A series of cold fronts triggered scattered thunderstorms over southeast PA during the afternoon on 5-6 September 2014. Deep moisture combined with strong instability and relatively slow storm motions/training to produce torrential rains and localized flash flooding.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CTP wrote it up.
A series of cold fronts triggered scattered thunderstorms over southeast PA during the afternoon on 5-6 September 2014. Deep moisture combined with strong instability and relatively slow storm motions/training to produce torrential rains and localized flash flooding.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before the first event at Sep 5, 3:03 PM EST, 54 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 403 PM EDT FRI SEP 5 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC COAST LATE TODAY AND TONIGHT...KEEPING VERY WARM AND HUMID CONDITIONS OVER THE REGION. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK...ACCOMPANIED BY A REFRESHINGLY COOLER AND DRIER AIRMASS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... REGIONAL VIS AND RADAR LOOP SHOWS A QUICK TRANSITION TO ISOLATED SHOWERS AND A FEW PULSE TSRA IN THE UNSEASONABLY WARM AND VERY HUMID AIRMASS ACROSS CENTRAL PENN. TERRAIN FEATURES ARE PLAYING A DOMINANT ROLE IN THE LOCATION AND SLOW EASTWARD MOVEMENT OF THE CONVECTION. WE SHOULD SEE THE SHOWERS AND TSRA QUICKLY DISSIPATE EARLY THIS EVENING...BUT COULD DRIFT UP TO A FEW TENS OF MILES EAST OF THEIR TRIGGER POINTS BEFORE FALLING APART COMPLETELY BY 01Z. THESE SLOW MOVING...AND VERY EFFICIENT RAIN-MAKERS WILL LEAD TO SOME LOCALLY AND GENERALLY BRIEF TORRENTIAL RAINS. HOWEVER...MOST LOCATIONS SHOULDN/T SEE A DROP OF RAIN THROUGH 08Z SATURDAY BEFORE THE LEADING EDGE OF 40-45MM PWAT AIR AND STRONGER LOW TO MID LEVEL FLOW AHEAD OF A COLD FRONT ENTERS THE REGION FROM THE OHIO VALLEY. SKIES FOR MUCH OF THE OVERNIGHT SHOULD BE PARTLY CLOUDY /MAINLY PATCHY STRATO CU AND SOME ALTO CU/. IT WILL BE VERY MUGGY ONCE AGAIN /ESPECIALLY FOR EARLY SEPT/ WITH LOW TEMPS IN THE 60S...TO AROUND 70F IN THE SE. PATCHY FOG WILL FORM FOR A FEW HOUR AROUND DAYBREAK /ESPECIALLY ACROSS THE SOUTH AND EAST. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... MDL TIMING OF COLD FRONT CONTINUES TO SUGGEST SHRA/TSRA WILL MOVE INTO THE NW MTNS ARND OR SHORTLY AFTER DAWN SATURDAY. LATEST 12Z MODELS SHOW LITTLE REASON TO MODIFY THE ALREADY HIGH POPS PAINTED IN OUR GRIDDED DATABASE /AROUND 80 PERCENT/ FOR SHOWERS AND SCTD TSRA ALONG AND AHEAD OF THE CFRONT SATURDAY. SREF AND GEFS PWATS ARE BTWN 1-2SD ABV NORMAL IN ADVANCE OF CDFRONT. 09Z/12Z ENSEMBLES GUIDANCE SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING SHOWERS ACROSS THE NW MTNS SHOULD PUSH SE AND TRANSITION/GROW INTO NUMEROUS +SHRA AND A FEW BKN LINES OF TSRA IN THE AFTERNOON OVR THE SERN HALF OR SO OF THE FCST AREA...WHERE EARLY HEATING WILL RESULT IN A MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. SREF PROB FOR CAPES EXCEEDING 2000 J/KG RAMP UP QUICKLY IN THE 15-18Z TIMEFRAME ALONG AND EAST OF A LINE FROM NEAR KJST...TO KUNV AND KELM. HOWEVER...FAIRLY MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR WX THREAT. BEST CHC APPEARS TO BE ACROSS THE LOWER SUSQ VALLEY DURING THE MID AFTERNOON TO EARLY EVENING. LOCALLY HEAVY RAINS OF AN INCH OR SO IN UNDER ONE HOUR MAY BE AN EQUALLY IMPORTANT IMPACT FROM THE CFROPA AND ACCOMPANYING TSRA. MAX TEMPS SAT AFTERNOON WILL VARY FROM JUST THE L70S ACROSS THE NW...TO THE U80S IN THE SE ZONES. PARTIAL LATE NIGHT CLEARING SATURDAY NIGHT /WITH WET GROUND AND STILL MODERATE DEWPOINTS IN THE 50S TO NEAR 60F/ WILL LEAD TO LOCALLY DENSE VALLEY FOG AFTER 06Z SUNDAY THROUGH 13Z SUNDAY UNDER LIGHT NW TO NRLY SFC FLOW. && .LONG TERM /SUNDAY THROUGH FRIDAY/... *COOLER/DRY WEATHER SUNDAY INTO MONDAY *NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK /SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS SOUTH CENTRAL CANADA. AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED. SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... ISOLATED TO SCT...MAINLY TOPOGRAPHICALLY ANCHORED...SLOW-MOVING PULSE SHOWERS AND TSRA WILL CONTINUE ACROSS MAINLY CENTRAL AND SRN PENN THROUGH 00Z SAT. LOCAL RESTRICTIONS WILL ACCOMPANY THIS CONVECTION. HIGH DEWPOINTS REMAIN IN PLACE TONIGHT AHEAD OF AN APPROACHING COLD FRONT. THIS WILL LEAD TO REDEVELOPMENT OF FOG/HAZE...AND AN ENCROACHING MVFR CLOUD DECK ALONG WITH A CHANCE FOR SHOWERS AFTER 06Z IN THE NW. AREAS OF LIFR ARE POSSIBLE ACROSS THE EASTERN TWO THIRDS OF THE STATE...WITH VLIFR POSSIBLE ACROSS SOME PORTIONS OF THE SUSQ VALLEY BETWEEN 10-13Z SATURDAY. NUMEROUS SHOWERS AND TSRA WITH OCNL RESTRICTIONS WILL OCCUR SATURDAY /MAINLY AFTER 18Z ACROSS THE SE...LOWER SUSQ VALLEY AIRFIELDS SUCH AS KMDT...KCXY...KLNS AND KTHV/. OUTLOOK... SUN...AM FOG POSS NW MTNS. MON...PATCHY AM VALLEY FOG POSS. TUE...CHC SHOWERS/TSTMS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...FITZGERALD/GARTNER AVIATION...LAMBERT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 1240 PM EDT FRI SEP 5 2014 PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066-061645- 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- 1240 PM EDT FRI SEP 5 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. GARTNER
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1241 PM EDT FRI SEP 5 2014
PAZ063-064-051745-
CUMBERLAND PA-ADAMS PA-
1241 PM EDT FRI SEP 5 2014
...STRONG THUNDERSTORMS ARE AFFECTING THE AREA...
AT 1239 PM EDT...DOPPLER RADAR INDICATED A FEW STRONG THUNDERSTORMS
ALONG A LINE EXTENDING FROM NEAR PINE GROVE FURNACE TO NEAR
ORRTANNA...AND MOVING SLOWLY TO THE EAST AT 5 MPH.
BRIEF...40 MPH WIND GUSTS AND UP TO DIME SIZE HAIL WILL BE POSSIBLE
WITH THESE STORMS. VERY HEAVY RAIN OF OVER ONE INCH IN JUST 30
MINUTES IS ALSO POSSIBLE IN A FEW LOCATIONS.
THE STRONG THUNDERSTORMS WILL BE NEAR...
PINE GROVE FURNACE AROUND 100 PM EDT.
CASHTOWN AROUND 110 PM EDT.
ASPERS AROUND 120 PM EDT.
OTHER LOCATIONS IMPACTED BY THESE STORMS INCLUDE BIGLERVILLE...
ARENDTSVILLE...MCKNIGHTSTOWN...FAIRFIELD...BENDERSVILLE AND LIBERTY
MOUNTAIN RESORT.
LAT...LON 3990 7747 4002 7739 4007 7720 3977 7727
3976 7746
TIME...MOT...LOC 1639Z 248DEG 6KT 3999 7733 3982 7740
LAMBERTSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
350 PM EDT FRI SEP 5 2014
PAZ065-066-052030-
YORK PA-LANCASTER PA-
350 PM EDT FRI SEP 5 2014
...A STRONG THUNDERSTORM IS AFFECTING THE AREA...
AT 350 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM NEAR
WRIGHTSVILLE...MOVING NORTHEAST AT 5 MPH.
50 MPH WIND GUSTS AND PEA SIZE HAIL ARE POSSIBLE WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE...
LANCASTER...COLUMBIA...MILLERSVILLE...WILLOW STREET...MOUNT
JOY...AND RED LION.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
INTENSE RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.
&&
LAT...LON 3984 7654 3999 7670 4012 7653 4010 7637
4000 7627
TIME...MOT...LOC 1950Z 223DEG 5KT 3999 7652
DANGELOSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE STATE COLLEGE PA 403 PM EDT FRI SEP 5 2014 PAZ036-052030- FRANKLIN PA- 403 PM EDT FRI SEP 5 2014 ...A STRONG THUNDERSTORM IS AFFECTING THE AREA... AT 403 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER CLAYLICK. THIS STORM WAS NEARLY STATIONARY. 50 MPH WIND GUSTS AND PEA SIZE HAIL WILL BE POSSIBLE WITH THIS STORM. VERY HEAVY RAIN IS ALSO POSSIBLE. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF SOUTH CENTRAL FRANKLIN COUNTY...INCLUDING THE FOLLOWING LOCATIONS...WHITETAIL SKI AREA...UPTON...WARRENTON AND STATE LINE. THIS INCLUDES INTERSTATE 81 BETWEEN MILE MARKERS 0 AND 10. PRECAUTIONARY/PREPAREDNESS ACTIONS... INTENSE RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. && LAT...LON 3983 7794 3986 7768 3972 7773 3972 7800 TIME...MOT...LOC 2003Z 290DEG 3KT 3976 7789 EVANEGO
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
417 PM EDT FRI SEP 5 2014
PAZ065-052045-
YORK PA-
417 PM EDT FRI SEP 5 2014
...A STRONG THUNDERSTORM IS AFFECTING THE AREA...
AT 416 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM NEAR
PARKVILLE...DRIFTING SOUTHWEST AT 10 MPH.
50 MPH WIND GUSTS AND DIME SIZE HAIL WILL BE POSSIBLE WITH THIS
STORM. VERY HEAVY RAIN IS ALSO POSSIBLE.
THIS STRONG THUNDERSTORM WILL BE NEAR...
PARKVILLE AROUND 420 PM EDT.
PENNVILLE AROUND 430 PM EDT.
OTHER LOCATIONS IMPACTED BY THIS STORM INCLUDE GLENVILLE AND SEVEN
VALLEYS.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
INTENSE RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.
&&
LAT...LON 3972 7700 3977 7700 3990 7676 3990 7675
3972 7670
TIME...MOT...LOC 2016Z 049DEG 7KT 3977 7691
EVANEGOThe national radar mosaic for the moment the first event began.
2 flash flood. Local standard time, as filed.
Torrential thunderstorm rains and flash flooding closed SR 441 in Washington Borough.
Torrential thunderstorm rains caused flash flooding and prompted water rescues near Kinzers and Gap.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2014Every state in 2014This day in weather historyWarnings in Pennsylvania, September 2014
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 539758, 539759.