Severe Thunderstorm Warning 90, NWS Pittsburgh, PA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1258 PM EDT TUE JUN 19 2007

.SYNOPSIS...
COLD FRONT NOW CROSSING THE GREAT LAKES WILL CAUSE NUMEROUS
THUNDERSTORMS INTO EARLY TONIGHT. SOME MAY BE SEVERE WITH DAMAGING
WIND AND LARGE HAIL. THIS WILL USHER A CHANGE IN THE UPPER LEVEL
JET STREAM PATTERN THAT WILL CAUSE TEMPERATURES TO BE CLOSE TO
SEASONAL LEVELS INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 9 PM THIS EVENING/...
SEVERE THUNDERSTORM WATCH NOW IN EFFECT FOR NORTHERN AND WESTERN
PARTS OF THE WFO PITTSBURGH (PBZ) COUNTY WARNING AREA (PBZ CWA).
INSTABILITY HAS BECOME UNCAPPED AND THUNDERSTORMS ARE DEVELOPING
OVER THE UPPER OHIO VALLEY. MAIN THREAT WILL BE DAMAGING WIND.
LARGE HAIL WILL BE THE SECOND THREAT. BESIDES MONITORING RADAR,
ALSO MONITORING SEVERE PARAMETERS LIKE EFFECTIVE SHEAR FOR
SUPERCELL DEVELOPMENT (WITH VALUES OVER 40 KTS). INSTABILITY SHOULD
REACH OVER 1000 J/KG, SUFFICIENT FOR DEEP THUNDERSTORM FORMATION.
LOWLEVEL HELICITY SHOULD REMAIN LOW IN VALUE, SO TORNADO
POSSIBILITIES WOULD BE LIMITED TO INTERSECTING BOUNDARIES. OVERALL
BEST SEVERE THREAT SHOULD BE NORTH OF I-80 AS INDICATED BY SPC
INITIATED SEVERE THUNDERSTORM WATCH.

&&

.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AFTER COOL FRONTAL PASSAGE TONIGHT, PRECIPITATION POTENTIAL WILL
BE RAPIDLY DECREASING. WITH SURFACE DEW POINTS ALSO DECREASING,
FOG FORMATION WILL BE LIMITED, DESPITE WETTED GROUNDS FROM
THUNDERSTORM RAINS INTO EARLY TONIGHT.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
FOR THE WEEKEND/START OF NEW WEEK...TEMPERATURES WILL BE NEAR
SEASONAL AVERAGES WITH SHORT WAVES IN NORTHWEST TO ZONAL FLOW
DEFINING SMALL PRECIP CHANCES, MAINLY LATE THURSDAY AND AGAIN LATE
SATURDAY. OVERALL CONFIDENCE RMNS LOW DUE TO AFORE REFERENCED TIMING
ISSUES. TEMPERATURES ARE EXPECTED TO MODERATE EARLY NXT WEEK UNDER
BLDG RIDGE.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
EXPECT MOST DEVIATION IN FLIGHT CONDITIONS TO IFR TO BE WITH
THUNDERSTORMS INTO EARLY TONIGHT. WINDS CAN ALSO GUST ABOVE 25 KTS
AS VERTICAL MIXING INCREASES IN VICINITY OF THUNDERSTORMS. OF
COURSE, ALONG THE LEADING EDGE OF THUNDERSTORMS, WIND GUSTS HAVE THE
POTENTIAL TO EXCEED 50 KTS. HAIL ALSO POSSIBLE.

AFTER THE FRONT MOVES THROUGH THIS EVENING, FLIGHT CONDITIONS
WILL MAINLY VFR INTO THE WEEKEND. ALBEIT, FOG FORMATION COULD
LEAD TO ISOLATED IFR PATCHES EARLY WEDNESDAY, MAINLY IN RIVER
VALLEYS BELOW TAF SITE ELEVATIONS. DID INCLUDE MVFR VISIBILITY FOR
KZZV, KFKL, AND KDUJ. ALSO, PASSING THUNDERSTORMS LATE THURSDAY
AND LATE SATURDAY COULD RESULT IN SHORT-LIVED IFR/MVFR CONDITIONS.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
123 PM EDT TUE JUN 19 2007

OHZ039>041-048>050-057-058-PAZ007>009-013>016-020-022-WVZ001-201730-
TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-JEFFERSON OH-
MUSKINGUM-GUERNSEY-MERCER-VENANGO-FOREST-LAWRENCE-BUTLER-CLARION-
JEFFERSON PA-BEAVER-ARMSTRONG-HANCOCK-
123 PM EDT TUE JUN 19 2007

...SEVERE THUNDERSTORM WATCH 418 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL OHIO...NORTHWEST
PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA
AND NORTHERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

THERE IS A CHANCE THAT THUNDERSTORMS FORMING IN ADVANCE OF A COLD
FRONT WILL BECOME SEVERE THIS AFTERNOON AND EARLY THIS EVENING.
THE PRIMARY SEVERE THREAT WILL BE FROM DAMAGING WIND
GUSTS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED.

MDZ001-OHZ059-068-069-PAZ021-023-029>032-WVZ002>004-012-021>023-041-
201730-
GARRETT-BELMONT-NOBLE-MONROE-ALLEGHENY-INDIANA-WASHINGTON-
WESTMORELAND-GREENE-FAYETTE-BROOKE-OHIO-MARSHALL-WETZEL-MARION-
MONONGALIA-PRESTON-TUCKER-
123 PM EDT TUE JUN 19 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST
CENTRAL OHIO...SOUTHWEST PENNSYLVANIA...WEST CENTRAL
PENNSYLVANIA...NORTHERN WEST VIRGINIA AND NORTHERN PANHANDLE OF
WEST VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A CHANCE THAT THUNDERSTORMS IN ADVANCE OF A COLD FRONT
WILL BECOME SEVERE THIS AFTERNOON AND EARLY THIS EVENING. THE
PRIMARY SEVERE THREAT WILL COME FROM DAMAGING WIND
GUSTS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
149 PM EDT TUE JUN 19 2007

OHZ039>041-049-050-059-PAZ007-008-013>016-020>023-029-030-WVZ001>004-
191845-
ALLEGHENY PA-ARMSTRONG PA-BEAVER PA-BELMONT OH-BROOKE WV-BUTLER
PA-CARROLL OH-CLARION PA-COLUMBIANA OH-HANCOCK WV-HARRISON OH-INDIANA
PA-JEFFERSON PA-JEFFERSON OH-LAWRENCE PA-MARSHALL WV-MERCER PA-OHIO
WV-TUSCARAWAS OH-VENANGO PA-WASHINGTON PA-WESTMORELAND PA-
149 PM EDT TUE JUN 19 2007

...THUNDERSTORMS...

THUNDERSTORMS WILL BE MOVING ACROSS THE REGION THIS AFTERNOON. THE
MOST ACTIVE STORMS EARLY THIS AFTERNOON WERE IN MERCER COUNTY
PENNSYLVANIA AND COLUMBIANA AND JEFFERSON COUNTIES IN OHIO. THE
THUNDERSTORMS WERE MOVING TO THE NORTHEAST ABOUT 25 MPH.

BE ALERT FOR BRIEF HEAVY RAIN, SMALL HAIL, DANGEROUS LIGHTNING AND
GUSTY WINDS. ALSO, WARNINGS COULD BE ISSUED IF THESE STORMS
INTENSIFY.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM FOR PARTS
OF THE REGION.

PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.