Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 181914
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
314 PM EDT SAT APR 18 2015

.SYNOPSIS...
A DRY COLD FRONT WAS PUSHING THROUGH THE SUSQUEHANNA VALLEY THIS
AFTERNOON...FOLLOWED BY A GUSTY NORTHWEST WIND. A RIDGE OF HIGH
PRESSURE WILL SLIDE EAST ACROSS THE REGION TONIGHT WITH TRANQUIL
CONDITIONS. RAIN WILL OVERSPREAD THE SOUTHWEST HALF OF THE STATE
LATE AFTERNOON AND EVENING...PRECEDING A WARM FRONT. THE RAIN WILL
BE STEADIEST AND HEAVIEST SUNDAY NIGHT AND EARLY MONDAY WITH SOME
LOCATIONS RECEIVING A LITTLE OVER ONE INCH. ADDITIONAL SHOWERS
AND SCATTERED THUNDERSTORMS WILL OCCUR MONDAY AFTERNOON AND EARLY
MONDAY NIGHT AS A COLD FRONT MOVES THROUGH THE STATE. A LARGE
UPPER LEVEL LOW WILL THEN SET UP OVER UPPER ONTARIO AND QUEBEC
CANADA FOR THE MIDDLE AND LATTER PART OF THE UPCOMING
WEEK...USHERING IN UNSEASONABLY CHILLY AIR. THE AIR WILL BECOME
COLD ENOUGH FOR SNOW SHOWERS ACROSS THE MOUNTAINS OF NORTHERN AND
WESTERN PENNSYLVANIA WITH MIXED RAIN AND SNOW SHOWERS IN THE
CENTRAL VALLEYS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DRY SFC COLD FRONT EXTENDED FROM KIPT TO KCBE AT 18Z WITH A GUSTY
NW WIND IN ITS WAKE. GUSTS WILL BE HIGHEST AND IN THE 20-25 KT
RANGE ACROSS THE MOUNTAINS NORTH AND EAST OF KIPT FOR THE NEXT
SEVERAL HOURS. SEE FIRE WX SECTION BELOW FOR THE IMPACTS OF THIS
WIND AND DRY CONDITIONS.

MID AFTERNOON TEMPS ARE RIGHT NEAR THEIR FCST MAXES IN THE LOWER
70S ACROSS THE HIGH TERRAIN OF THE NORTH AND WEST...AND MID TO
UPPER 70S ELSEWHERE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
CLEAR TONIGHT WITH A SFC AND UPPER RIDGE SLIDING OVERHEAD LATE
TONIGHT AND EARLY SUNDAY MORNING.

A DECENT AMOUNT OF SUN IS EXPECTED SUNDAY MORNING THROUGH AN
ADVANCING VEIL OF CIRRUS/CIRROSTRATUS. LAYERED CLOUDS WILL
LOWER/THICKEN-UP FROM THE SOUTHWEST DURING THE MIDDAY AND
AFTERNOON HOURS SUNDAY...AND BASED ON THE 12Z OPER MODELS AND 09Z
SREF RAIN WILL SPREAD INTO OUR FAR WRN/SWRN ZONES BETWEEN 20-22Z
BEFORE REACHING THE CENTRAL MTNS AROUND OR SHORTLY AFTER DUSK. 12Z
GEFS MEAN APPEARS TO BE UP TO A FEW HOURS QUICKER WITH THE ONSET
OF THE RAIN...AND WITH STRONG WAA PATTERNS SUCH AS THE UPCOMING
EVENT...THIS IS ALWAYS SOMETHING TO STRONGLY CONSIDER AND MONITOR.

STRONG SERLY LLJ OF 50-60KT AT 2-4 KFT AGL COULD MAKE FOR A
GUSTY SFC WIND IN FAVORED AREAS /I.E. RIDGE TOPS AND TO THE NORTH
OF GAPS IN THE RIDGES/ AS THE RAIN MOVES IN...AND WILL SUPPLY
PLENTY OF MOISTURE IN THE FORM OF 1-1.5INCH PWATS. RAIN OF VARYING
INTENSITY IS EXPECTED FOR A GOOD PORTION OF SUNDAY NIGHT. RAINFALL
TOTALS OF 0.5 TO 1.0 INCH BY 12Z MONDAY WILL LEAD TO SOME RISES ON
STREAMS...BUT RIVER RESPONSE LOOKS TO BE GENERALLY MINOR.

LOW TEMPS TONIGHT WILL RANGE FROM NEAR FREEZING IN THE COLD SPOTS
UP NORTH...TO THE UPPER 30S TO MID 40S ACROSS THE SOUTHERN HALF OF
THE STATE. HIGH TEMPS SUNDAY WILL REACH THE LOWER TO MID 60S IN
THE EAST...BUT COOLER MID TO UPPER 50S IN THE WEST. HIGH IN THE
WEST COULD TURN OUT 3-5 DEG F COOLER WITH AN EARLIER ONSET TO THE
THICKENING CLOUDS AND AFTERNOON RAIN.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
THERE WILL PROBABLY BE A BRIEF BREAK IN THE ACTION MONDAY MORNING
AS WE GET INTO THE WARM SECTOR. A ROUND OF SHOWERS THEN PUSHES
THROUGH WITH COLD FRONT LATER MON INTO MON NIGHT. QPF THROUGH THE
WHOLE EVENT LOOKS TO BE AROUND OR JUST OVER AN INCH IN THE SRN
TIER. MU CAPES IN THE 800-1200J/KG RANGE WILL LIKELY ALLOW TSRA TO
FORM. IF TOO MUCH CLOUD COVER HANGS AROUND THROUGH THE
MORNING/EARLY AFTN...TSRA WILL BE QUELLED OR AT LEAST MUCH LESS
WIDESPREAD THAN CURRENT THINKING.

BEHIND THE COLD FRONT MIDWEEK...THE UPPER LOW HANGS AROUND S
CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW
ACROSS PA. THIS WILL BRING A STEADY STREAM OF COOLER AIR AS TEMPS
SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A
SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER
LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST...
MAINLY DURING THE DAYTIME HOURS.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
A DRY COLD FRONT WILL PUSH ACROSS THE SUSQ AND POINTS EAST LATE
THIS AFTERNOON AND EARLY THIS EVENING...FOLLOWED BY A 3-5 HOUR
PERIOD OF GUSTY NW WINDS. WIND GUSTS OF 15-20 KTS LIKELY ACROSS
THE CENTRAL AND NEPA TAF SITES. GUSTS TO THE SW OF A KBFD TO KUNV
AND KMDT LINE WILL BE GENERALLY AOB 15KTS BETWEEN 19-23Z.

VFR CONDITIONS AND LIGHTER NORTH WIND /VEERING TO EAST...THEN SE/
WILL PREVAIL FOR TONIGHT AND MUCH OF SUNDAY.

MVFR CIGS AND VSBYS LIKELY DEVELOPING ACROSS THE SW HALF OF PENN
BETWEEN 20-23Z SUNDAY AS WARM ADVECTION THICKENING CLOUDS AND RAIN
QUICKLY SPREADS IN FROM THE SW.

LOW-LEVEL WIND SHEAR LIKELY SUNDAY NIGHT WITH A STRONG SOUTH TO
SERLY 50-60 KT WIND IN THE 2-4 KFT AGL LAYER. WIDESPREAD POOR
FLYING CONDITIONS /IFR TO LIFR/ EXPECTED IN RAIN OF VARYING
INTENSITY SUNDAY NIGHT THROUGH MONDAY AS A WARM/COLD FRONT
COMBINATION MOVES THROUGH THE REGION.

OUTLOOK...

MON...SHOWERS EXPECTED WITH IFR/LIFR LIKELY IN THE
MORNING...POSSIBLY IMPROVING TO OCNL MVFR MONDAY AFTERNOON WITH
SCATTERED TSRA DEVELOPING ACROSS THE WRN HALF OF PENN ALONG AND
JUST AHEAD OF A COLD FRONT..

TUE-THU...MVFR AND OCNL IFR LIKELY ACROSS THE NRN AND WRN MTNS
WITH SCATTERED SHOWERS OF RAIN /AND SNOW/. VFR TO OCNL MVFR CIGS
AND VSBYS IN -SHRASN THROUGHOUT THE CENTRAL RIDGE AND VALLEY
REGION. MAINLY VFR ACROSS THE LOWER SUSQ VALLEY AND ADJACENT SE
PENN AIRFIELDS.

&&

.FIRE WEATHER...
IT WILL BE WARM AND DRY FOR THE REST OF TODAY...WITH A GUSTY NW
WIND IN THE WAKE OF A DRY COLD FRONT.

WIND GUSTS OF 20-30 MPH WILL BE COMMON ACROSS THE NE THIRD OF THE
STATE THROUGH 23Z...WITH LESS IN THE WAY OF WIND ACROSS THE SW
PART OF THE FORECAST AREA.

RELATIVE HUMIDITY WILL STAY IN THE 25 TO 30 PERCENT RANGE FOR THE
NEXT FEW HOURS BEFORE SLOWLY INCREASING BY SUNSET AS TEMPS COOL
BUT DEWPOINTS STAY NEARLY THE SAME.

DRY FINE FUELS AND THE GUSTY WINDS MEET THE RED FLAG WARNING
CRITERIA...AND WILL KEEP THE RFW GOING THROUGH ITS EXPIRATION AT
00Z SUNDAY.

WHILE WINDS FROM THE SE MAY BECOME GUSTY...WE WILL SEE AN
INCREASE IN MOISTURE FROM THE S/SE AND A STEADY MODERATE RAIN WILL
MOVE IN SUNDAY EVENING.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR PAZ006-011-
012-018-019-025>028-037-041-042-045-046-049>053-056>059-063.

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...RXR
AVIATION...LAMBERT
FIRE WEATHER...LAMBERT



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