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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 130605
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
205 AM EDT THU MAR 13 2014

.SYNOPSIS...
AN INTENSE LATE WINTER STORM WILL CONTINUE TO MOVE INTO SOUTHERN
NEW ENGLAND OVERNIGHT...TO BE OVER DOWN-EAST MAINE BY THURSDAY
MORNING. TEMPERATURES WILL PLUMMET TONIGHT INTO EARLY THURSDAY AS
STRONG AND GUSTY NORTHWEST WINDS IN THE WAKE OF OUR DEPARTING
STORM SWEEP ACROSS THE REGION. THE COLD BLAST WILL BE SHORT-LIVED
WITH A NICE REBOUND IN TEMPERATURES ON FRIDAY. A SERIES OF
CANADIAN FRONTAL PASSAGES OVER THE WEEKEND WILL SEND TEMPERATURES
BACK TO SEASONABLY COLD LEVELS INTO EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MESO ANAL SHOWS THE DEEPENING SURFACE LOW MOVING OVER NORTHERN
NJ/SERN NY TOWARD NEW ENGLAND. A LARGE ISALLOBARIC PRESSURE RISE
COUPLET OF 20MB/6HR IS MOVING INTO SWRN PA...PROVIDING A VERY
BLUSTERY EVENING. HAVE DECIDED TO EXPAND THE WIND ADVISORY BASED
ON THE ROBUST PRESSURE RISES AND SCATTERED REPORTS OF STRONG WIND
GUSTS FROM SOCIAL MEDIA. A PRESSURE RISE COUPLET OF THIS MAGNITUDE
IS GENERALLY STRONG ENOUGH TO PROVIDE WARNING STRENGTH WIND
GUSTS...HOWEVER AT LEAST TWO FACTORS KEEPING WIND GUSTS AT
RELATIVELY MODEST LEVELS ARE THE WIND SPEEDS FROM 850 THROUGH
700MB AVERAGING GENERALLY UNDER 50KT...AND A RESPECTABLE AMOUNT
OF DIRECTIONAL SHEAR THROUGH THAT LAYER LASTING WELL INTO THE
EVENING. BY THE TIME WE GET FAVORABLE ALIGNMENT OF WIND DIRECTIONS
THROUGH A DEEP LAYER...WIND SPEEDS ARE FCST TO BE ONLY IN THE
35-45KT RANGE UP THROUGH 700MB.

HAVE ALSO DROPPED ALL SNOW ADVISORY HEADLINES GIVEN THE RAPID
DRYING AND DROP OFF TO JUST SCATTERED LIGHT SNOW SHOWERS BEHIND
THE DEPARTING STORM. STILL SOME RAIN SHOWERS OVER THE FAR SE BUT
TEMPS ARE FALLING FAST THERE.

THE BIG PICTURE REMAINS LARGELY UNCHANGED WITH THE PRECIP
EXPECTED TO CONTINUE TO WIND DOWN OVER THE AREA DURING THE EVENING
HOURS AS THE LOW CONTINUES TO DEEPEN AND RACE TOWARD THE NEW
ENGLAND COASTAL WATERS.

FOR THE REST OF THE OVERNIGHT...THE BIGGEST ISSUES WILL BE THE
COLD AND WIND. RARE MID-MARCH SUB ZERO READINGS EXPECTED OVER MY
FAR NRN TIER...WHILE SINGLE DIGITS AND TEENS WILL BE COMMONPLACE
FURTHER SOUTH. GUSTY WINDS WILL BRING WIND CHILL VALUES DOWN TO
BETWEEN 15 AND 20 BELOW ZERO OVER THE HIGH TERRAIN OF THE WEST AND
NORTH WHERE A WIND CHILL ADVISORY IS IN EFFECT.

ANOTHER CONCERN WILL BE FOR RAPID REFREEZE OF ROADS AND WALKWAYS
AS TEMPERATURES PLUMMET THIS EVENING.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
COLD WINDY START....BUNDLE UP ON WAY OUT IN THE MORNING.

WINDS SHOULD DIMINISH LATE MORNING INTO THE MID AFTERNOON HOURS.
VERY WINDY VERY COLD.

NO SIGNIFICANT PRECIPITATION.

JUST A COLD WINTRY DAY WITH A SHOT AT SOME NEAR RECORD LOW HIGH
TEMPERATURES IF TEMPERATURES DO NOT BEGIN TO RISE BEFORE SUNRISE
ON FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE GOOD NEWS IS THAT THE COLD BLAST WILL BE SHORT-LIVED...WITH A
RAPID MODERATION OCCURRING ON FRIDAY. TEMPS SHOULD EVEN LEVEL OFF
OR GO NON-DIURNAL LATE THU NGT INTO THE PREDAWN HOURS FRI MORNING
ESPECIALLY ACRS THE WRN MTNS. SOME OF THE SHELTERED VALLEYS IN THE
ERN PART OF THE CWA MAY STILL DECOUPLE TOWARD DAYBREAK.

BREEZY SW RETURN FLOW IN ADVANCE OF NRN CLIPPER SFC LOW TRACKING
ACRS THE UPPER GREAT LAKES/SRN ONTARIO AND DOWNSLOPING EFFECTS
SHOULD HELP TO BOOST TEMPS INTO THE LOW/MID 40S NORTH AND LOW/MID
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. 12Z MODEL GUIDANCE INDICATES
SOME LGT SHOWER ACTIVITY ALONG THE COLD FRONT...WITH THE HIGHEST
POPS BASED ON CONSENSUS BLEND ACRS NWRN SXNS BTWN 00-06Z SAT

GFS AND EC ENSEMBLES SHOW A COLD UPPER-LEVEL TROUGH REMAINING A
FIXTURE OVER ERN CANADA AND THE NERN CONUS...WITH RIDGING ALONG
THE WEST COAST POSSIBLY BREAKING DOWN INTO EARLY NEXT WEEK. AT
THE SFC...A MODESTLY STRONG/1040MB HIGH PUSHING SEWD FROM THE
UPPER MIDWEST/WRN GRT LKS SHOULD DIRECT COLDER AIR INTO THE
REGION BEHIND A REINFORCING CANADIAN FROPA ON SUNDAY...WITH TEMPS
TRENDING LOWER ON DAY 5/6.

THE KEY FEATURE OF INTEREST WILL BE A SFC WAVE MIGRATING NEWD FROM
THE TX/LA GULF COAST ACRS THE SOUTHEAST TO THE OUTER BANKS BY 12Z
MONDAY. THE 12Z GFS TRENDED IN THE DIRECTION OF THE 00/12Z ECMWF
WHICH HAS INDICATED A DEEPER AND `MORE DEFINED` LOW FOR THE PAST
FOUR CYCLES. THE 12Z UKMET IS VERY CLOSE TO THE ECMWF AND JUST A
TAD WEAKER. THE GFS AND ESPECIALLY THE GEFS ARE MORE SUPPRESSED VS
THEIR NON-NCEP COUNTERPARTS. REGARDLESS OF THE SOLN CHOICE...THE
MAIN FCST CHALLENGE WILL INITIALLY BE THE TRACK FOLLOWED BY POTNL
RAIN/SNOW TRANSITION LINE ON NW PERIPHERY OF THE ASSOCD PCPN
SHIELD. FINAL POPS WERE NUDGED IN THE DIRECTION OF THE ECMWF
BRINGING CHC MENTIONS OF RAIN/SNOW TO MUCH OF SOUTH-CENTRAL PA
SUN NGT INTO MONDAY.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A STRENGTHENING STORM SYSTEM ON THE NEW ENG COAST WILL CREATE
STRONG...GUSTY NW WINDS ACROSS MOST OF CENTRAL PA THIS MORNING.
BUFKIT SOUNDINGS SUPPORT FREQUENT GUSTS TO ARND 30KTS. THE OTHER
AVIATION CONCERN IN THE NEAR TERM WILL BE OCNL LOW VSBYS AT KJST
IN LIGHT SNOW...THE RESULT OF UPSLOPE FLOW AND AIDED BY PASSAGE
OF AN UPPER LVL DISTURBANCE. NAM/RAP MDL OUTPUT INDICATES MUCH
DRIER AIR WILL OVERSPREAD THE AREA BY ARND 08Z...ENDING THE THREAT
OF SIG VIS REDUCTIONS AT KJST.

SOME MVFR CIGS COULD LINGER UNTIL ARND 12Z AT KBFD AND KJST...THE
RESULT OF LINGERING LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN.
OTHERWISE...ARRIVAL OF DRY AIR MASS SHOULD ENSURE WIDESPREAD VFR
CONDS DURING THE DAYLIGHT HOURS OF THURSDAY. MAIN AVIATION CONCERN
WILL BE THE ACTIVE NW WIND...WHICH SHOULD CONTINUE TO GUST TO NR
30KTS FOR MUCH OF THE DAY.

HIGH PRESSURE WILL BUILD INTO THE STATE TONIGHT...BRINGING
DIMINISHING WINDS AND VFR FLYING CONDS.

OUTLOOK...
FRI...SHRA/REDUCED CIGS POSS FRI NITE AT KBFD.
SAT...AM -SHRASN/REDUCED CIGS POSS W MTNS.
SUN...NO SIG WX EXPECTED.
MON...SNOW POSSIBLE SOUTHERN PA.

&&

.HYDROLOGY...
WITH RAINFALL TODAY...WE EXPECT MINOR TO MODERATE RISES ON RIVERS
AND STREAMS OVER THE NEXT SEVERAL DAYS. THE MOST SIGNIFICANT
RISES ARE EXPECTED ON THE MAIN STEM SUSQ.

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. ICE JAMS ARE POSSIBLE BUT NOT PREDICTABLE.
MONITOR WATER LEVELS CLOSELY FOR THE REST OF THE WEEK. SOME MINOR
FLOODING/PONDING OF WATER IS POSSIBLE IN AREAS WHERE SNOW AND ICE
BLOCK DRAINS AND SLOW RUN OFF.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON EDT TODAY FOR PAZ012-017>019-024>028-
033>036-041-042-045-046-049>053-056>059-063>066.
WIND CHILL ADVISORY UNTIL NOON EDT TODAY FOR PAZ004>006-
010>012-017-018-024-033-037-041-042.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
HYDROLOGY...