Severe Thunderstorm Warning 49, NWS State College, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1200 PM EDT FRI MAY 28 2010

.SYNOPSIS...
A BACK DOOR COLD FRONT OVER EASTERN PENNSYLVANIA WILL MOVE LITTLE
THROUGH SATURDAY. THIS FRONT WILL RESULT IN THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND
EVENING HOURS. THE FRONT WILL MOVE EAST OF THE AREA ON
SUNDAY...RESULTING IN A WESTERLY FLOW OF WARMER AIR.

ANOTHER COLD FRONT FROM THE UPPER GREAT LAKES WILL MOVE ACROSS
THE KEYSTONE STATE LATE MEMORIAL DAY...BRINGING ANOTHER CHANCE OF
SHOWERS AND STORMS TO THE AREA.

COOLER AIR WILL MOVE INTO THE AREA BY TUESDAY...AS HIGH PRESSURE
BUILDS SOUTHEAST FROM THE CANADIAN PLAINS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STATIONARY FRONT AND PRONOUNCED INVERTED SFC TROF EXTEND NORTHWARD
THROUGH PA INTO NY STATE. AREA OF LOW CLOUDS IS CREEPING NW FROM
THE LOWER SUSQ VALLEY ON SE WINDS ALONG THE SFC TROF. INCREASING
CLOUDS WILL KEEP TEMPS LOWER THAN PAST FEW DAYS BUT IT WILL STILL
BE A WARM...HUMID AND SOMEWHAT HAZY LATE SPRING AFTERNOON. SFC
CONVERGENCE ALONG THE BOUNDARY/SFC TROF WILL COMBINE WITH WEAK
IMPULSES MOVING SOUTH FROM NY TO INITIATE SHOWERS AND TSTORMS
THIS AFTN INTO THIS EVENING OVER MUCH OF CENTRAL PA.

LOWER TEMPS WILL KEEP INSTABILITY IN CHECK AND SHEAR IS
UNIDIRECTIONAL AND WEAK...SO POTENTIAL FOR STRONG STORM IS
LOW...BUT EXPECTED SLOW STORM MOVEMENT WITH POTENTIAL FOR
REPEATING/TRAINING CELLS...0-6KM MEAN STORM MOTION IS 340 AT
8KTS...THE POSSIBILITY OF LOCALIZED HEAVY RAIN IS STILL A CONCERN
INTO THIS EVENING. WILL HOLD OFF ON ANY FLOOD WATCHES ATTM AS DEWPOINTS
ARE NOT EXCEEDINGLY HIGH AND FLASH FLOOD GUIDANCE MOST PLACES IS
IN THE 2 TO 4 INCH RAIN OVER 3 HOURS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
DID TAPER POPS OFF AFTER MIDNIGHT. MOST OF THE SHOWERS
AND STORMS SHOULD DIE DOWN BY THEN.

BEST CHC FOR ANYTHING ON SATURDAY WOULD BE DURING THE AFT...
BUT NOT AS HIGH OF CHANCE AS TODAY.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
BY SUNDAY...H5 HEIGHTS WILL BE BUILDING AS UPPER FLOW TRANSITIONS
TO MORE OF A NORTHWESTERLY DIRECTION. LOW LEVEL FLOW BECOMES
SOUTHWESTERLY WHICH WILL CONTINUE THE WARMING TREND INTO MEMORIAL
DAY AS MOST LOCATIONS GET INTO THE 80S SUN AND MON. A COLD FRONT
IS PROGGED TO CROSS THE GREAT LAKES AND OHIO VALLEY EARLY NEXT
WEEK...WITH HPC PROGS SHOWING THE FRONT TRAVERSING THE AREA LATE
MON NIGHT INTO TUESDAY...SUGGESTING AT LEAST A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS IN MOST AREAS FOR MEMORIAL DAY...WITH
MOST LIKELY TIMING BEING LATE AFTERNOON AND INTO THE EVENING...
THOUGH THIS TIMING COULD SLOW DOWN A BIT AND PUSH BEST CHANCES FOR
SHOWERS INTO TUES.

FOR NOW...DID SLOW TIMING DOWN SOME FOR MONDAY...DID CUT BACK
ON POPS FOR MONDAY MORNING. THE ECMWF IS SLOWER WITH THE SYSTEM.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
LOW LVL MOISTURE IN THE FORM OF PATCHY MVFR CIGS/FOG WILL MIX OUT
TO VFR EVERYWHERE BY LATE MORNING. A STALLED FRONT ALONG THE
ALLEGHENY MTNS WILL BE THE FOCUS FOR A NEW ROUND OF TSRA
DEVELOPING BY THIS AFTN. ANY TSRA COULD CREATE BRIEF VSBY/CIGS
REDUCTIONS AND GUSTY WINDS THIS AFTN. HOWEVER...THE BULK OF THE
DAY SHOULD BE VFR AND LGT WINDS. SCT TSRA SHOULD DISSIPATE WITH
LOSS OF HEATING AFTER SUNSET. HOWEVER...RESIDUAL LOW LVL
MOISTURE...PARTIAL CLEARING AND LGT WINDS COULD RESULT IN AREAS OF
FOG LATE TONIGHT.

OUTLOOK...
SAT...AM IFR CIGS/VSBYS POSS. PM TSRA POSSIBLE.
SUN...NO SIG WX EXPECTED.
MON...PM TSRA POSSIBLE.
TUE...TSRA POSSIBLE.

&&

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

&&

SYNOPSIS...MARTIN
NEAR TERM...GARTNER/MARTIN
SHORT TERM...MARTIN
LONG TERM...MARTIN
AVIATION...FITZGERALD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
525 AM EDT FRI MAY 28 2010

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-290930-
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-
525 AM EDT FRI MAY 28 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY AND TONIGHT.

A NEARLY STATIONARY FRONT OVER EXTREME EASTERN PENNSYLVANIA
EARLY THIS MORNING WILL RESULT IN SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING. SOME STORMS MAY BE NEARLY STATIONARY AND
PRODUCE TORRENTIAL RAINFALL IN ISOLATED SPOTS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

WHILE STORMS WILL BE MORE ISOLATED ON SATURDAY...THERE WILL
STILL BE A CHANCE FOR A FEW STORMS TO PRODUCE VERY HEAVY
RAINFALL...ESPECIALLY NEAR THE MARYLAND BORDER.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. HOWEVER...
SPOTTERS SHOULD REPORT RAINFALL AMOUNTS EXCEEDING ONE INCH.

MARTIN

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
157 PM EDT FRI MAY 28 2010

PAZ011-281830-
CAMERON PA-
157 PM EDT FRI MAY 28 2010

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN CAMERON COUNTY...

AT 153 PM EDT...A STRONG THUNDERSTORM WAS 24 MILES EAST OF ST.
MARYS...MOVING SOUTHWEST AT 5 MPH.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.
VERY HEAVY RAIN WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO
POND ON ROADS AND FILL POOR DRAINAGE AREAS. THIS STORM WILL BE NEAR
DRIFTWOOD AROUND 225 PM AND HICKS RUN AROUND 230 PM.

THIS WILL IMPACT STATE ROAD 120.

LAT...LON 4144 7799 4136 7800 4122 7810 4122 7816
      4125 7824 4133 7824 4133 7826 4138 7826
      4150 7815

EXPERIMENTAL

FORECASTER: STEINBUGL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
225 PM EDT FRI MAY 28 2010

PAZ034-281915-
BEDFORD PA-
225 PM EDT FRI MAY 28 2010

...STRONG THUNDERSTORMS WILL AFFECT WESTERN BEDFORD COUNTY...

AN AREA OF STRONG THUNDERSTORMS COVERED PORTIONS OF BEDFORD COUNTY AT
222 PM EDT. THE STRONG THUNDERSTORMS WERE GENERALLY MOVING EAST AT 5
MPH.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STRONG
THUNDERSTORMS. EXPECT INTENSE LIGHTNING FROM THESE STRONG
THUNDERSTORMS. DO NOT STAY IN THE OPEN NOR SEEK SHELTER UNDER TREES
WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN A THUNDERSTORM
APPROACHES. VERY HEAVY RAIN WILL FALL FROM THESE STRONG
THUNDERSTORMS...AND WILL CAUSE WATER TO POND ON ROADS AND FILL POOR
DRAINAGE AREAS. THE RAIN WILL CAUSE RAPID RISES ON SMALL STREAMS AND
CREEKS.

THIS WILL IMPACT THE FOLLOWING CENTRAL PENNSYLVANIA INTERSTATES...THE
PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 132 AND 147...I-99 BETWEEN
MILE MARKERS 0 AND 8.

THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 30...ROUTE
220.

LAT...LON 3972 7879 3980 7877 3982 7876 3985 7876
      4018 7868 4016 7845 3972 7856

EXPERIMENTAL

FORECASTER: STEINBUGL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
228 PM EDT FRI MAY 28 2010

PAZ011-012-017-018-281915-
CAMERON PA-CLEARFIELD PA-NORTHERN CENTRE PA-NORTHERN CLINTON PA-
228 PM EDT FRI MAY 28 2010

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL CENTRE...
NORTHEASTERN CLEARFIELD...SOUTHEASTERN CAMERON AND WEST CENTRAL
CLINTON COUNTIES THROUGH 315 PM EDT...

AT 218 PM EDT...AN AREA OF STRONG THUNDERSTORMS WAS CENTERED 3 MILES
SOUTH OF DRIFTWOOD...MOVING SOUTH AT 5 MPH.

WIND GUSTS TO 50 MPH AND PENNY SIZE HAIL ARE POSSIBLE WITH THIS
STORM. EXPECT FREQUENT...DANGEROUS CLOUD TO GROUND LIGHTNING FROM
THIS STORM. DO NOT STAY IN THE OPEN NOR SEEK SHELTER UNDER TREES
WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN A THUNDERSTORM
APPROACHES. VERY HEAVY RAIN OF UP TO 2 INCHES WILL FALL FROM THIS
STORM IN JUST A 30 TO 60 MINUTE PERIOD...AND WILL CAUSE WATER TO POND
ON ROADS AND FILL POOR DRAINAGE AREAS. THE RAIN WILL CAUSE RAPID
RISES ON SMALL STREAMS AND CREEKS. THIS STORM WILL BE NEAR KARTHAUS
AROUND 315 PM.

THIS WILL IMPACT STATE ROAD 120.

LAT...LON 4132 7798 4106 7794 4108 7831 4123 7825
      4124 7824 4125 7824 4136 7820

EXPERIMENTAL

FORECASTER: LAMBERT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
244 PM EDT FRI MAY 28 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0230 PM     HAIL             MANNS CHOICE            40.00N 78.59W
05/28/2010  E0.88 INCH       BEDFORD            PA   TRAINED SPOTTER

            HAIL MOSTLY PENNY SIZE FEW NICKELS

&&

PAH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
256 PM EDT FRI MAY 28 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0230 PM     HAIL             2 NW MANNS CHOICE       40.02N 78.62W
05/28/2010  E1.75 INCH       BEDFORD            PA   EMERGENCY MNGR

            GOLF BALL SIZE HAIL ON PA TURNPIKE

&&

PAH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
328 PM EDT FRI MAY 28 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     FLASH FLOOD      3 N SKI GAP             40.37N 78.52W
05/28/2010                   BLAIR              PA   EMERGENCY MNGR

            KNOB RUN ROAD AT JOHNSTOWN ROAD CLOSED DUE TO FLOODING.
            WATER COVERING SKI GAP ROAD...RIGHT HAND GAP...AND THE
            INTERSECTION OF JOHNSTOWN AND POLE CAT ROAD.

&&

PAJ