Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1996

Severe Thunderstorm Warning 118, NWS Philadelphia/Mount Holly

September 13, 1996Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 13, 1996, 6:15 PM EDT for Montgomery County, Pennsylvania. It was in force for 30 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Sep 13, 1996, 6:15 PM EDT (22:15 UTC)
Expired
Sep 13, 1996, 6:45 PM EDT
In force
30 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 86 km from the middle of the area, began a volume at 22:14 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Sep 13, 6:30 PM EDTThunderstorm WindLansdale, PA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.3 hours before the alert went out and 224 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 1996-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 1996-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -136 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
20 J/kg
Mixed-layer CIN
-109 J/kg
Mixed-layer LCL
639 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
-136 m²/s²
0-3 km storm-relative helicity
-42 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KPHL 132216
SVRPHL
PAC091-132245-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
615 PM EDT FRI SEP 13 1996

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY NJ HAS
ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 645 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN  PENNSYLVANIA

   ...MONTGOMERY COUNTY
 
AT 611 PM EDT...A SEVERE THUNDERSTORM WAS INDICATED BY NWS DOPPLER
RADAR AND SPOTTER REPORTS 3 MILES SOUTHWEST OF OAKS MOVING NORTHEAST
AT 35 MPH.

THIS STORM MAY AFFECT THE FOLLOWING NEARBY AREAS... OAKS... MONT
CLARE... AUDUBON... ROYERSFORD... KING OF PRUSSIA... COLLEGEVILLE...
TRAPPE... BRIDGEPORT... LIMERICK... NORRISTOWN... GRATERFORD... WEST
CONSHOHOCKEN... CONSHOHOCKEN... SCHWENKSVILLE... OBELISK...
FREDERICK... HARLEYSVILLE... GWYNEDD VALLEY... LANSDALE... NORTH
WALES... FLOURTOWN... FORT WASHINGTON... GREEN LANE... AMBLER AND
HATFIELD.

LARGE TREE BRANCHES WERE BROKEN BY THUNDERSTORM WINDS IN WEST CHESTER
AT AROUND 550 PM.

IF YOU ARE IN THE PATH OF THIS STORM...SEEK SHELTER NOW.  AFTER THE
STORM HAS PASSED...REPORT ANY SEVERE WEATHER OR FLOODING TO YOUR
LOCAL LAW ENFORCEMENT AGENCY AND HAVE THEM RELAY YOUR SEVERE WEATHER
REPORT ON TO THE NATIONAL WEATHER SERVICE.

SEVERE THUNDERSTORMS CONTAIN WINDS GREATER THAN 58 MILES AN HOUR...
DIME SIZE HAIL OR LARGER...VERY HEAVY RAINS AND DEADLY LIGHTNING.

STAY TUNED TO NOAA WEATHER RADIDO...THE VOICE OF THE NATIONAL WEATHER
SERVICE...OR TO COMMERCIAL RADIO OR TELEVISION STATIONS FOR THE
LATEST STORM INFORMATION.
 

AMC/RWP
&

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Sep 13, 3:16 PM EDT, 2 hours 59 minutes before
NJZ014-023>026-DEZ004-140400-

SPECIAL WEATHER STATEMENT - HEAVY SURF
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
315 PM EDT FRI SEP 13 1996

...HEAVY SURF IS POSSIBLE TONIGHT AND SATURDAY ALONG THE NEW JERSEY AND
DELAWARE COASTS...

SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE NEW JERSEY AND DELAWARE
COASTS FOR TONIGHT AND SATURDAY.  SWELLS GENERATED BY HURRICANE
HORTENSE HAVE BEGUN TO AFFECT THE COASTAL WATERS TODAY AND WILL
INCREASE OVERNIGHT INTO SATURDAY MORNING. THE HURRICANE...WHICH WAS
SOME 450 MILES SOUTHEAST OF CAPE HATTERAS AT 11 AM...IS FORECAST MOVE
NORTHWARD OVERNIGHT AND REACH A POINT ABOUT 350 MILES EAST OF ATLANTIC
CITY EARLY SATURDAY MORNING.

THE FORECAST TRACK IS SLIGHTLY EAST OF THAT TAKEN BY HURRICANE EDOUARD
IN AUGUST SO THE EFFECTS ALONG THE COAST SHOULD BE SIMILAR OR SOMEWHAT
LESS...ESPECIALLY SINCE HORTENSE IS ALSO FORECAST TO WEAKEN SOMEWHAT AS
IT MOVES NORTHWARD OVER COLDER WATER.

NONETHELESS...BOATERS AND SWIMMERS ALONG THE COAST ON SATURDAY SHOULD
EXERCISE CAUTION AS LARGE SWELLS FROM HORTENSE WILL LIKELY CREATE ROUGH
SURF AND POSSIBLY ALSO DANGEROUS RIP CURRENTS.  IF YOU ARE CAUGHT IN A
RIP CURRENT...DON/T SWIM TOWARD SHORE FIGHTING THE CURRENT.  INSTEAD
SWIM PARALLEL TO SHORE UNTIL YOU ESCAPE THE CURRENT.

CONDITIONS WILL IMPROVE LATE SATURDAY INTO SUNDAY AS HURRICANE HORTENSE
MOVES RAPIDLY AWAY TO THE NORTHEAST.

THERE WERE NO REPORTS OF TIDAL FLOODING AROUND THE TIME OF HIGH TIDE
THIS MORNING.  WINDS ALONG THE SHORE HAVE SHIFTED TO THE SOUTHWEST AND
WILL BECOME WESTERLY THIS EVENING.  TIDES WHICH HAVE BEEN RUNNING
AROUND 1 AND 1/2 FEET ABOVE NORMAL SHOULD BEGIN DECREASE AND EVEN MINOR
FLOODING SEEMS UNLIKEjLY THIS EVENING.

STAY TUNED TO NOAA WEATHER RADIO...THE VOICE OF THE NATIONAL WEATHER
SERVICE...FOR THE LATEST WEATHER INFORMATION.

AMC/NATIONAL WEATHER SERVICE

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 13, 5:37 PM EDTSevere Thunderstorm WarningPHIChester48 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1996Every severe thunderstorm warning in 1996

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.