAL FOR SEVERE WEATHER WILL GO THROUGH EARLY EVENING LATEST GUIDANCE ALSO SUGGESTS TIMING FOR GREATEST THREAT OF SEVERE GUIDANCE WILL FALL DURING THE MID AFTERNOON...ROUGHLY BETWEEN 2PM AND 6PM WHEN INSTABILITY AND SHEAR VALUES ARE AT THERE HIGHEST LEVELS FOR THE DAY. PREV DISCUSSION FOLLOWS.. A STRONG SHORTWAVE WILL IMPACT THE REGION TODAY...TRIGGERING THUNDERSTORMS AS IT TRANSITIONS ACROSS THE FORECAST AREA. CURRENT WATER VAPOR IMAGERY SHOWS THE ASSOCIATED LONGWAVE DEEPENING OVER THE LAST COUPLE HOURS AS A JET MAX ESTIMATED AROUND 100KTS BASED OF OF SATELLITE DERIVED WINDS AND MDCRS PLOTS ENTERS THE BASE OF THE TROUGH. THE UPPER TROUGH SHOULD BECOME MORE NEGATIVELY TILTED AS THE STRONG MID AND UPPER LEVEL WINDS ROUND THE BASE. ALTHOUGH LAPSE RATES ARE NOT OVERLY IMPRESSIVE AND MUCAPE VALUES ARE FORECAST TO TOP OUT BETWEEN 1500-2000 J/KG...THIS COMBINED WITH 0-6KM BULK SHEAR AROUND 45-50KTS WILL LIKELY RESULT IN AT LEAST SOME STORMS THAT DEVELOP TODAY ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE BECOME SEVERE. DAMAGING WINDS WILL BE THE PRIMARY THREAT BUT LARGE HAIL WILL ALSO BE POSSIBLE ALONG WITH LOCALIZED FLOODING OVER AREAS THAT SEE MULTIPLE THUNDERSTORMS WITH PWAT VALUES INCREASING TO OVER 1.75 INCHES. ALTHOUGH THE THREAT IS LOW...ISOLATED TORNADOES ARE ALSO NOT OUT OF THE QUESTION AS HODOGRAPHS INDICATE THE POTENTIAL FOR SUPERCELLS TO DEVELOP AND 0-3KM HELICITY VALUES ARE PROGGED TO BE RANGE BETWEEN 250 AND 300 DURING THE AFTERNOON. CONSIDERING THE SHORTWAVE AND HEIGHT FALLS EXPECTED AS THE TROUGH PASSES TODAY...THUNDERSTORM DEVELOPMENT LOOKS LIKELY EVEN IF CLOUD COVERAGE HAMPERS THE DEGREE OF ADDED INSTABILITY THAT WOULD RESULT FROM ANY DAYTIME HEATING. A COLD FRONT WILL FOLLOW THE SHORTWAVE AND CROSS THE REGION DURING THE NIGHT...AND KEEP THE CHANCE OF SHOWERS AND THUNDERSTORMS IN PLACE THROUGH THE MAJORITY OF THE NIGHT WITH ACTIVITY DIMINISHING FROM WEST TO EAST AFTER MIDNIGHT. INSTABILITY WITH COLDER AIR ALOFT WITH TROUGHING OVER THE REGION WILL CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY ON WEDNESDAY BEFORE HIGH PRESSURE BEGINS TO REGAIN CONTROL WEDNESDAY NIGHT.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... SFC HIGH PRESSURE BUILDS IN OVER THE SRN GREAT LAKES WEDS NIGHT INTO THURS WITH DRYING EXPECTED. DAYTIME HIGHS SHOULD TOP OUT NEAR AVERAGE FOR THIS TIME OF YEAR...WHILE NIGHTTIME LOWS THURS AND FRI COULD BE A FEW DEGREES COOLER THAN AVERAGE AS MOSTLY CLEAR SKIES AND CALM WINDS WILL ALLOW ENHANCED RADIATIONAL COOLING. TAX && .LONG TERM /SATURDAY THROUGH MONDAY/... SFC HIGH GETS SQUEEZED OUT OF THE AREA SAT AS A WEAK AND RELATIVELY DRY FRONT SAGS SOUTHWARD THROUGH THE GREAT LAKES AND APPROACHES FOR SUN. MODELS HAVING A DIFFICULT TIME CONVERGING ON A SINGLE SOLN NEXT WEEKEND...BUT THEY DO DEPICT THE FRONT REINFORCING THE BROAD UPPER TROF OVER THE ERN CONUS. COOLER AIR SHOULD BEGIN TO SEEP IN FROM THE NORTHWEST UNDER THIS REGIME...WITH MULTIPLE DISTURBANCES PASSING THROUGH THE TROF. TRENDED TEMPS A BIT LOWER HEADING INTO NEXT WEEKEND...AND CONTINUED WITH LESS DETERMINISTIC POPS...ORIENTING HIGHER CHC POPS ALONG THE FRONT. TAX && .AVIATION /09Z TUESDAY THROUGH SATURDAY/...
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SHOWERS/THUNDERSTORMS/GUSTY WINDS LIKELY TODAY AS A DISTURBANCE PASSES ACROSS THE REGION FROM WEST TO EAST. ALTHOUGH THERE WILL BE A CHANCE OF STORMS THROUGHOUT THE AFTERNOON AND EVENING THE BEST CHANCES WILL BE CHANCES WILL BE BETWEEN 18 AND 22Z TODAY. CLOUD BASES WILL BE LOWER AND RESULT IN MVFR RESTRICTIONS WITH ANY STORMS AND WIND GUSTS IN EXCESS OF 55 MPH WILL BE POSSIBLE AS SOME STORMS MAY BE SEVERE. .OUTLOOK.../WEDNESDAY THROUGH SATURDAY/... SCATTERED SHOWERS AND STORMS MAY RESULT IN MVFR CONDITIONS WEDNESDAY...WITH VFR CONDITIONS EXPECTED THE REMAINDER OF THE WEEK.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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