Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 301254 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 854 AM EDT WED JUL 30 2014 .SYNOPSIS... THE UPPER LEVEL LOW OVER THE UPPER GREAT LAKES AND EASTERN CANADA WILL PERSIST INTO THE WEEKEND. WHILE THE UPPER LOW MAY OPEN UP AND LIFT A BIT NORTHWARD...AN OFF SHORE HIGH PRESSURE AREA WILL DIRECT MORE GULF AND ATLANTIC MOISTURE INTO THE REGION OVER THE WEEKEND. TEMPERATURES WILL REMAIN COOLER THAN NORMALS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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830 AM UPDATE... A BOUT OF TRUE /MID SUMMER/ LAKE EFFECT RAIN NEAR THE I-90 CORRIDOR IN NWRN PENN WILL BE BREAKING UP AND SHIFTING A BIT INLAND INTO WARREN AND MCKEAN COUNTIES LATE THIS MORNING AS TEMPS SLOWLY CLIMB TO NEAR 60F AND THE LAKE/LAND TEMP DIFF DROPS BELOW 10C. OTHERWISE...CLOUDS /IN THE FORM OF HIGH-BASED STRATO CU AND ALTOCU/ WILL BE SPREADING ACROSS THE NRN AND WESTERN MTNS THROUGH MIDDAY. AS THE CONVECTIVE TEMP IS REACHED AROUND 16-17Z...AND CAPES RAMP UP TO AROUND SEVERAL HUNDRED J/KG...A NEW BKN LINE OR TWO OF SHOWERS WILL FORM NEAR AND TO THE WEST OF RT 219...PER GOOD AGREEMENT BETWEEN THE HRRR...NAM...AND SREF. EXPECT THE SHOWERS TO BECOME MORE SCATTERED AS THEY SPREAD ACROSS THE NCENT MTNS AND PERHAPS AS FAR SOUTH AS A KIPT...KSEG AND KAOO LINE BY 20Z. THE LOWER SUSQ VALLEY MAY STAY ENTIRELY DRY TODAY...BEING WITHIN A DISTINCT SFC RIDGE. ...MOST OF PREVIOUS DISCUSSION FOLLOWS... WHAT APPEARS TO BE A PAIR OF PREVIOUSLY DISTINCT SHORT WAVE TROUGHS SHOULD BE ROTATING AROUND THE BASE OF THE PESKY UPPER LEVEL LOW THIS MORNING AND SLIDE OVERHEAD THROUGH THE DAY. THIS SHOULD PROVIDE PLENTY OF FORCING TO GO ALONG WITH THE INSTABILITY DOWNWIND OF THE LOWER LAKES IN THE HEATING OF THE DAY. HIGHEST POPS WILL BE OVER THE NWRN HALF OF THE AREA...WHERE THE COOLER AIR ALOFT RESIDES. A FEW SHOWERS COULD SNEAK INTO THE SERN HALF OF THE AREA LATER IN THE DAY. THERE WILL BE SCATTERED THUNDERSTORMS LATE THIS MORNING AND THIS AFTERNOON...BUT CAPES LOOK MEAGER OFF RUC/NAM BUFKIT SOUNDINGS...BUT THE GFS IS MORE ROBUST WITH THE CAPES. WET BULB ZERO LEVELS SHOULD BE PRETTY LOW TODAY...HANGING AROUND 7 OR 8KFT. SO WHILE THE CONVECTION MAY NOT GROW VERY TALL...THEY WILL HAVE PLENTY OF ICE IN THEM. THEREFORE...HAVE KEPT MENTIONS OF SMALL HAIL IN THE FCST FOR THE NW. MOST RECENT SPC DAY1 OUTLOOK DOES NOT MENTION ANYTHING SPECIFICALLY ABOUT THE GREAT LAKES...BUT WE STILL EXPECT TO SEE SOME PEA TO DIME SIZE HAIL OUT OF THE STRONGER CELLS. INITIALLY CLEAR SKIES WILL GROW MORE-CLOUDY THROUGH THE MID- MORNING IN THE NW. EXPANSIVE CU FIELD EXPECTED AGAIN TODAY. HOWEVER...PLENTY OF BREAKS IN THE SKY COVER WILL ALLOW TEMPS TO GET BACK TO THE NOT-SO-LOFTY HEIGHTS OF TUESDAY AND ADD A FEW DEGREES ON FOR MOST LOCATIONS. STILL WELL BELOW NORMALS. TRY TO BANK THE SAVINGS YOU WILL HAVE ON THE A/C THIS JULY WHICH SHOULD END UP SLIGHTLY BELOW NORMAL DESPITE THE 7 DAYS 90F OR BETTER IN HARRISBURG THIS MONTH.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... THE DIURNAL CONVECTION SHOULD SLIDE TO THE EAST THIS EVENING WHILE DYING OUT. THE COLD AIR ALOFT AND CYCLONIC FLOW WILL LIKELY KEEP A FEW SHOWERS AROUND THROUGH THE NIGHT IN THE NW. CHC POPS FOR SCT COVERAGE SHOULD BE FINE THERE. MINS WILL BE BACK CLOSER TO NORMALS TONIGHT...BUT 40S STILL POSSIBLE IN THE HIGHER ELEVATIONS. THE UPPER LOW THROWS ONE MORE UPPERCUT ON THURSDAY MORNING...AND SCT/NMRS SHOWERS EXPECTED IN THE FORE-NOON. THE AFTERNOON MIGHT BE MAINLY DRY...BUT THE TEMPS ALOFT ARE STILL COOL AND DAYTIME INSTABILITY SHOULD BE GOOD ENOUGH FOR ISOLD-SCT SHOWERS IN THE WEST/NORTH. HIGHS ON THURSDAY DO HAVE THE POTENTIAL TO GET BACK TO NORMAL IN THE SE...BUT THE N/W WILL PROBABLY STILL BE 8-10 DEGS BELOW SEASONAL NORMALS. FOR NOW...THE 12-18 HOURS AROUND THE THURSDAY NIGHT PERIOD SEEM LIKE THE LEAST LIKELY TIME FOR ANY SHOWERS TO DEVELOP. THE BIG SHORT WAVE WILL HELP TO HEAVE THE UPPER LOW A BIT TO THE NORTH. HEIGHTS RISE ABOUT 12DAM FROM THURSDAY MORNING TO FRIDAY MORNING. LOWS THURSDAY NIGHT WILL PROBABLY BE SIMILAR TO THE PREV FEW WITH SKIES TRYING TO CLEAR AND WINDS LIGHT/VARIABLE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A DEEP UPPER LEVEL TROUGH WILL BE PRESENT ACROSS SOUTHEASTERN CANADA EARLY IN THE LONG TERM PERIOD...BUT WILL RELOAD WITH A SIGNIFICANT CHUNK ENERGY DIGGING INTO IT/S SW FLANK ACROSS THE MID MISS AND OHIO RIVER VALLEYS LATE THIS WEEK AND OVER THE UPCOMING WEEKEND /AS THE CANADIAN PORTION SHEARS OUT TO THE NE/. THIS POTENT SHORTWAVE TROUGH /AND AN ASSOCIATED WELL-DEFINED RIGHT ENTRANCE REGION OF A 90-95 KT 300 MB JET/ WILL LIFT NORTHEAST ACROSS THE MID ATLANTIC REGION FRIDAY THROUGH SUNDAY BEFORE SHIFTING TO THE SOUTHERN NEW ENGLAND COAST BY THE START OF NEXT WEEK. A SLOW MOVING /AND LIKELY STRENGTHENING/ BAROCLINIC ZONE... AND ONE OR MORE WAVES OF WEAK LOW PRESSURE MVG NE ALONG IT WILL BE LOCATED ACROSS CENTRAL OR ERN PENN DURING THIS 2-3 DAY PERIOD. PERIODS OF UNSETTLED WEATHER /SHOWERS AND TSTMS/ WILL OCCUR LATER FRIDAY...SATURDAY AND SUNDAY. THE STRENGTH OF THE LARGE SCALE FORCING AND INCREASINGLY ANOMALOUS HIGH PWAT AIR BENEATH THE NORTHWARD MIGRATING JET AND ITS THERMALLY DIRECT BRANCH WILL BRING THE POTENTIAL FOR SOME LOCALLY HEAVY/TRAINING SHOWERS AND TSRA... ESP ACROSS THE EASTERN HALF OF THE STATE/. MODEL DETAILS DIFFER SLIGHTLY WITH RESPECT TO THE TIMING AND LOCATION OF THE STRONGEST MESO/LARGER SCALE FORCING. BUT ALL GUIDANCE AGREES ON THE BASIC EVOLUTION AND NE MOVEMENT OF THIS TROUGH AND AXIS OF HIGH 40-50MM PWAT AIR RIDING NWD UP ALONG THE MID ATLANTIC PIEDMONT AND SPREADING ACROSS THE EASTERN HALF OF OUR CWA. AS A RESULT OF THESE TIMING/LOCATION DIFFERENCES...POPS WERE CAPPED OFF IN THE HIGH CHC CATEGORY. BUT AS THE FINER DETAILS UNFOLD WITH HIGHER RES MODEL GUIDANCE OVER THE NEXT FEW DAYS...POPS WILL UNDOUBTEDLY TREND HIGHER FOR SEVERAL PERIODS BETWEEN LATE FRIDAY AND SUNDAY. GRADUAL IMPROVEMENT WITH NEAR NORMAL TEMPS IS EXPECTED FOR EARLY NEXT WEEK. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... SOME AREAS CLEAR NOW. STILL SOME SC STILL ACROSS THE WESTERN AREAS. MAIN THING NOW IS AREA OF SHOWERS ACROSS THE FAR NW. ALSO SOME LOWER CIGS AT IPT. ANYWAY...SHOWERS AND THUNDERSTORMS ACROSS THE NW WILL WORK EASTWARD TODAY. SOME STORMS COULD HAVE SOME SMALL HAIL AND GUSTY WINDS...GIVEN THE COLD AIR ALOFT. FOR EARLY THU AM...ADDED SOME LOWER CIGS ETC AT IPT. A STRONGER 500 MB TROUGH WILL ROTATE ACROSS THE AREA ON THU...THUS SHOWERS AND STORMS WITH SMALL HAIL WILL LIKELY BE MORE WIDESPREAD THAN TODAY. PERHAPS A SMALL BREAK IN THE ACTION FOR FRIDAY. MODELS SHOW SOME CHC OF SHOWERS ACROSS THE SOUTH BY LATE IN THE DAY. SOME MODEL SPREAD. WITH THE LONGWAVE TROUGH TO THE WEST...NOT SEEING MUCH CHANCE FOR ANY ONE DAY BEING DRY PRIOR TO NEXT MONDAY...IF THEN. OUTLOOK... THU...SCT TSRA IMPACTS POSSIBLE. FRI-SUN...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...DANGELO LONG TERM...LAMBERT/STEINBUGL AVIATION...MARTIN

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