Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 250914 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 514 AM EDT FRI JUL 25 2014 .SYNOPSIS... HIGH PRESSURE WILL DRIFT EAST AND MAINTAIN FAIR WEATHER TODAY. THE WEATHER PATTERN WILL BECOME UNSETTLED ONCE AGAIN AS A SERIES OF DISTURBANCES APPROACH THE AREA BEGINNING SATURDAY...AND CONTINUING THROUGH MONDAY. A DEEP UPPER TROUGH WILL MOVE INTO THE EASTERN US NEXT WEEK BRINGING ANOTHER SHOT OF UNSEASONABLY COOL TEMPERATURES TO THE REGION. && .NEAR TERM /THROUGH TONIGHT/... TODAY WILL BE THE LAST FAIR DAY FOR A WHILE AS HIGH PRESSURE BUILDS ACROSS THE FORECAST AREA. OTHER THAN SOME THIN HIGH CLOUDS...AND POSSIBLY SOME SMOKE FROM WESTERN FOREST FIRES...WE WILL HAVE A SUNNY AND VERY PLEASANT DAY WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S. DEWPOINTS IN THE 40S WILL BE UNSEASONABLY DRY...BUT REFRESHING. DEWPOINTS WILL SLOWLY START TO CREEP BACK UP TONIGHT AS THE HIGH SLIPS OFF TO OUR EAST AND WE BEGIN TO SEE A RETURN SOUTHERLY FLOW DEVELOP. OTHER THAN A VERY SMALL CHANCE OF A SHOWER MAKING IT INTO THE FAR NW BY MORNING...IT WILL REMAIN DRY. && .SHORT TERM / SATURDAY THROUGH 6 AM SUNDAY/... SATURDAY WILL START OFF DRY IN MOST AREAS. TIMING AND PLACEMENT OF EVENTUAL CONVECTION WILL BE VERY DEPENDENT ON UPSTREAM DEVELOPMENTS AS WE COME UNDER A ROBUST WNW FLOW ALOFT. IN RESPONSE TO THE APPROACH OF A STRONG UPPER JET STREAK NOSING INTO THE LOWER LAKES BY LATE IN THE DAY...SHORT RANGE OPERATIONAL MODELS AND ENSEMBLE PACKAGES AGREE IN DEVELOPING AN ANOMALOUSLY STRONG WSW LOW LEVEL JET AND SURGING IT INTO THE REGION...ESPECIALLY DURING SATURDAY AFTERNOON. MOISTURE INITIALLY LOOKS LIMITED...HELPING TEMPER HOW MUCH INSTABILITY WE WILL EXPERIENCE. I LEANED AWAY FROM THE VERY WET SREF POPS...USING A BLEND OF MODEL GUIDANCE TO COME UP WITH JUST A CHANCE OF SHOWERS AND STORMS...THE BETTER CHANCES BEING IN THE AFTERNOON. HIGHS SATURDAY WILL BE VERY PLEASANT FROM THE MID 70S NW TO MID 80 SE...BUT DEWPOINTS WILL BEGIN CREEPING UP BRINGING HUMIDITY BACK INTO THE NOTICEABLE RANGE. && .LONG TERM /SUNDAY THROUGH THURSDAY/... SPC SHOWS A SLIGHT RISK FROM THE CENTRAL PLAINS INTO WESTERN PA FOR THEIR DAY 2 OUTLOOK. THEY SEEM TO BE KEYING ON A SECONDARY EVEN STRONGER DISTURBANCE THAT WILL BE DROPPING INTO THE UPPER MIDWEST...EVENTUALLY SPARKING OFF AN MCS THAT COULD AFFECT THE AREA LATE SATURDAY NIGHT AND EARLY SUNDAY. LATEST TIMING HAS SUNDAY BEING SOMEWHAT IN BETWEEN SYSTEMS AS THE EXPECTED MCS MENTIONED ABOVE FADES AND MAINLY MOVES SOUTH OF THE REGION. LACKING CONFIDENCE IN PRECIP TIMING OR PLACEMENT...I KEPT POPS IN THE CHANCE RANGE GIVEN THE STEADILY FALLING UPPER HEIGHTS...A TAD BELOW MOST GUIDANCE. HIGHS SUNDAY WILL STILL BE IN THE 70S AND 80S...BUT WILL REPRESENT A DOWNWARD TREND THAT WE WILL SEE FOR THE UPCOMING WEEK AS AN ANOMALOUSLY DEEP UPPER TROUGH TAKES AIM AT THE EASTERN US. BY THE TIME WE GET INTO SUNDAY NIGHT AND MONDAY...THERE ARE DIFFERENCES IN TIMING AND STRENGTH OF A SURFACE LOW THAT COMES ALONG WITH THE DEEPENING UPPER SHORTWAVE. THE GFS/GEFS SHOW A STRONGER SYSTEM AND IMPLY WE COULD BE DEALING WITH A STRONG MCS/SLUG OF HEAVY RAIN. THE SREF IS LESS DEFINED SINCE THE NAM WANTS TO BREAK SURFACE DEVELOPMENTS INTO PIECES NW AND SE OF THE AREA. THE ECMWF IS MORE IN LINE WITH THE GEFS/GFS AND A SINGLE STRONGER LOW...BUT IS SLOWER. THIS TIMEFRAME SEEMS TO REPRESENT THE PERIOD OF HIGHEST CONFIDENCE FOR RAINFALL SO LIKELY MOS POPS LOOK REASONABLE. BY EARLY NEXT WEEK...A DEEP UPPER TROUGH WILL HELP DELIVER ANOTHER CHILLY AIRMASS THAT WILL LAST FOR MUCH IF NOT ALL OF THE WEEK. GEFS SHOWS 500 HEIGHTS SOME 3-4 STD DEV BELOW NORMAL DEVELOPING AND SETTLING DOWN OVER THE CAROLINAS THROUGH WEDNESDAY...BEFORE THE TROUGH IS MADE TO BEGIN FILLING AND SLOWLY LIFTING OUT. IT SHOULD EQUATE TO SEVERAL DAYS WITH LITTLE OR NO RAIN AND TEMPERATURES RUNNING SEVERAL DEGREES COLDER THAN NORMAL FOR THE END OF JULY. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... 06Z TAFS SENT. HIGH PRESSURE AND ASSOC DRY AIR MASS WILL RESULT IN A NEAR CERTAINTY OF VFR CONDS AND LGT WIND FOR ALMOST ALL OF CENTRAL PA OVERNIGHT. THE EXCEPTION WILL BE THE DEEP VALLEYS OF THE ALLEGHENIES...WHERE UNSEASONABLY COOL TEMPS COMBINED WITH WARM RIVER/STREAM WATER AND A CALM WIND...WILL RESULT IN LOCALLY DENSE FOG A FEW HOURS EITHER SIDE OF DAWN. CLIMATOLOGY AND LATEST MOS GUIDANCE INDICATE KBFD IS THE ONLY AIRFIELD LIKELY TO EXPERIENCE A PERIOD OF LOW VSBYS...WHILE A SLIGHT CHANCE EXISTS AT KUNV...KAOO AND KIPT. ANY EARLY VALLEY FOG SHOULD BURN OFF BY 14Z...THEN A NEAR CERTAINTY OF VFR CONDS/LGT WIND FOR THE REST OF FRIDAY AS HIGH PRESSURE DRIFTS OVER THE STATE. OUTLOOK... SAT...SCT TSRA IMPACTS POSSIBLE...ESP NW MTNS. SUN...AM LOW CIGS POSS NW MTNS. SCT TSRA IMPACTS POSS SOUTHERN PA. MON...ONCL VIS RESTRICTIONS POSS IN SHRA/TSRA. TUE...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...FITZGERALD/MARTIN

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