-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 301542
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1142 AM EDT WED JUL 30 2014

.SYNOPSIS...
THE UPPER LEVEL LOW OVER THE UPPER GREAT LAKES AND EASTERN CANADA
WILL PERSIST INTO THE WEEKEND. WHILE THE UPPER LOW MAY OPEN UP
AND LIFT A BIT NORTHWARD...AN OFF SHORE HIGH PRESSURE AREA WILL
DIRECT MORE GULF AND ATLANTIC MOISTURE INTO THE REGION OVER THE
WEEKEND. TEMPERATURES WILL REMAIN COOLER THAN NORMALS.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
-- Changed Discussion --
11 AM UPDATE...

MID LEVEL CLOUDS WERE SPREADING EAST ACROSS NRN AND WRN PENN
/AND ABOUT TO SPILL OVER INTO THE CENTRAL RIDGE AND VALLEY
REGION/ AS A RESULT OF WEAK WESTERLY ISENTROPIC UPGLIDE WITHIN
THE 300-310K THETA LAYER.

BREAKS IN THIS CLOUD DECK WILL COMBINE WITH BLYR HEATING AND WEAK
LARGE SCALE LIFT AHEAD OF AN APPROACHING UPPER LEVEL SHORT WAVE TO
BRING A BKN LINE OR TWO OF SHOWERS AND ISOLATED LOW-TOPPED TSRA
TO THE NW HALF OF THE CWA THIS AFTERNOON AND EARLY THIS EVENING.

THE LOWER SUSQ VALLEY MAY STAY DRY RIGHT THROUGH THE DAYLIGHT
HOURS BEFORE A FEW WEAKENING SHOWERS DRIFT INTO THE AREA AROUND
DUSK...AS THE LEADING EDGE OF THE POOL OF SLIGHTLY STEEPER MID
LEVEL LAPSE /6-6.5C PER KM/ APPROACHES.

HIGH TEMPS THIS AFTERNOON VARY FROM THE MID AND UPPER 60S ACROSS
THE NW MTNS...TO THE LOWER AND MID 70S IN THE CENTRAL
VALLEYS...AND AROUND 80F THROUGHOUT THE LOWER SUSQ VALLEY.

THESE READINGS ARE STILL WELL BELOW NORMAL IN MOST LOCATIONS
/ESPECIALLY ACROSS THE NW MTNS WHERE THE EARLIER DVLPMT OF THE
CLOUD COVER HAS FLATTENED THE DIURNAL TEMP CURVE/.
-- End Changed Discussion --

&&

.SHORT TERM /8 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE DIURNAL CONVECTION SHOULD SLIDE TO THE EAST THIS EVENING WHILE
DYING OUT. THE COLD AIR ALOFT AND CYCLONIC FLOW WILL LIKELY KEEP A
FEW SHOWERS AROUND THROUGH THE NIGHT IN THE NW. CHC POPS FOR SCT
COVERAGE SHOULD BE FINE THERE. MINS WILL BE BACK CLOSER TO NORMALS
TONIGHT...BUT 40S STILL POSSIBLE IN THE HIGHER ELEVATIONS.

THE UPPER LOW THROWS ONE MORE UPPERCUT ON THURSDAY MORNING...AND
SCT/NMRS SHOWERS EXPECTED IN THE FORE-NOON. THE AFTERNOON MIGHT BE
MAINLY DRY...BUT THE TEMPS ALOFT ARE STILL COOL AND DAYTIME
INSTABILITY SHOULD BE GOOD ENOUGH FOR ISOLD-SCT SHOWERS IN THE
WEST/NORTH. HIGHS ON THURSDAY DO HAVE THE POTENTIAL TO GET BACK TO
NORMAL IN THE SE...BUT THE N/W WILL PROBABLY STILL BE 8-10 DEGS
BELOW SEASONAL NORMALS.

FOR NOW...THE 12-18 HOURS AROUND THE THURSDAY NIGHT PERIOD SEEM
LIKE THE LEAST LIKELY TIME FOR ANY SHOWERS TO DEVELOP. THE BIG
SHORT WAVE WILL HELP TO HEAVE THE UPPER LOW A BIT TO THE NORTH.
HEIGHTS RISE ABOUT 12DAM FROM THURSDAY MORNING TO FRIDAY MORNING.
LOWS THURSDAY NIGHT WILL PROBABLY BE SIMILAR TO THE PREV FEW WITH
SKIES TRYING TO CLEAR AND WINDS LIGHT/VARIABLE.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
A DEEP UPPER LEVEL TROUGH WILL BE PRESENT ACROSS SOUTHEASTERN
CANADA EARLY IN THE LONG TERM PERIOD...BUT WILL RELOAD WITH A
SIGNIFICANT CHUNK ENERGY DIGGING INTO IT/S SW FLANK ACROSS THE
MID MISS AND OHIO RIVER VALLEYS LATE THIS WEEK AND OVER THE
UPCOMING WEEKEND /AS THE CANADIAN PORTION SHEARS OUT TO THE NE/.

THIS POTENT SHORTWAVE TROUGH /AND AN ASSOCIATED WELL-DEFINED RIGHT
ENTRANCE REGION OF A 90-95 KT 300 MB JET/ WILL LIFT NORTHEAST
ACROSS THE MID ATLANTIC REGION FRIDAY THROUGH SUNDAY BEFORE
SHIFTING TO THE SOUTHERN NEW ENGLAND COAST BY THE START OF NEXT
WEEK. A SLOW MOVING /AND LIKELY STRENGTHENING/ BAROCLINIC ZONE...
AND ONE OR MORE WAVES OF WEAK LOW PRESSURE MVG NE ALONG IT WILL
BE LOCATED ACROSS CENTRAL OR ERN PENN DURING THIS 2-3 DAY PERIOD.

PERIODS OF UNSETTLED WEATHER /SHOWERS AND TSTMS/ WILL OCCUR LATER
FRIDAY...SATURDAY AND SUNDAY. THE STRENGTH OF THE LARGE SCALE
FORCING AND INCREASINGLY ANOMALOUS HIGH PWAT AIR BENEATH THE
NORTHWARD MIGRATING JET AND ITS THERMALLY DIRECT BRANCH WILL BRING
THE POTENTIAL FOR SOME LOCALLY HEAVY/TRAINING SHOWERS AND TSRA...
ESP ACROSS THE EASTERN HALF OF THE STATE/.

MODEL DETAILS DIFFER SLIGHTLY WITH RESPECT TO THE TIMING AND
LOCATION OF THE STRONGEST MESO/LARGER SCALE FORCING. BUT ALL
GUIDANCE AGREES ON THE BASIC EVOLUTION AND NE MOVEMENT OF THIS
TROUGH AND AXIS OF HIGH 40-50MM PWAT AIR RIDING NWD UP ALONG THE
MID ATLANTIC PIEDMONT AND SPREADING ACROSS THE EASTERN HALF OF OUR
CWA.

AS A RESULT OF THESE TIMING/LOCATION DIFFERENCES...POPS WERE
CAPPED OFF IN THE HIGH CHC CATEGORY. BUT AS THE FINER DETAILS
UNFOLD WITH HIGHER RES MODEL GUIDANCE OVER THE NEXT FEW
DAYS...POPS WILL UNDOUBTEDLY TREND HIGHER FOR SEVERAL PERIODS
BETWEEN LATE FRIDAY AND SUNDAY.

GRADUAL IMPROVEMENT WITH NEAR NORMAL TEMPS IS EXPECTED FOR EARLY
NEXT WEEK.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
INCREASING /BUT MAINLY VFR CLOUDS/ WILL OCCUR EAST OF THE
I-99/ROUTE 22 CORRIDOR IN CENTRAL PENN THIS AFTERNOON. THE NW MTNS
AND LAUREL HIGHLAND AIRFIELDS WILL SEE A DUAL LAYER OF STRATO CU
AND ALTO CU CLOUDS WITH CONVECTIVE BASES AROUND 3-4 KFT AGL WITH
THE MID LEVEL BASES AROUND 7 KFT AGL. SKC OVER MUCH OF THE SE
THIRD OF PENN WILL BECOME DOTTED WITH SCATTERED CU THIS
AFTERNOON.

THE APPROACH OF A WEAK COLD FRONT AND UPPER TROUGH WILL SPARK
SCATTERED SHOWERS AND ISOLATED TSRA WITH BRIEF MVFR RESTRICTIONS
POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING...MAINLY TO THE NW
OF A LINE FROM KAOO TO KIPT.

MAINLY VFR FOR TONIGHT WITH LINGERING BKN ALTO CU CLOUDS...AND
PERHAPS A FEW STRAY LIGHT SHOWERS.

A STRONGER 500 MB TROUGH WILL ROTATE ACROSS THE AREA
ON THU...THUS SHOWERS AND STORMS WITH SMALL HAIL WILL
LIKELY BE MORE WIDESPREAD THAN TODAY.

PERHAPS A SMALL BREAK IN THE ACTION FOR FRIDAY.
MODELS SHOW SOME CHC OF SHOWERS ACROSS THE SOUTH BY
LATE IN THE DAY. SOME MODEL SPREAD.

WITH THE LONGWAVE TROUGH TO THE WEST...NOT SEEING MUCH
CHANCE FOR ANY ONE DAY BEING DRY PRIOR TO NEXT MONDAY...IF
THEN.

OUTLOOK...
THU...SCT TSRA IMPACTS POSSIBLE.
FRI-SUN...SCT PM TSRA IMPACTS POSSIBLE.
-- End Changed Discussion --

&&

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

&&

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