Severe Thunderstorm Warning 203, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
230 PM EDT TUE AUG 9 2011

.SYNOPSIS...
AN UNSEASONABLY DEEP 500 HPA TROUGH WILL DOMINATE THE PATTERN OVER
OUR REGION AND MUCH OF THE EASTERN UNITED STATES THROUGH MOST OF
THE FORECAST PERIOD. A SERIES OF IMPULSES MOVING THROUGH THE
NORTHWEST FLOW COULD TRIGGER SHOWERS AS EACH USHERS IN COOLER
DRIER AIR FROM THE NORTHWEST. AFTER TO DAYS WAVE...MOST WILL BE
MOISTURE STARVED. OVERALL IT WILL BE COOLER THROUGH MOST OF THE
COMING WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
ATTEMPTED TO USE RADAR AND HIGH RESOLUTION MODELS TO THE
PROGRESSION OF THE MORE ORGANIZED RAIN AND THUNDERSTORMS MOVING
ACROSS SOUTH CENTRAL PA THIS AFTERNOON. KEPT POPS IN THE 20 TO 35
RANGE FOR MOST AREAS OUTSIDE OF THIS ESE MOVING FEATURE. FOLLOWED
IT UNTIL ABOUT 8 PM. ADDED SOME CONVECTION IN THE SOUTHWEST BASED
ON HRRR AND 4KM NAM SHOWING LESS ORGANIZED SHRA/TSRA IN THE WEST
AGAIN LATER THIS AFTERNOON AND EARLY EVENING.

DUE TO CLOUDS AND RAIN...TEMPS HAVE DONE SOME YOYOING SO TRIED TO
SHOW THIS BETTER AND WAS FORCED TO LOWER THE TEMPS OVER MOST AREAS.

CLOUDS WERE PROBLEMATIC INTEGRATED SATELLITE...VIS ONLY...INTO
MOS/MODEL BLEND AT 8 PM TONIGHT.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
SOME PATCHY FOG IS LIKELY OVERNIGHT WITH THE RESIDUAL RAIN. KEPT
THE TEMPS CLOSE TO GUIDANCE. SHOWED VISBY IN GRIDS ONLY IN THE 3-4
RANGE. SOME TAF SITES ARE LOWER.

ANY FOG AND LOW CLOUDS SHOULD BURN OFF WITHIN 1-3 HOURS OF SUNRISE.

NEW GUIDANCE IS NOT AS ROBUST WITH RAINFALL POTENTIAL ON
WEDNESDAY. I LEANED TOWARD THE DRIER SREF AND GEFS GUIDANCE. BOTH
INDICATED THE WAVE SOME GFS MEMBERS HAD...AND THUS HIGHER
POPS...SHOULD PASS TO OUR SOUTH AND WEST TOMORROW.

WEDNESDAY SHOULD BE A BETTER DAY FOR MOST THAN TODAY WAS. PW VALUE
ARE FORECAST TO BE BELOW NORMAL WEDNESDAY. ANY SHOWERS SHOULD BE
SHORT-LIVED AND LACK MOISTURE. THERE IS A FRONT IN THE NW FLOW
WITH COLDER 850 HPA TEMPS BEHIND IT TO SERVE AS A TRIGGER...BUT
THE AIR IS DRY.

TEMPS CLOSE TO GUIDANCE AND LOWER POPS RELATIVE TO PREVIOUS
FORECAST IS THE KEY.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ZONAL AND MODERATELY PROGRESSIVE FLOW WILL TRANSITION TOWARD
MORE AMPLIFICATION TOWARD THE END OF THE PERIOD...WITH LARGE
TROUGHS FORMING ALONG THE WEST COAST AND OVER THE GREAT
LAKES...AND AN UPPER RIDGE DEVELOPING BETWEEN. THE GRADUAL
LONGWAVE PATTERN CHANGE SHOULD BE ACCOMPANIED BY A SIGNIFICANT
REDISTRIBUTION OF THE HEAT WHICH HAS PLAGUED PARTS OF THE CONUS
THIS SUMMER...WITH THE HOTTEST TEMPERATURES SHIFTING TOWARD THE
DEEP SOUTH EARLY IN THE PERIOD BEFORE EXPANDING WESTWARD THEN
NORTHWARD BENEATH THE BUILDING RIDGE OVER THE ROCKIES.
THEREFORE...EXPECT CENTRAL PA TO EXPERIENCE A COOLER THAN NORMAL
PERIOD AS A LONGWAVE TROUGH EXTENDS SOUTHWARD FROM HUDSON BAY. IN
TERMS OF SENSIBLE WEATHER...A LARGE AREA OF HI PRES AND
ACCOMPANYING BELOW NORMAL PRECIPITABLE WATER VALUES WILL
OVERSPREAD THE STATE THURS-FRI PROVIDING FAIR AND DRY CONDS.
MORNING LOWS COULD BE CHILLY WITH READINGS IN THE UPPER 40S AND
LOW 50S. A SHORTWAVE TROUGH AND ASSOCIATED LOW PRES/FNTL SYSTEM
WILL BRING THE NEXT CHANCE FOR RAIN SAT-SUN.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
A LINE OF SHOWERS AND THUNDERSTORMS IS MOVING THROUGH SOUTHWESTERN
SECTIONS...NEAR RELEASE TIME THERE WAS A THUNDERSTORM AT KJST.
THIS LINE WILL WORK ITS WAY EAST SO MENTION VCTS OR CB IN THE TAFS
TIMING THE LINE ACROSS THE STATE. STRONGEST STORMS WERE WELL TO
OUR EAST THIS AFTERNOON. GOING EAST THIS AFTERNOON...CHECK THE
RADAR.

DUE TO CYCLONIC FLOW A FEW MORE POP UP SHOWERS ARE LIKELY MONITOR
RADAR BEFORE FLYING.

SHOWER ACTIVITY SHOULD DIMINISH THIS EVENING. ALL THE
MOISTURE LAID DOWN WILL CAUSE PATCHY FOG AT MOST LOCATIONS
ESPECIALLY VALLEY LOCATIONS.

WEDNESDAY SHOULD BE A BIT BETTER THAN TODAY...FEWER ORGANIZED
BANDS OF SHOWERS AND STORMS. THOUGH COULD BE AREAS MVFR AND IFR A
FEW HOURS EITHER SIDE OF SUNRISE.

THU INTO AT LEAST THE FIRST PART OF SAT LOOK DRY AT THE CURRENT
TIME...WITH MAINLY VFR CONDITIONS.

OUTLOOK...
WED...AM FOG POSSIBLE. CHC OF MVFR SCTD SHRA/TSRA.
THU...MAINLY VFR COULD BE SOME MVFR WITH SOME PASSING SHOWERS.
FRI...PRIMARILY
VFR. SAT...PRIMARILY VFR. CHC OF SHRA/TSTM LATE EVENING OR
OVERNIGHT INTO SUNDAY.

&&

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

&&

SYNOPSIS...GRUMM
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM
LONG TERM...STEINBUGL
AVIATION...GRUMM/MARTIN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
248 AM EDT TUE AUG 9 2011

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-100700-
WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD-
NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN-
JUNIATA-SOMERSET-BEDFORD-FULTON-FRANKLIN-TIOGA-NORTHERN LYCOMING-
SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR-
NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND-
ADAMS-YORK-LANCASTER-
248 AM EDT TUE AUG 9 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
212 PM EDT TUE AUG 9 2011

PAZ026-028-056-063-091845-
CUMBERLAND PA-HUNTINGDON PA-JUNIATA PA-PERRY PA-
212 PM EDT TUE AUG 9 2011

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT EAST CENTRAL
HUNTINGDON...JUNIATA...NORTHWESTERN CUMBERLAND AND PERRY COUNTIES...

AT 208 PM EDT...A LINE OF STRONG THUNDERSTORMS WAS LOCATED FROM
MIFFLINTOWN TO PERULACK...MOVING EAST AT 30 MPH.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THESE STORMS. THESE STORMS
WILL AFFECT SPRUCE HILL...THOMPSONTOWN...MILLERSTOWN AND COLONEL
DENNING STATE PARK.

THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 11/15...ROUTE
322/22.

LAT...LON 4027 7766 4029 7767 4027 7769 4032 7786
      4037 7779 4037 7776 4050 7761 4063 7743
      4061 7695 4057 7699 4052 7699 4020 7741

FORECASTER: KREKELER