Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 230928 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 528 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 /10Z SATURDAY THROUGH WEDNESDAY/... SHOWER ACTIVITY CONTINUES OVER THE MIDDLE AND UPPER SUSQUEHANNA VALLEY REGION....AS WELL AS CENTRAL AND SOUTHERN TIER COUNTIES. 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 VFR CONDITIONS ACROSS THE REGION...BUT WITH A SC BKN/OVC DECK OF ABOUT 35K TO 45K ACROSS THE AREA. EXPECT A FEW SHOWERS TO ALSO REGENERATE DURING THE AFTERNOON. 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...FOG AND DRIZZLE EARLY...THEN VFR WITH SCT SHRA. 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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