Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 180007 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 807 PM EDT WED SEP 17 2014 .SYNOPSIS... A TROUGH OF LOW PRESSURE OVER EASTERN NORTH AMERICA WILL SLOWLY WEAKEN INTO SATURDAY BEFORE RE-INTENSIFYING LATER ON SUNDAY ONCE AGAIN. OVERALL IT SHOULD BE A RELATIVELY COOL AND DRY PERIOD WITH A BRIEF WARM UP OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... HIGH PRESSURE MAINTAINING FAIR AND DRY CONDITIONS ACROSS CENTRAL PA ONCE AGAIN THIS EVENING. PATCHY VALLEY FOG WILL BE THE ONLY SENSIBLE WEATHER LATER TONIGHT. MIN TEMPS WILL STILL BE ON THE COOL SIDE...RANGING FROM THE LOWER TO MIDDLE 40S OVER THE NORTHERN TWO THIRDS OF CENTRAL PA...TO THE LOWER 50S ACROSS THE SOUTH. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... ANOTHER DRY AND SEASONABLY COOL DAY. A WEAK FRONTAL BOUNDARY WILL MOVE ACROSS THE REGION BRINGING SLIGHTLY COOLER AIR AND JUST SCATTERED CLOUD COVER. THURSDAY NIGHT WILL BY QUITE COLD WITH FROST POSSIBLE ACROSS THE COLDEST VALLEYS...AND A FROST ADVISORY MAY HAVE TO BE ISSUED FOR PORTIONS OF WESTERN PA FOR FRIDAY MORNING ON THURSDAY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... WARMER AIR AND HIGHER MOISTURE WILL ADVECT INTO THE REGION THIS WEEKEND ON INCREASING SW FLOW AROUND A HIGH PRESSURE AREA /RETREATING TO THE EAST/. AT THE SAME TIME...TROUGH BEGINS TO CARVE INTO ZONAL FLOW OVER THE GREAT LAKES AS A SYSTEM APPROACHES PA FOR SUN/MON. THE RESULT WILL BE A PAIR OF ABOVE NORMAL TEMPERATURE DAYS SAT-SUN WITH TEMPS MAINLY IN THE 70S...AND TAKING A RUN AT 80F IN THE SE. WE/LL ALSO GET A BREAK FROM OUR RUN OF CHILLY OVERNIGHTS AS LOWS REMAIN WELL INTO THE 40S AND 50S. SHOWER ACTIVITY SHOULD REMAIN CONFINED TO THE UPPER MIDWEST THROUGH EARLY SUNDAY. THE CENTER OF THE APPROACHING LOW PRESSURE SYSTEM WILL REMAIN WELL TO OUR NORTH...BUT A WEAK COLD FRONT WILL PUSH THROUGH PA SUNDAY INTO SUN NIGHT. THIS WILL BE THE BEST CHANCE OF RAIN/SHOWERS THROUGH DURATION OF THE EXTENDED FORECAST. THE LATEST ECMWF IS THE WETTEST WITH QPF POTENTIALLY UP TO 0.25...WHILE THE GFS BRINGS LIGHTER AMOUNTS. THE 500 HPA TROUGH BEHIND THE FRONT DEEPENS OVER THE REGION MONDAY INTO TUESDAY. THIS WILL KEEP MENTION FOR SCT INSTABILITY SHOWERS MONDAY INTO TUESDAY...MAINLY IN HIGHER TERRAIN OF N/W CWA. COOLER AIR ON NW FLOW WILL GRADUALLY FILTER BACK INTO THE REGION...WITH MONDAY/S HIGHS ABOUT 8-10F COOLER AND TUESDAY FALLING ANOTHER 5F OR SO. OVERNIGHT LOWS WILL SLIP BACK INTO THE 40S MON NIGHT...WITH SOME MID/UPPER 30S POSS IN THE NORTHERN MTNS TUE NIGHT. TROUGH LIFTS TO THE NE BY MIDWEEK AS HIGH PRESSURE SETTLES BACK IN. AS FLOW AGAIN TURNS AROUND TO THE SW...REGION SHOULD SEE ANOTHER GRADUAL WARMUP FOR LATE WEEK. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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A CALM WIND UNDER HIGH PRESSURE SYSTEM WILL PROMOTE PATCHY VALLEY FOG LATE TONIGHT. HOWEVER...LATEST MDL DATA AND EVENING IR SATL LOOP SUGGESTS THERE WILL BE SOME PERSISTENT CU TONIGHT ACROSS CENTRAL PA...LIMITING THE RADIATIONAL COOLING AND FOG THREAT. BASED ON THIS AND LATEST RAP AND NAMPARA OUTPUT...HAVE DOWNPLAYED THE FOG POTENTIAL ACROSS MUCH OF CENTRAL PA. HOWEVER...CONFIDENCE NOT PARTICULARLY HIGH AND STILL CAN/T RULE OUT A PERIOD OF IFR CONDS FROM FOG IN THE 07Z-13Z TIME FRAME. ANY FOG THAT DOES FORM SHOULD BURN OFF BTWN 13Z-14Z. A MOISTURE-STARVED COLD FRONT WILL BE PUSHING SE THRU THE REGION THU AFTN. CAN/T RULE OUT AN ISOLD SHRA ACROSS THE N MTNS...BUT CONFIDENCE IN VFR CONDS IS HIGH ACROSS ALL OF CENTRAL PA. OUTLOOK... FRI...PATCHY AM FOG POSSIBLE...MAINLY NORTH. SAT...AM LOW CIGS/FOG POSSIBLE. SUN...SLIGHT CHC OF PM TSRA IMPACTS W MTNS. MON...NO SIG WX EXPECTED.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ROSS NEAR TERM...ROSS/DEVOIR SHORT TERM...ROSS LONG TERM...RXR AVIATION...FITZGERALD

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