Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 290517 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 117 AM EDT MON JUN 29 2015 .SYNOPSIS... A WEAK RIDGE OF HIGH PRESSURE WILL BRING FAIR WEATHER AND MILDER TEMPERATURES TO CENTRAL PENNSYLVANIA TODAY. A FRONTAL SYSTEM MOVING THROUGH THE UPPER OHIO VALLEY INTO THE LOWER GREAT LAKES WILL BRING AN INCREASED RISK FOR SHOWERS TONIGHT INTO TUESDAY MORNING...FOLLOWED BY SCATTERED THUNDERSTORMS TUESDAY AFTERNOON. EXPECT AN UNSETTLED WEATHER PATTERN TO PERSIST INTO THE UPCOMING HOLIDAY WEEKEND AS A BROAD UPPER LEVEL TROUGH REMAINS POSITIONED OVER THE LOWER 48...EAST OF THE CONTINENTAL DIVIDE. && .NEAR TERM /THROUGH TONIGHT/... SHORTWAVE ENERGY ROTATING AROUND THE BACKSIDE OF DEPARTING UPPER CYCLONE ALONG WITH RELATIVELY COOL AIR ALOFT SHOULD BE ENOUGH TO KEEP A LOW CHANCE FOR SHOWERS ALONG THE PA/NY BORDER EARLY THIS MORNING. RADAR OBS CURRENTLY SHOW -RA FROM BFD TO ELZ TO ITH. A WEAK RIDGE OF HIGH PRESSURE SHOULD BRING FAIR AND DRY WEATHER TO MUCH OF THE AREA THROUGH THE AFTERNOON...BUT CLOUDS WILL BE ON THE INCREASE FROM THE WEST AS WARM ADVECTION PATTERN SHIFTS EAST IN ADVANCE OH VALLEY SHORTWAVE AND SFC WARM FRONT. MODEL CONSENSUS FAVORS SHOWERS OVER NW PA BY TONIGHT AS SFC LOW REACHES LAKE ERIE BY 12Z TUE. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... SEVERAL SHORTWAVE TROUGHS WILL TOP THE WRN CONUS RIDGE AND DIG SEWD ACROSS THE UPPER/MID MS VALLEY...THEN EWD INTO THE NRN MIDDLE ATLANTIC REGION EARLY IN THE UPCOMING WEEK. THESE FEATURES WILL REINFORCE A DEVELOPING LONG-WAVE TROUGH THAT SHOULD GRADUALLY SHIFT EAST ACROSS THE OH VALLEY AND REACH THE APPALACHIANS BY THE END OF TUESDAY/D3. SPC HAS A MARGINAL TSTM RISK FOR ALL OF CENTRAL PA ON DAY 3 /TUESDAY/...WITH POTENTIAL FOR ORGANIZED STORMS GIVEN SEASONALLY STRONG DEEP LAYER FLOW...COMBINED WITH AN AREA OF SLIGHTLY ABOVE PWAT AIR /ESPECIALLY ACROSS THE SE HALF OF PENN...ALONG AND AHEAD OF A LIKELY DEVELOPING LEE SFC TROUGH/. TEMPERATURES ARE FORECAST TO MODERATE BUT STILL AVG A FEW DEGREES BELOW NORMAL. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AN AMPLIFIED FLOW PATTERN ALOFT IS EXPECTED TO PREVAIL ACROSS THE NORTH AMERICA IN THE MEDIUM RANGE WITH AN UPPER-LEVEL ANTICYCLONE SLOWLY MIGRATING NORTHWESTWARD FROM THE CENTRAL GREAT BASIN TO THE PACIFIC NORTHWEST COAST. A BROAD UPPER-LEVEL CYCLONE OVER NORTHERN HUDSON BAY WILL KEEP A TROUGH POSITIONED OVER THE LOWER 48 --- PRIMARILY EAST OF THE CONTINENTAL DIVIDE. THE NORTHWEST FLOW PATTERN EXPECTED WILL MIGRATE A SERIES OF MID-LEVEL DISTURBANCES SOUTHEASTWARD FROM WEST CENTRAL CANADA ACROSS THE UPPER GREAT LAKES AND MID-MISSISSIPPI VALLEY THROUGH THE BASE OF THE PERSISTENT TROUGH...PROMOTING PERIODS OF CLOUDS AND OPPORTUNITIES FOR RAINFALL CHANNELING EASTWARD ACROSS THE OHIO VALLEY INTO MID ATLANTIC REGION. THE EC/GEFS/GFS ARE IN FAIR AGREEMENT THROUGH FRIDAY ON THE TRACK OF THESE SYSTEMS. HOWEVER GIVE THE EPISODIC NATURE OF THE PATTERN...CONFIDENCE IS LOW IN TRYING TO PICK A DAY OR PERIOD WITH `BETTER` ODDS FOR RAIN. TEMPERATURES THOUGH ARE TRENDING UPWARD AND SHOULD CONTINUE TO DO SO INTO THE JULY 4TH HOLIDAY WEEKEND. THE MODELS DO DIVERGE INTO NEXT WEEK AND THE SOLUTION BECOMES DIVERGENT. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... IN THE WAKE OF THE SHOWERS THAT HAVE PRETTY MUCH ENDED ACROSS THE REGION...MVFR TO IFR CONDITIONS ARE WIDESPREAD ACROSS THE NORTHERN AND WESTERN MOUNTAINS INCLUDING KBFD AND KJST. MVFR CIGS EXIST ACROSS THE CENTRAL RIDGE/VALLEY AREAS...WITH VFR CONDITIONS TO THE EAST. SATELLITE TRENDS HAVE SHOWN A SIGNIFICANT EROSION OF THE LOWER CLOUD DECK OVER THE LAST 3 HOURS ACROSS THE SOUTHERN 2/3 OF CENTRAL PENNSYLVANIA. HOWEVER...CLOUDS CONTINUE TO HOLD TOUGH ACROSS THE NORTH IN RELATION TO THE LOW...AND UPSLOPE INTO THE RIDGES HELPING TO KEEP CLOUDS HERE AS WELL. WILL CONTINUE THE FORECAST OF IFR/LIFR IN THE NORTHERN AND WESTERN AREAS OVERNIGHT. AS WINDS SLACKEN...THERE IS A CHANCE FOR FOG ESPECIALLY WHERE LOWER CLOUDS HAVE ERODED TO SEE FOG DEVELOPMENT OVERNIGHT. AT THIS TIME...HAVE NOT BROUGHT WIDESPREAD FOG VSBY RESTRICTIONS INTO THE TAFS...AS WINDS ARE MAINTAINING THEMSELVES AT A RESPECTABLE 5 TO 12 KNOTS IN MOST LOCATIONS. HOWEVER...SHOULD WINDS GO LIGHT OR CALM...FOG FORMATION COULD BECOME WIDESPREAD OVERNIGHT. ANY MORNING RESTRICTIONS WILL FADE AND VFR CONDITIONS EXPECTED FOR MUCH OF MONDAY. RESTRICTIONS ONCE AGAIN WILL LINGER LONGEST IN THE NORTH AND WEST...POSSIBLY THROUGH 16Z/18Z. UNSETTLED PATTERN WITH A SERIES OF FRONTS AFFECTING THE REGION MUCH OF NEXT WEEK. BEST CHANCES OF RESTRICTIONS WILL BE TUESDAY INTO WEDNESDAY. OUTLOOK... MON...MORNING RESTRICTIONS NORTH AND WEST...THEN GENERALLY VFR. TUE-WED...MAINLY VFR...BUT SOME POSSIBLE RESTRICTIONS IN SHRA/TSRA. THU-THU...AGAIN MAINLY VFR....BUT RESTRICTIONS POSSIBLE IN SHRA AND POSSIBLE TSRA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...LAMBERT LONG TERM...CERU/STEINBUGL AVIATION...JUNG

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