Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 151238 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 838 AM EDT TUE APR 15 2014 .SYNOPSIS... A STRONG COLD FRONT WILL PUSH ACROSS THE CENTRAL MOUNTAINS AND SUSQUEHANNA VALLEY LATE THIS MORNING...PRECEDED BY RAIN OF VARYING INTENSITY...AND FOLLOWED BY SHARPLY COLDER TEMPERATURES AND A CHANGEOVER TO A PERIOD OF SNOW OR SNOW SHOWERS. A SLUSHY COATING OF SNOW IS EXPECTED IN THE MOUNTAINS TODAY AND EARLY TONIGHT. BELOW NORMAL TEMPERATURES WILL FOLLOW BEHIND THE FRONT AND LAST THROUGH MID- WEEK...WITH A GRADUAL MODERATION TOWARD THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TEMPS HAVE DROPPED TO NEAR FREEZING IN FAR WESTERN PA AND WRN NY STATE. STRONG SFC CFRONT IS PUSHING JUST TO THE EAST OF ROUTE 219 AT 12Z AND WILL CROSS THE CENTRAL MTNS AND SUSQ VALLEY LATE THIS MORNING. RAIN OF VARYING INTENSITY PRECEDES THIS COLD FRONT...WITH THE PLUME OF HEAVIEST RAIN BECOMING CONFINED PRIMARILY TO THE EAST OF THE SUSQ MAINSTEM AFTER 13Z. RAINFALL RATES WITHIN THIS PLUME HAVE BEEN 0.2 TO 0.3 OF AN INCH PER HOUR AND AMOUNT OVER THE NEXT 3-4 HOURS WILL BE BETWEEN 0.75 AND 1.00 INCH IN OUR EASTERN ZONES. 3 HR FFG IS IN THE 1.5-2.0 INCH RANGE...AND BASED ON THE AFOREMENTIONED RAINFALL FCST AMOUNTS THROUGH THE NEXT 3-5 HOURS...IT SHOULD BE HANDLED WITHOUT ANY MORE THAN SOME NUISANCE FLOODING - AND MAINLY IN THE URBAN AREAS. WITHOUT A WIDESPREAD THREAT FOR MORE THAN NUISANCE FLOODING...WILL STAY THE COURSE OF NOT POSTING A FLOOD WATCH AFTER EARLIER COORD WITH NEIGHBORING OFFICES. ACRS THE CENTRAL AND WRN MTNS...LIGHT TO OCNLY MDT RAIN WILL MIX WITH THEN CHANGE TO PERIODS OF WET SNOW OR SNOW SHOWERS THIS AFTERNOON IN THE WAKE OF THE FRONT AS TEMPS DIVE SOME 15F IN AROUND ONE HOUR. THE HILL TOPS WILL LIKELY CHANGE FASTER THAN THE VALLEYS. WILL STILL PLACE 1-2 INCH AMOUNTS FOR A SLUSHY WET ACCUM IN THE GRASSY SPOTS - BUT TRUE MID APRIL SUN ANGLE/RADIATION IS TOUGH TO OVERCOME TO MAKE IT REALLY STICK ON THE ROADS. SLICK SPOTS MAY DEVELOP ON THE ROADS...BUT RECENT WARM WEATHER AND MILD GROUND TEMPS SHOULD HELP MAKE TRAVEL ONLY SLIGHTLY INCONVENIENT. A FEW RUMBLES OF THUNDER ARE POSSIBLE IN THE EAST TODAY AS THE FRONT NEARS AND INTERACTS WITH HIGH MSTR PULLED NORTHWARD ON AN INCREASING SRLY FLOW. THE LL JET INCREASES TO 55-60KTS BY MID DAY. IT THEN SLIDES TO THE EAST...DECREASING THE THREAT FOR THUNDER BY LATE AFTN. GUSTS WILL BE 20-25 OVER MOST PLACES TODAY...BUT MAINLY IN THE S. THE BEST CHANCE FOR ANY DEEP MIXING AND HIGHER GUSTS WILL BE IN THE SE - BUT IT SEEMS PRETTY CLOUDY TO GET TOO UNSTABLE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... THE FRONT USHERS IN DRIER AIR AS WELL...AND PRECIP SHOULD DRY UP LATE THIS AFTN IN THE CENTRAL/WEST AND BY SUNSET IN THE EAST. UPPER LOW IS FILLING SLIGHTLY AS IT MOVES OVERHEAD TONIGHT. CLOUDS WILL OF COURSE LINGER OFF LAKE ERIE AND OVER THE NRN MTS EARLY TONIGHT. BUT THE CLEARING AND SIGNIFICANT CAA WILL DROP TEMPS INTO THE 20S. EVEN THE SE WILL GET INT THE M20S - EVEN WITH A 10-15KT NWRLY WIND THROUGH THE NIGHT. THEREFORE...THE FREEZE WATCH WAS UPGRADED TO A FREEZE WARNING FOR THOSE ZONES WHICH HAVE JUST PASSED THE CLIMATOLOGICAL MEAN DATE OF LAST SPRING FREEZE. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... WITH THE GROWING SEASON STARTING ON WEDNESDAY APRIL 15TH FOR SEVERAL COUNTIES IN THE LWR SUSQ VLY...HAVE COORDINATED WITH LWX/PHI ON A FREEZE WATCH FOR LATE TUESDAY NIGHT INTO EARLY WEDNESDAY. CONCERN IS FOR HIGH CONFIDENCE IN SUB-FREEZING TEMPERATURES /25-30F/ ADVERSELY IMPACTING EARLY-BLOOMING/SENSITIVE VEGETATION. IT IS PROBABLY A LITTLE TOO EARLY FOR SIGNIFICANT IMPACTS TO AGRICULTURAL INTERESTS..BUT NONETHELESS PRECAUTIONS SHOULD BE TAKEN TO PROTECT EARLY-SEASON PLANTS AND CROPS. ADDITIONAL HEADLINES ARE POSSIBLE FOR WED NGT INTO EARLY THURS...IN A MORE TYPICAL FROST/FREEZE REGIME WITH CLR SKIES AND LGT/VRB WINDS. THIS CONTINUES TO BE HIGHLIGHTED IN THE HWO. HIGH PRESSURE WILL ARRIVE FROM THE UPPER OH VALLEY AND STRENGTHEN TO +3-4SD OVER NORTHERN NEW ENGLAND THROUGH THURSDAY...BEFORE SLOWLY WEAKENING INTO THE UPCOMING WEEKEND. THIS SHOULD SET UP AN INCREASINGLY MOIST EAST/SOUTHEAST LLVL UPSLOPE FLOW TOWARD THE END OF THE WEEK...WITH MARITIME REGIME POSSIBLY ADVECTING LOW CLOUDS AND PERHAPS SOME LGT RAIN/DZ INTO THE SERN ZONES. MORE UNSETTLED WX APPEARS IN STORE FOR THE WEEKEND AND INTO EARLY NEXT WEEK. TEMPERATURES WILL BOTTOM OUT ON WEDNESDAY WITH HIGHS -10 TO -15 DEGREES BELOW NORMAL. A MILDER SW FLOW ALOFT WILL ALLOW READINGS TO MODERATE TOWARD SEASONAL LEVELS THURS-MON...BUT LKLY STILL AVG BELOW NORMAL FOR THE REMAINDER OF THE PERIOD. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... COLD FRONT ABOUT READY TO MOVE INTO THE BFD AREA. WAS A LITTLE SLOW WITH THE COLD FRONT. ADJUSTED THE 09Z TAFS. WILL ADJUST MORE ON THE 12Z TAFS. WHILE CONDITIONS WERE NOT BAD EARLIER...EXPECT CIGS ETC TO DROP AS RAIN BECOMES MORE WIDESPREAD AND COLD FRONT MOVES IN. ANYWAY...MAIN ISSUE IS LLWS ACROSS THE EAST THIS MORNING. THE PROBLEM LATER THIS AFT WILL BE SNOW MIXING WITH THE RAIN. LLWS WAS ADDED TO THE EASTERN TAF SITES AS A DECENT 50-60KT LOW-LEVEL JET ARRIVES TUES MORNING. SFC WINDS WILL SHIFT TO THE WEST THEN NORTHWEST AND BECOME QUITE BLUSTERY AFTER SUNRISE TUESDAY AT WESTERN AIRFIELDS /KJST KBFD/...AND BY EARLY AFTN IN THE EAST /KIPT KMDT KLNS/. STRONG COLD ADVECTION WILL CAUSE LINGERING SHRA TO CHANGEOVER TO SHSN FROM WEST TO EAST TODAY. WED THRU FRI SHOULD BE FAIRLY BENIGN...WITH ANOTHER ROUND OF WET WEATHER POSSIBLE BY SAT. OUTLOOK... .WED-FRI...GENERALLY VFR. .SAT...REDUCED CIGS/VSBYS IN RAIN. && .CTP WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM 2 AM TO 8 AM EDT WEDNESDAY FOR PAZ057-059- 063>066. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...MARTIN/EVANEGO

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