Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 272344 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 744 PM EDT MON JUL 27 2015 .SYNOPSIS... A FRONT ALONG THE MASON DIXON LINE WILL DISSIPATE AS IT SLOWLY SAGS FURTHER TO THE SOUTH. HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH MIDWEEK AS THE TEMPERATURE AND HUMIDITY INCREASE. THE NEXT FRONT WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT AND THURSDAY...BEFORE SEASONABLY WARM CONDITIONS RETURN. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... TWO AREAS OF PERSISTENT ISOLATED CONVECTION...ONE OVER THE LAUREL HIGHLANDS AND THE OTHER IN THE MID SUQ VALLEY...SHOULD GRADUALLY WEAKEN WITH LOSS OF HEATING OVER NEXT COUPLE OF HOURS. THOUGH A FEW NEW CELLS WILL PROB REGENERATE IN THESE AREAS VIA GUST FRONT INTERACTIONS. AN ISOLATED CELL STILL POSS THROUGH MID EVE IN THE LOWER SUSQ...BUT LOOKING MORE AND MORE UNLIKELY. QUITE MILD TEMPS WILL JUST SLOWLY FALL ACROSS CENTRAL/SOUTH THROUGH LATE EVE...WHILE LOWER DEWPOINTS ACROSS NORTHERN MTNS WILL ALLOW TEMPS TO FALL FASTER THERE. && .SHORT TERM /MIDNIGHT THROUGH 6 PM TUESDAY/... HIGH PRESSURE TAKES OVER THROUGH THE LATE EVENING AND CAUSES SKIES TO CLEAR OUT. THE SUMMERY DEWPOINTS...CLEAR SKIES AND STILL AIR WILL ALLOW FOG TO FORM IN AT LEAST THE VALLEYS OF THE N/C COS BUT ALSO ACROSS THE SOUTH - ESP WHERE ANY RAIN HAD FALLEN EARLIER. MINS WILL DIP INTO THE 50S IN THE NRN VALLEYS...AND SHOULD HIT THE CROSSOVER TEMPS IN ALMOST ALL LOCATIONS AS EVEN THE SRN TIER SHOULD FALL INTO THE 60S. TUESDAY LOOKS VERY NICE IF YOU LIKE THE HOT AND HUMID STUFF. MAXES WILL RUN AT 90F IN THE SOUTH WITH 575 THICKNESSES AND 8H TEMPS OF 18-20C. M80S ELSEWHERE. ONLY THE LAURELS MAY STAY IN THE L80S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... RIDGE OVER CENTRAL U.S. WILL EXPAND INTO THE GREAT LAKES AND MID ATLANTIC REGION THROUGH MIDWEEK. THEN RIDGING WILL BE REPLACED BY BROAD TROUGH OVER EASTERN U.S. AS MAIN LARGE BUBBLE OF HIGH PRESSURE RETROGRADES WESTWARD TO THE FOUR CORNERS REGION LATER IN THE WEEK. DRY PERIOD LASTS INTO WEDNESDAY WITH HIGH PRESSURE IN CONTROL AT THE SFC AND ALOFT. NEXT CHC FOR RAIN/TSTMS WILL ARRIVE WED NIGHT INTO THURSDAY AS NEXT TROUGH AND ITS ASSOCD COLD FRONT REACHES THE APPALACHIANS. BEHIND THAT SYSTEM...MAINLY DRY WEATHER RETURNS FOR FRI AND SAT. ANOTHER WAVE SLIDES IN FROM THE WEST SUN INTO MON RE-ESTABLISHING THE TROUGH. ECMWF/GFS STILL LOOK TO BE LATCHING ONTO AT LEAST A WEAK WAVE ORIGINATING OVER THE SOUTHEAST U.S. AND LIFTING IT NORTHWARD ALONG THE APPALACHIANS BY MON...WHICH COULD HAVE IMPACTS ON THAT FORECAST PERIOD. BUT FOR NOW WILL BROADBRUSH IN GENERALLY UNSETTLED WEATHER FOR LATE NEXT WEEKEND INTO START OF NEXT WEEK. TEMPS WILL BE GENERALLY ABOVE NORMAL FOR MUCH OF THE WEEK...WITH A PEAK IN THE HEAT OCCURRING AROUND WED IN THE NORTH AND WED-THU ACROSS THE SOUTH...WITH HIGHS PEAKING FROM THE MID 80S TO LOWER/MID 90S. DEWPOINTS WILL ALSO INCREASE MIDWEEK...AS HEAT INDEX VALUES MAY APPROACH 100F IN THE LWR SUSQ VLY. COOLER AND LESS HUMID WEATHER RETURNS AS WE HEAD INTO NEXT WEEKEND. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SURFACE COLD FRONT THAT TRIGGERED THE NUMEROUS THUNDERSTORMS SUNDAY EVENING HAS WASHED OUT FROM THE LOWER SUSQ VALLEY... WESTWARD ALONG THE MASON-DIXON LINE. A RIBBON OF HIGHER AMTS OF MOISTURE EXTENDS ABOVE THIS BOUNDARY FROM THE LAUREL HIGHLANDS AND ARCS NORTH AND EAST ALONG THE ALLEGHENY FRONT...HELPING TO ENHANCE THE VERTICAL DVLPMT OF THE CU FIELD AND SUPPORT A FEW...HIGHLY ISOLATED RAIN SHOWERS THAT WERE DRIFTING SSE. DRIEST AIR WAS OVER THE LOWER SUSQ VALLEY AND NRN TIER OF PENN. WILL BE REMOVING MENTION OF ANY SHOWERS FROM THE KMDT AND KLNS TAFS BASED ON THE RELATIVELY DRIER LOW-MID LEVEL AIR IN THAT AREA. THE CU AND TCU WILL FIZZLE OUT OVER THE NEXT SEVERAL HOURS...AND SKIES WILL BECOME CLEAR IN ALL AREAS BY LATE THIS EVENING. FOG WILL BECOME A PROBLEM FOR MANY SITES OVERNIGHT. MANY LOCATIONS COULD GO IFR OR EVEN LIFR AS TEMPS SHOULD DROP BELOW CROSSOVER TEMPS. AFTER ANY FOG/STRATUS BRNS AWAY TUES...THERE SHOULD NOT BE MUCH IN THE WAY OF CLOUDS AS UPSTREAM RIDGING GETS NEARER. OUTLOOK... WED...MAINLY VFR. THU...CFROPA W/VERY BRIEF REDUCTIONS DUE TO TSRA. FRI...MAINLY VFR. SAT...MAINLY VFR AM...SHRA/TSRA POSS NW. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/RXR NEAR TERM...DANGELO/RXR SHORT TERM...DANGELO LONG TERM...RXR AVIATION...DANGELO/LAMBERT

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