Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 171939 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 339 PM EDT THU APR 17 2014 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL EXTEND FROM THE CANADIAN MARITIMES...SOUTHWEST TO THE MID ATLANTIC COAST...KEEPING FAIR AND DRY WEATHER ACROSS MOST OF THE REGION THROUGH FRIDAY. A WEAK COLD FRONT WILL MOVE EAST FROM THE GREAT LAKES REGION AND BRUSH NORTHERN AND WESTERN PENNSYLVANIA WITH SOME CLOUDS AND PERHAPS A FEW RAIN SHOWERS LATE FRIDAY AND FRIDAY NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL BUILD EAST INTO THE COMMONWEALTH FOR THE WEEKEND SUPPLY ANOTHER FEW DAYS OF PLEASANT MID SPRING WEATHER. TEMPERATURES WILL MODERATE FURTHER THIS WEEKEND AND RISE ABOVE NORMAL BY EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... VARIABLE AMOUNTS OF MAINLY THIN CIRRUS WILL OCCUR ACROSS CENTRAL AND NWRN PENN FOR THE REST OF TODAY...ACCOMPANIED BY A SOUTHEASTERLY WIND OF 10-12KTS WITH GUSTS OF 15-20KTS IN MANY LOCATIONS. ALTHOUGH WINDS ARE SIMILAR TO YESTERDAY /ALBEIT FROM THE OPPOSITE DIRECTION/ MOTHER NATURE IS LESS DECEIVING WITH RESPECT TO TEMPS...WHICH ARE 8-10F WARMER IN ALL LOCATIONS COMPARED TO THIS SAME TIME WEDNESDAY. SOME LLVL MARINE MOISTURE /THE BULK OF IT WHICH IS STILL LURKING ALONG...AND OFF THE SOUTHERN NJ AND DELMARVA COAST/ IS CONTINUING TOO ADVECT NW AND ACROSS THE LOWER SUSQ VALLEY. THE EXTENT OF THESE SHALLOW...SCT-BKN STRATO CLOUDS SHOULD CONTINUE TO INCREASE AND COVER MOST OF THE REGION ALONG AND TO THE SE OF I-81 BY DUSK. TEMPS REMAIN ON TRACK TO REACH MID TO LATE AFTERNOON HIGHS IN THE LOW TO MID 50S. AS THE RELATIVELY SHALLOW VERTICAL MIXING SUBSIDES THIS EVENING...WE SHOULD SEE THE STRATO CU DECK ACROSS THE LOWER SUSQ VALLEY AND ADJACENT SERN AND ECENT PA SOLIDIFY INTO A MORE UNIFORM BKN- OVC CLOUD LAYER AND ADVANCE INTO THE CENTRAL RIDGE AND VALLEY REGION AS THE MEAN SFC-850 MB FLOW REMAINS FROM THE SOUTHEAST. ELSEWHERE...PERIODS OF CIRRUS WILL OCCUR. THE CLOUDS /AND HIGHER DEWPOINTS /IN THE 20S/ WILL HELP TO CURB THE TEMP DROP TONIGHT...AND MINS EARLY FRIDAY WILL BE SEVERAL DEG F OR MORE HIGHER THAN EARLY THIS THURSDAY MORNING. THE UNCERTAINTY OF THE AMOUNT OF CLOUD COVER TONIGHT AND EARLY FRIDAY...COMBINED WITH THE INCREASING SFC DEWPOINTS...AND LIGHT SE WINDS HAS DIRECTED US TOWARD TRANSITIONING FROM A FREEZE WATCH TO A FROST ADVISORY...WITH MIN TEMPS IN THE 32-35 RANGE IN MOST LOCATIONS. SOME OF THE TYPICALLY COLDER RURAL VALLEYS COULD SEE DAYBREAK TEMPS IN THE UPPER 20S /ESP IF A PERIOD OF CLEARING OCCURS/. TEMPS ACROSS THE CENTRAL AND NW ZONES WILL BE JUST A TAD LOWER THAN THOSE LOWER SUSQ COUNTIES COVERED BY THE FROST ADVISORY. && .SHORT TERM /FRIDAY/... THE MEAN BLYR FLOW VEERS A BIT MORE TO THE SSE OR SOUTH DURING THE DAY FRIDAY...WHICH WILL HELP AN ILL-DEFINED WARM FRONT LIFT NORTH ACROSS THE REGION AND INTO NEW YORK STATE. A BROAD...NEARLY NORTH-SOUTH AXIS OF LLVL MOISTURE CONVERGENCE AND HIGHER DEWPOINTS WILL HELP TO CREATE MORE IN THE WAY OF STRATO CU...THAN THE NEARLY NON-EXISTENT AMOUNTS THAT WE/VE SEEN IN THE UNUSUALLY COLD...AND BONE-DRY AIRMASS THE PAST FEW DAYS. OTHERWISE...THE LLVL RIDGE AXIS STAYS IN PLACE ALONG THE MID ATLANTIC PIEDMONT AND HELPS TO DEFLECT A WEAK NORTHERN STREAM SYSTEM TO OUR NORTH. A SIGNIFICANTLY STRONGER SRN STREAM STORM WILL ALSO BE HELD AT BAY WELL TO THE SOUTH OF THE AREA. A FEW LIGHT SHOWERS MAY GRAZE THE NWRN COS LATE FRIDAY...OR FRIDAY NIGHT. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
THE 17/12Z MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE HAS COME INTO MUCH BETTER AGREEMENT ON THE LARGE SCALE PATTERN EVOLUTION ACROSS THE LOWER 48 THIS PERIOD...SUPPORTING INCREASING CONFIDENCE IN THE FORECAST. THE MAIN THEME FOR CENTRAL PA OVER THE NEXT 7+ DAYS WILL BE A DRY AND RELATIVELY BENIGN WEATHER PATTERN...WITH NO SIGNIFICANT RAIN-PRODUCING SYSTEMS ON THE HORIZON. THIS SHOULD CONTRIBUTE TO INCREASING FIRE WEATHER CONCERNS. TEMPERATURES WILL MODERATE THROUGH NEXT WEEK...TRENDING WARMER WITH THE ODDS FAVORING A TILT TOWARD THE WARMER-SIDE OF LATE APRIL CLIMATOLOGY. NRN STREAM SHORTWAVE TROUGH AND SFC COLD FRONT PUSHING EASTWARD FROM THE GREAT LAKES REGION INTO THE NORTHEAST STATES WILL BRING SCT...VERY LIGHT RAIN SHOWERS TO NW/N-CENTRAL PA LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. LIMITED RETURN FLOW AND RELATIVELY COOL/DRY AIRMASS IN PLACE AHEAD OF THIS SYSTEM SHOULD LIMIT QPF AMTS TO AOB 0.10 INCH. MODEL CONSENSUS KEEPS PCPN ASSOCIATED WITH CLOSED SRN STREAM LOW TO THE SOUTH OF THE AREA...WITH CANADIAN HIGH PRESSURE REGAINING CONTROL OF THE SYNOPTIC PATTERN THROUGH THE REMAINDER OF EASTER WEEKEND. GUIDANCE TEMPERATURES APPEAR MARGINAL FOR FROST SUN-MON MORNING ACROSS THE LOWER SUSQ VLY WHERE THE GROWING SEASON IS OFFICIALLY UNDERWAY. THE BEST OPPORTUNITY/HIGHEST PROBABILITY FOR APPRECIABLE RAINFALL /0.25 TO 0.50 INCH AMOUNTS/ OVER THE NEXT 7 DAYS WILL LIKELY COME ON TUESDAY...WITH SLIGHTLY BETTER MOISTURE IN PLACE AHEAD OF AN APPROACHING SHORTWAVE TROUGH AND SFC COLD FRONT. THE ECMWF IS MORE AGGRESSIVE IN BRINGING HEIGHT FALLS INTO THE NORTHEAST ON DAY 7/WED EVENTUALLY CLOSING OFF A 500MB LOW NEAR SOUTHERN NEW ENGLAND. MEANWHILE THE GFS/GEFS ARE NOT AS STRONG AND GENERALLY MORE PROGRESSIVE ALOFT...WHICH LEADS TO FASTER HEIGHT RISES HEADING INTO THE SECOND HALF OF NEXT WEEK. THE SENSIBLE WEATHER HIGHLIGHT IS PROBABLY A RELATIVE MINIMUM IN DAYTIME HIGH TEMPERATURES FOR NEXT WEDNESDAY WITH BOTH MODELS/EFS DEPICTING A WEAK NEGATIVE H5-H7 ANOMALY INVOF THE NEW ENGLAND COAST. UPPER TROUGH/CLOSED LOW IS PROGGED TO MIGRATE EWD ACROSS THE NRN ROCKIES INTO THE UPPER MIDWEST WED-FRI. DOWNSTREAM RIDGE AXIS OVER THE CENTRAL PLAINS/MS VLY/MID-SOUTH SHOULD REACH THE EAST COAST BY THE END OF NEXT WEEK. THIS SUGGESTS A WARMING TREND FOLLOWING THE BRIEF COOL-DOWN MIDWEEK WITH MAX TEMPS POSSIBLY HEADING BACK TO/OR ABOVE 70F.
-- End Changed Discussion --
&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/... VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING. A LAYER OF SHALLOW/BKN MVFR-LOW END VFR STRATOCU WILL BE SLIDING IN FROM THE SE /DURING THE MID TO LATE AFTERNOON ACROSS THE LOWER SUSQ VALLEY AIRFIELD/...AND REACHING THE CENTRAL MTNS LATE TONIGHT/EARLY FRIDAY MORNING. MAINLY SUNNY SKIES WILL CONTINUE WITH SOUTHEAST TO SOUTH-SOUTHEAST WINDS AVERAGING TO 8-12 KTS WITH OCCASIONAL GUSTS AROUND 20 KTS. THE WIND WILL SUBSIDE DURING THE EARLY EVENING. CHANCE FOR LIGHT RAIN TO IMPACT MAINLY NW LATE FRIDAY AFTERNOON OR FRIDAY NIGHT WITH LOW PROB OF RESTRICTIONS. VFR ELSEWHERE. OUTLOOK... FRI...GENERALLY VFR. AREAS OF MVFR CIGS POSS ACROSS CENTRAL AND SE PA EARLY. FRI NIGHT-SAT...REDUCED CIGS/VSBYS POSS WITH CHANCE OF LIGHT RAIN SHOWERS /MAINLY NW HALF/. SUN-MON...NO SIG WX. TUE...A FEW...TO SEVERAL-HOUR PERIOD OF MVFR CIGS WITH BRIEF MVFR VSBYS IN SHOWERS ACCOMPANYING A COLD FRONTAL PASSAGE. && .CTP WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 2 AM TO 8 AM EDT FRIDAY FOR PAZ057-059- 063>066. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...DANGELO/LAMBERT LONG TERM...STEINBUGL AVIATION...LAMBERT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.