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000
FXUS61 KCTP 120825
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
425 AM EDT WED MAR 12 2014

.SYNOPSIS...
A STRONG LATE-WINTER STORM WILL IMPACT THE AREA TODAY...FOLLOWED
BY COLD AND BLUSTERY CONDITIONS WITH WELL-BELOW NORMAL
TEMPERATURES FOR THURSDAY. TEMPERATURES WILL REBOUND TO NEAR
SEASONAL LEVELS FRIDAY INTO THE WEEKEND...AHEAD OF A FRONTAL
SYSTEM PUSHING SOUTHEAST FROM THE GREAT LAKES. THIS FRONT MAY
PRODUCE SOME RAIN OR SNOW SHOWERS ON SATURDAY.

&&

.NEAR TERM /THROUGH TODAY/...
LOTS OF ACTION THIS PERIOD WITH RAIN ALREADY STRAFING THE NRN
BORDER. MORE RADAR RETURN OVER CENTRAL OH ARE MOVING QUICKLY THIS
WAY. THE FRONTAL BOUNDARY IS LAID OUT FROM PHL ALONG THE MASON-
DIXON LINE TO KDAY AND KIND. SFC LOW IS CONSOLIDATING OVER THE
WABASH AND IS ABOUT 995MB AT 08Z. GUSTS ON THE BACKSIDE OF THE LOW
ARE ALREADY INTO THE 20S AND 30S. STRONG WARM ADVECTION OVER THE
STATE IS KEEPING TEMPS IN THE 40S...EXCEPT ALONG THE NY BORDER
WITH 30S NUDGING IN ON LIGHT N/NE WIND. DEWPOINTS HAVE RISEN
SLIGHTLY AND ARE GENERALLY IN THE 30S. WET BULBS IN THE NRN MTS
WILL STILL LIKELY YIELD RAIN AT FIRST...BUT NAM/RUC PROFILES DO
MAKE IT MAINLY ISOTHERMAL FOR THE LOWEST FEW KFT THIS MORNING.
THUS...IT COULD BE ANYTHING FOR THE FIRST FEW HOURS. THEN...IT
GETS COLD AS PRECIP INTENSITY SHOULD PICK UP LATER THIS MORNING.

COUPLED JET STRUCTURE STILL LOOKING LIKE A CLASSIC EXAMPLE...AND
INTERACTION SHOULD DROP THE PRESSURE OF THE MAIN SFC LOW AS IT
TRAVERSES THE PA TURNPIKE THROUGH THE LATE MORNING AND INTO THE
EVENING. IT WILL TAKE IT/S OWN TOLL BY BRINGING MODERATE TO HEAVY
RAIN TO MOST OF THE STATE TODAY...BUT RUC POINTS TO A LOWERING OF
THE LI/S AND TRUE INSTABILITY ACROSS THE SRN THIRD/HALF OF THE
AREA LATE THIS AFTN AND EARLY THIS EVENING. SPC HAS A SLIGHT RISK
AREA COVERING THAT ROUGH AREA...AND HAVE ADDED GUSTY WIND WORDING
TO THE GRIDS FOR THAT TIME FRAME - RIGHT AS THE LOW PASSES
OVERHEAD.

THE SNOW WILL BE HEAVIEST IN THE N IN THE MID DAY AND AFTERNOON.
QPF IS IMPRESSIVE BUT MAY BE TAINTED BY CONVECTIVE FEEDBACK ON
SOME MDL SOLUTIONS. STILL...THE OVERALL PICTURE OF 1-1.25 INCHES N
AND 0.5-0.75 S IS LOOKING GOOD. THUS...WITH THE BULK OF THE PRECIP
FALLING AS SNOW ALONG THE NY BORDER...ESP WARREN AND MCKEAN
COS...THE GOING STORM TOTALS LOOK SOLID WITH 8-10 THERE. THE SNOW
ACCUMULATION GRADIENT WILL BE TIGHT - ESP DURING THE DAYTIME -
WITH ALMOST NO SNOW SOUTH OF ROUTE 6 IN THE MORNING AND NOT FAR S
OF THE NRN TIER OF COS THIS AFTERNOON...DESPITE FALLING TEMPS. THE
WARM AIR ALOFT IS JUST TOO MUCH AND SUN ANGLE NOW HIGH ENOUGH TO
MAKE THE SNOW FORECAST A REAL TROUBLE. AS THE TEMPS GET COLD THIS
AFTERNOON/EVENING...THERE IS A DANGER OF THE RAIN-WET ROADS
BECOMING ICY QUICKLY AS THE PRECIP TYPE CHANGE OVER OCCURS FROM N
TO S.

THE SFC LOW SHOULD CONTINUE TO DEEPEN AS IT MOVES INTO NJ THIS
EVENING. THE PRECIP SHOULD TAPER RATHER ABRUPTLY IN THE CENTRAL
AND SERN ZONES THIS EVENING. BY 01Z...LITTLE IF ANY PRECIP IS LEFT
THERE. SO BY THE TIME THE PROFILES GET COLD ENOUGH FOR SNOW
THERE...IT SHOULD BE ENDING. WILL KEEP ALL SNOW TOTALS AND TIMING
AS IS WITH JUST MINOR EDITING.

THE WINDS WILL GET STRONG/GUSTY IN THE NORTHERN MTS LATE THIS
MORNING...BUT THE PASSAGE OF THE LOW AND ANY STORMS IN THE SOUTH
WILL KICK THEM UP THERE IN THE EARLY EVENING.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
THE SNOW SHOULD BE TAPERING OFF TO SCT SHSN IN THE EVENING ACROSS
THE NRN AND WRN MTS...BUT WILL KEEP CURRENT TIMING ON WSW FLAGS TO
ALLOW FOR LINGERING SNOW AND BLOWING SNOW PROBLEMS. LOW PRESSURE
CONTINUES TO DEEPEN AS IT MOVES AWAY AND CREATES WIND PROBLEMS
FOR THE LOCAL AREA. THE WINDS WILL GET FASTER ACROSS THE SRN HALF OF
THE AREA TONIGHT AND SUSTAINED SPEEDS AND GUSTS MAY BOTH REACH
WIND ADVY CRITERIA. HAVE THUS POSTED AN ADVY FOR THOSE AREAS
THROUGH THURSDAY NOON. WHILE WINDS WILL BE STRONGEST THERE IN THE
SOUTH...THE TEMPS DO NOT DROP FAST ENOUGH TO GET WIND CHILLS BELOW
ADVY THE LINE OF -15F. WILL ISSUE AN ADVY FOR THE NW HALF AS THE
CRITERIA SHOULD EASILY BE MET. IF THE TIMING OF THE SNOW WERE TO
BE ENDING LATER THURS MORNING...WE MAY HAVE BEEN ABLE TO FORGO A
WIND CHILL ADVY AND JUST WRAP IT INTO THE WSW. BUT THE CHILLS WILL
LAST MUCH LONGER THAN THE ACCUMULATING SNOW...THROUGH THE ENTIRE
MORNING...WHEREAS THE SNOW SHOULD BE VIRTUALLY DONE BY 2 AM/06Z.

THURSDAY SHOULD BE ONE OF THE COLDEST WE HAVE SEEN YET THIS
WINTER. THIS IS EVEN MORE IMPRESSIVE GIVEN THE MID-MARCH TIMING.
8H TEMPS DROP INTO THE MINUS 20S C IN THE MORNING...BUT THIS
NASTINESS GETS DRAGGED THROUGH THE AREA RATHER QUICKLY DUE TO THE
SHARPNESS OF THE TROUGH AND PROGRESSIVE NATURE OF THE FLOW ALOFT.

LITTLE BREAKS IN THE CLOUDS OVER THE S/SE OVERNIGHT SHOULD LEAD
TO GREATER BREAKS IN THE MORNING OVER THE SRN TIER AND SERN AREAS
COULD CLEAR UP TOTALLY BY THE END OF THE MORNING. WILL PLAY IT
MORE-CLOUDY THAN THAT FOR NOW. EVEN WITH THE SUN AND
DOWNSLOPE...THE MAXES IN THE SE WILL ONLY BE IN THE M/U20S. THAT
WOULD BE WELCOME IN THE NRN TIER WHERE MAXES MAY NOT MAKE IT INTO
THE TWEENS /10-12F/.

THE GUSTY WINDS WILL GRADUALLY SUBSIDE DURING THE DAY THURS WITH
DAYTIME HIGHS 25-30F BELOW NORMAL. DAILY RECORD LOW/MINI-MAXES ARE
IN JEOPARDY. IN ADDITION...LOW TEMPS THURS MORNING ACRS WRN PA
WILL ALSO BE NEAR DAILY RECORD. SUFFICE IT TO SAY...IT MAY NOT BE
THIS COLD AGAIN /ESPECIALLY DURING THE DAYLIGHT HOURS/ UNTIL NEXT
WINTER.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE GOOD NEWS IS THAT THE COLD BLAST WILL BE SHORT-LIVED...WITH A
RAPID MODERATION OCCURRING ON FRIDAY. BREEZY SW RETURN FLOW IN
ADVANCE OF NRN CLIPPER SFC LOW TRACKING ACRS THE UPPER GREAT LAKES
AND DOWNSLOPING SHOULD HELP TO BOOST TEMPS INTO THE 40S NORTH AND
50S SOUTH. THE MODELS TURN THE LOW TO THE NORTHEAST UP THE ST.
LAWRENCE VLY ON DAY 5/SAT...DRAGGING A TRAILING/WEAK COLD FRONT
ACRS THE NORTHEAST AND MID-ATL STATES. MODEL CONSENSUS INDICATES
SOME LGT PCPN IS POSSIBLE WITH CHC POPS AS THE FRONT SHIFTS SEWD
ACRS THE CWA.

GEFS/EC ENSEMBLE MEANS SHOW THE LARGE SCALE PATTERN REVERTING BACK
TO A WRN RIDGE/ERN TROUGH CONFIGURATION INTO EARLY NEXT WEEK. THIS
HAS BEEN THE FAVORED/PREVAILING FLOW REGIME THIS WINTER...WITH A
COLD POLAR VORTEX OVER EASTERN CANADA. A STRONG SFC HIGH PUSHING
SEWD FROM THE UPPER MS VLY SHOULD DIRECT COLDER AIR INTO THE REGION
BEHIND A REINFORCING FROPA ON SUNDAY...WITH TEMPS LKLY TRENDING
LOWER BY DAY 7/MON. THE NON-NCEP OPRNL MODELS /12Z CMC AND ECMWF/
ARE MORE BULLISH ON CYCLOGENESIS INVOF THE GULF STREAM JUST EAST
OF THE CAROLINAS...WITH THE NW EDGE OF POTNL PCPN SHIELD POSSIBLY
REACHING SRN/SERN PA ON ST. PATRICK`S DAY. CONFIDENCE IS LOW GIVEN
THE LARGE SPREAD BTWN THE GFS AND ECMWF/CMC. SOMETHING TO MONITOR
IN THE DAYS TO COME.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS NOTED BELOW...VFR CONDITIONS WILL PREVAIL FOR A WHILE
LONGER...MAIN AREA OF RAIN NORTH PA BORDER.

06Z TAFS SENT.

EARLIER DISCUSSION BELOW.

VFR CONDITIONS WILL CONTINUE THROUGH THE FIRST HALF OF THE
OVERNIGHT PERIOD.

SAT SHOWS LOW TO MID CLOUDS STREAMING THROUGH WITH CEILINGS AT
MOST TAF SITES. THESE WILL SLOWLY LOWER AS THE NIGHT CONTINUES AND
RESTRICTIONS WILL ARRIVE AS LIGHT RAIN /AND POSS SNOW NORTH/
AROUND 06Z IN THE NW...AND HEAVIER AREA OF PRECIP ARRIVING STARTING
AROUND 12Z WED. BULK OF HEAVIER PRECIPITATION WILL BE BETWEEN LATE
WED MORNING AND EARLY WEDNESDAY EVENING.

WIDESPREAD ADVERSE CONDITIONS ON WED...WITH RAIN ACROSS MUCH OF
THE AREA...SNOW ACROSS THE FAR NORTH...AND SOME RISK OF STRONG
TSTMS NEAR THE MD BORDER. BY AFTERNOON...STRONG WIND FIELDS WILL
BRING INCREASING NORTHERLY FLOW...LLWS...AND GUSTY WINDS UP TO 40
MPH. THESE CONTINUE THROUGH THE FIRST HALF OF THU AS VERY COLD AIR
STAMPEDES INTO PA. WITH STRONG STORM DYNAMICS...CONCERN EXISTS FOR
A BURST OF HEAVY WET CONVECTIVE SNOW /AND POSS THUNDER/ NEAR THE
CENTER OF THE LOW WED/WED NIGHT.

HAVE UPDATED TAFS WITH LLWS AT ALL CENTRAL AND WESTERN TAF SITES
FROM 16Z TO AROUND 22Z.

OUTLOOK...
WED...WIDESPREAD MVFR- IFR
RESTRICTIONS IN RAIN AND SNOW. STRONG N/NW WINDS DEVELOPING. LLWS.
THU...STRONG/GUSTY N/NW WINDS...GRADUALLY DIMINISHING IN THE
AFTERNOON. FRI-SUN...NO SIG WX EXPECTED.

&&

.HYDROLOGY...
WITH WARMER TEMPERATURES RAINFALL TODAY...WE EXPECT MODERATE
RISES ON RIVERS AND STREAMS. THERE IS STILL ENOUGH ICE IN SPOTS TO
LEAD TO ICE JAMS...THOUGH SIGNIFICANT DECAY HAS OCCURRED AT MANY
LOCATIONS DUE TO THE RECENTLY WARM WEATHER. ANY ICE JAMS WILL BE
ISOLATED IN NATURE. MONITOR WATER LEVELS CLOSELY FOR THE REST OF
THE WEEK.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 8 AM THIS MORNING TO 8 AM EDT
THURSDAY FOR PAZ004-005.
WINTER WEATHER ADVISORY FROM 8 AM THIS MORNING TO 8 AM EDT
THURSDAY FOR PAZ006-010-011-037.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EDT
THURSDAY FOR PAZ017-024-033.

&&

$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...CERU/MARTIN/RXR
HYDROLOGY...CTP