Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 012315
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
615 PM EST SUN FEB 1 2015

.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT...AND CROSS THE
STATE ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA INTO MONDAY MORNING. A PERIOD OF FREEZING RAIN IS
LIKELY ACROSS THE SOUTHERN AND CENTRAL SECTIONS OF THE STATE
OVERNIGHT. ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY
AFTERNOON INTO TUESDAY...WITH LOW WIND CHILLS TUESDAY MORNING. A
COLD FRONT MOVING THROUGH WEDNESDAY WILL BE ACCOMPANIED BY SOME
LIGHT SNOW...MAINLY IN THE NORTHWESTERN HALF OF THE STATE.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
BANDS OF MODERATE TO HEAVY SNOW MOVED QUICKLY ACROSS THE REGION
SINCE 3 PM. HEAVIEST BANDS ACROSS THE NORTHERN TIER NOW...BUT
WITH LOW TRACKING TOWARD PA...EXPECT MORE HEAVY BANDS THIS
EVENING.

ACROSS THE SE...JUST A BRIEF PERIOD OF SNOW SO FAR AT LNS. THIS
FITS GOOD WITH THE CURRENT PACKAGE.

ACROSS THE FAR SOUTH...RADAR RETURNS NOW WEAK...LITTLE SNOW HAS
BEEN REPORTED IN THIS AREA. BASED ON THIS AND MODEL DATA...EXPECT
SOME PATCHY MIXED PCPN TO START TO MIX IN ACROSS THIS AREA THIS
EVENING.

WILL KEEP CURRENT WARNINGS AND ADVISORIES FOR NOW.

WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED.

EARLIER DISCUSSION BELOW.

PRETTY SOLID BAND OF WAA SNOW IS PUSHING THROUGH WRN PA BUT NOT
MUCH BEHIND IT. MESO MODELS HAVE BEEN PLAYING THAT BREAK UP FOR A
LITTLE WHILE...AND IT LOOKS LIKE IT IS COMING TO FRUITION. THIS
WILL YIELD A 3-4 HOUR BREAK IN THE SNOW FOR MOST PLACES. WHILE IT
HAS BEEN SNOWING ALL DAY OUT THE WINDOW...IT STILL REALLY HAS NOT
STARTED STICKING TO ANYTHING. THIS APPEARS TO BE THE CASE ALMOST
EVERYWHERE IN THE CWA JUDGING BY WEB CAMS. BUT THE HIGHER ELEVS OF
THE LAURELS SHOULD BE GETTING WHITE ANY TIME NOW. WILL JUST WORK
THE POPS AROUND TO TRY TO SHOW THAT LITTLE BREAK...BUT IT IS SUCH
A SMALL-SCALE FEATURE THAT IT MAY JUST END UP WASHING OUT IN THE
BIGGER PICTURE. TEMPS DANCING AROUND 32F IN THE CENTRAL COS BUT
WELL INTO THE M30S IN THE SE. PRECIP THERE WILL BE VERY LIGHT
UNTIL MUCH LATER/THIS EVENING. SO...P-TYPE WILL BE DIFFICULT TO
PIN DOWN. CERTAINLY IF IT DECIDES TO SNOW HEAVILY...IT WILL BE
SNOW FOR THAT TIME...BUT WILL LIKELY BE A MIX WHEN LIGHT IN THE
S/SE. TEMPS MOVE LITTLE ALL EVENING...BUT WILL PROBABLY COOL JUST
A LITTLE WITH WET BULBING. DEWPOINTS ALREADY RISING SOME LOCALLY.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE BEST PERIOD OF SNOW CONTINUES TO LOOK LIKE IT WILL BE BETWEEN
00-09Z WITH THE WORST OF IT ACROSS THE NRN HALF OF THE AREA. THE
WARM AIR ALOFT LOOKS TO MAKE IN-ROADS ALL THE WAY TO I-80 BY
SUNRISE MONDAY. THUS...THE ICING POTENTIAL IS STILL THERE. SO
WHILE THE SNOW AMOUNTS - ESPECIALLY IF YOU ONLY MEASURE IN THE
MORNING - WILL BE LOWER THAN PREVIOUSLY ADVERTISED IN THE SRN HALF
OF THE AREA...THERE IS STILL SOME /WEAK/ JUSTIFICATION FOR HOLDING
ONTO THE WARNING ALONG THE RTE 22 CORRIDOR...FOR NOW.

THE QPF IS A MIXED-BAG OF SIGNALS RIGHT NOW. GFS AND EURO ARE
HOLDING ONTO 0.80 OR MORE IN THE NRN HALF OF THE AREA...WITH ONLY
REAL SNOW THERE. THE NAM AND THE SREF MEAN TOTALS THERE ARE ONLY
ABOUT 0.50. WILL CONTINUE WITH THE PARTY LINE OF 8-10 FOR A STORM
TOTAL...BUT REWORKED THE NUMBERS DOWN BARELY AN INCH ON THE WHOLE
SO THE TERRIBLE DARK BLUE OF 10-14 DOES NOT HIT PEOPLE IN THE
FACE. AGAIN...JUST HALF AN INCH TO AN INCH OF A DOWNWARD MOVE ON
THE SNOW. THIS IS DUE TO THE RELATIVELY HIGH UNCERTAINTY AT THIS
RANGE. STILL LOOKS LIKE A SOLID WARNING ANY WAY YOU SLICE IT UP
FOR OUR ENTIRE NRN HALF. SOME PRETTY WICKED SF RATES WILL BE HAD
OVERNIGHT AND VERY EARLY MONDAY IN THE NORTH AND PERHAPS AS FAR S
AS STATE COLLEGE AND SUNBURY BUT MOST LIKELY - THE HEAVIEST SNOW
WILL BE JUST TO THE NORTH OF THOSE TWO CITIES.

PRECIP CUTS OFF PRETTY QUICKLY AFTER 12Z/14Z IN THE CENTRAL COS.
THE EAST MAY SEE PRECIP LINGER INTO THE MID MORNING AS THE COLD
AIR MOVES IN AND TEMPS DROP. AFTER WHAT MAY ONLY BE A BRIEF
BREAK...THE NW WINDS WILL UPSLOPE INTO THE ALLEGHENIES AND
LAURELS. CAA WILL CREATE NUMEROUS SHSN OVER THE WRN HIGH TERRAIN
AND FLURRIES ELSEWHERE. THERE MAY EVEN BE SOME DECENT SHSN AS THE
PRECIP ENDS IN THE SERN THIRD OF THE AREA. YET ANOTHER REASON TO
NOT MONKEY WITH THE WARNINGS/ADVYS JUST YET. IT COULD BE A MESSY
COMMUTE FOR GROUNDHOG MORNING. WINDS WILL GET STRONG AND RATHER
GUSTY - ESP ON THE HILL TOPS AND IN THE SERN THIRD/DOWNSLOPE AREAS
CLOSEST TO THE DEEPENING LOW MOVING OFF THE COAST.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS POSSIBLY NEEDING A WIND CHILL ADVISORY /-15F/
MON NIGHT INTO EARLY TUE.

ENSEMBLE MEAN 5H PATTERN SHOWS AN ALBERTA CLIPPER DIVING SE INTO
THE REGION WED/THU. ALL MED RANGE GUIDANCE TRACKS ASSOC SFC LOW
NORTH OF THE STATE EARLY WED...LIKELY PRODUCING A BIT OF LGT SNOW
ACROSS NORTHERN PA. A WEAK LOW ON TRAILING COLD FRONT COULD
SUPPORT SOME LINGERING LGT SNOW ACROSS THE REGION /MAINLY
ALLEGHENIES/ INTO EARLY THURSDAY.

MODERATING TEMPS AHEAD OF CLIPPER COULD RESULT IN A DAY OF NEAR
NORMAL HIGHS WEDNESDAY. HOWEVER...A REINFORCING SHOT OF ARCTIC
AIR LOOKS NEARLY CERTAIN BEHIND CLIPPER LATE THIS WEEK.

NO RESPITE FROM THE BLW NORMAL TEMPS IN THE EXTENDED...AS LATEST
MED RANGE GUIDANCE MAINTAINS UPPER LVL TROF AXIS ACROSS THE
NORTHEAST CONUS.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 17Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV/KIPT BTWN 19Z-21Z. ACROSS THE
SOUTHEAST COUNTIES...LATEST MDL DATA SUGGESTS A BAND OF LGT
SNOW/VIS REDUCTIONS COULD COME THROUGH BTWN 22Z-01Z AT KMDT/KLNS.
HOWEVER...CONFIDENCE IN IFR CONDS WILL INCREASE MARKEDLY AT
KMDT/KLNS BTWN 03Z-06Z...AS HEAVIEST SNOW ARRIVES.

WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. MARGINAL LLWS REMAINS
A POSSIBILITY LATE TONIGHT ACROSS SOUTHERN PA...AS CORE OF STRONG
WINDS ALOFT SLIDES ACROSS THE AREA. HOWEVER...LATEST MODEL
SOUNDINGS SUGGEST MOST PLACES WILL REMAIN JUST BLW CRITERIA.

MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS. FOCUS WILL
SHIFT TOWARD STRONG GUSTY WINDS MON PM. GUSTS TO ARND 40KTS ARE
POSSIBLE MON AFTN AND EVENING...AS STRENGTHENING STORM SYSTEM
PASSES EAST OF PA.

OUTLOOK...

MON...AM RAIN/SNOW AND LOW CIGS. PM GUSTY NW WINDS.

TUE...NO SIG WX EXPECTED.

WED...AM LGT SNOW POSSIBLE NW MTNS.

THU...AM LGT SNOW POSSIBLE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/MARTIN
SHORT TERM...DANGELO
LONG TERM...FITZGERALD
AVIATION...FITZGERALD



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