-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 152148
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
548 PM EDT TUE APR 15 2014

.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH EAST OF PENNSYLVANIA EARLY THIS
EVENING. MUCH COLDER AIR WILL COVER THE COMMONWEALTH TONIGHT AND
WEDNESDAY...WITH POSSIBLE RECORD LOW TEMPERATURES EARLY WEDNESDAY
MORNING. A GRADUAL REBOUND IN TEMPERATURES ACCOMPANIED BY
FAIR...DRY WEATHER WILL OCCUR FOR THURSDAY AND FRIDAY. A POTENT
UPPER AIR DISTURBANCE WILL MOVES EAST FROM THE GREAT LAKES ON
SATURDAY...BRINGING COOLER TEMPERATURES WITH SOME MOUNTAIN RAIN
AND SNOW SHOWERS POSSIBLE.

&&

.NEAR TERM /UNTIL 11 PM THIS EVENING/...
AFTER A MILD START TO THE DAY WITH TEMPS IN THE LOWER TO MID
60S ACROSS CENTRAL AND ERN PENN...TEMPS HAVE PLUMMETED WELL DOWN
INTO THE 30S ACROSS THE NRN AND WRN MTNS...AND INTO THE U30S AND
40S ACROSS THE CENTRAL MTNS AND MUCH OF THE SUSQ VALLEY.

A WEAK WAVE OF LOW PRESSURE AND ASSOCIATED UPPER SHORT WAVE RIDING
NE FROM THE MID ATLANTIC PIEDMONT WILL MAINTAIN PLENTY OF THICK
CLOUDS AND PERIODS OF RAIN ACROSS THE SUSQ VALLEY AND POINTS EAST
LATE THIS AFTERNOON INTO EARLY THIS EVENING. A FEW HOUR PERIOD OF
SNOW WILL IMPACT THE NRN AND WESTERN MTNS BETWEEN
19-23Z...BRINGING A SLUSHY INCH OR TWO TO ELEVATIONS AOA 1400 FT
MSL...WITH ONLY A COATING IN THE DEEPER RIVER VALLEYS. SIMILAR
LIGHT ACCUMULATION IS LIKELY ACROSS THE LAURELS.

THE RAIN WILL MIX WITH AND CHANGE TO A LITTLE WET SNOW LATE TODAY
AND THIS EVENING OVER...AND TO THE EAST OF...THE SUSQ VALLEY. A
SLUSHY INCH IS POSSIBLE ON COLDER GRASSY AREAS ACROSS THE HIGHER
TERRAIN OF SCHUYLKILL COUNTY...NORTH TO SULLIVAN COUNTY BEFORE ANY
LINGERING SNOW FIZZLES OUT BY 03Z.

HI RES WRF ARW AND 09Z SREF /ALONG WITH VARIOUS OTHER OP MODEL
GUIDANCE/ INDICATES UP TO A FEW TENTHS OF QPF FALLING AS MAINLY
SNOW ACROSS OUR FAR ERN ZONES BETWEEN 22Z-02Z WED...BUT RECENT
WARMTH HAS KEPT GROUND TEMPS QUITE WARM...SO LITTLE PROBLEM IS
EXPECTED TRAVEL-WISE IN THE EAST.

&&

.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
PRECIP SHOULD DRY IN THE WAKE OF THE CFRONT BY SHORTLY AFTER DARK
IN THE EAST...WITH JUST SOME SCATTERED LIGHT SNOW SHOWERS
LINGERING ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST AS THE
SUBSIDENCE INVERSION BASE CRASHES TO BELOW 4 KFT AGL.

THE NW WIND /AND GUSTS/ WILL PEAK EARLY TONIGHT AS THE COLDER AIR
DEEPENS IN COMBINATION WITH A MODERATELY TIGHT LLVL P-GRADIENT.
GUSTS AROUND 30 KTS WILL BE COMMON THROUGH ABOUT 04-06Z.

CLOUDS WILL OF COURSE LINGER OFF LAKE ERIE AND OVER THE NRN MTS
EARLY TONIGHT.

MIN TEMPS EARLY WED ARE EXPECTED TO SETTLE NEAR...OR EVEN SEVERAL
DEG F BELOW RECORD LOWS FOR THE DATE. SEE CLIMO SECTION BELOW FOR
SPECIFIC RECORDS AT VARIOUS LOCATIONS ACROSS THE REGION.

THE CLEARING AND SIGNIFICANT CAA WILL DROP TEMPS INTO THE 20S.
EVEN THE SE WILL GET INT THE M20S - EVEN WITH A 10-15KT NWRLY WIND
THROUGH THE LATE NIGHT/EARLY MORNING HOURS WED. A FREEZE WARNING
IS IN EFFECT FOR THOSE ZONES WHICH HAVE JUST PASSED THE
CLIMATOLOGICAL MEAN DATE OF LAST SPRING FREEZE...AND A FREEZE
WATCH WAS RECENTLY POSTED FOR WEDNESDAY NIGHT ACROSS THE SAME SE
ZONES.

A MAINLY SUNNY...BUT UNSEASONABLY COLD DAY IS SHAPING UP FOR THE
ENTIRE REGION WEDNESDAY. WINDS WILL BE MUCH LIGHTER AS HIGH
PRESSURE BUILDS IN FROM THE OHIO VALLEY...BUT WITH 850 MB TEMPS
AVERAGE MINUS 8-12...MAXS WILL ONLY REACH THE UPPER 30S ACROSS
PARTS OF THE NRN AND WESTERN MTNS...AND UPPER 40S IN THE SE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
STG RIDGING WILL EXTEND SWWD ALONG/EAST OF THE APPALACHIANS FROM
STG HP CELL CENTERED OVER MAINE AND THE CANADIAN MARITIMES. THE
SYNOPTIC CONDITIONS LOOK FAVORABLE FOR FROST/FREEZE CONDITIONS
AGAIN WED NGT INTO AM THURS...AND THEREFORE ISSUED A FREEZE WATCH
FOR THE SERN ZONES WHERE THE GROWING SEASON IS UNDERWAY.

HIGH PRESSURE WILL STRENGTHEN TO +3-4SD OVER NORTHERN NEW ENGLAND
THROUGH THURSDAY...BEFORE SLOWLY WEAKENING INTO THE UPCOMING
WEEKEND. THIS SUGGESTS A POSSIBLE EASTERLY MARITIME LLVL FLOW WITH
LOW CLOUDS AND PERHAPS SOME LGT RAIN/DZ POSSIBLY REACHING INTO THE
SERN ZONES.

THERE IS GENERAL AGREEMENT IN A SHORTWAVE TROUGH CROSSING THE
GREAT LAKES REGION FRI-SAT WITH THE BEST CHC FOR RAIN OVER THE NW
1/3 OF THE CWA. THE MODELS GENERALLY AGREE ON THIS IDEA BUT TIMING
DIFFS MAY BE AN ISSUE. THE UPPER LEVEL PATTERN BRIEFLY RELAXES
LATE IN THE WEEKEND BEFORE REAMPLIFYING UPSTREAM...WITH STRONG
HEIGHT FALLS /CUT-OFF LOW PROGGED ALONG THE WEST COAST...SLIGHTLY
ABOVE- AVG 500MB RIDGING EXPANDING INTO THE N-CENTRAL PLAINS AND
TROUGHING LINGERING OVER THE NERN CONUS. THERE IS LOW CONFIDENCE
IN THE PCPN PATTERN DUE THE COMPLEXITY OF THE LW FLOW...WITH
SEVERAL LOW-MEDIUM CHC OPPORTUNITIES FOR RAIN IN THE OUTER
PERIODS.

TEMPERATURES WILL BOTTOM OUT ON WEDNESDAY WITH HIGHS -10 TO -15
DEGREES BELOW NORMAL. A MILDER SW FLOW ALOFT WILL ALLOW READINGS
TO MODERATE THROUGH THE END OF THE PERIOD...BUT LKLY STILL AVG
BELOW LATE APRIL CLIMO.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...

-- Changed Discussion --
PERIODS OF RAIN WILL PERSIST ACROSS THE SUSQ VALLEY AND POINTS
EAST 22-00Z WED. ELSEWHERE ACROSS THE CENTRAL AND WEST...MVFR
SITES WILL BE BECOMING IFR...WITH JST AND AOO LEADING THE WAY DUE
TO SNOW SHOWERS. LOW-END VFR CONDITIONS WILL BE BECOMING MVFR AS
THE RAIN HAS TRAINSITIONED TO SCATTERED LIGHT SNOW SHOWERS ACROSS
THE CENTRAL VALLEYS. THESE CONDITIONS WILL CONTINUE THROUGH THE
EARLY EVENING HOURS.

GRADUAL IMPROVEMENT TO MAINLY VFR WILL FOLLOW FOR TONIGHT ACROSS
THE CENTRAL AND EASTERN ZONES...WITH LINGERING MVFR TO IFR CIGS
AND VSBYS IN SNOW SHOWERS ACROSS THE WRN MTNS THROUGH AT LEAST
EARLY TONIGHT.

WED THRU FRI SHOULD BE FAIRLY BENIGN...WITH ANOTHER ROUND OF WET
WEATHER POSSIBLE BY SAT.

OUTLOOK...
.WED-FRI...GENERALLY VFR.
.SAT...REDUCED CIGS/VSBYS IN RAIN /AND POSSIBLY SOME WET SNOW
ACROSS THE HIGHER TERRAIN/.
.SUN...MAINLY VFR UNDER A WEAK RIDGE OF HIGH PRESSURE.
-- End Changed Discussion --

&&

.CLIMATE...
MORNING TEMPERATURES TOMORROW AND THURSDAY WILL CHALLENGE RECORD
LOWS. BELOW ARE SELECTED RECORDS FROM AROUND THE AREA.

AOO... WEDNESDAY 24/1950/... THURSDAY 23/1980/
BFD... WEDNESDAY 18/1980/... THURSDAY 16/1983/
IPT... WEDNESDAY 20/1943/... THURSDAY 25/1904/
MDT... WEDNESDAY 25/1943/... THURSDAY 29/1980/

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR PAZ057-059-063>066.
FREEZE WARNING FROM 2 AM TO 8 AM EDT WEDNESDAY FOR PAZ057-059-
063>066.

&&

$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
CLIMATE...