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000
FXUS61 KCTP 100529
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
129 AM EDT MON MAR 10 2014

.SYNOPSIS...

TWO CLIPPER TYPE SYSTEMS WILL TRACK RAPIDLY THROUGH UPSTATE NEW
YORK AND NORTHERN NEW ENGLAND TODAY AND TUESDAY. A LATE WINTER
STORM SYSTEM WILL IMPACT THE AREA ON WEDNESDAY...FOLLOWED BY COLD
AND BLUSTERY CONDITIONS FOR THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...

SATELLITE SHOWS AMPLE MID/HIGH CLOUDINESS TO BRING MOSTLY CLOUDY
SKIES WHICH WILL CONTINUE OVERNIGHT. FRESHENING SOUTHWEST BREEZE
ON THE SOUTH SIDE OF A WEAK CLIPPER LOW PASSING TO OUR NORTH WILL
ADVECT MILDER AIR IN AND RESULT IN OVERNIGHT TEMPS NEARLY STEADY
ACROSS THE WEST OR PERHAPS EVEN A RISE TOWARDS MORNING.

SHELTERED VALLEYS ACROSS THE MIDDLE TO LOWER SUSQUEHANNA RIVER
VALLEY WILL BE COLDEST... GENERALLY IN THE MID TO UPPER 20S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
SMALL SCALE SHORTWAVE DISTURBANCE WILL SHIFT EWD FROM LK HURON
ACRS SRN ONTARIO AND INTO UPSTATE NEW YORK EARLY MONDAY. MODEL
CONSENSUS CONTINUES TO SUPPORT SOME SCT LIGHT SNOW/RAIN SHOWERS
EARLY TOMORROW/PRIOR TO 18Z MAINLY NORTH OF I80. THE AFTN SHOULD
FEATURE IMPROVING CONDS WITH TEMPS WARMING NICELY INTO THE LOW-
MID 40S NORTH TO LOW-MID 50S SOUTH. DEPENDING ON CLOUD
TRENDS...COULD SEE WARMER MAX TEMPS ESPECIALLY OVER SRN PA GIVEN
DOWNSLOPE FLOW. DRY/QUIET WX CONTINUES INTO MON NGT WITH RELATIVELY
MILD LOWS RANGING FROM AROUND 30F IN THE NORTH TO NEAR 40F IN THE
SOUTH.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS IN QUITE GOOD AGREEMENT ON OVERALL PATTERN INTO THE
WEEKEND...PROVIDING A HIGHER CONFIDENCE FORECAST ON MAIN WEATHER
FEATURES.

CLIPPER SYSTEM SLIDES BY MON NIGHT...SAGGING A WEAK FRONTAL
BOUNDARY SOUTHWARD ACROSS CWA. BUT LOW LEVEL FLOW BEHIND IT
RUNNING PARALLEL TO ISOTHERMS WILL KEEP MILDER TEMPS IN PLACE
THROUGH A FAIRLY NONDESCRIPT DAY. MID-HIGH CLOUDS WILL BEGIN TO
INCREASE AND THICKEN THROUGH THE DAY AS APPROACHING STORM SYSTEM
GETS ORGANIZED OVER THE SOUTHERN PLAINS.

THIS SYSTEM...CURRENTLY AN UPPER WAVE OFF THE WEST COAST OF
CANADA...WILL DROP SE ACROSS THE NW U.S AND THROUGH THE ROCKIES.
AS TROUGH DEEPENS...SURFACE LOW WILL FORM BY THE TIME IT DROPS
INTO THE SOUTHERN PLAINS /KS-OK/. A SECOND WAVE DROPPING OUT OF
THE CANADIAN ROCKIES WILL FURTHER SHARPEN AND DEEPEN THE TROUGH AS
IT DIGS TOWARD THE OHIO VALLEY BY WED...DRAGGING THE SURFACE LOW
EASTWARD THROUGH THE TENN VALLEY...TRACKING JUST SOUTH OF THE
MASON/DIXON LINE AND THEN TOWARD NEW ENGLAND. AGAIN...LATEST MODEL
GUIDANCE VERY MUCH IN STEP WITH EACH OTHER...WITH GFS SPEED JUST A
SHADE FASTER THAN THE ECMWF. BOTH INDICATING A SLIGHTLY DEEPER LOW
THAN PREV RUNS. EVEN 850MB TEMP FIELDS BEGINNING TO MATCH BETTER
IN 12Z RUNS IN BOTH INITIAL PLACEMENT AND PROGRESSION OF COLDER
AIR ACROSS CWA ON BACK END OF STORM.

THIS SET UP HAS US STARTING OFF RATHER MILD...MAKING THE INITIAL
PRECIP TYPE LIKELY TO BE RAIN IN ALL BUT FAR NORTHERN COUNTIES.
LIGHT PRECIP WILL WORK INTO THE NW TUE NIGHT...WITH ONLY MINOR
IMPACTS. THE HEAVIEST PRECIP ARRIVES DURING THE DAY WED...WITH THE
COLDEST AIR REMAINING CONFINED TO MAINLY NORTHERN MTNS THROUGH THE
FIRST HALF OF THE DAY...THEN AS THE UPPER TROUGH AND SURFACE LOW
BEGIN TO DEEPEN AND MOVE EAST...COLDER AIR WILL BE DRAGGED DOWN
FROM THE NORTH BRINGING ABOUT A CHANGEOVER TO SNOW/SLEET FURTHER
SOUTH INTO MOST AREAS BUT EXTREME SE. AT THIS RANGE THOUGH...ITS
STILL A SOMEWHAT IRRESPONSIBLE CALL TO DRAW SPECIFIC LINES...BUT
IT IS BECOMING MORE LIKELY THAT NORTHWESTERN INTO PARTS OF
CENTRAL MTNS STAND A HIGH PROBABILITY OF RECEIVING A FAIRLY
PROLONGED PERIOD OF MODERATE TO EVEN HEAVY SNOW AS THE COLD AIR
SWEEPS IN WEDNESDAY INTO WED EVENING. WITH INHERENT UNCERTAINTY IN
THE FINE DETAILS AND THE FACT THAT THIS STORM IS STILL IN PERIOD 6
OF THE FORECAST...HAVE USED THE HAZARDOUS WEATHER OUTLOOK /HWOCTP/
PRODUCT TO HIGHLIGHT THE MIDWEEK WINTRY POTENTIAL.

QUITE COLD AIR /AROUND -20C/ DRIVES IN BEHIND THE EXITING LOW WED
NIGHT INTO THU...WITH BY FAR THE COLDEST DAY OF THE WEEK IN STORE.
TEMPS WILL AGAIN FALL TO WELL BELOW NORMAL...WITH HIGHS BELOW
FREEZING IN THE SOUTHEAST...AND STRUGGLING TO APPROACH 20F ACROSS
THE NORTHERN AND WESTERN HIGHER TERRAIN. COMBINED WITH A STIFF
BREEZE...WIND CHILLS BELOW ZERO WILL BE LIKELY ACROSS NW HALF OF
CWA FOR A DECENT PORTION OF THE DAY.

THE WELL-BELOW NORMAL COLD WILL BE SHORT-LIVED THOUGH...AS TEMPS
REBOUND DECENTLY FRI INTO SAT...BOUNCING BACK TO NEAR SEASONAL
NORMALS. HOWEVER THIS WINTERS DEFINING FEATURE...THE PERSISTENT
WEST COAST RIDGE...AGAIN RE-ESTABLISHES ITSELF HEADING INTO NEXT
WEEK. THIS WILL ALLOW FOR COOLER AIR TO FILTER BACK INTO THE
REGION IN PERSISTENT NW FLOW OVER PA...KEEPING TEMPS NEAR OR
SLIGHTLY BELOW NORMAL AND PREVENTING ANY KIND OF SIGNIFICANT WARM
UP. IT MAY ALSO SET THE STAGE FOR ANOTHER POTENTIAL LOW PRESSURE
SYSTEM IN THE SUN NIGHT-MON NIGHT TIME FRAME.

&&

.AVIATION /05Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE RIDGE OVER PENNSYLVANIA WILL PROVIDE A HIGH
CONFIDENCE OF VFR FLYING CONDS TONIGHT ACROSS CENTRAL PA. BIGGEST
AVIATION CONCERN WILL BE THE POSSIBILITY OF LLWS DEVELOPING IN
RESPONSE TO INCREASING WEST WINDS ALOFT. LATEST BUFKIT SOUNDINGS
SUGGEST LLWS CRITERIA WILL LIKELY BE MET BTWN 05Z-13Z OVER MUCH OF
THE AREA. STRONGER SFC WINDS ON THE RIDGE-TOP AT KJST AND LIGHTER
WINDS ALOFT OVR KMDT/KLNS WILL RESULT IN LESS CHANCE OF LLWS
CRITERIA AT THOSE LOCATIONS.

A WEAK LOW/UPPER LEVEL DISTURBANCE WILL TRACK SEWD ACRS THE AREA
LATE MON MORNING. THIS FEATURE SHOULD SUPPORT ISOLD-SCT -SHSN OVER
THE NRN AIRSPACE WITH MVFR CIGS POSSIBLE LATE AM AT KBFD. LOW VFR
CIGS AROUND 4KFT ARE LKLY ACROSS THE NORTHERN HALF OF THE STATE
INTO THE AFTN...WITH A LOW CHC OF MARGINAL RESTRICTIONS AT KBFD.

OUTLOOK...
TUE...AM LOW CIGS POSS W MTNS.
WED...MVFR-IFR RESTRICTIONS LIKELY IN RAIN OR SNOW. WINDY LATE.
THU...STRONG/GUSTY NNW WINDS POSSIBLE.
FRI...NO SIG WX EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...DEVOIR/LA CORTE
SHORT TERM...STEINBUGL
LONG TERM...LA CORTE/RXR
AVIATION...FITZGERALD