Area Forecast Discussion
Issued by NWS State College, PA

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108 FXUS61 KCTP 042058 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 358 PM EST THU FEB 4 2016 .SYNOPSIS... A WAVE OF LOW PRESSURE RIDING UP THE EAST COAST MAY SPEAD A VERY LIGHT ACCUMULATION OF SNOW INTO SOUTHEASTERN PA TONIGHT. OTHERWISE...AN UPPER LEVEL TROUGH OVER THE GREAT LAKES WILL KEEP TEMPERATURES CLOSE TO OR SLIGHTLY ABOVE SEASONAL NORMALS FOR THE NEXT COUPLE OF DAYS. GENERALLY LIGHT ACCUMULATIONS OF LAKE EFFECT AND UPSLOPE SNOWS COULD OCCUR ACROSS THE NORTHWEST SNOWBELT WITH DRY WEATHER ELSEWHERE INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... THE 150KT JET STREAK ALOFT WILL TILT TO NEARLY N-S ORIENTATION AND THE FAVORABLE RIGHT-ENTRANCE REGION OF THE STREAK SHOULD LEAD TO DEVELOPMENT OF A WAVE OF LOW PRESSURE ALONG AN OLD FRONT OFF THE EAST COAST TONIGHT. THE SFC LOW WILL REMAIN OFF THE COAST FAR ENOUGH TO MAKE VERY LITTLE IMPACT ON THE MAJORITY OF THE CWA. HOWEVER...THERE COULD BE SOME SNOW SLIDE IN FROM THE EAST OVERNIGHT. MOST MODEL AND SREF MEAN QPF DO MAKE MEAS PRECIP OVER FAR ERN LANC CO. THE MILLION DOLLAR QUESTION IS JUST HOW FAR DOES THIS BACK/NWRN EDGE OF THE SNOW GET INTO THE CWA - IF AT ALL. THE DRYING NNW FLOW WILL KEEP THE EDGE SHARP AND IT IS THAT CHALLENGE WHICH AWAITS US TONIGHT. WITH THE PREPONDERANCE OF EVIDENCE POINTING TO A GUILTY VERDICT /VERY MINOR ACCUM/...WILL KEEP THE DUSTING TO AN INCH ACCUMS IN THE CURR FCST FOR LNAC CO. HAVE INCHED POPS UP TO THE WEST A LITTLE INTO YORK CO...MAINLY IN RESPONSE TO THE MORE-WET 12Z RUNS. THE STRONG JET MAX IS THE BIGGEST MASS-FEATURE TO MOVE THE FORECAST TO A MORE DEVELOPED SYSTEM. IT MAY BE A GOOD TREND TO FOLLOW...BUT A CONSERVATIVE BUMP IN POPS TO EVEN CHC LEVELS IS BEST WHEN DEALING WHEN ADDING THE SIMPLE YET REACTION-CAUSING /SNOW/ WORD TO THE FORECAST. AGAIN...ALL THIS IS VERY HEAVY ON CONTINUITY AND ALSO IN COLLABORATION WITH NEIGHBORING OFFICES THINKING. CLOUDS WILL TAKE A BREAK IN THE CENTRAL COS TONIGHT AS THE LLVL FLOW BECOMES A LITTLE LESS CYCLONIC. WILL CONTINUE THE MENTION OF SCT/ISOLD SHSN IN THE NW THO AS THE STRONG VORT MAX NEAR PA FROM THE W. THE FLOW IS STILL OFF THE LAKE AND UPSLOPE INTO THE HIGHER ELEVS OF PA. JUST A DUSTING THERE AS WELL. MINS WILL BE LOWEST IN THE NW WHERE CAA BRINGS 8H TEMPS DOWN TO DOUBLE DIGITS BELOW 0C. THE OFFSHORE LOW PULLS OFF TO THE NW AND THE AXIS OF THE JET STREAM PASSES OUR LONGITUDE EVEN BEFORE SUNRISE. SO...IMPROVEMENT SHOULD BEGIN AND ANY LIGHT SNOW IN THE EAST SHOULD STOP IN THE PRE-DAWN HOURS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... IMPROVEMENT WILL OCCUR ON ALL FRONTS WITH THE LOW WELL OFF TO THE NE AND VORT MAX/SHORT WAVE OVERHEAD IN THE MORNING. WILL LINGER MENTION OF --SHSN IN THE ALLEGHENIES FOR THE MORNING. ELSEWHERE...THE NWRLY WIND WILL PICK BACK UP. SKIES SHOULD CLEAR OUT OVER MOST OF THE CWA. TEMPS SHOULD BE VERY NEAR NORMAL FOR MAXES WITH NIL ADVECTION AND 8H TEMPS AROUND -10C. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
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MODERATELY AMPLIFIED BUT PROGRESSIVE UPPER FLOW PATTERN ACROSS THE CONUS AT THE START OF THE LONG TERM PERIOD IS FORECAST TO BECOME MORE AMPLIFIED AND SLOW DOWN THROUGH THE END OF NEXT WEEK. PATTERN WILL TRANSITIONS TO A WELL AMPLIFIED UPPER RIDGE OVER THE WESTERN U.S. WITH A CORRESPONDING DOWNSTREAM UPPER TROF OVER THE EASTERN HALF OF THE COUNTRY. AFTER A QUIET START TO THE PERIOD THIS WEEKEND...THE WEATHER WILL TREND COLDER AND UNSETTLED FOR MUCH OF NEXT WEEK AS SEVERAL SHOTS OF ARCTIC AIR AND SEVERAL ROUNDS OF SNOW SHOWERS PUSH THROUGH THE REGION. THE POSSIBILITY OF ANY SIGNIFICANT PCPN AT THIS POINT APPEARS LOW TO MODERATE. MAIN THREAT WILL BE IN THE MONDAY TO TUESDAY TIME FRAME...WITH POSSIBLE COASTAL DEVELOPMENT STILL HINTED AT THE MEDIUM RANGE GUIDANCE. LATEST TRENDS HOWEVER ARE FOR DEVELOPMENT TO BE FARTHER EAST THAN YESTERDAYS SOLUTIONS.
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&& .AVIATION /21Z THURSDAY THROUGH TUESDAY/... VFR COVERS MOST SITES DESPITE STRATO CU CLOUD DECK IN THE W AND HIGHER CLOUDS SNEAKING IN FROM THE SE IN THE SE. EXPECT THIS TO CONTINUE FOR THE FIRST HALF OF THE NIGHT. BUT A WAVE OF LOW PRESSURE WILL DEVELOP NEAR KHAT AND MOVE NE OVERNIGHT AND FRI. THIS COULD LEAD TO SOME -SN AT KLNS. THE SNOW SHOULD STAY TO THE E OF KMDT. KBFD AND KJST WILL CONTINUE TO BOUNCE IN AND OUT OF MVFR. -SHSN WILL BE SCT ABOUT THE NW MTNS TONIGHT AS A DEEP UPPER TROUGH SHARPENS SOME AND MOVES IN FROM THE W. BUT MOISTURE IS ALMOST NIL. THEREFORE...ANY REDUCTYIONS TO IFR WILL BE RARE AND BRIEF. IMPROVEMENT TO VFR COMES TO THE SE BEFORE SUNRISE AND TO THE NW THROUGH THE MORNING ON FRI AS PRESSURE BUILDS UP A LITTLE FROM THE SW. OUTLOOK... SAT-SUN...NO SIG WX. MON-TUE...MVFR/IFR POSS MON-TUE IN LIGHT SNOW - MAINLY W. && .HYDROLOGY... OBVIOUS 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. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...LAMBERT/GARTNER AVIATION...DANGELO HYDROLOGY...

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