Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | 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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
480 FXUS61 KCTP 091829 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 129 PM EST TUE FEB 9 2016 .SYNOPSIS... AN UPPER LOW WILL MOVE INTO THE REGION FROM THE OHIO VALLEY AND TRANSITION INTO A LONG WAVE TROUGH. AN ONGOING WIDESPREAD LIGHT TO MODERATE SNOW WILL TAPER OFF THIS EVENING. LAKE EFFECT AND UPSLOPE SNOW SHOWERS WILL FOLLOW FOR MID-WEEK INTO THE FIRST PART OF THE WEEKEND...WHERE ADDITIONAL ACCUMULATIONS ARE LIKELY IN THE FAVORED NORTHWEST SNOWBELT AND HIGHER TERRAIN ALONG THE ALLEGHENIES AND LAURELS. THE COLDEST AIRMASS OF THE WINTER IS POISED TO BRING FRIGID TEMPERATURES AND DANGEROUS WIND CHILLS FOR VALENTINES WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1230PM UPDATE... BANDS OF MODERATE SNOW CONTINUE TO IMPACT THE LOWER SUSQ WHERE RATES IN HIGHEST RADAR RETURNS ARE RUNNING AROUND AN INCH/HOUR. THIS WILL CONTINUE INTO MID/LATE AFTERNOON BEFORE DIMINISHING AS AREA OF SNOW DRIFTS EASTWARD...WITH ONLY LIGHT ACCUMS LINGERING INTO THE EVENING HOURS. ELSEWHERE...HRRR HAS BEEN HINTING AT A N-S ORIENTED BAND OF SNOW DEVELOPING OVER THE WESTERN HIGHER TERRAIN...WHICH IS FORMING AS I TYPE. THIS BAND COULD BRING A SHORT PERIOD OF MODERATE SNOW TO WESTERN/CENTRAL AREAS BUT OVERALL ACCUMS WILL NOT ADD UP TO MUCH. OVER THE LAURELS...PERSISTENT LIGHT SNOW WILL CONTINUE TO GRADUALLY ACCUMULATE THROUGH THE AFTERNOON. TEMPS BASICALLY STEADY THIS AFTERNOON BEFORE FALLING INTO THE UPPER 20S THIS EVENING. 630 AM UPDATE... FINALLY SNOWING OUT THE WINDOW BUT NO ACCUM YET - EVEN ON THE CARS. MCV-LIKE FEATURE EASY TO PICK OUT ON THE IR LOOP THIS MORNING OVER WV. THIS FEATURE WILL SLIDE INTO THE STATE FROM THE SW. THE FORCING AHEAD OF IT IS ALREADY BEGINNING TO CREATE A COHERENT AREA OF LIGHT SNOW. RADAR RETURNS GRADUALLY INCREASING IN THE LAST FEW FRAMES AND SPREADING NORTHWARD FROM WV/MD. WORST OF THE VSBYS ARE KHGR AND KMDT - BUT THEY ARE >1SM AT THIS TIME. WILL CONTINUE TO RIDE THE FCST AS IS...ALLOWING THE SNOW TO FALL FOR A WHILE BEFORE TAKING ANY FURTHER ACTION. PREV... LOTS OF DECISIONS THIS MORNING WITH THE OVERWHELMING MESSAGE ONE OF LOWER SNOWFALL NUMBERS. HAVE MADE ONE SMALL CHANGE TO THE FLAGS BY ADDING SCHUYLKILL COUNTY INTO THE ADVY. REASONING IS THAT THE TEMPERATURE PROFILE WILL FAVOR AN ELEVATION-DEPENDENT SNOWFALL. THE TEMPS IN THE VALLEYS WILL BE MARGINAL FOR EFFICIENT ACCUMULATIONS. HOWEVER...THE IN-CLOUD PROFILE AND TEMPS IN THE HIGHER ELEVATIONS DO FAVOR SOME 15:1 RATIOS DURING THE DAYLIGHT HOURS. SO...ARMED WITH THAT...HAVE DECIDED TO HOLD ONTO THE WARNING AND REST OF THE ADVYS AS IS FOR THE TIME-BEING. HAVE TRIED REALLY HARD TO KEEP ACCUMS IN THE WARNING RANGE - BUT HAVE CONFINED THEM TO THE HIGHER ELEVATIONS. IT WILL LIKELY WORK OUT THAT THE HILLTOPS IN THE WARNING-AREA COULD GET 5-7 INCHES WHILE THE CITIES AND LOWEST ELEVATIONS GET ONLY AN INCH OR TWO. THE DISORGANIZED LOOK TO THE FORCING WILL PROBABLY MEAN NO LONG-LIVED BANDING AND ONLY LIMITED TIMES OF 1 IN/HR RATES IF ANY AT ALL. QPF AMOUNTS LOOKING PRETTY TENUOUS AS WELL WITHOUT ANOMALOUS PWATS AND NO GOOD OFF-OCEAN/GULF FLOW TO TAP INTO ADDITIONAL HELP. WITH THE EXPECTED MELTING...WE ARE IN DANGER OF NOT MAKING WARNING NUMS - CERTAINLY IF WE TAKE INTO ACCOUNT THE 12-HR CRITERIA. SO MANY THINGS GOING AGAINST WARNING SNOW ACCUMS...BUT THE CAT IS OUT AND RUNNING AROUND ALREADY. SINCE WE ALREADY HAVE THE WARNING UP...HAVE CHOSEN TO GIVE IT A LITTLE MORE TIME FOR THE STORM TO SHOW IT/S HAND. RATHER NOT TAKE DOWN THE WARNING BEFORE IT EVEN HAS A CHANCE TO GET INTO THE PROGGED HEAVIEST PRECIPITATION. TIMING LOOKS LIKE THE SRN TIER WILL GET SOME STEADY SNOW THIS MORNING BUT THEN THE BEST FORCING SEEMS LIKE IT WILL BE OVER THE LAURELS THIS AFTERNOON AND SLIDE ACROSS THE CENTRAL MOUNTAINS AND OFF TO THE EAST THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... UPPER LOW WILL BE FILLING AND LOSING IT/S CLOSED CONTOURS...BECOMING A LONG WAVE TROUGH TONIGHT. SNOW WILL PROBABLY BE SLIDING STEADILY TO THE EAST IN THE EVENING AND BE OFF TO THE EAST OF CENTRAL PA BY MIDNIGHT. THE HEIGHTS STILL LOWER SOME...THOUGH...AND SOME 1/2 TO 1 IN/HR RATES ARE POSSIBLE ALONG WHAT MAY TURN OUT TO BE A FRONTAL BAND AS THE BEST COLD AIR MOVES IN AT LOW LEVELS AND WINDS PICK UP FROM THE WEST. THINGS THEN TRANSITION TO A PLAIN-OL UPSLOPE SNOW SITUATION FOR THE LAURELS. A LM CONNECTION DEVELOPS UNDER HIGHLY-FAVORABLE TEMPERATURES/CONDITIONS. THE AIR DOES DRY OUT ON THE WHOLE...SO MOST OTHER LOCATIONS WILL SEE LITTLE MORE THAN FLURRIES. DOWNSLOPE MAY ALLOW THE SE TO GET A DEG OR TWO WARMER THAN TODAY. THE LAKE EFFECT IN THE NW WILL BE RAMPING UP...BUT THE STACKED WEST WIND PROFILE FAVORS WRN NY STATE THAN NW PA. OF COURSE...THE COLD AIR WILL LIKELY EXTEND SOME BANDS INTO WARREN CO. HAVE CHOSEN TO HOLD OFF ON ANY LK EFF FLAGS FOR NOW - SINCE THE NEED FOR A WATCH/WARNING IS NOT QUITE 50PCT AND TIMING IS SUCH THAT THE CURRENT WIDESPREAD SNOW AND WARNS/ADVYS ELSEWHERE MAY BE CONFUSING. IT WILL BE COMPLICATED ENOUGH FOR THE LAURELS WHERE THE SNOW WILL NEVER REALLY TAKE A BREAK. TEMPS DROP OFF QUITE QUICKLY LATE WED. MINS MAY GET INTO THE SINGLE DIGITS ON THE HILL TOPS OF THE ALLEGHENIES AND LAURELS. WIND CHILLS WILL GO BELOW ZERO. && .LONG TERM /THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
*IMPACT WEATHER HIGHLIGHTS: SNOW SQUALLS POSSIBLE WITH ARCTIC FRONT FRIDAY NIGHT-EARLY SATURDAY; FRIGID TEMPERATURES/DANGEROUS WIND CHILLS FOR VALENTINES WEEKEND. POLAR VORTEX DIVES FROM HUDSON BAY SOUTHEAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND THURSDAY-SUNDAY. THE GLOBAL MODELS AND ENSEMBLE MEANS KEEP A `MILDER` TROUGH PATTERN IN PLACE OVER THE NORTHEAST CONUS INTO NEXT WEEK. THE FIRST SHOT OF COLD AIR ARRIVES ON THURSDAY WITH LAKE EFFECT AND UPSLOPE SNOW SHOWERS TAPERING OFF THURSDAY NIGHT. LIGHT TO MODERATE SNOW ACCUMULATIONS ARE LIKELY IN THE FAVORED NORTHWEST SNOWBELT AND HIGHER TERRAIN ALONG THE ALLEGHENIES/LAUREL HIGHLANDS. THE COLDEST AIRMASS OF THE 2015-16 WINTER SEASON REMAINS POISED TO ARRIVE THIS WEEKEND...AS A BLAST OF ARCTIC AIR DELIVERS A SHORT DURATION COLD OUTBREAK TO CENTRAL PENNSYLVANIA. SNOW SQUALLS ARE POSSIBLE WITH THE ARCTIC FRONTAL PASSAGE FRIDAY NIGHT INTO EARLY SATURDAY. MAX/MIN TEMPERATURE DEPARTURES OF -20 TO -25 DEGREES BELOW CLIMO ARE FCST SATURDAY AND SUNDAY. MINIMUM TEMPERATURES SATURDAY NIGHT INTO EARLY SUNDAY MORNING RANGE FROM AROUND 0F IN THE LOWER SUSQ. VALLEY TO -10F IN THE NORTHWEST ALLEGHENIES. THE FRIGID TEMPERATURES COMBINED WITH DANGEROUS WIND CHILLS /-10 TO -25 BELOW ZERO/ WILL RESULT IN AN INCREASED RISK FOR FROSTBITE AND HYPOTHERMIA. A SLOW MODERATION (WARMING TREND) IS EXPECTED INTO EARLY NEXT WEEK...BUT WITH A POTENTIAL OVERRUNNING/WAA TYPE SNOW EVENT.
-- End Changed Discussion --
&& .AVIATION /19Z TUESDAY THROUGH SUNDAY/... IFR/LIFR CONDITIONS WILL REMAIN WIDESPREAD...ESP SOUTH OF I-80...AS LIGHT TO MODERATE SNOW EVENT CONTINUES THIS AFTERNOON. IMPROVEMENT EXPECTED THIS EVENING...ESPECIALLY TO VSBY...AS SNOW TAPERS TO FLURRIES. CIGS WILL REMAIN LOW THROUGH THE EVENING...BUT AS WESTERLY FLOW INCREASES A BIT OVERNIGHT CIGS WILL IMPROVE AS WELL IN CENTRAL AND EASTERN AREAS. LOWER SUSQ WILL IMPROVE TO VFR WITH CENTRAL MTNS HOLDING ON TO AN MVFR DECK. WESTERN HIGHER TERRAIN WILL CONTINUE TO SEE SOME SNOWFLAKES IN THE AIR WITH UPSLOPE FLOW KEEPING MAINLY IFR CIGS IN PLACE. OUTLOOK... WED...MAINLY IFR IN SNOW WRN AIRSPACE. MVFR-VFR CIGS CENTRAL/EAST. THU-SAT...MVFR IN -SHSN W MTNS. VFR ELSEWHERE. SUN...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR PAZ025>028-034>036-056>059-063. WINTER WEATHER ADVISORY UNTIL 7 PM EST WEDNESDAY FOR PAZ024- 033. WINTER STORM WARNING UNTIL 1 AM EST WEDNESDAY FOR PAZ064>066. && $$ SYNOPSIS...DANGELO/RXR NEAR TERM...DANGELO/RXR SHORT TERM...DANGELO 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.