Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 050812 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 312 AM EST FRI FEB 5 2016 .SYNOPSIS... A WEAK WAVE OF LOW PRESSURE WILL MOVE UP AND JUST OFF THE EAST COAST TODAY...BEFORE HIGH PRESSURE BUILDS IN ITS WAKE AND BRINGS FAIR AND DRY WEATHER FOR THE WEEKEND. UNSETTLED CONDITIONS WILL START THE NEW WORKWEEK AS A COMPLEX AND SLOW MOVING STORM SYSTEM MOVES INTO THE EASTERN US. && .NEAR TERM /THROUGH TONIGHT/... LIGHT PRECIPITATION...IN THE FORM OF SNOW HAS BROKEN OUT AT COATSVILLE...JUST EAST OF THE LANCASTER BORDER. HRRR AND RAP BOTH AGREE IN BRINGING AN AREA OF LIGHT SNOW...POSSIBLY MIXED WITH A BIT OF SLEET OR RAIN...OVER THE FAR SERN PORTION OF THE CWA THROUGH SUNRISE...BASICALLY BEING OVER BY MID MORNING. QPF ON THE ORDER OF A TRACE TO UNDER A TENTH OF AN INCH REMAINS THE CONSENSUS FORECAST. TEMPERATURES SHOULD REMAIN ABOVE FREEZING SO ACCUMULATIONS IF THERE ARE ANY WILL PROBABLY BE CONFINED TO GRASSY SURFACES. FURTHER WEST A SHORTWAVE ALOFT IS HELPING TRIGGER SOME LIGHT SNOW SHOWERS THAT ARE GAINING A LITTLE PUSH FROM SOME OROGRAPHIC FORCING. LITTLE OR NO ACCUMULATION IS EXPECTED IN THESE AREAS. PRECIPITATION IS EXPECTED TO BE OVER...EXCEPT FOR PERHAPS SOME LINGERING FLURRIES OVER THE USUAL HIGHER ELEVATIONS OF THE NW...AS THE UPPER HEIGHTS REBOUND RAPIDLY FOR THE SECOND HALF OF THE DAY. CLOUDS WILL BREAK OVER OVER ALL BUT THE FAR NORTH TONIGHT AS THE SURFACE HIGH SLIDES BY JUST TO OUR SOUTH. TEMPS WILL DROP OFF INTO THE 20S REGION-WIDE TONIGHT...WHICH FOR EARLY FEBRUARY WILL AVERAGE ABOUT 5-10 DEG ABOVE NORMAL. && .SHORT TERM /SATURDAY/... SATURDAY LOOKS TO REMAIN DRY WITH THE MOST CLOUDS OVER NORTHERN AREAS...AND PARTLY TO MOSTLY SUNNY SKIES OVER THE CENTRAL AND SOUTHERN ZONES. HIGHS WILL BE A LITTLE WARMER THAN NORMAL FOR THE TIME OF YEAR...RISING INTO THE MID 30S TO MID 40S. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... A COMPLEX UPPER PATTERN IS MADE TO EVOLVE OVER THE EASTERN US EARLY NEXT WEEK...WITH A VIGOROUS UPPER LOW FORECAST TO DROP STEEPLY SE OUT OF THE NORTHERN PLAINS AND INTO OHIO VALLEY. AT THIS TIME THE OPERATIONAL GFS/ECMWF DO NOT GENERATE ANY KIND OF SIGNIFICANT SURFACE LOW/HEAVY PRECIP THREAT...BUT THE ENSEMBLE PLUMES FOR EARLY NEXT WEEK ARE ALL OVER THE PLACE WITH ANYWHERE FROM AN INCH OR TWO TO A FOOT OR MORE OF SNOW. ECENS SHOWS A PROLONGED PERIOD OF LIGHT-MODERATE PRECIP WITH THE POTENTIAL FOR A FEW INCHES OF SNOW...FAVORING THE HIGHER WESTERN AND NORTHERN AREAS. THE MAIN THING IS THERE IS NO INDICATION OF A SINGLE ROBUST SURFACE LOW THAT WOULD BRING MORE WIDESPREAD SIGNIFICANT STORMINESS...YET. THE SEEMINGLY MOST CERTAIN PART OF THE FORECAST IS THAT THE UPPER TROUGH IS EXPECTED TO BE SLOW MOVING OVER THE EASTERN US...DRIVING COLDER AIR INTO THE REGION...AND A CHUNK OF UNSEASONABLY COLD AIR DOWN INTO THE GULF STATES. THE NW FLOW WILL KEEP THE NORMAL LAKE EFFECT AND OROGRAPHIC SNOW SHOWERS GOING INTO LATE WEEK AS A SERIES OF WEAK DISTURBANCES IN THE NW FLOW ALOFT KEEP US ON THE CHILLY AND UNSETTLED SIDE. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... 06Z TAFS SENT. MAIN CHANGE WAS TO ADD A LINE AFTER SUNSET...AS WINDS DIE DOWN. WILL BE WATCHING THE RADAR CLOSELY...CONCERN TO HOW FAR WEST RAIN AND SNOW SHOWERS COULD MOVE IN THE NEXT FEW HOURS...AS A WAVE OF LOW PRESSURE FORMS ON THE COLD FRONT AND TRACKS NE. EARLIER DISCUSSION BELOW. THE ONLY AVIATION CONCERN ACROSS CENTRAL PA THRU 06Z WILL BE MVFR STRATOCU DECK/SCT FLURRIES AT KBFD/KJST ASSOC WITH WEAK OROGRAPHIC LIFT OVR THE MTNS. FOCUS LATE TONIGHT WILL SHIFT TOWARD SE PA...AS A WAVE OF LOW PRES LIFTS UP THE EAST COAST. ALL THE LATEST MDL DATA SUGGESTS KLNS WILL BE ON THE WESTERN EDGE OF THE SNOW. THIS COULD POTENTIALLY LEAD TO A PERIOD OF LOW /IFR/ VSBYS AT KLNS BTWN 08Z-12Z FRIDAY. LATEST HRRR OUTPUT AS OF 03Z SUGGESTS THE SIG VIS REDUCTIONS MAY REMAIN JUST EAST OF KLNS...BUT TOO CLOSE TO CALL ATTM. HIGH CONFIDENCE IN AT LEAST MVFR CONDS AT KBFD AND KJST FRIDAY MORNING WITH OCNL -SHSN. LATEST MDL SOUNDINGS AND EXPERIMENTAL HRRR PRODUCTS SUGGEST OCNL IFR CONDS ARE ALSO POSSIBLE AT KBFD/KJST EARLY FRIDAY AM...AS BLYR MOISTURE/-SHSN INCREASE AHEAD OF APPROACHING UPPER TROUGH MOVING IN FROM THE W. ANY SNOW AT KLNS SHOULD END BY ARND 11Z. FOCUS WILL THEN BE ON LINGERING STRATOCU ACROSS THE W MTNS. MDL SOUNDINGS SUGGEST EVEN KBFD/KJST WILL IMPROVE TO VFR CONDS BY AFTN...AS HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY. OUTLOOK... SAT-SUN...NO SIG WX EXPECTED. MON-TUE...SNOW/LOW CIGS POSS...MAINLY W MTNS. && .HYDROLOGY... ICE EFFECTS AT MARIETTA WILL CONTINUE FOR QUITE A WHILE. BUT FLOWS ARE NOT VERY HIGH. THE LOCAL STREAMS WILL START TO COME DOWN SOME...BUT SHOW DAILY AFTN BUMPS UP AS RESIDUAL SNOW MELTS WITH AFTN TEMPS IN THE 40S EACH OF THE NEXT FEW DAYS WHERE PATCHY SNOW LINGERS IN THE SE. WILL CONTINUE TO MONITOR THE SITUATION...AS MORE RAIN AND SNOW NOT THAT FAR AWAY. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...FITZGERALD/MARTIN HYDROLOGY...

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