Flash Flood Warning 22, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
335 PM EDT SAT AUG 1 2009

.SYNOPSIS...
A NEARLY STATIONARY UPPER LOW PRESSURE SYSTEM WILL REMAIN IN THE
VICINITY OF HUDSON BAY FOR THE NEXT WEEK. DISTURBANCES ROTATING
AROUND THIS SYSTEM WILL PUSH A WEAK COLD FRONT THROUGH PENNSYLVANIA
ON SUNDAY. A STRONGER COLD FRONT WILL LIKELY PUSH THROUGH THE
REGION ON TUESDAY.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
ISOLD SHWRS WILL CONTINUE TO DEVELOP OVER PORTIONS OF THE SCENT
MTNS AND LWR SUSQ VLY THROUGH THIS AFTN. RELATIVELY HIGH SBCAPES
AND WEAK DEEP LYR WIND SHEAR SUPPORT SLOW MVMT WITH LCLY HVY RAIN
PSBL. VERTICAL CROSS SECTIONS INDICATED STORMS ARE STRUGGLING TO
GET ABOVE THE -10C LEVEL...AND WHICH SUGGESTS LIGHTNING WILL BE
HARD TO COME BY. THIS ACTIVITY WILL REMAIN WDLY SCT AND DIURNALLY
DRIVEN...DISSIPATING WITH THE LOSS OF DAYTIME HEATING.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY NIGHT/...
WEAKENING FNTL BNDRY WILL APPROACH THE REGION FROM THE GRT LKS
TONIGHT. HAVE BUMPED UP TEMPS OVERNIGHT GIVEN INC CLOUDS/MSTR.
NAM/WRF SUGGESTS LOW CLOUDS DEVELOPING ACROSS THE CENTRAL MTNS AND
SUSQ VLY...AS A REMNANT WARM FRONT LIFTS NEWD ALONG THE MID ATLC
COAST. SOME WARM ADV SHWRS ARE ALSO PSBL AHEAD OF THE FNT LATE TNT.

THE CLD FNT WILL CROSS THE STATE DURING THE DAY ON SUNDAY...ACCOMPANIED
BY SCT TO NMRS SHRWS AND TSRA.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
THE OVERALL PATTERN APPEARS TO KEEP A BROAD MID LVL TROUGH ACROSS
THE CANADIAN PRAIRIES STRETCHING SOUTH THROUGH THE NORTHERN PLAINS
AND WESTERN GREAT LAKES...DRIFTING EAST TOWARDS THE MIDDLE OF NEXT
WEEK. ENSEMBLE MEMBERS BEGIN TO DIVERGE TOWARDS THE LATER PERIODS OF
THE EXTENDED...WHICH SUGGESTS A LOWER CONFIDENCE AS THE PATTERN MAY
BEGIN TO CHANGE TOWARDS MORE SEASONAL CONDS.

MON/TUE WILL FEATURE A WARM SURGE...AS A DECENT 850MB THERMAL RIDGE
RIDES ALONG LEE-SIDE OF APPALACHIANS AT 17 TO 19 DEG C. ISO AREAS
ACROSS SUSQ-VALLEY COULD APPROACH 20 DEG C...AND PROVIDE A COUPLE
DAYS IN THE THE VALLEY/S OF 90 DEGREES. THE WILDCARD WITH TEMPS THIS
WARM WILL BE FLOW AND MOISTURE...WHICH APPEARS ATTM TO BE LGT
WESTERLY/SOUTHWESTERLY SUPPORTING A DOWNSLOPING EFFECT FOR LOWER
SUSQ-VALLEY LOCATIONS MON/TUE AFTN RESPECTIVELY. LLVL LAPSE RATES
SHUD STEEPEN DUE TO SUBSTANTIAL SFC HEATING...ALLEVIATING TO
INCREASED AFTN DESTABILIZATION. SO WILL MAINTAIN CHC FOR SHRA/TSRA
BOTH DAYS...HOWEVER FOCUS WILL BE TUE AFTN.

COLD FRONT IS PRESENTLY POISED TO PUSH THRU THE REGION WED...HOWEVER
TIMING IS DIFFICULT WITH RECENT SOLUTIONS. BEST DYNAMICS SHUD PASS
TO OUR NORTH WITH CURRENT TRACK OF SHORTWAVE IN 500MB TROUGH.
ENSEMBLE MEMBERS SUPPRESS INSTABILITY WED AFTN TO THE
SOUTH...HOWEVER WITH MUCH COOLER AIR ALOFT CAN/T RULE OUT AN AFTN
LOW TOPPED SHRA/TSRA.

BROAD SFC RIDGE IS SUPPORTED BY GEFS TO CLOSE OUT THE
WEEK...THUR/FRI SHUD PRIMARILY BE DRY.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR CONDS WILL PREVAIL THIS AFTN INTO EARLY TNT. XPC SCT-BKN
CUMULUS FIELD WITH BASES 4.5-7KFT AGL. MDL GUID SUGGESTS MVFR/IFR
RESTRICTIONS POSSIBLE AFT MIDNIGHT...MAINLY OVR EAST-CENTRAL SXNS.

WEAK COLD FRONT APPROACHING FROM MIDWEST WILL PROVIDE THE FOCUS
FOR SCT TO NMRS SHRA/TSRA ON SUNDAY. CLEARING SKIES FROM WEST TO
EAST SUNDAY NIGHT MAY RESULT IN AREAS OF FOG...ESP WHERE IT RAINS.

OUTLOOK...
SUN...MAINLY VFR WITH LCL MVFR/IFR RESTRICTIONS IN SHRA/TSRA.
MON...AM FOG...THEN VFR.
TUE...MAINLY VFR. SCT MVFR IN SHRA/TSRA MAINLY N/W AHEAD OF CLD FNT.
WED...MAINLY VFR. SHOWERS PSBL EARLY IN THE S/E.

&&

.CLIMATE...
THE AVERAGE TEMPERATURE LAST MONTH AT HARRISBURG WAS /73.0/
DEGREES OR (-2.9) DEGREES BELOW NORMAL. THIS TIES JULY 1920 AS
THE NINTH COLDEST ON RECORD.

THE AVERAGE TEMPERATURE LAST MONTH AT WILLIAMSPORT WAS /70.0/
DEGREES OR (-2.4) DEGREES BELOW NORMAL. THIS MAKES JULY 2009 THE
FIFTH COLDEST ON RECORD.

&&

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

&&

SYNOPSIS...FITZGERALD/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD/BEACHLER
AVIATION...STEINBUGL
CLIMATE...STEINBUGL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
927 AM EDT SAT AUG 1 2009

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-021330-
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-
927 AM EDT SAT AUG 1 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

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
248 PM EDT SAT AUG 1 2009

PAZ066-011925-
LANCASTER PA-
248 PM EDT SAT AUG 1 2009

...A SLOW MOVING HEAVY SHOWER WILL AFFECT CENTRAL LANCASTER COUNTY...

AT 244 PM EDT...A MODERATE TO HEAVY SHOWER WAS LOCATED 4 MILES
SOUTHWEST OF MILLERSVILLE...MOVING SLOWLY EAST AT 5 MPH.

VERY HEAVY RAIN WILL FALL FROM THIS SHOWER...AND WILL
CAUSE WATER TO POND ON ROADS AND FILL POOR DRAINAGE AREAS.

THIS SHOWER WILL BE NEAR MILLERSVILLE AROUND 310 PM AND WILLOW STREET
AROUND 315 PM.

THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 30...ROUTE 222.

LAT...LON 3992 7640 3993 7641 3993 7644 3999 7648
      4011 7625 3991 7614 3992 7639

EXPERIMENTAL

FORECASTER: STEINBUGL