Severe Thunderstorm Warning 94, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
821 PM EDT SAT JUL 11 2009

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE STATE TONIGHT. HIGH PRESSURE
WILL PROVIDE MAINLY DRY CONDITIONS FOR INTO EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 8 AM SUNDAY MORNING/...
ATM REMAINED QUITE MOIST IN THE WAKE OF EARLIER CONVECTION...AHEAD
OF THE MAIN COLD FRONT NOW CROSSING OVER THE LOWER GREAT LAKES.
SUFFICIENT SHEAR PROFILES AND LINGERING INSTABILITY ALLOWED FOR
REDEVELOPMENT OF TSTORMS -- WHICH QUICKLY BECAME WELL-ORGANIZED AND
EVENTUALLY STRONG/SEVERE. RADAR INTERROGATION SHOWED MULTIPLE
BOWING SEGMENTS AND INTENSE ROTATIONAL COUPLETS/TORNADO VORTEX
SIGNATURES. THE STRONGEST STORMS HAD 60DBZ ELEVATED CORES OVER
20KFT.

XPC STORMS TO GRADUALLY WEAKEN THROUGH EARLY TONIGHT WITH THE
LOSS OF DAYTIME HEATING. HOWEVER...LARGE SCALE FORCING AND COOLING
ALOFT ASSOC WITH APPROACHING UPPER TROUGH/COLD FRONT WILL
MAINTAIN A SEVERE THREAT FOR THE NEXT FEW HOURS. STILL ANTICIPATE
A DRY SECOND HALF OF THE NIGHT AS THE LOW LEVELS DRY OUT FROM NW
TO SE IN THE WAKE OF THE FROPA.

&&

.SHORT TERM /8 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
CLEARING LINE SHOULD SLIDE ACROSS THE NRN MTNS TONIGHT WITH TEMPS
AND DEWPOINTS FALLING OFF FROM NORTH TO SOUTH. SFC HIGH PRES
BUILDING IN FROM THE OH VLY WILL LKLY PROVIDE FAIR WX INTO EARLY
NEXT WEEK. HOWEVER...THE AREA WILL REMAIN SUSCEPTIBLE TO LOW
AMPLITUDE SHORTWAVE ENERGY TRANSLATING SEWD WITHIN THE FAST NW
FLOW ALOFT -- IN BTWN STRONG SCENTRAL U.S. UPPER RIDGE AND
PERSISTENT CLOSED VORTEX NEAR HUDSON BAY. SREF GUID SHOWS BLW
NORMAL H5 HEIGHTS AND 850 TEMPS WHICH WILL KEEP TEMPS ON THE COOL
SIDE OF CLIMO. A WEAK SECONDARY TROUGH AXIS SLIDING SEWD FROM THE
LWR GRT LKS MAY TOUCH OFF A FEW SHOWERS ON MONDAY...BUT PROB/CVRG
LOOKS QUITE LOW ATTM SO WILL CONT DRY FCST ATTM.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MADE ONLY MINOR CHANGES TO THE MEDIUM-LONG TERM FORECAST THIS AM
GIVEN THE IMPENDING SEVERE WEATHER THREAT. TODAYS 00/06Z ENSEMBLE
RUNS SHOW VERY LITTLE CHANGE IN THE OVERALL FLOW PATTERN
ALOFT...WITH STUBBORN TROUGHING REMAINING ALONG THE WCOAST OF
NOAM AND ACROSS SERN CANADA/NORTHEASTERN CONUS FOR THE FORESEEABLE
FUTURE.

INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS STILL XPCD FROM
MID WEEK ON AS THE LOW LEVEL FLOW VEERS AROUND TO THE SOUTH/WEST.
HPC PROGS CONTINUE TO SHOW A WARM FRONT LIFTING NEWD FROM THE OH
VLY WED FOLLOWED BY A COLD FROPA FOR THUR/FRI. TEMPERATURES WILL
REMAIN NEAR TO SLIGHTLY BELOW NORMAL AS HEIGHTS REMAIN SUPPRESSED
OVER THE NORTHEAST STATES THROUGH THE END OF THE PD.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LAST GASP OF SHOWERS AND HEAVY THUNDERSTORMS MOVING THROUGH
CENTRAL PA AT THIS TIME. ONLY AIRFIELDS TO BE AFFECTED WILL BE
KIPT AND KMDT. THROUGH 12/02Z. ELSEWHERE...IMPROVING CONDITIONS TO
MVFR THEN VFR OVER THE NEXT FEW HOURS PER UPSTREAM OBS.

AS THE FRONT PASSES FROM WEST TO EAST THIS EVENING...WENT VFR TO
MVFR OVERNIGHT THEN GOOD VFR FROM EARLY MORNING HOURS ON SUNDAY.
WINDS BEHIND THE FRONT ON SUNDAY WILL BE BREEZY FROM THE NORTHWEST.

OUTLOOK...
SUN-TUE...VFR. LCL/VLY BR/FG PSBL EACH AM.
WED...MAINLY VFR. MVFR IN SHRA PSBL.

&&

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

&&

SYNOPSIS...DANGELO
NEAR TERM...STEINBUGL
SHORT TERM...BEACHLER/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...TYBURSKI

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1011 AM EDT SAT JUL 11 2009

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-121415-
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-
1011 AM EDT SAT JUL 11 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING...AS A COLD FRONT PUSHES ACROSS THE REGION. THE MAIN
THREATS WOULD BE FOR DAMAGING WIND GUSTS AND HAIL...BUT TORNADOES
MAY BE POSSIBLE.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED.

DANGELO

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1011 PM EDT SAT JUL 11 2009

PAZ066-120330-
LANCASTER PA-
1011 PM EDT SAT JUL 11 2009

...STRONG THUNDERSTORMS WILL AFFECT NORTHERN AND EASTERN LANCASTER
COUNTY THROUGH 1130 PM EDT...

AT 1009 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM
MYERSTOWN TO MOUNT JOY...MOVING SOUTHEAST AT 25 MPH.

WIND GUSTS TO 40 MPH AND HAIL UP TO DIME SIZE ARE POSSIBLE WITH THESE
STORMS. EXPECT FREQUENT...DANGEROUS CLOUD TO GROUND LIGHTNING FROM
THESE STORMS. DO NOT STAY IN THE OPEN NOR SEEK SHELTER UNDER TREES
WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN A THUNDERSTORM
APPROACHES.

THESE STORMS WILL BE NEAR LITITZ...AND LANDISVILLE AROUND 1020 PM...
ROTHSVILLE...EPHRATA...EAST PETERSBURG...AND DENVER AROUND 1025 PM...
REAMSTOWN...AKRON...AND ADAMSTOWN AROUND 1030 PM AND LANCASTER AROUND
1035 PM.

THIS WILL IMPACT THE PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 268
AND 295.

THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...STATE HIGHWAY
283...ROUTE 30...ROUTE 222...ROUTE 322...STATE ROAD 41...STATE ROAD
501.

LAT...LON 4013 7590 4011 7593 4005 7594 3997 7599
      3993 7599 3992 7601 4012 7654 4023 7643
      4025 7637 4025 7632 4032 7615 4015 7589

EXPERIMENTAL

FORECASTER: LAMBERT

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