Area Forecast Discussion
Issued by NWS State College, PA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KCTP 121629
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1129 AM EST FRI FEB 12 2016

.SYNOPSIS...
AN ARCTIC COLD FRONT WILL MOVE THROUGH NORTHWESTERN PENN THIS
EVENING...AND PUSH ACROSS THE SUSQ VALLEY SHORTLY AFTER MIDNIGHT.
THIS FRONT WILL BE FOLLOWED BY THE COLDEST AIR OF THE SEASON JUST
IN TIME FOR VALENTINES WEEKEND. HIGH PRESSURE WILL SETTLE ACROSS
THE STATE LATE IN THE WEEKEND...THEN A STRENGTHENING STORM WILL
LIFT UP THE EAST COAST EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS WILL CONTINUE TO LOWER/THICKEN-UP THROUGH THIS AFTERNOON
AS WAA OVERSPREADS THE AREA IN ADVANCE OF UPPER LOW /POLAR
VORTEX/ PLUNGING SOUTH FROM JAMES BAY. NEAR TERM MDLS CONTINUE TO
INDICATE ISENTROPIC LIFT WILL RESULT IN SOME PATCHY LGT SNOW
DEVELOPING DURING THE AFTN AND EARLY EVENING...PRODUCING SOME
MEAGER ACCUMS OF LESS THAN AN INCH. SW FLOW AHEAD OF APPROACHING
ARCTIC COLD FRONT WILL DRAW SLIGHTLY MILDER AIR INTO THE
REGION...AND MID AFTERNOON MAX TEMPS WILL LIKELY RANGE FROM THE
UTEENS OVR THE ALLEGHENY PLATEAU...TO THE M20S ACROSS THE SUSQ
VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
ARCTIC FRONT WILL PLOW SE ACROSS CENTRAL PA THIS EVENING...LIKELY
ACCOMPANIED BY A ROUND OF SNOW SQUALLS. STEEP LOWER TROPOSPHERIC
LAPSE RTS AND STRONG FORCING AHEAD OF MID LVL SHORTWAVE SHOULD
SUPPORT A BAND OF SQUALLS ENTERING THE NW MTNS ARND 00Z AND
EXITING THE EASTERN COUNTIES LATE AT NIGHT. BRIEF WHITEOUT CONDS
WILL LIKELY CREATE TRAFFIC/TRAVEL PROBLEMS THIS EVENING ACROSS THE
NW COUNTIES AND POSSIBLY FURTHER SE LATE TONIGHT. CAN/T RULE OUT
A RUMBLE OF THUNDER ACROSS THE NW MTNS BTWN 00Z-03Z SAT...WHERE
MDLS INDICATE A BIT OF CAPE. ELSEWHERE...HAVE REMOVED MENTION OF
THUNDER BASE ON LATEST SPC GUIDANCE AND LACK OF ANY CAPE IN MDL
DATA. 00Z NCAR ENSEMBLE SUGGESTS THE HEAVIEST SQUALLS WILL FALL
OVR THE N MTNS...CLOSEST PATH OF SHORTWAVE.

HAVE OPTED TO FOREGO ANY ADVISORIES FOR SNOW AT THIS POINT...AS
LATEST SPC SSEO AND NCAR ENSEMBLE OUTPUT INDICATE SNOW AMTS FROM
FRONT AND FOLLOWING LAKE EFFECT WILL FALL SHORT OF ADVISORY
CRITERIA. PLAN TO COVER THE TRAVEL HAZARD FROM EVENING SQUALLS IN
THE HWO AND FOLLOW UP WITH SPS AS THE EVENT UNFOLDS THIS EVENING.

ARCTIC AIR MASS WILL POUR INTO THE REGION EARLY SATURDAY...ACCOMPANIED
BY GUSTY NW WINDS...WHICH WILL PRODUCE DANGEROUS WIND CHILLS
ACROSS AT LEAST THE NORTHERN AND WESTERN MTNS. CURRENT WIND/TEMP
GRIDS RESULTING IN MARGINAL WCHILL WARNING READINGS OF ARND -25F
ACROSS THE N MTNS SAT AM THRU SUN AM. THUS...WITH SUCH BORDERLINE
NUMBERS...WILL KEEP WATCH INTACT AND DEFER WARNING/ADVISORY
DECISION TO THE DAY SHIFT. FURTHER SOUTH...HAVE ISSUED WCHILL
ADVISORY ALONG THE ALLEGHENY PLATEAU...WHERE CONFIDENCE IS HIGH
FOR WCHILLS BTWN 15F-25F. GEFS MEAN 8H TEMPS BTWN -22F AND -25F
SHOULD SUPPORT HIGH TEMPS SATURDAY NO GREATER THAN ARND 0F OVR
THE NW MTNS TO THE MTEENS ACROSS THE LOWER SUSQ VALLEY.

DRY ARCTIC AIR MASS SHOULD PRECLUDE SIG LAKE EFFECT SNOW ACROSS
CENTRAL PA SATURDAY. HOWEVER...LK HURON CONNECTION SHOULD SHOULD
FOCUS THE MOST PERSISTENT SNOW SHOWERS ACROSS THE NW WARREN CO AND
THE LAUREL HIGHLANDS...WHERE AN ADDITIONAL INCH OR SO SEEMS LIKELY
BASED ON NCAR MESOSCALE ENSEMBLE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
*IMPACT WEATHER HIGHLIGHTS: FRIGID TEMPERATURES AND DANGEROUS WIND
 CHILLS FOR VALENTINES WEEKEND. POTENTIAL WINTER STORM EARLY NEXT
 WEEK.

POLAR VORTEX DIVING INTO NORTHERN NEW ENGLAND WILL DELIVER THE
COLDEST AIR OF THE SEASON WITH ARCTIC BLAST INTO CENTRAL PA
LATE SAT-SUN. THE GLOBAL MODELS AND ENSEMBLES KEEP A MEAN TROUGH
IN PLACE OVER THE EASTERN US INTO THE MIDDLE OF NEXT WEEK. THE
MOST NOTABLE FEATURE DURING THE PERIOD WILL BE A LOW PRESSURE
SYSTEM TRACKING UP THE EAST COAST ON TUESDAY. THE LATEST 12/00Z
MODEL GUIDANCE HAS TRENDED WEST WITH THE LOW TRACK...BUT THERE IS
STILL A DECENT SPREAD. AT THIS TIME PRECIPITATION WITH THIS SYSTEM
APPEARS LIKELY MON-TUE BUT THE TRACK WILL ULTIMATELY DETERMINE
PRECIPITATION TYPE. NEXT WEEK SHOULD END ON A MILDER NOTE.

THE COLDEST TEMPS/WCHILLS EXPECTED SAT NIGHT OVR THE AREA...AS
8H TEMP ANOMALIES OF NEAR 3SD BLW CLIMO GRAZE THE AREA. MINIMUM
TEMPERATURES SATURDAY NIGHT INTO EARLY SUNDAY MORNING EXPECTED TO
RANGE FROM ARND ZERO IN THE LOWER SUSQ VALLEY TO -10F IN THE
NORTHWEST MTNS. THE FRIGID TEMPERATURES COMBINED WITH DANGEROUS
WIND CHILLS /-10 TO -25 BELOW ZERO/ WILL RESULT IN AN INCREASED
RISK FOR FROSTBITE AND HYPOTHERMIA. MAY NEED TO ADD COUNTIES TO
THE CURRENT WIND CHILL ADVISORYF FOR SAT NIGHT.

A MODERATION (WARMING TREND) IS EXPECTED INTO EARLY NEXT WEEK.
THE MODEL SPREAD HAS NARROWED A BIT CONCERNING A POTENTIAL WINTER
STORM SYSTEM IMPACTING THE MID ATLC/NORTHEAST NEXT MON-TUE. LATEST
GEFS AND ECENS INDICATING A SFC LOW TRACK ACROSS EASTERN PA IS
MOST LIKELY...WHICH WOULD FAVOR RAIN ACROSS ALL BUT PERHAPS THE W
MTNS. CONFIDENCE REMAINS LOW ON PTYPES ACROSS WESTERN PA...BUT
NOW DEFINITELY FAVORS RAIN ACROSS THE EAST. ALL THE MODELS ARE
SIGNALING A SIGNIFICANT QPF EVENT...AND THEREFORE HAVE INCREASED
POPS IN THE LKLY RANGE FOR MON NGT-TUESDAY.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
MOST OF CENTRAL PA WILL CONTINUE TO BE VFR INTO THE MID
AFTERNOON. W/SW WINDS WILL BE 10 MPH OR LESS MUCH OF THE DAY.

TROUGH MOVES THROUGH THE REGION LATE THIS AFTERNOON AND EVENING
FOLLOWED BY A BLAST OF ARCTIC AIR. AHEAD OF THAT...SOME WAA LIGHT
SNOW WILL DEVELOP DURING THE MID-LATE AFTERNOON...BRINGING
GENERALLY MVFR REDUCTIONS TO CIGS/VSBY. WHEN ARCTIC AIR ARRIVES
/REACHING NW MTNS BY 00Z/... MORE SIG SNOW SHOWERS/SQUALLS WILL
BRING PERIODS OF LIFR/VLIFR IN THIS EVENING INTO SATURDAY MORNING
- ESP OVER THE NW HALF OF CWA. THESE WILL BE ACCOMPANIED BY GUSTY
NORTHWESTERLY WINDS...AND THESE BRISK WINDS WILL CONTINUE INTO
SATURDAY.

DOWNSLOPE FLOW KICKS IN LATE TONIGHT...BRINGING IMPROVEMENT TO VFR
IN MOST PLACES. WESTERN HIGHER TERRAIN WILL CONTINUE TO SEE
RESTRICTIONS IN SNOW SHOWERS/BLOWING SNOW/UPSLOPE FLOW INTO THE
WEEKEND.

OUTLOOK...

SAT...WINDY. SHSN/REDUCED VIS POSS W MTNS...MAINLY AM.

SUN...NO SIG WX EXPECTED.

MON...PM SNOW POSSIBLE.

MON NIGHT AND TUE...SNOW LIKELY NW HALF OF PENN...WITH RAIN OR
SNOW IN THE SE.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
PAZ004>006-037-041-042.
WIND CHILL ADVISORY FROM 4 AM SATURDAY TO 11 AM EST SUNDAY FOR
PAZ010>012-017-018-024-033.

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...LAMBERT/RXR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.