Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 231142
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
742 AM EDT SAT AUG 23 2014

.SYNOPSIS...
A MOIST LOW LEVEL EASTERLY FLOW WILL CREATE PLENTY OF CLOUDS...
COOL TEMPERATURES...AND PERIODS OF RAIN AND DRIZZLE FOR MUCH OF
THE REGION TODAY INTO TONIGHT. UPPER RIDGING WILL SLOWLY BUILD
OVER THE REGION BY SUNDAY...BRINGING AN END TO THE RECENT SIEGE OF
SHOWER AND THUNDERSTORM ACTIVITY. THE UPPER RIDGE WILL DOMINATE
THE WEATHER PATTERN OVER THE NORTHEAST UNITED STATES AND
SOUTHEASTERN CANADA DURING THE EARLY AND MIDDLE PART OF THE
UPCOMING WEEK...WITH THE NEXT CHANCE OF RAINFALL NOT ARRIVING
UNTIL LATE WEDNESDAY OR THURSDAY FROM AN APPROACHING MIDWESTERN
FRONTAL SYSTEM.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK...1014 MB SFC LOW WAS CENTERED JUST TO THE WEST OF THE
LAUREL HIGHLANDS EARLY TODAY...WITH AN INVERTED TROUGH EXTENDING
NORTH ALONG THE ROUTE 219 CORRIDOR. MEANWHILE...A BACKDOOR FRONT
WAS PRESSING SLOWLY WESTWARD FROM THE SUSQ VALLEY EARLY THIS
MORNING...SPARKING A FEW NEARLY STATIONARY AREAS OF VERY HEAVY
RAIN AND ONE SMALL AREA OF FLASH FLOODING JUST TO THE WEST OF
KSEG.

DIGITAL PRECIP RATES HAVE DROPPED OFF SIGNIFICANTLY OVER THE PAST
HOUR OR SO WITH JUST A FEW SMALL AREAS EXCEEDING ONE INCH PER
HOUR. THE WARM CLOUD DEPTH IS SEVERAL KFT...AND NO LIGHTNING HAS
OCCURRED IN THESE TROPICAL LIKE RAIN SHOWERS ACROSS THE CWA OVER
THE PAST SEVERAL HOURS.

THE PERSISTENT...AND ANOMALOUS SFC-850 MB EAST TO SERLY FLOW AND
APPROX 1.5 INCH PWAT AIR WILL MAINTAIN WIDESPREAD/THICK CLOUD
COVER AND INCREASING COVERAGE OF LIGHT TO MODERATE RAIN AS WE HEAD
THROUGH THE SECOND HALF OF THIS MORNING.

PERIODS OF RAIN/DRIZZLE AND FOG-SHROUDED RIDGE TOPS WILL OCCUR
THIS AFTERNOON INTO THIS EVENING BEFORE SFC HIGH PRESSURE AND
DRIER PWAT AIR ADVECTS SOUTH AND SWWD INTO THE AREA. BASED ON
A BLEND OF THE EC...SREF AND GEFS...RAINFALL AMOUNTS TODAY SHOULD
AVERAGE BETWEEN 2 AND 3 TENTHS ACROSS MUCH OF CENTRAL PENN AND
THE SUSQ VALLEY...WITH LESS AMTS FOR MOST LOCATIONS NEAR AND TO
THE WEST OF RT 219 IN WRN PENN.

FAR NORTHWEST SECTIONS...AWAY FROM THE MARITIME FLOW AND IN
DOWNSLOPE FLOW...MAY WARM INTO THE 70S. THE RESULTING INSTABILITY
COULD POTENTIALLY RESULT IN A PM TSRA ACROSS WARREN CO.

TEMPS MAINLY IN THE MID TO UPPER 60S AT 0830Z...WON/T BUDGE MUCH
AT ALL TODAY...THANKS TO THE INCREASING COVERAGE OF RAIN AND FEW
DEG OF WET BULB COOLING. THE AFTERNOON READINGS IN THE U60S WILL
BE NEARLY 15F BELOW ACROSS THE SUSQ VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
MOSTLY CLOUDY TO OVERCAST SKIES WILL PERSIST FOR MUCH /OR PERHAPS
ALL OF THE OVERNIGHT/ WITH A CHANCE OF LIGHT RAIN AND DRIZZLE
MAINLY BEFORE MIDNIGHT...AND ACROSS THE SE HALF OF THE CWA.

ANY CLEARING LATE TONIGHT WILL COMBINE WITH THE MOIST GROUND AND
LIGHT WIND TO PRODUCE AREAS OF FOG...THAT WILL BECOME LOCALLY
DENSE AFTER MIDNIGHT. LOW TEMPS EARLY SUNDAY WILL RANGE FROM THE
MID 50S ACROSS THE NORTH...TO AROUND 60F IN THE SOUTHERN VALLEYS.

A POCKET OF MUCH LOWER PWAT AIR BELOW ONE INCH WILL ADVECT SSW
INTO THE CWA DURING THE DAY SUNDAY ACCOMPANIED BY A SPRAWLING
1022 MB AREA OF SFC HIGH PRESSURE.

AREAS OF MORNING CLOUDS AND PERHAPS SOME PATCHY LIGHT DRIZZLE...
WILL TRANSITION INTO INCREASINGLY SUNNY SKIES DURING THE MIDDAY
AND AFTERNOON HOURS SUNDAY. TEMPS SUNDAY WILL REBOUND NICELY FROM
SATURDAY/S CHILL WITH AFTERNOON HIGHS IN THE MID 70S ACROSS THE
MTNS...AND AROUND 80F THROUGHOUT THE SUSQ VALLEY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EXTENDED WILL FEATURE A HIGH AMPLITUDE...588 DAM UPPER RIDGE
ACROSS THE MISS RIVER VALLEY SUNDAY...NOSING ACROSS THE GLAKES
REGION AND INTO SERN CANADA EARLY IN THE WEEK.

FAIR WEATHER WILL DEVELOP ALONG WITH WARMING TEMPERATURES AS THE
RIDGE ESTABLISHES ITSELF AND MAINTAINS ITS HOLD UNTIL AT LEAST
THURSDAY WHEN THE NEXT FRONTAL SYSTEM IS ADVERTISED TO
APPROACH...ALBEIT IN DIFFERENT FASHIONS BY THE VARIOUS MED RANGE
GUIDANCE PACKAGES.

THE OPERATIONAL GFS AND ECMWF KEEP US DRY THROUGH AT LEAST LATER
WEDNESDAY WHILE THE GEFS IS MORE PESSIMISTIC BRINGING MEASURABLE
RAINS EAST QUICKER UNDER A FLATTER UPPER FLOW. THE GEFS UPPER
PATTERN MORE CLOSELY RESEMBLES THE OPERATIONAL ECMWF SHOWING A
WEAKER TROUGH HANGING BACK IN THE MID WEST AS HEIGHTS IN THE EAST
SLOWLY FALL WITH THE EAST COAST RIDGE FLATTENING OUT IN TIME.

THE DIFFERENCES ARE AT THE END OF THE FORECAST PERIOD THROWING
DOUBT ON THE FORECAST SO I OPTED FOR A RATHER BLAND CHANCE OF
SHOWERS STARTING WEDNESDAY NIGHT LASTING INTO THURSDAY NIGHT.

OVERALL THE LAST FULL WEEK OF AUGUST WILL BE A SUMMERY ONE FOR
THE FIRST DAYS OF SCHOOL IN MANY COMMUNITIES. TEMPS WILL BE NEAR
TO A BIT ABOVE NORMAL MONDAY...THEN WILL REMAIN ABOVE NORMAL AT
LEAST THROUGH THE END OF THE WEEK WHEN THE AIRMASS SITUATION
BECOMES A LITTLE LESS CERTAIN.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHOWER ACTIVITY CONTINUES OVER MUCH OF CENTRAL AND EASTERN
PENNSYLVANIA. WIDESPREAD MVFR TO IFR CONDITIONS ACROSS THE
REGION...WITH FOG AND LOW CIGS. SOME AREAS OF LIFR TO VLIFR OVER
THE WESTERN AND NORTHERN MOUNTAINS REGION.

MORNING LOW CLOUDS AND FOG...ALONG WITH SHOWERS AND PATCHY
DRIZZLE...WILL SLOWLY GIVE WAY TO A BRIEF WINDOW OF VFR
CONDITIONS ACROSS THE REGION DURING THE MID AND LATE AFTERNOON.
HOWEVER...FOG AND CEILING RESTRICTIONS WILL AGAIN OVERSPREAD THE
AREA TONIGHT.

IN THE LONGER RUN...HIGH PRESSURE WILL SLOWLY BUILD INTO THE
NORTHEAST THROUGH THE WEEKEND AND INTO MID WEEK. FRONT APPROACHING
LATER WEDNESDAY AND THURSDAY MAY BRING THE NEXT ROUND OF
SHRA/TSRA.

OUTLOOK...
SUN...LOW CIGS AND FOG EARLY...THEN VFR
MON- WED...MORNING RESTRICTIONS FROM FOG POSSIBLE...OTHERWISE
VFR.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LA CORTE/LAMBERT
AVIATION...JUNG


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