Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 031040
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
640 AM EDT SUN MAY 3 2015

.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHERN APPALACHIANS WILL DRIFT EAST AND
OFF THE CAROLINA COAST TONIGHT. A DEVELOPING SOUTHWESTERLY FLOW
WILL LEAD TO WARMER TEMPERATURES THAT WILL CONTINUE THROUGH AT
LEAST THE MIDDLE OF THE UPCOMING WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9 IR SATL LOOP AND SFC OBS INDICATING JUST SOME PATCHES OF
MID LEVEL AC CLOUDS ROAMING ABOUT THE AREA EARLY THIS MORNING.
A RIDGE OF HIGH PRESSURE EXTENDING NORTH/SOUTH ACROSS THE SUSQ
VALLEY WAS PROVIDING VERY LIGHT AND VARIABLE WIND...AND DRY
DEWPOINTS LEADING TO STRONG RADIATIONAL COOLING OF THE AIR NEAR
THE GROUND.

MESO OBS SHOW TEMPS HAVE PLUMMETED WELL INTO THE 30S THROUGHOUT
THE NORMALLY COLD VALLEYS UP NORTH. COUDERSPORT IN CENTRAL POTTER
COUNTY TAKE THE PRIZE FOR THE ICE BOX SO FAR THIS MORNING WITH A
TEMP OF 30F AT 0815Z. READINGS IN THE 40S TO LOWER 50S WERE COMMON
THROUGHOUT MOST OF THE REST OF CENTRAL PENN AND THE SUSQ VALLEY.

TEMPS WILL FALL ANOTHER 2 OR 3 DEG F OVER THE NEXT FEW HOURS WITH
MINS AT SUNRISE VARYING FROM THE LOW-MID 30S ACROSS THE NW
MTNS...TO 45-50F IN THE LOWER SUSQ VALLEY. THE COLDEST SPOTS IN
THE NORTH SHOULD DIP TO ABOUT 28F WITH FROST.

PATCHY FOG AND AREAS OF LOW CLOUDS ARE POSSIBLE FOR A FEW HOURS
AROUND DAYBREAK ACROSS LANCASTER CO...WHERE MDLS POOL LL MOISTURE
IN VICINITY OF OLD SFC TROF.

FOR THE REST OF TODAY...NICE EARLY MAY WEATHER IS ON TAP. ASIDE
FROM SOME PATCHY HIGH BASED CU OR ALTO CU...AND SOME THIN
CIRRUS...CONDITIONS WILL BE MOSTLY SUNNY TO SUNNY.

HIGH TEMPS THIS AFTERNOON WILL BE SIMILAR...IF NOT A DEG OR TWO F
WARMER THAN SATURDAY...RANGING FROM AROUND 70 ACROSS THE NORTHERN
MTNS...TO BETWEEN 74 AND 78F IN THE SOUTHERN VALLEYS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
DEEPENING...THOUGH STILL RELATIVELY WEAK SWRLY FLOW WILL LEAD TO
JUST SOME PATCHY HIGH BASED STRATO CU AND ALTO CU CLOUDS WITH VERY
LIGHT SFC WIND. TEMPS SHOULD BE ABOUT 5 DEG F MILDER EARLY MONDAY
COMPARED TO SUNRISE SUNDAY. STILL...A FEW MID TO UPPER 30S SHOULD
BE SCATTERED ABOUT THE COLD SPOTS OF THE NORTHERN MTNS.

MONDAY WILL FEATURE MORNING SUNSHINE FOLLOWED BY SCT-BKN AFTERNOON
CU. ANY CHC FOR SHRA/TSRA SHOULD BE ACROSS THE NW MTNS AND LIMITED
TO LATE IN THE AFTERNOON AND EVENING AS A COLD FRONT SAGS SE FROM
THE GLAKES.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
SHORTWAVES TRACKING EAST ACROSS SOUTHERN CANADA TO NORTH OF THE
GREAT LAKES WILL HELP PUSH A BACKDOOR-STYLE SFC COLD FRONT INTO
CENTRAL OR SRN PA BY EARLY TUESDAY. THE FRONT WILL WAVER NEAR OR
MORE LIKELY JUST TO THE SOUTH OF THE MASON-DIXON LINE INTO THE
MIDDLE OF THE UPCOMING WEEK...AND WILL SERVE AS A FOCUS FOR
CLOUDS AND SHOWERS MAINLY ALONG AND NORTH OF THE BOUNDARY.

THE LATEST ENSEMBLE DATA SHOWS ABOVE NORMAL PWS ALONG THE E-W
FRONTAL ZONE WHICH IS USUALLY A GOOD INDICATOR OF AT LEAST CLIMO
OR BETTER POPS BUT DUE TO THE N-S MDL QPF DIFFERENCES WILL UTILIZE
A BLEND AND CAP POPS AROUND THE HIGH CHC LEVEL /40-50 PCT/ FOR
DAYS 3-4.

FROM THE MIDDLE TO LATER PART OF THE WEEK...THE GLOBAL NUMERICAL
MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRESSURE MOVING EAST FROM
THE NORTHERN HIGH PLAINS TO THE WESTERN GREAT LAKES/UPPER MIDWEST
BY FRIDAY. THIS SHOULD ALLOW THE WRN PORTION OF THE E-W FRONTAL
ZONE TO BE LIFT NWD THROUGH THE OH VLY WHILE THE ERN SEGMENT
WEAKENS AND WAVERS JUST WEST/SOUTH OF THE PA AND OH/WV/MD BORDERS.
IN GENERAL THE PCPN PATTERN SHOULD BE MORE SUMMER-LIKE WITH WEAK
FORCING UNDER HIGH HEIGHTS ALOFT AND SCT DIURNAL SHOWER/ISOLD TSTM
ACTIVITY NEAR THE BNDRY AND PERHAPS INITIATING OVER THE WRN HIGH
TERRAIN. THEREFORE KEPT POPS IN THE SCHC TO LOW CHC RANGE WED-FRI
WITH GRADUAL INCREASE INTO THE WEEKEND AS THE PLAINS FRONTAL
SYSTEM APPROACHES.

TEMPERATURES SHOULD AVG NEAR TO ABOVE NORMAL THROUGH THE PERIOD.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NO BIG CHANGES NEEDED FOR THE 12Z TAF PACKAGE.

ONLY A FEW MID LVL CLDS TO THE EAST.

EXPECT VFR CONDITIONS TODAY...WITH RATHER LIGHT WINDS FOR THIS
TIME OF YEAR. A TASTE OF FINE SPRING WEATHER.

AN APPROACHING COLD FRONT MAY TRIGGER SOME SHOWERS ACROSS
NORTH CENTRAL PA ON TUESDAY. THE FRONT WILL LIKELY SLOW AND
CREATE LOW CIGS/SHOWERS AGAIN ON WED. THE FRONT MAY PUSH TO THE
SOUTH ON THURS.

OUTLOOK...

TUE...VFR EARLY...THEN SHRA IN THE NORTH.
WED-THU...MORE SHOWERS POSSIBLE.

&&

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

&&

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


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