September 22nd, 2010, Severe Weather Event

Overview

A cold front pressed southward through the state on Wednesday, the 22nd of September, 2010. Ahead of the cold front, numerous thunderstorms formed in the unseasonably warm and humid air over the state. Many of these thunderstorms produced damaging wind gusts and hail.

A long-lived thunderstorm cell tracked from west of Du Bois, PA, through Berwick, PA. The cell started as a supercell - a violently rotating thunderstorm. It produced wind damage and large hail over Jefferson County (west of Du Bois) and then moved into western Clearfield County around 3 PM EDT. It then moved across all of Central PA along and just to the north of I-80. Along the way, the storm turned into a bow-echo, a thunderstorm that races forward - usually producing very strong wind gusts. The winds from these bow-echoes can be as fast and as damaging as a weak tornado.

As the bow-echo pushed through Williamsport, PA, and Southern Lycoming County, it continued to intensify, producing a 60 mph wind gust at the Williamsport Regional Airport in Montoursville, PA.

It produced the most concentrated and severe damage in the town of Muncy, where it toppled many trees, power lines and damaged some structures. Two people died in Muncy around 445 PM EDT when a large tree fell on their vehicle.

A Storm Damage Survey was conducted in Muncy on the afternoon of the 23rd to determine the cause of the high winds. It was determined that a thunderstorm microburst was the cause.

Many more intense thunderstorms also produced damage across the rest of Central PA, especially in the Laurel Highlands and in the Southeastern Piedmont/lower Susquehanna Valley. Power outages were common as the trees fell on power lines.

Radar & Warnings
Storm Reports

Radar & Warnings


Storms that made damage in the DuBois areas	Storm that made damage in the Williamsport and Muncy areas	Storms that made damage in the Laurel Highlands	Storms that made damage in the Muncy area

Storm Reports

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE STATE COLLEGE PA
916 PM EDT WED SEP 22 2010

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

0248 PM     TSTM WND DMG     PENFIELD                41.21N 78.60W
09/22/2010                   CLEARFIELD         PA   EMERGENCY MNGR

            TREES DOWN ON STATE PARK ROAD BLOCKING BOTH LANES BY
            PARKER DAM

0339 PM     TSTM WND DMG     3 S CARLISLE            40.16N 77.20W
09/22/2010                   CUMBERLAND         PA   EMERGENCY MNGR

            TREES AND WIRES DOWN ON LEIBIGH DRIVE IN SOUTH MIDDLETOWN
            TWP.

0354 PM     TSTM WND DMG     LOCK HAVEN              41.14N 77.45W
09/22/2010                   CLINTON            PA   LAW ENFORCEMENT

            NUMEROUS TREES AND WIRES REPORTED DOWN AROUND LOCK HAVEN.


0355 PM     TSTM WND DMG     SIDDONSBURG             40.15N 76.96W
09/22/2010                   YORK               PA   TRAINED SPOTTER

            LARGE BRANCHES DOWN IN THE VICINITY OF SIDDONSBURG.

0416 PM     TSTM WND DMG     JERSEY SHORE            41.20N 77.27W
09/22/2010                   LYCOMING           PA   LAW ENFORCEMENT

            TREES AND WIRES REPORTED DOWN IN JERSEY SHORE.

0418 PM     TSTM WND DMG     GERMANTOWN              39.77N 77.16W
09/22/2010                   ADAMS              PA   EMERGENCY MNGR

            TREES DOWN

0428 PM     TSTM WND DMG     MANCHESTER              40.06N 76.72W
09/22/2010                   YORK               PA   LAW ENFORCEMENT

            SCATTERED REPORTS OF TREES AND WIRES DOWN ACROSS YORK
            COUNTY.

0430 PM     TSTM WND DMG     1 W WILLIAMSPORT        41.24N 77.04W
09/22/2010                   LYCOMING           PA   TRAINED SPOTTER

            TREES REPORTED DOWN ON THE WEST-SIDE OF WILLIAMSPORT.

0435 PM     TSTM WND DMG     2 N WATSONTOWN          41.11N 76.86W
09/22/2010                   NORTHUMBERLAND     PA   TRAINED SPOTTER

            TREES DOWN ON RIVER ROAD NEAR DEWART.

0439 PM     TSTM WND DMG     MUNCY                   41.20N 76.79W
09/22/2010                   LYCOMING           PA   TRAINED SPOTTER

            TREES AND WIRES REPORTED DOWN IN MUNCY...ALONG WITH
            DIME-SIZED HAIL. SPOTTER REPORTED 67 MPH WIND GUST ON A
            DAVIS WEATHER STATION.

0452 PM     TSTM WND DMG     JERSEYTOWN              41.09N 76.60W
09/22/2010                   COLUMBIA           PA   LAW ENFORCEMENT

            TREES REPORTED DOWN IN JERSEYTOWN.

0512 PM     TSTM WND DMG     FAWN GROVE              39.73N 76.45W
09/22/2010                   YORK               PA   TRAINED SPOTTER

            TREES AND POWER LINES DOWN IN FAWN GROVE AND SUNNYBURN.

0513 PM     TSTM WND DMG     BERWICK                 41.06N 76.25W
09/22/2010                   COLUMBIA           PA   LAW ENFORCEMENT

            NUMEROUS REPORTS OF TREES DOWN AND SEVERAL ROOFS DAMAGED
            ACROSS COLUMBIA COUNTY.

0516 PM     HAIL             4 SW WESTMONT           40.28N 79.01W
09/22/2010  E1.00 INCH       SOMERSET           PA   PUBLIC

            ONE-INCH HAIL REPORTED ON LAUREL MTN SOUTHWEST OF
            WESTMONT.

0518 PM     TSTM WND DMG     HOOVERSVILLE            40.15N 78.91W
09/22/2010                   SOMERSET           PA   LAW ENFORCEMENT

            TREES AND WIRES REPORTED DOWN ACROSS MUCH OF NORTHWESTERN
            SOMERSET COUNTY.

0628 PM     TSTM WND DMG     SCHUYLKILL HAVEN        40.63N 76.17W
09/22/2010                   SCHUYLKILL         PA   LAW ENFORCEMENT

            WIDESPREAD WIND DAMAGE REPORTED ACROSS SOUTHERN
            SCHUYLKILL COUNTY.

0632 PM     TSTM WND DMG     ST. THOMAS              39.94N 77.74W
09/22/2010                   FRANKLIN           PA   PUBLIC

            WIRES DOWN ON MAIN STREET IN ST. THOMAS.

0635 PM     TSTM WND DMG     CHAMBERSBURG            39.93N 77.66W
09/22/2010                   FRANKLIN           PA   TRAINED SPOTTER

            TELEPHONE POLES DOWN ALONG ROUTE 30 NEAR CHAMBERSBURG.

0642 PM     TSTM WND DMG     1 W SHIPPENSBURG        40.05N 77.54W
09/22/2010                   FRANKLIN           PA   EMERGENCY MNGR

            ROOF BLOWN OFF HOUSE ON MOLLY PITCHER HIGHWAY

0645 PM     TSTM WND DMG     SUMMIT STATION          40.58N 76.22W
09/22/2010                   SCHUYLKILL         PA   EMERGENCY MNGR

            TREES AND UTILITY LINES DOWN IN SUMMIT STATION

0648 PM     TSTM WND DMG     SHIPPENSBURG            40.05N 77.52W
09/22/2010                   CUMBERLAND         PA   EMERGENCY MNGR

            NUMEROUS TREES AND POWER LINES DOWN IN TOWN

0717 PM     TSTM WND DMG     NEW OXFORD              39.86N 77.06W
09/22/2010                   ADAMS              PA   EMERGENCY MNGR

            MULTIPLE TREES AND WIRES DOWN ON RT 94. RT 94 IS CLOSED.

0730 PM     TSTM WND DMG     SPRING GROVE            39.88N 76.86W
09/22/2010                   YORK               PA   PUBLIC

            NUMEROUS REPORTS OF TREES AND WIRES DOWN ACROSS YORK
            COUNTY.

0804 PM     TSTM WND DMG     1 E LANDISVILLE         40.09N 76.40W
09/22/2010                   LANCASTER          PA   LAW ENFORCEMENT

            TREES AND WIRES REPORTED DOWN IN EAST HEMPFIELD TWP.