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 180620 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 220 AM EDT FRI APR 18 2014 .SYNOPSIS... A RIDGE OF HIGH PRESSURE FROM THE CANADIAN MARITIMES DOWN THROUGH THE CAROLINAS WILL KEEP FAIR AND DRY WEATHER ACROSS MOST OF THE REGION THROUGH FRIDAY. A WEAK COLD FRONT WILL BRUSH NORTHWESTERN PENNSYLVANIA LATE TOMORROW AND TOMORROW NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL BUILD EAST INTO THE COMMONWEALTH FOR THE WEEKEND. TEMPERATURES WILL MODERATE THIS WEEKEND AND RISE ABOVE NORMAL BY EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... SOME LOW CLOUDS MOVED ACROSS THE SOUTHERN AREAS AND APPEARED TO HAMPER THE FROST ADVISORY BUT WE HAVE HAD SOME CLEARING AS THIS FEATURE MOVED WEST AND NOW HAVE REPORTS OF TEMPERATURES IN THE 34-37F RANGE THOUGH BIGGER CITIES STILL NEAR 40. SO WILL KEEP FROST ADVISORY IN EFFECT AS SOME LOCATIONS NOW BELOW THE MAGIC 36F SHELTER HEIGHT. WINDS HAVE LUFT A BIT TOO. MOST OF WEST IS CLEAR AND TEMPERATURES RUNNING WARMER THAN LAST NIGHT. REALLY MASSIVE 1040 HPA HIGH OVER NEW ENGLAND WITH +3 SIGMA PRESSURE ANOMALIES HAS KEPT COLD AIR IN AT LOW LEVELS BUT NOW BRINGING SOME MARINE LAYER AIR INTO SOUTHEAST. SATELLITE IMAGERY SHOWS THE SYSTEM TO OUR WEST WHICH WILL TRY TO MOVE INTO THIS LARGE ANTICYCLONE. SREF SHOWS SOME CHANCE POPS AS THE ANEMIC FRONT PUSHES INTO PA LATER TODAY AND THIS EVENING. KEPT POPS IN NORTHERN TIER AND USED 3-HOUR SREF PROBABILITY DISTRIBUTION FUNCTION "POPS" TO SHOW PROGRESSIVE EVOLUTION. I LOWERED THE VALUES AS THESE ARE NOT STATISTICAL POPS AS IN MOS BUT A DISTRIBUTION FUNCTION IN A SYSTEM WITH A LOW QPF WET BIAS. HARD TO GET EXCITED ABOUT A TROUGH THAT HAS POSITIVE PRESSURE ANOMALIES! ANY RAIN WOULD BE LIGHT AND THE ANTICYCLONE BEHING THIS SYSTEM AT 1030 HPA IS A BIT WEAKER. ITS A GOOD TIME FOR ANTICYCLONES. && .SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/... 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 /SATURDAY NIGHT THROUGH THURSDAY/... 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. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... A LAYER OF SHALLOW/BKN MVFR-LOW END VFR STRATOCU WILL BE SLIDING INTO SUSQ VALLEY AIRFIELDS FROM THE SE OVERNIGHT...AND ULTIMATELY EDGING INTO PORTIONS OF THE CENTRAL MTNS JUST BEFORE SUNRISE. 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 BY 00Z. DURING THE DAY ON FRI...CHANCE FOR LIGHT RAIN TO IMPACT MAINLY NW LATE IN THE AFTERNOON INTO THE EVE WITH LOW PROB OF RESTRICTIONS. VFR ELSEWHERE. LIGHT SOUTHEAST WINDS WILL SHIFT TO THE SOUTH AND THEN SW THROUGH THE DAY...WITH INCREASES TO 5-10 KTS WITH GUSTS TO AROUND 15 KTS. OUTLOOK... TONIGHT-SAT...REDUCED CIGS/VSBYS POSS WITH CHANCE OF LIGHT RAIN SHOWERS MAINLY NW HALF. VFR ELSEWHERE. SUN-MON...NO SIG WX. TUE...SEVERAL-HOUR PERIOD OF MVFR CIGS POSS WITH BRIEF MVFR VSBYS IN SHOWERS ACCOMPANYING A COLD FRONTAL PASSAGE. && .CTP WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR PAZ057-059- 063>066. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...DANGELO/LAMBERT LONG TERM...STEINBUGL AVIATION...RXR

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