211
FXUS61 KCTP 161614
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1114 AM EST MON DEC 16 2024
SYNOPSIS
WITH ONE WINTER STORM DEPARTING AND THE NEXT RAIN MAKER ON THE
WAY THIS EVENING, MUCH OF TODAY WILL BE CLOUDY WITH DRIZZLE AND
PATCHY FOG. AFTER A PERIOD OF RAIN THIS EVENING INTO TONIGHT,
HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY INTO EARLY
WEDNESDAY. THEN A WEAK AREA OF LOW PRESSURE LIFTING OUT OF THE
OHIO VALLEY IS LIKELY TO PUSH INTO PENNSYLVANIA BY LATE
WEDNESDAY WITH ANOTHER PERIOD OF RAIN POSSIBLY ENDING AS SNOW.
NEAR TERM /UNTIL 8 PM THIS EVENING/
A WEAK RIDGE OF HIGH PRESSURE AND LIGHT WIND OVER CENTRAL PA
WILL DO LITTLE OR NOTHING TO IMPROVE THE WIDESPREAD LOW STRATUS
AND RIDGE SHROUDING FOG TODAY WITH ONLY SOME PATCHY LIGHT
DRIZZLE EXPECTED THROUGH THE MID AFTERNOON. LATER TODAY, ANOTHER
ROUND OF PRECIP WILL SPREAD ENE ACROSS THE REGION, BUT THIS
TIME THE PTYPE WILL BE EXCLUSIVELY LIQUID AS TEMPS AT THE SFC
AND ALOFT WILL BE A FEW TO SEVERAL DEG C ABOVE FREEZING.
THE LEADING EDGE OF THE RAIN REACHES A LINE FROM MERCERSBURG,
STATE COLLEGE AND COUDERSPORT BY SUNSET.
TEMPERATURES WILL BE STUCK IN THE 30S MOST OF THE DAY FOR THE
CENTRAL RIDGES AND VALLEYS, WITH THE WARMEST TEMPS (MID 40S)
FOUND IN THE LOWER SUSQ VALLEY AND THE WESTERN HIGHLANDS.
SHORT TERM /8 PM THIS EVENING THROUGH WEDNESDAY/
PERIODS OF RAIN WILL CONTINUE TONIGHT AS A WARM FRONT LIFTS
NORTH THROUGH THE REGION. MUCH OF THE STEADIER RAIN WILL BE ON
THE FRONT END OF THE SYSTEM EARLY THIS EVENING WHEN ISENTROPIC
ASCENT AND MOISTURE TRANSPORT ARE STRONGEST, WHILE ANY LINGERING
RAIN AFTER MIDNIGHT WILL LIKELY COME IN THE FORM OF SCATTERED
SHOWERS. TOTAL RAINFALL WILL LIKELY RANGE FROM 0.15-0.50 INCH.
HIGH PRESSURE BRIEFLY ATTEMPTS TO BUILD IN BEHIND A COLD FRONT
TUESDAY NIGHT INTO THE FIRST HALF OF WEDNESDAY, WHICH WILL KEEP
THE REGION MAINLY DRY. TUESDAY WILL BE THE WARMEST DAY OF THE
PERIOD WITH HIGHS IN THE 40S AND 50S.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
THE NEXT SYSTEM WILL BE MORE ENERGETIC WITH RAIN RETURNING TO
THE FORECAST WEDNESDAY AFTERNOON OR EVENING, AS A DEVELOPING
SURFACE LOW TRACKS OVER OR JUST EAST OF PENNSYLVANIA AND A
PERIOD OF STRONG ISENT LIFT SPREADS ACROSS THE REGION IN
ASSOCIATION WITH THE PASSAGE OF A SOUTHWESTERLY LLJ OF 55-65
KTS.
PRECIP WILL START OFF AS RAIN, BUT THE LATEST OPER MODELS AND
ENSEMBLES SUGGEST ENOUGH COULD AIR SHOULD MOVE IN FROM THE WEST
TO ALLOW FOR THE RAIN TO MIX WITH OR FULLY TRANSITION TO SNOW
FOR AREAS WEST OF THE ALLEGHENY FRONT.
BOTH THE GFS AND ECMWF CONTINUE TO SHOW ANOTHER SYSTEM TRACKING
SE FROM THE GLAKES FRI/SAT, THOUGH WITH FAIRLY LIMITED MOISTURE
SINCE THERE'S NO NOTABLE NE-EASTERLY FLOW OFF THE ATLANTIC AND
TIMING OF THE UPPER TROUGH AMPLIFICATION IS TOO LATE/FAR TO THE
EAST TO TRANSPORT ANY GOMEX MOISTURE NE.
THERE IS STILL APPRECIABLE SPREAD IN THEIR RESPECTIVE ENSEMBLES
AS TO HOW THE DISTURBANCE AND SPECIFIC DETAILS WILL EVOLVE.
SOME MEMBERS SHOW A WEAK SURFACE LOW TRACKING DIRECTLY OVER
PENNSYLVANIA, BRINGING FAIRLY WIDESPREAD LIGHT SNOWFALL WITH IT,
WHILE OTHERS SHOW A WEAKENING SURFACE LOW TRACKING TO OUR NORTH
AS THE UPPER LEVEL WAVE TRANSFERS ITS ENERGY TO A DEVELOPING
LOW OFF OF THE COAST. BOTH OF THESE SOLUTIONS, ALONG WITH
OTHERS, SUPPORT MAINTAINING AT LEAST A CHANCE OF SNOW DURING
THAT TIME PERIOD ACROSS MOST OF THE REGION.
REGARDLESS OF WHAT HAPPENS WITH THIS SYSTEM, TEMPERATURES WILL
BE ON A DOWNWARD TREND INTO THE WEEKEND WITH HIGHS IN THE 20S
AND 30S ONCE AGAIN BY SATURDAY, AND OVERNIGHT LOWS POTENTIALLY
IN THE SINGLE DIGITS AND TEENS. UPSLOPE AND LAKE EFFECT SNOW
SHOWERS LINGER THROUGH THE DAY ON SATURDAY BEFORE HIGH PRESSURE
BUILDS IN FOR THE SECOND HALF OF THE WEEKEND.
AVIATION /16Z MONDAY THROUGH FRIDAY/
WIDESPREAD IFR/LIFR CONDITIONS WILL CONTINUE THROUGHOUT THE
MAJORITY OF THE TAF PERIOD WITH HIGH (~80-90%) CONFIDENCE IN ALL
AIRFIELDS PREVAILING IFR TO LIFR THROUGH 12Z TUESDAY.
MILER AND MOIST AIR ALOFT STREAMING NE OVER THE SHALLOW, COLDER
AIR LOCKED IN PLACE ACROSS CENTRAL PA WILL HELP TO
FORM/TRANSPORT AN AREA OF STEADY LIGHT, TO BRIEFLY MODERATE
RAIN ACROSS ALL CENTRAL PA AIRFIELDS LATER THIS AFTERNOON
THROUGH TONIGHT.
THIS INJECTION OF MOISTURE AND AN UPTICK IN THE SOUTH TO
SOUTHEASTERLY LOW-LEVEL FLOW WILL KEEP IFR/LIFR RESTRICTIONS IN
PLACE ACROSS ALL AIRFIELDS THROUGH AT LEAST 10Z TUESDAY.
ANOTHER ASPECT OF FLIGHT CONDITIONS, MAINLY BETWEEN 22Z MONDAY
AND 10Z TUESDAY, WILL BE LLWS THRESHOLDS BEING MET WITH A SLIGHT
ENHANCEMENT OF SOUTHERLY WINDS AT 925MB ALLOWING FOR SOME SHEAR
WITH WINDS SOUTHWESTERLY WINDS AT THE SURFACE. THE AIRFIELDS OF
MOST CONCERN AT OF 06Z MONDAY REMAIN ACROSS EASTERN AIRFIELDS
(BFD/JST/AOO) WITH SLIGHTLY LOWER CONFIDENCE (BUT STILL
NOTEWORTHY IN THE 12Z TAF PACKAGE) AT UNV/IPT/MDT/LNS.
OUTLOOK...
TUE...IMPROVING CONDITIONS.
WED-THU...FOG POSSIBLE WED MORNING, THEN RAIN MOVES IN DURING
THE AFTERNOON AND CONTINUES INTO THURSDAY, BEFORE PARTIAL
CLEARING LATER THURSDAY.
FRI...RESTRICTIONS POSSIBLE WITH SNOW SHOWERS.
CLIMATE
ASTRONOMICAL WINTER (SOLSTICE) BEGINS ON SATURDAY, DECEMBER 21ST
AT 4:19 A.M. EST.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT/COLBERT
NEAR TERM...LAMBERT/COLBERT
SHORT TERM...LAMBERT/COLBERT
LONG TERM...LAMBERT/BAUCO
AVIATION...LAMBERT/NPB
CLIMATE...STEINBUGL
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