Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 182143 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 543 PM EDT FRI APR 18 2014 .SYNOPSIS... SPRAWLING HIGH ALOFT AND AT THE SURFACE OVER THE WESTERN ATLANTIC WILL SLOWLY WEAKEN OVER THE NEXT SEVERAL DAYS AS ANOTHER RIDGE OVER THE U.S. ROCKIES REACHES THE NORTHEAST LATE SATURDAY AND SUNDAY. THE RESULT IS MAINLY FAIR WEATHER WITH SURFACE RIDGING AND COLD AIR DAMMING EAST OF THE ALLEGHENIES INTO EARLY NEXT WEEK. A TROUGH IN THE NORTHERN STREAM SHOULD WEAKEN THE RIDGE AND COULD TRIGGER SHOWERS TUESDAY- WEDNESDAY BUT YET ANOTHER RIDGE MOVES IN QUICKLY BEHIND THIS SYSTEM BY NEXT THURSDAY. NEAR NORMAL TEMPERATURES ARE EXPECTED MOST OF THE PERIOD. && .NEAR TERM /THROUGH SATURDAY/... SFC RIDGE AXIS EXTENDS FROM GULF OF MAINE SOUTHWESTWARD THROUGH CENTRAL NJ TO EAST CENTRAL VIRGINIA THIS AFTERNOON. EARLIER EASTERLY FLOW AND SHALLOW MARITIME AIR MASS OVER MY SOUTHEAST COUNTIES HAS MIXED OUT WITH THE SLIGHT SOUTHEAST ADJUSTMENT OF THE SFC RIDGE AXIS...ALLEVIATING THE EASTERLY COMPONENT. MUCH OF PA IS NOW ENJOYING A GOOD AMOUNT OF SUNSHINE THROUGH THIN BKN-OVC HIGH CLOUDS. TEMPS ARE RESPONDING WITH RETURN FLOW WEST OF THE RIDGE AXIS WITH WIDESPREAD 50S ACROSS CENTRAL AND WESTERN AREAS...AND EVEN KBFD APPROACHING 60F OVER THE INTERIOR NORTHWEST...WHILE EASTERN AREAS ARE SLOWER TO RECOVER FROM THE MORNING MARITIME INFLUENCE AND REMAIN IN THE UPPER 40S TO AROUND 50 AT MID AFTERNOON. A SHEARING SFC FRONT IS NOW PUSHING ACROSS LAKE ERIE AND WILL APPROACH MY NORTHWEST COUNTIES LATE THIS AFTERNOON AND THIS EVENING...BRINGING A SLIGHT CHANCE OF -SHRA WITH IT. BROADBRUSHED A SLIGHT CHC -SHRA ACROSS THE ENTIRE NORTHERN TIER IN COLLABORATION WITH KBGM...BUT ANY RAIN THAT DOES FALL WILL BE BRIEF AND VERY LIGHT. ANY CHC OF SHOWERS COMES BEFORE 06Z...WITH HIGH PRESSURE REBUILDING SOUTHWARD FROM A 1036 MB RIDGE CENTERED OVER EASTERN ONTARIO BY 12Z SAT. MINS SAT MORNING WILL REACH THE LOWER 30S NORTH...WHILE THE SOUTHERN HALF OF CENTRAL PA SEES MINS IN THE LOWER 40S. && .SHORT TERM /SATURDAY NIGHT THROUGH 6 PM SATURDAY/... AFOREMENTIONED CANADIAN SFC HIGH WILL KEEP FAIR AND DRY CONDITIONS OVER PA THIS WEEKEND. NORTHERLY GRADIENT AND DRY AIR MASS WILL PROVIDE MOSTLY SUNNY SATURDAY ACROSS CENTRAL PA...WITH 850 MB TEMPS IN THE +3 TO 0C RANGE...YIELDING HIGHS RANGING FROM MID 50S NORTH TO LOW TO MID 60S CENTRAL AND SOUTH AND LIGHT NLY BREEZES. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... AN ACTIVE SPLIT FLOW PATTERN OVER NORTH AMERICA IS FORECAST TO EVOLVE INTO A FAIRLY WELL PHASED UPPER RIDGE OVER THE EASTERN U.S. TOWARD THE END OF THE PERIOD. THIS WILL RESULT IN LIMITED CHANCES FOR PRECIPITATION THROUGH MUCH OF THE PERIOD. AT THIS TIME THE ENSEMBLES SUGGEST THE BEST CHANCE OF RAIN IN THE NEXT WEEK WILL BE IN THE TUESDAY-WEDNESDAY TIMEFRAME. GEFS FAVORS RAIN AHEAD OF THE DEEPENING TROUGH AND FRONTAL SYSTEM MAINLY TUESDAY. BUT TIMING COULD CHANGE AND SOME CHANCE LINGERING INTO EARLY WEDNESDAY. THE COMING 7 DAYS IN GENERAL... SATURDAY NIGHT INTO SUNDAY THE REGION WILL BE DOMINATED BY A STRONG ANTICYCLONE. SHOULD BE GENERALLY FAIR DRY WEATHER. THE ANTICYCLONE WEAKENS MONDAY BUT STILL IN A RIDGE. VERY WEAK FLOW AHEAD OF THE APPROACHING FRONTAL BOUNDARY. THERE IS NO PRESSURE GRADIENT OVER MOST OF THE EASTERN UNITED STATES MONDAY IN THE GEFS OR NAEFS. A SHORTWAVE AND FRONT SHOULD TRIGGER SHOWERS AND RAIN TUESDAY INTO EARLY WEDNESDAY. TROUGH OVER A RIDGE AND NO BIG PW SURGE...NOT A BIG RAIN EVENT. HEIGHTS SHOULD DROP SLIGHTLY BELOW NORMAL WEDNESDAY AND 850 HPA TEMPS DROP TO JUST BELOW NORMAL. HEIGHTS AND TEMPERATURES REBOUND BACK TOWARD NORMAL THURSDAY AND FRIDAY COULD BE A RELATIVELY WARM DAY. UNCERTAINTY GROWS IN FORECAST AND SOME ENSEMBLE MEMBERS SHOW SURGE OF MOISTURE IN WARM AIR AHEAD OF YET ANOTHER POTENTIAL TROUGH. THE CHANCE OF RAIN SHOULD GRADUALLY INCREASE IN THE FRIDAY OR SATURDAY TIME FRAME. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
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EARLY EVENING UPDATE TWEAKED THE WINDS AND CURRENT MID LEVEL BROKEN CEILING. AS THE SUN SETS...WINDS WILL DIMINISH. CLOUDS WILL ALSO DIMINISH OVERNIGHT AS THE WEAKENING FRONTAL BOUNDARY EXITS TO THE NORTH. OUTLOOK... TONIGHT-SAT...AREAS MVFR THIS EVENING NORTHWEST...VFR ELSEWHERE. SUN-MON...NO SIG WX. TUE...SEVERAL-HOUR PERIOD OF MVFR CIGS POSS WITH BRIEF MVFR VSBYS IN SHOWERS ACCOMPANYING A COLD FRONTAL PASSAGE. WED...MVFR NORTH/WEST WITH CHC -SHRA...VFR ELSEWHERE.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/DEVOIR NEAR TERM...GRUMM/DEVOIR SHORT TERM...DANGELO/LAMBERT LONG TERM...GRUMM/GARTNER AVIATION...TYBURSKI

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