Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 080333 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1133 PM EDT MON JUL 7 2014 .SYNOPSIS... A VERY WEAK COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE REGION TONIGHT...BEFORE RETREATING BACK TO THE NORTH AS A WARM FRONT EARLY TUESDAY. ANOTHER COLD FRONT WILL PUSH SOUTHEAST ACROSS PENNSYLVANIA TUESDAY NIGHT AND EARLY WEDNESDAY. THESE WEATHER FEATURES WILL SPARK A FEW ROUNDS OF SHOWERS AND THUNDERSTORMS THIS EVENING THROUGH TUESDAY EVENING. A POOL OF MUCH COOLER AIR ALOFT WILL BRING SOME AFTERNOON SHOWERS TO MAINLY THE NORTHERN MOUNTAINS WEDNESDAY. HIGH PRESSURE BUILDING OVER THE COMMONWEALTH THURSDAY AND FRIDAY WILL BRING CLEARING AND DRY CONDITIONS. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE REMAINDER OF SEVERE THUNDERSTORM WATCH NO 397 HAS BEEN CANCELLED ABOUT AN HOUR EARLY ACROSS THE CENTRAL PORTION OF OUR CWA. DIFFUSE FRONTAL BOUNDARY WILL STRING OUT OVERNIGHT ACROSS CENTRAL AND SOUTHERN PENN WITH LINGERING ISOLATED TO SCATTERED SHRA...AND SOME AREAS OF LATE NIGHT FOG WHERE RAIN OCCURRED MONDAY EVENING. PLENTY OF CLOUDS AND RELATIVELY HIGH SFC DEWPOINTS MAINLY IN THE MID 60S WILL LEAD TO ANOTHER QUITE MILD NIGHT. LOW TEMPS WILL RANGE FORM THE MID 60S ACROSS THE MTNS...TO AROUND 70F ACROSS THE LOWER SUSQ VALLEY. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... THE AFOREMENTIONED...ILL-DEFINED FRONTAL BOUNDARY WILL MIGRATE BACK TO THE NORTH TUESDAY MORNING AS THE MEAN LLVL FLOW BACKS BY ABOUT 30 DEG /TO THE SW/. MUCH BETTER SHEAR AND MOISTURE PUSHING EAST INTO THE REGION FOR THE AFTERNOON AND EVENING. DEEP LAYER PW WILL BE APPROACHING 2" AND THE 850 MB LLJ WILL RAMP UP TO >40 KTS ACROSS THE LAUREL HIGHLANDS DURING LATE AFTERNOON AND EVENING. WARM AND MUGGY CONDITIONS WILL PREVAIL FOR ANOTHER DAY...WITH HIGHS RANGING FROM UPPER 70S NORTH TO UPPER 80S SOUTHEAST. AS A MORE POTENT UPPER AIR DISTURBANCE AND SFC CFRONT PUSHES EAST OUT OF THE OHIO VALLEY...EXPECT ANOTHER ROUND OR TWO OF SHOWERS AND TSRA WITH GUSTY WINDS AND BRIEF TORRENTIAL RAINFALL RATES. PRACTICALLY ALL OF THE CWA /WITH THE EXCEPTION OF SERN YORK AND SERN LANCASTER COUNTY/ IS IN SPC/S DAY 2 SLIGHT RISK AREA. MODELS INDICATE THE POTENTIAL FOR A COMPACT SFC WAVE TO DEVELOP INVOF KERI/KBFD IN THE 21Z TUE-00Z WED WINDOW /BENEATH THE LEFT EXIT REGION OF A 90 KT UPPER JET/. THIS FEATURE ALONG WITH THE CORRESPONDING BELT OF ANOMALOUSLY STRONG /PLUS 3-4 ST DEVIATION/ 45-55KT SWRLY 850 MB WINDS /AND AXIS OF NEARLY OFF-THE-CHARTS... 5-6 ST DEVIATION 850 MB MOISTURE FLUX/ WILL FOCUS/ENHANCE THE SEVERE WEATHER /AND TORNADO/ POTENTIAL ACROSS THE NRN MTNS MID- LATE TUESDAY AFTERNOON...THEN CENTRAL MTNS AND SUSQ VALLEY EARLY TUESDAY EVENING. STORMS THAT CAN STRENGTHEN INTO POCKETS OF 0-1KM EHI IN THE 2-3 M2/S2 RANGE COULD CONTAIN SOME LONG-LASTING MESOS AND A FEW TORNADOES. THE PRIMARY SEVERE WEATHER THREAT ACROSS THE SOUTHERN THIRD OF THE CWA /GIVEN THE INCREASING AND STRONG UNIDIRECTIONAL FLOW FROM THE SW/ SHOULD BE BOWING LINE SEGMENTS AND MICROBURSTS. BRIEF QLCS TORNADOES COULD ACCOMPANY BKN-S SIGNATURES IN THE LINES. WOULD NOT BE SURPRISED TO SEE SPC UPGRADE TO A MDT RISK FOR A PORTION OF OUR CWA WITH LATER...DAY 1 CONVECTIVE OUTLOOKS ON TUESDAY. MAX TEMPS WILL BE IN THE U70S TO LOWER 80S ACROSS THE NORTH...AND 85-90F IN THE CENTRAL AND SOUTHERN VALLEYS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... NOT MANY BIG CHANGES TO PREVIOUS EXTENDED FORECAST. TSTM CHANCES CONTINUE INTO TUE NIGHT/EARLY WED AS COLD FRONTAL BOUNDARY SLOWLY CROSSES PA...FOLLOWED LATER IN THE DAY BY SECONDARY FRONT THAT WILL PUSH HIGH PWAT AIR FURTHER TO THE SE. DID HOLD MENTION OF LOW POPS IN SE INTO THU...THOUGH ACTIVITY MAY BE FURTHER SE. HIGH PRESSURE TAKES OVER FOR LATE WEEK...WITH MOISTURE CREEPING BACK IN FROM THE SOUTH OVER THE WEEKEND BRINGING INCREASING POPS SAT INTO SUNDAY AS MID LEVEL LAPSE RATES GRADUALLY INCREASE. BROAD TROUGH REMAINS OVERHEAD INTO EARLY NEXT WEEK...WITH MODELS DIFFERING ON STRENGTH...SO LOW DAILY POPS WILL CONTINUE. TEMPERATURES START OFF ABOVE NORMAL WITH NOTICEABLE HUMIDITY /ESP SE/...BUT GRADUALLY COOL BACK TO SEASONAL NORMS BY LATE WEEK...FOLLOWED BY ANOTHER WARMUP NEXT WEEK. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/...
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SHOWERS HAVE LARGELY DISSIPATED LATE THIS EVENING...AS ATMOS COOLS/STABILIZES. FORECAST CONCERN NOW SHIFTS TOWARD THE POSSIBILITY LOW CIGS DEVELOPING OVR THE NW MTNS LATE TONIGHT. LATEST MDL DATA SUGGESTS A PLUME OF MOISTURE AHEAD OF DYING COLD FRONT OVR THE E GRT LKS WILL ASCEND THE HIGH TERRAIN OF NW PA...POSSIBLY RESULTING IN LOW CIGS AT KBFD LATE TONIGHT. A MORE SIGNIFICANT COLD FRONT WILL APPROACH CENTRAL PA LATE TUESDAY. THIS FRONT WILL BRING ANOTHER ROUND OF TSRA TO CENTRAL PA LATE IN THE DAY. DESPITE WIDESPREAD VFR CONDS...A BRIEF VIS REDUCTION AND STRONG WGUST IS POSSIBLE FROM THESE STORMS LATE IN THE DAY AND EVENING. OUTLOOK... WED...AM LOW CIGS/FOG POSS W MTNS. SLIGHT CHC OF PM TSRA IMPACTS SE. THU-SAT...NO SIG WX EXPECTED.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...RXR AVIATION...FITZGERALD

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