Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 250623
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
223 AM EDT SAT APR 25 2015

.SYNOPSIS...
HIGH PRESSURE WILL BRING A CLEAR AND COLD CONDITIONS EARLY TODAY
ACROSS MUCH OF CENTRAL AND EASTERN PENNSYLVANIA...WHILE A LAYER OF
MID LEVEL CLOUDS SPREADS INTO THE WESTERN PART OF THE STATE.
LOW PRESSURE MOVING FROM THE MID MISSISSIPPI TO THE CAROLINA
COAST THIS WEEKEND WILL BRING THE RISK OF LIGHT RAIN ACROSS
SOUTHERN PENNSYLVANIA LATER TODAY INTO SUNDAY...WITH THE
POSSIBILITY OF SOME WET SNOW MIXING IN ACROSS THE HIGHEST
ELEVATIONS OF THE LAUREL HIGHLANDS. A PERSISTENT UPPER LEVEL
TROUGH OVER THE NORTHEASTERN UNITED STATES WILL FAVOR UNSEASONABLY
COOL TEMPERATURES THROUGH THE END OF THIS MONTH.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
MCLEAR SKIES...DRY AIR /WITH SFC DEWPOINTS IN THE LOWER TO MID
TEENS/...AND A LIGHT NORTH TO NW WILL OCCUR FOR THE NEXT SEVERAL
HOURS AS A RIDGE OF SFC HIGH PRESSURE SLIDES EAST ACROSS THE
REGION. THESE FAVORABLE CONDITIONS FOR RADIATIONAL COOLING OF THE
EARTH/S SURFACE WILL ALLOW TEMPS TO TUMBLE TO NEAR RECORD LOWS
ACROSS PARTS OF CENTRAL PA EARLY TODAY.

ALL GUIDANCE CONTINUES TO POINT TOWARD A NEAR CERTAINTY OF BELOW
FREEZING TEMPS ACROSS CENTRAL/NORTHERN PA. ACROSS THE SOUTHERN
COUNTIES...IT MAY BE A CASE OF URBAN AREAS/HILLTOPS REMAINING JUST
ABV FREEZING...WHILE THE NORMALLY COLDER VALLEYS GET A FREEZE.

A FREEZE WARNING REMAINS IN EFFECT THROUGH 13Z TODAY FOR THE
COUNTIES ACROSS THE SOUTHEAST...WHERE GROWING SEASON HAS BEGUN.
HOWEVER...LATEST GUIDANCE SUGGESTS NOT ALL SPOTS ACROSS THE SE
WILL DROP BLW FREEZING. IT MAY BE THE COLDEST MORNING UNTIL THE
FALL. RECORD LOWS OF 30F AND 26F AT KMDT AND KIPT ARE PROBABLY
SAFE...BUT IT SHOULD BE CLOSE.

INITIAL ARM OF MID LEVEL WAA LIGHT RAIN /AHEAD OF A WEAKENING
SHORTWAVE TROUGH/ WAS SPREADING SE ACROSS WRN LAKE ERIE AND NRN
OHIO AT 0530Z. HIGH RES MODELS INDICATE THAT MOST OR ALL OF THIS
RAIN WILL FIZZLE OUT AS IT HEADS INTO THE RIDGING AND VERY DRY
LLVL AIR ACROSS THE FCST AREA. THERE COULD BE A FEW LIGHT
FLURRIES...OR ICE PELLETS THAT FALL FROM THE INCREASING MID CLOUD
DECK ACROSS THE LAUREL HIGHLANDS WITHIN A FEW HOURS EITHER SIDE
OF SUNRISE. KEPT POPS THERE BELOW 20 PERCENT THIS MORNING.

THE INCREASING CLOUDS ACROSS THE SW COUNTIES EARLY TODAY SHOULD
LEAD TO TEMPS SLOWLY RISING BEFORE DAWN.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SUNDAY/...
LATEST GUIDANCE SUGGESTS WEAK SHORTWAVE...WHICH COULD PRODUCE AN
EARLY AM -SHRASN OVR PARTS OF THE LAUREL HIGHLANDS...WILL PASS
SOUTH OF THE STATE SHORTLY AFTER 12Z. THE REST OF THE DAYLIGHT
HOURS LOOK DRY ACROSS NEARLY ALL OF THE AREA...AS RIDGING ALOFT
WORKS INTO THE STATE. WAA ALOFT IN ADVANCE OF A MORE POTENT
SHORTWAVE LIFTING OUT OF THE MISS VALLEY SHOULD SPREAD A FAIR AMT
OF MID/HIGH LVL CLOUDINESS ACROSS SW PA. RH TIMESECTIONS SUPPORT
MAINLY CLOUDY WORDING ACROSS THE SW HALF OF THE CWA AND MSUNNY
ACROSS THE NE COUNTIES. TEMPERATURES WILL CONTINUE TO RUN BELOW
AVERAGE...THOUGH SHOULD RECOVER SIGNIFICANTLY AFTER THE CHILLY
MORNING.

WEAKENING SHORTWAVE APPROACHING FROM THE MISS VALLEY WILL LIKELY
SPREAD RAIN INTO THE SW COUNTIES TOWARD EVENING. MDLS SHOWING A
SHARP MOISTURE GRADIENT ACROSS SOUTHERN PA TONIGHT. THUS...WILL
CARRY CAT POPS ACROSS SOMERSET CO OVERNIGHT...BUT CARRY NO
MENTION OF RAIN FROM I-80 NORTHWARD. ONLY A FEW ENSEMBLE MEMBERS
BRING MEASURABLE RAIN AS FAR NORTH AS KUNV.

POPS DECREASE LATE TONIGHT/EARLY SUNDAY...AS LG SCALE FORCING
WANES BEHIND DEPARTING SHORTWAVE. HOWEVER...MDLS INDICATE
LINGERING FGEN FORCING/DEEP LYR MOISTURE ALONG THE S TIER THRU SUN
AM...SO OCNL LGT RAIN MAY LINGER THRU SUN AM DOWN THERE.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
WAVE SLIDING W-E THROUGH THE MID ATLANTIC REGION ALONG A FRONTAL
BOUNDARY WILL KEEP MENTION OF PRIMARILY LIGHT RAIN IN THE FORECAST
HEADING INTO SUNDAY FOR SOUTHERN PORTIONS OF CWA...WITH PRECIP
SHIELD ALREADY RECEDING TOWARD THE SE BY 12Z SUN...AND EXITING
THE REGION BY LATE MORNING. CONSENSUS OF MED RANGE MDLS SUPPORTS
FAIR AND COOL WX FOR REMAINDER OF SUNDAY...AS WEAK SFC RIDGING
BUILDS SOUTHWARD ACROSS PA.

EARLY NEXT WEEK A SHOT OF COOL UNSETTLED WEATHER ARRIVES AS A BACK
DOOR COLD FRONT IS NUDGED SOUTHWARD ACROSS PA FROM AN UPPER LOW
OVR NEW ENG. COOL TEMPS ALOFT ASSOC WITH UPPER LOW WILL LIKELY
LEAD TO A GOOD DEAL OF DAYTIME CLOUDINESS AND SCT SHRA /ESP OVR
THE MTNS/ MONDAY AND TUESDAY.

BY MIDWEEK...THIS LOW FINALLY LIFTS OUT FOR GOOD. BUT DIGGING
TROUGH FROM UPPER MIDWEST WILL EXTEND INTO THE SOUTHEAST U.S. BY
LATE WEEK...COMBINED WITH A SOUTHERN STREAM SHORTWAVE LIFTING OUT
OF THE S PLAINS TOWARD THE E COAST WILL BRING POSSIBILITY OF A
DEVELOPING STORM SLIDING NORTHEASTWARD OFF THE EASTERN SEABOARD.
TRACK/STRENGTH STILL QUITE UNCERTAIN...BUT AT THIS TIME LOOKS LIKE
WE/LL BE BETWEEN THAT LOW PRESSURE AREA AND A HIGH OVER OHIO
VALLEY...LIKELY KEEPING CLOUDS AND SCT SHOWERS AROUND AS TEMPS
COOL BACK DOWN A BIT.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SFC HIGH PRES INITIALLY PROVIDING M/CLR SKIES AND LGT/VRB WINDS
WILL YIELD TO LOW PRESSURE TRACKING EASTWARD FROM THE CENTRAL
PLAINS TO JUST WEST OF THE CENTRAL APPALACHIANS BY TONIGHT BEFORE
REDEVELOPING OFF THE NC COAST ON SUNDAY. CLOUDS WILL THICKEN AND
GRADUALLY LOWER TODAY BUT EXPECT FLGT CATS TO GENERALLY REMAIN
VFR. JST AND AOO HAVE THE HIGHEST RISK FOR A PERIOD OF LIGHT RAIN
AND MVFR CIGS FROM THIS EVENING THROUGH TONIGHT.

A LARGE UPPER LEVEL LOW OVER NEW ENGLAND WILL DOMINATE THE
REGIONAL WEATHER PATTERN EARLY NEXT WEEK WITH SEVERAL SMALL SCALE
DISTURBANCES ROTATING AROUND THE WESTERN PERIPHERY OF THE
CIRCULATION CENTER. THE MODELS SEEM TO AGREE THAT ONE OF THESE
DISTURBANCES WILL BRING A PERIOD OF SHOWERS TO THE AIRSPACE ON
MONDAY. THE N-NW FLOW SHOULD FAVOR THE GREATEST RISK OF MVFR CIGS
OVER THE NRN AND WRN AIRSPACE IN ZOB SECTOR.

OUTLOOK...
TUE...IMPROVING CONDITIONS WEST TO EAST.
WED...GENERALLY VFR EARLY WITH CHC OF PM SHOWERS.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR PAZ026>028-035-
036-049>052-056-057-059-063>066.

&&

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



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