Area Forecast Discussion
Issued by NWS State College, PA

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919
FXUS61 KCTP 071212
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
712 AM EST SUN FEB 7 2016

.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE ONE MORE FAIR AND RELATIVELY MILD
DAY TODAY. A SLOW MOVING UPPER LOW WILL BRING A PROLONGED PERIOD
OF UNSETTLED WEATHER STARTING LATER MONDAY AND CONTINUING AT
LEAST THROUGH MID WEEK. TEMPERATURES WILL TREND COLDER WITH
TIME...ENHANCED BY AN ARCTIC FRONT TOWARD THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
SKIES ARE ALMOST PERFECTLY CLEAR ACROSS THE FORECAST AREA AS WE
REMAIN SANDWICHED BETWEEN CLOUDS TO THE NORTH AND SOUTH.

FAIR AND MILD CONDITIONS WILL CONTINUE TODAY SQUEEZING IN ONE
LAST DAY BEFORE A SLOWLY DEVELOPING UPPER LOW DROPS INTO THE
EASTERN US AND BRINGS A PROLONGED PERIOD OF INCLEMENT WEATHER TO
THE REGION FOR THE NEW WORK WEEK.

FOR THE OVERNIGHT WE WILL BEGIN TO SEE A SLOW INCREASE IN
CLOUDINESS. IT WILL STILL BE RELATIVELY MILD WITH LOWS IN THE 20S
IN MOST AREAS.

&&

.SHORT TERM /MONDAY/...
CONSIDERABLE UNCERTAINTY EXISTS WITH THE ONSET OF WHAT AT LEAST
INITIALLY LOOKS LIKE SOME LIGHT PRECIPITATION AS THE UPPER LOW
DIGS THROUGH THE UPPER MIDWEST ON A TRACK TOWARD THE OHIO VALLEY
AND EVENTUALLY NERN US.

THE SREF WAS SLOWEST IN BRINGING IN THE PRECIP MONDAY...WHICH
COULD ACTUALLY BE A LIGHT MIX OF RAIN AND SNOW GIVEN THE EXPECTED
HIGHS IN THE 30S TO LOWER 40S. I USED OUR BLENDED MODEL POPS WHICH
ARE A BIT HIGHER THAN THE DRY SREF FOR THE AFTERNOON...WITH THE
BEST CHANCE OF SOME LIGHT SNOW...OR A LIGHT RAIN/SNOW MIXTURE
BEING OVER WESTERN AREAS...WITH LESSER CHANCES OVER EASTERN ZONES.

IN GENERAL I CUT THE ALREADY LIGHT WPC-GUIDANCE SNOWFALL AMOUNTS
BY ABOUT HALF GIVEN THAT SKIN TEMPS WILL BE RELATIVELY WARM AND
WITH PRECIP RATES WHICH ARE EXPECTED TO BE ON THE LIGHT SIDE.
THAT USUALLY MAKES IT HARD FOR SNOW TO STICK TO MUCH MORE THAN
GRASSY SURFACES...EVEN IN AREAS WHERE IT DOES NOT MIX WITH RAIN.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE LONG TERM IS EXPECTED TO BEGIN WITH A PERIOD OF UNSETTLED
WEATHER...FOLLOWED BY A SHOT OF COLDER AIR FOR THE LAST HALF OF
THE WEEK INTO THE WEEKEND.

IT IS FAIRLY CERTAIN CENTRAL PA WILL EXPERIENCE A PROLONGED PERIOD
OF LIGHT...POSSIBLY MODERATE PRECIP FOR THE EARLY PART OF THE
EXTENDED PERIOD OF THE FORECAST. CONFIDENCE REMAINS LOW HOWEVER
AS TO WHICH PERIOD WILL SEE THE BEST CHANCE OF SNOW AMOUNTS THAT
MIGHT WARRANT HEADLINES. THE GEFS SHOWS AT BEST A 30% PROB OF HALF
INCH QPF IN THE PERIOD BETWEEN 06Z AND 18Z TUESDAY. THE ECENS IS
SIMILARLY LOW KEY REGARDING THE BEST PERIOD FOR ACCUM
SNOW...TAKING 6 DAYS TO REACH 6 INCH TOTALS...AND THOSE ARE IN THE
USUAL LAKE EFFECT AND LAUREL HIGHLAND UPSLOPE AREAS...NOT
NECESSARILY ASSOCIATED WITH A SINGLE COHERENT SURFACE CYCLONE.

THE 00Z GFS COMES THE CLOSEST TO ZEROING IN ON A THREAT
AREA...SHOWING THE SERN 1/3 OF THE CWA UNDER THE GUN AFTER 06Z
TUESDAY THROUGH 18Z...WITH AN ELONGATED SURFACE LOW HELPING
SUPPORT AN AREA OF FRONTOGENETIC FORCING INTO THE LOWER SUSQ
VALLEY. IT SUPPORTS THIS IDEA WITH ABOUT 12-18 HOURS OF FAIRLY
STRONG EASTERLY LOW LEVEL FLOW WHICH THE GEFS IS NOT NEARLY AS
ROBUST IN PORTRAYING. THE ECENS FOR THE SAME TIME FRAME HAS A
MUCH LESS VIRILE DEPICTION OF THIS WRAP-BACK INTO THE SERN AREAS.
THE NAM/SREF ARE SIMILARLY LESS IMPRESSIVE WITH THE POTENTIAL FOR
SIG SNOW OVER SERN ZONES. IT ALL POINTS TO CONTINUING LOW
CONFIDENCE IN PICKING OUT THE BEST PERIODS FOR THE MOST QPF...BUT
A RELATIVELY HIGH CONFIDENCE THAT ONCE PRECIP BEGINS...IT WILL
CONTINUE FOR SEVERAL FORECAST PERIODS.

WHILE THE FIRST SEVERAL DAYS OF THE NEW WEEK WILL PRESENT
PRECIPITATION TIMING AND AMOUNT PROBLEMS..THERE IS A HIGHER
CONFIDENCE FOR MUCH COLDER AIR TO BE DELIVERED INTO THE REGION FOR
THE END OF THE WEEK INTO NEXT WEEKEND. THE COLDEST AIR IN THE GEFS
IS MADE TO ARRIVE THURSDAY NIGHT AND FRIDAY. THE ECENS IS EVEN
COLDER BRINGING A CHUNK OF -25C/850MB AIR INTO THE REGION FOR
LATER SATURDAY INTO SUNDAY. 00Z ECMWF ENSEMBLE MOS IS NOT IN
YET...BUT THE 12Z RUN HAD JUST 4 ABOVE FOR A MAX IN BRADFORD NEXT
SATURDAY...WITH OVERNIGHT LOWS BELOW ZERO A SURE BET.

GOING TO BE A CHILLY VALENTINE`S DAY.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
12Z TAFS SENT.

SOME FOG AT LNS AT TIMES...BUT OVERALL LOOKING AT VFR CONDITIONS
TODAY.

HIGH PRESSURE OVER THE AREA WILL RESULT IN JUST A FEW HIGH CLDS
LATE TODAY. NICE DAY FOR EARLY FEB.

A COMPLEX WEATHER PATTERN MAY RESULT IN SOME SNOW AND COLDER
TEMPERATURES AFTER TODAY.

OUTLOOK...

MON...PM LGT SNOW POSSIBLE...ESP W MTNS.

TUE...LGT SNOW POSSIBLE...ESP W MTNS.

WED...IFR/MVFR IN SHSN WRN AIRSPACE. MVFR-VFR CIGS CENTRAL/EAST.
SFC WIND GUSTS 20+KT FROM 270-300.

THU...MVFR IN -SHSN POSSIBLE W MTNS.

&&

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

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...MARTIN



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