Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 230541 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 141 AM EDT THU OCT 23 2014 .SYNOPSIS... A SLOW MOVING LOW PRESSURE SYSTEM OFF THE MID ATLANTIC COAST WILL CONTINUE TO BRING MOSTLY CLOUDY AND COOL WEATHER TO CENTRAL PA ALONG WITH INTERMITTENT RAIN THROUGH THE END OF THE WEEK. IMPROVING CONDITIONS ARE FORECAST OVER THE WEEKEND AS THE LOW MOVES NORTH THROUGH THE CANADIAN MARITIMES. HIGH PRESSURE SHOULD MIGRATE ACROSS THE APPALACHIANS TO THE EAST COAST BY EARLY NEXT WEEK WHICH SHOULD RESULT IN FAIR WEATHER AND WARMER TEMPERATURES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SLOWLY DEEPENING OFFSHORE COASTAL LOW WILL WOBBLE NORTHEASTWARD TOWARDS SOUTHEAST NEW ENGLAND OVERNIGHT. STRONG AND MOIST LLVL NE FLOW AROUND THE LOW CENTER WILL PERSIST ACROSS CENTRAL AND EASTERN PA THROUGH THURSDAY...KEEPING PERSISTENT CLOUDY AND DAMP CONDITIONS IN PLACE ACROSS MOST OF CENTRAL AND EASTERN PA. LATE EVENING WATER VAPOR LOOP SHOWS THE ENE WOBBLE TO THE UPPER LOW OFFSHORE...AS GRADUALLY WEAKENING WESTWARD MOISTURE FLUX INTO CENTRAL AND ESPECIALLY EASTERN PA PERSISTS TO THE WNW OF THE UPPER CIRCULATION. ANY RAINFALL OVER CENTRAL AND EASTERN PA IS LIGHT...BUT IT IS A FAIRLY RAW EVENING FROM RT 15 EAST TO THE NJ BORDER...AS NNW WINDS ARE GUSTING BETWEEN 15 AND 25 MPH ON THE OUTER EDGE OF THE SLOWLY INTENSIFYING LOW. AS PER LATEST RADAR TRENDS AND GUIDANCE...WILL KEEP 50/60 POPS OVER MY FAR NORTHEAST COUNTIES THROUGH LATE TONIGHT WITH LOW CHC EXTENDING INTO THE CENTRAL MOUNTAIN REGION. STILL EXPECT SHOWER ACTIVITY/POPS TO FADE AGAIN WELL PAST MIDNIGHT AFTER THE CURRENT SURGE APPROACHING THE POCONO PLATEAU TRACKS TOWARDS THE ENDLESS AND MOUNTAINS AND WYOMING VALLEY EARLY THU MORNING...AS THE UPPER SUPPORT PULLS AWAY SLOWLY TO THE ENE OVERNIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... THE DEEP-LAYER CYCLONE WILL MOVE LITTLE ON DAY 2 OFF THE NORTHEAST U.S. COAST AS SHORTWAVE ENERGY CROSSING THE UPPER MIDWEST WEAKENS AND SPLITS THROUGH THE MS VLY. THE MODELS SHOW THE SRN BRANCH WAVE APPROACHING THE APPALACHIANS BY 12Z FRI WITH THE GFS BEING FLATTER AND MORE PROGRESSIVE THAN THE EC. THE MAIN WRAP-AROUND PCPN AREA SHOULD SHIFT INTO NERN PA ON BACKSIDE OF THE SLOWLY DEPARTING COASTAL STORM SYSTEM. THURS WILL BE ANOTHER RAW DAY WITH BRISK NORTHERLY WINDS AND HIGHS ABOUT 5F BELOW LATE OCTOBER NORMALS. POPS SHOULD CONTINUE TO TREND LOWER INTO TOMORROW NIGHT WITH PORTIONS OF SRN/SWRN PA STARTING TO SEE SOME BREAKS IN THE CLOUD COVER. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... BY THU EVE...COASTAL LOW WILL BE DRIFTING INTO THE GULF OF MAINE WHICH SHOULD END PRECIP CHANCES FOR CENTRAL PA. AFTER WEAK RIDGING THU NIGHT INTO EARLY FRI...THE NEXT FEATURE UP WILL BE A SPLITTING WAVE OVER THE GREAT LAKES THAT WILL SEND A PIECE OF ENERGY ACROSS PA FRI NIGHT WITH MINIMAL IMPACT. A STRONGER SYSTEM FOLLOWING BEHIND THE INITIAL SPLITTING WAVE WILL DROP ACROSS THE LAKES FOR LATE WEEKEND...WITH THE EC TRENDING FASTER THAN THE GFS INITIALLY /THOUGH THE GFS CATCHES UP IN PLACEMENT OVER NEW ENGLAND BY SUNDAY/. THIS SYSTEM WILL BRING A GLANCING BLOW OF COOLER AIR INTO PA POSS AS EARLY AS SAT NIGHT...BUT MORE LIKELY SUN INTO MON AS CORE OF UPPER JET SWINGS A MOISTURE-STARVED COLD FRONT THROUGH. ANY LIGHT PRECIP FROM THIS WILL THE BULK OF PCPN LIKELY OCCUR BEHIND THE FRONT IN THE COLDER NW FLOW IN THE FORM OF LAKE EFFECT AND UPSLOPE RAIN SHOWERS. THIS REGIME WILL BE REPLACED QUICKLY BY A LARGE RIDGE SLIDING IN FROM THE CENTRAL U.S. THIS RIDGE WILL AMPLIFY OVER THE EAST COAST AS A WAVE DROPS INTO THE ROCKIES...BRINGING A NOTICEABLE WARMUP LATER MON AND ESP TUES -WHEN TEMPS SHOULD BE IN THE 60S AREAWIDE AND SHOULD TOUCH 70F IN THE SOUTHERN TIER. THE WESTERN SYSTEM WILL PROGRESS EASTWARD FOR MIDWEEK...WITH MODELS DIVERGING ON TIMING/STRENGTH. BUT OVERALL MODEL GUIDANCE IMPLIES A POTENTIAL SHOWERY PERIOD WITH TEMPS FALLING BACK TO SEASONAL NORMALS. && .AVIATION /05Z THURSDAY THROUGH MONDAY/...
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MAIN AVIATION CONCERN THIS MORNING WILL BE LOW CIGS AT KBFD AND KJST CAUSED BY MOIST NW FLOW ASCENDING THE HIGH TERRAIN OF THE ALLEGHENY MTNS. DOWNSLOPING FLOW EAST OF THE ALLEGHENIES WILL RESULT IN HIGHER /MVFR/ CIGS ACROSS THE REST OF CENTRAL PA THIS MORNING. A DEVELOPING STORM SYSTEM SOUTH OF NEW ENG MAY SPREAD A FEW SHRA AS FAR WEST AS KIPT/KMDT/KLNS EARLY THIS MORNING...BUT IT/S MAIN EFFECT WILL BE TO CREATE GUSTY NW WINDS. LIFTING CIGS EXPECTED BY THIS AFTN...AS DRIER AIR MOVES IN FROM THE NORTH. THE DRYING SHOULD BE MOST PRONOUNCED ACROSS THE WESTERN HALF OF THE STATE...WHERE CLEARING SKIES ARE EXPECTED. ACROSS THE SUSQ VALLEY...INCLUDING KIPT/KMDT/KLNS...MDL SOUNDINGS SUPPORT ONLY PARTIAL CLEARING BUT WIDESPREAD VFR CIGS BY AFTN. THE STRONGEST WIND GUSTS SHOULD DEVELOP DURING THE DAYLIGHT HRS...AS DIURNAL HEATING/DEEPENING BLYR DRAW STRONG WINDS ALOFT TO THE SFC. BUFKIT SOUNDINGS SUPPORT GUSTS TO ARND 35KTS AT KMDT AND KLNS TODAY AND 25-30KTS FURTHER WEST. THE STRONGEST GUSTS SHOULD DIMINISH THIS EVENING...AS THE STORM SYSTEM PULLS AWAY. ALTHOUGH WIDESPREAD VFR CONDS APPEAR A NEAR CERTAINTY THIS EVENING...THERE IS SOME RISK OF LOW CIGS RETURNING EARLY FRI AM AT KBFD AND KJST...THE RESULT OF PERSISTENT UPSLOPE FLOW AND DIURNAL COOLING OF MOIST BLYR. OUTLOOK... FRI-SAT...AM LOW CIGS POSS KBFD/KJST. SUN-MON...NO SIG WX EXPECTED.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GARTNER/STEINBUGL NEAR TERM...DEVOIR/GARTNER SHORT TERM...GARTNER/STEINBUGL LONG TERM...RXR/STEINBUGL AVIATION...FITZGERALD

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