Severe Thunderstorm Warning 200, NWS State College, PA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1030 AM EDT SUN AUG 29 2004

.SHORT TERM (REST OF TODAY)...

WERE GETTING A HEAD START COMPARED TO SATURDAY IN THE TEMP
DEPARTMENT...WITH PLENTY OF SUNSHINE CURRENTLY ACROSS THE CENTRAL
MTNS (AND SOON ACROSS ALL OF THE SUSQ VALLEY AFTER STRATUS DECK FROM
THE EARLY MORNING FOG THINS OUT). THERES PRACTICALLY NO CONVECTION
LIKE WE HAD ACROSS MUCH OF CENTRAL AND NW PENN EARLY SATURDAY...AND
THIS TRANSLATES INTO A MORE UNSTABLE ENVIRONMENT WITH THE
NORTH/SOUTH AXIS OF GREATEST (ALBEIT ONLY MODERATE) MID LVL LAPSE
RATES SLICING RIGHT THROUGH CENTRAL PENN AT 18Z AND 00Z TODAY.

12 KM ETA SFC BASED CAPES APPEAR TO REFLECT THE CURRENT AND
ANTICIPATED CLOUD COVER DISTRIBUTION QUITE WELL...AND VALUES CLIMB
BETWEEN 1800 AND 2500 J/KG DURING THE MID AFTERNOON AND EARLY
EVENING HOURS TO THE SE OF A LINE FROM KJST TO KUNV AND KIPT.

EXPECT TO SEE RAPID DEVELOPMENT OF PULSE STORMS AFTER
17Z...ESPECIALLY NEAR THE STRONGEST DIFFERENTIAL HEATING ON THE
EASTERN EDGE OF THE MID CLOUD DECK COVERING WRN PENN. TRAINING...NE
MOVING STORM CELLS WILL BRING THE THREAT FOR LOCALIZED FLASH
FLOODING...MAINLY OVER THE WRN HALF OF THE CWA WHERE WELL HAVE TO
DEAL WITH MORE WIDESPREAD SHOWERS/TSRA THIS EVENING CLOSER TO THE
FRONT AS CURRENTLY NOTED ACROSS NORTH CENTRAL OHIO.

THE PRIMARY CHANGE FOR THIS UPDATE WAS TO MODIFY THE PRECIP TIMING
FOR THIS AFTERNOON...AND TO BUMP UP HIGH TEMPS BY A FEW
DEG.

&&

.PREVIOUS DISCUSSION...
THE FOLLOWING WAS ORIGINALLY ISSUED AT 350 AM EDT SUN AUG 29 2004

AVIATION...
LIGHT SOUTHERLY FLOW CONTINUES TO SUPPORT MOIST LOW LEVEL CONDS
ACROSS THE REGION...THUS WITH SCT MVFR TO LOCALIZED IFR VIS DUE TO
FOG/HAZE EXPECTED OVERNIGHT. ISOLATED SHOWERS WILL DEVELOPE DURING
THE AFTERNOOON. VIS WILL IMPROVE TO VFR MOST AREAS BY 14-15Z THOUGH
LOCAL POCKETS OF HZ WILL REMAIN THROUGHOUT THE DAY. APPROACHING
FRONTAL SYSTEM WILL INCREASE COVERAGE OF CONVECTION AND LOWERD
VIS/CIGS THIS AFTN AND EVE OVER RECENT DAYS.

SHORT TERM (TODAY)...
SLOW MOVING UPPER TROF WILL ONCE AGAIN ACT ON ABUNDANT MOISTURE
(PWATS EXCEEDING 1.75) AND MODERATE INSTABILITY TO PRODUCE LOCALLY
HEAVY RAINFALL...ESPECIALLY OVER CENTRAL AND EASTERN AREAS WHERE
INVERTED SFC TROF AND LOW LEVEL THTE RIDGE ARE LOCATED.  WILL ISSUE
FLASH FLOOD WATCH FOR WESTERN HALF OF CWA FOR THIS THREAT...
EFFECTIVE UNTIL 900 PM THIS EVENING. DAY/EVENING SHIFT WL LIKELY
NEED TO EXTEND WATCH FURTHER GIVEN 850 MB FRONT STALLING ACROSS THE
AREA TONIGHT WITH PWS EXCEEDING 1.5 AHEAD OF IT TONIGHT INTO
MONDAY... BUT WILL ALLOW FUTURE SHIFTS THE OPPORTUNITY TO MAKE THIS
CALL.

LONG TERM (TONIGHT THROUGH SATURDAY)...
AS BOUNDARY STALLS ACROSS THE REGION TONIGHT...EXPECT WIDESPREAD
SHOWERS AND THUNDERSTORMS TO CONTINUE WITH LOCALLY HEAVY RAINFALL
ESPECIALLY DURING THE EVENING HOURS. MODELS HAVE SLOWED EASTWARD
PROGRESS OF FRONT FURTHER IN THE PAST 24 HOURS...SUGGESTING THAT THE
FRONT WILL LINGER OVER CENTRAL/SOUTHEAST AREAS THROUGH LATE MONDAY
NIGHT OR EVEN EARLY TUESDAY BEFORE UPPER LEVEL WESTERLIES FINALLY
NUDGE IT EAST OF THE AREA AND ADVECT DRIER AIR INTO THE REGION ON
TUESDAY. HOWEVER...UNCERTAINTY ABOUNDS CONCERNING THE TRACK OF
TROPICAL STORM GASTONS MOISTURE AS TPC FORECAST TRACK BRINGS IT AS
FAR NORTH AS SOUTHERN DELAWARE AND THEN NORTHEASTWARD TO JUST SOUTH
OF CAPE COD BY TUESDAY NIGHT...WHILE THE NEW GFS TRACKS THE STORM TO
SOUTHERN NJ TUESDAY MORNING. EASTERN AND ESPECIALLY SOUTHEAST PA
WOULD SEE AN INCREASED FLOOD THREAT SHOULD GASTONS MOISTURE BECOME
ENTRAINED AHEAD OF THE STALLED FRONT...AND WILL HAVE TO WATCH
CLOSELY NEXT 24 TO 48 HOURS.

DRIER WEST/NORTHWEST UPPER FLOW EXPECTED TO PREVAIL MID TO LATE WEEK
OVER THE NORTHEAST U.S. AS INTERESTS TURN TO THE SOUTH WHERE
HURRICANE FRANCES MAY APPROACH THE BAHAMAS THU/FRI AND SOUTHEAST
U.S. (FLORIDA) NEXT WEEKEND.
&&

.CTP WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FOR ZONES PAZ004>006-010>012-017>019-024>027-
     033>035-045 UNTIL 9 PM EDT.
&&

SHORT TERM (UPDATE)...LAMBERT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1229 PM EDT SUN AUG 29 2004

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-301627-
ADAMS PA-BEDFORD PA-BLAIR PA-CAMBRIA PA-CAMERON PA-CLEARFIELD PA-
COLUMBIA PA-CUMBERLAND PA-DAUPHIN PA-ELK PA-FRANKLIN PA-FULTON PA-
HUNTINGDON PA-JUNIATA PA-LANCASTER PA-LEBANON PA-MCKEAN PA-
MIFFLIN PA-MONTOUR PA-NORTHERN CENTRE PA-NORTHERN CLINTON PA-
NORTHERN LYCOMING PA-NORTHUMBERLAND PA-PERRY PA-POTTER PA-
SCHUYLKILL PA-SNYDER PA-SOMERSET PA-SOUTHERN CENTRE PA-
SOUTHERN CLINTON PA-SOUTHERN LYCOMING PA-SULLIVAN PA-TIOGA PA-
UNION PA-WARREN PA-YORK PA-
1229 PM EDT SUN AUG 29 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY:

SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL WILL FOCUS
ALONG A STALLED FRONTAL BOUNDARY ACROSS CENTRAL AND WESTERN PORTIONS
OF CENTRAL PENNSYLVANIA THIS AFTERNOON AND TONIGHT. A FLOOD WATCH HAS
BEEN POSTED FOR THE WESTERN HALF OF CENTRAL PENNSYLVANIA THROUGH 900
PM THIS EVENING. IN ADDITIONAL...SOME OF THE THUNDERSTORMS MAY
STRENGTHEN TO AROUND SEVERE LEVELS...PRODUCING BRIEF WIND GUSTS
AROUND 60 MPH. LARGE HAIL WILL BE A LESSER THREAT SINCE TEMPERATURES
ARE QUITE WARM THROUGH THE MID LEVELS OF THE ATMOSPHERE.

@0059
.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY:

THE REMNANTS OF TROPICAL STORM GASTON...CURRENTLY CENTERED JUST NORTH
OF CHARLESTON SOUTH CAROLINA...WILL MOVE SLOWLY NORTH OVER THE
INTERSTATE 95 CORRIDOR THROUGH MONDAY NIGHT. LOCALLY HEAVY RAIN OF
OVER 2 INCHES IS POSSIBLE MONDAY AND MONDAY NIGHT ACROSS THE LOWER
SUSQUEHANNA VALLEY...WHICH WILL BE CLOSEST TO THE STORMS PATH. A
FLOOD WATCH MAY BE ISSUED LATER TODAY FOR MUCH OF THE SUSQUEHANNA
RIVER VALLEY...WHICH WOULD LIKELY BE VALID MONDAY AND MONDAY NIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
938 AM EDT SUN AUG 29 2004

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-292337-
ADAMS PA-BEDFORD PA-BLAIR PA-CAMBRIA PA-CAMERON PA-CLEARFIELD PA-
COLUMBIA PA-CUMBERLAND PA-DAUPHIN PA-ELK PA-FRANKLIN PA-FULTON PA-
HUNTINGDON PA-JUNIATA PA-LANCASTER PA-LEBANON PA-MCKEAN PA-
MIFFLIN PA-MONTOUR PA-NORTHERN CENTRE PA-NORTHERN CLINTON PA-
NORTHERN LYCOMING PA-NORTHUMBERLAND PA-PERRY PA-POTTER PA-
SCHUYLKILL PA-SNYDER PA-SOMERSET PA-SOUTHERN CENTRE PA-
SOUTHERN CLINTON PA-SOUTHERN LYCOMING PA-SULLIVAN PA-TIOGA PA-
UNION PA-WARREN PA-YORK PA-
938 AM EDT SUN AUG 29 2004

...SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS CENTRAL PENNSYLVANIA AND
THE SUSQUEHANNA VALLEY THIS AFTERNOON AND EARLY THIS EVENING...

A SLOW MOVING COLD FRONT EXTENDING FROM NEAR BUFFALO TO CLEVELAND
THIS MORNING WILL DRIFT SLOWLY EAST TOWARD CENTRAL PENNSYLVANIA OVER
THE NEXT 24 HOURS. VERY WARM AND HUMID AIR...COMBINED WITH PLENTY OF
SUNSHINE INTO EARLY THIS AFTERNOON WILL ALLOW THE AIRMASS ACROSS
CENTRAL PENNSYLVANIA TO BECOME QUITE UNSTABLE THIS AFTERNOON AND
EVENING.

THIS WILL RESULT IN SCATTERED THUNDERSTORMS QUICKLY DEVELOPING AFTER
1 PM. THE STORMS WILL BE MOVING MAINLY TO THE NORTHEAST AT 20 TO 30
MPH. STRONG DOWNBURST WINDS AROUND 60 MPH COULD OCCUR NEAR THE
HEAVIEST RAIN AREAS WITHIN INDIVIDUAL THUNDERSTORMS. ISOLATED STORMS
MAY ALSO PRODUCE HAIL GREATER THAN THREE QUARTERS OF AN INCH IN
DIAMETER.

SOME OF THE THUNDERSTORMS ARE EXPECTED TO REFORM OR TRAIN ACROSS THE
SAME AREAS...SO LOCALIZED FLASH FLOODING IS ALSO A THREAT...MAINLY
ACROSS THE CENTRAL AND WESTERN MOUNTAINS OF THE STATE.

FREQUENT CLOUD TO GROUND LIGHTNING ALWAYS POSES A DANGER DURING
SEVERE THUNDERSTORMS. REFRAIN FROM BEING IN OPEN PLACES WHEN
LIGHTNING IS OCCURRING...OR IF YOU HEAR THUNDER. THIS INCLUDES GOLF
COURSES...BALL FIELDS...AND RECREATIONAL ACTIVITIES ON LAKES.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

FOR ADDITIONAL WEATHER INFORMATION...CHECK OUR WEB SITE AT...
WWW.ERH.NOAA.GOV/CTP

LAMBERT

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
206 PM EDT SUN AUG 29 2004

PAZ012-017-018-291930-
CLEARFIELD-NORTHERN CENTRE-NORTHERN CLINTON-
206 PM EDT SUN AUG 29 2004

...SLOW MOVING STRONG THUNDERSTORMS WILL AFFECT EASTERN CLEARFIELD
COUNTY...WESTERN AND NORTHERN CENTRE COUNTY...AND NORTHERN CLINTON
COUNTY THROUGH 330 PM...

AT 205 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS RAPIDLY DEVELOPING ALONG A LINE EXTENDING FROM
JUST SOUTHWEST OF RENOVO...TO AROUND PHILIPSBURG AND RAMEY.
 THE INDIVIDUAL THUNDERSTORM CELLS WERE MOVING NORTHEAST AT 25
MPH...WHILE THE LINE OF STORMS WAS SLIDING TO THE EAST AT ONLY 5
MPH. THE THUNDERSTORMS WILL BE NEAR TAMARACK...WESTPORT AROUND 215
PM...SANDY RIDGE AROUND 225 PM...PHILIPSBURG AROUND 230 PM...BLACK
MOSHANNON STATE PARK AROUND 250 PM...MOSHANNON AROUND 255 PM AND
RENOVO AROUND 300 PM.

VERY HEAVY RAIN OF UP TO A INCH WILL FALL IN A 30 TO 60 MINUTE PERIOD
...AND WILL CAUSE WATER TO POND ON ROADS AND QUICKLY FILL
ROADSIDE DITCHES AND SMALL STREAMS.

BRIEF WIND GUSTS BETWEEN 30 AND 40 MPH ARE ALSO POSSIBLE WITH THESE
STORMS...WITHIN THE AREAS OF HEAVIEST RAIN.

ALSO...EXPECT DANGEROUS CLOUD TO GROUND LIGHTNING FROM THESE STORMS.
DO NOT SEEK SHELTER UNDER TREES OR STAY IN THE OPEN WHEN LIGHTNING
THREATENS.

LAMBERT