Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1993

Severe Thunderstorm Warning 28, NWS Philadelphia/Mount Holly

July 14, 1993Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 14, 1993, 9:57 PM EDT for Montgomery County, Pennsylvania. It was in force for 33 min.

The area

The counties it named.

The facts

Issued
Jul 14, 1993, 9:57 PM EDT (01:57 UTC)
Expired
Jul 14, 1993, 10:30 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Montgomery County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 00:00Z, 2.0 hours before the alert went out and 112 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, Atlantic City In, NJ at 00:00Z on 1993-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 632 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Atlantic City In, NJ at 00:00Z on 1993-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 215 square meters per square second.193958Sfc1 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
632 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
215 m²/s²
0-3 km storm-relative helicity
278 m²/s²
Significant tornado parameter
0.8
Supercell composite
7.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 150157
SVRPHL
PAC091-150230-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
957 PM EDT WED JUL 14 1993
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1030 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...EASTERN MONTGOMERY COUNTY
 
WEATHER RADAR SHOWED A SEVERE THUNDERSTORM MOVING THROUGH CENTRAL
MONTGOMERY COUNTY...TOWARD THE SOUTHEAST AT ABOUT 20 MPH.
 
A STORM SPOTTER IN LANSDALE REPORTED A WIND GUST OF 59 MPH AT 1050 PM.
THIS STORM MAY ALSO PRODUCE LARGE HAIL AND LOCALLY HEAVY RAIN.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN THE WARNED AREA...PREPARE
FOR STRONG DAMAGING WINDS...LARGE HAIL...VERY HEAVY RAIN AND DEADLY
LIGHTNING.  SHOULD THE STORM APPROACH YOU...SEEK IMMEDIATE SHELTER
INDOORS...BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST
VULNERABLE TO HIGH WINDS AND SHOULD BE AVOIDED.
 
KRAUS
 
&

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, Jul 14, 9:06 PM EDT, 51 minutes before
PAZ011-016-150300 -

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ALLENTOWN PA...CORRECTED.
905 PM EDT WED JUL 14 1993

...SEVERE THUNDERSTORM WATCH FOR EAST CENTRAL PENNSYLVANIA AND
THE POCONOS HAS EXPIRED...
...THUNDERSTORMS MOVING THROUGH THE LEHIGH VALLEY METROPOLITAN AREA...

THE SEVERE THUNDERSTORM WATCH FOR EAST CENTRAL PENNSYLVANIA AND THE
POCONOS EXPIRED AT 9PM.  THIS MEANS THE THREAT OF SEVERE WEATHER HAS
DIMINISHED ACROSS THE REGION.  ALTHOUGH THE THREAT OF SEVERE THUNDERSTORMS
HAS ENDED...SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS THE
LEHIGH VALLEY METROPOLITAN REGION.  NATIONAL WEATHER SERVICE RADAR INDICATES
SHOWERS AND THUNDERSTORMS EXTENDING ACROSS NORTHAMPTON...LEHIGH AND
BERKS COUNTIES.  THE STRONGEST STORMS WERE LOCATED OVER BERKS COUNTY
NEAR SHILLINGTON AND SOUTH OF KUTZTOWN BETWEEN FLEETWOOD AND FREDERICKSVILLE.

THE THUNDERSTORMS STILL HAVE THE CAPABILITY OF PRODUCING LOCALLY HEAVY
DOWNPOURS AND CLOUD TO GROUND LIGHTNING.
SHOWERS AND THUNDERSTORMS SHOULD END BY MIDNIGHT WITH GRADUAL CLEARING
OVERNIGHT.

MILLER
Special weather statement, Jul 14, 9:17 PM EDT, 40 minutes before
PAZ012-NJZ002-150300-

SPECIAL WEATHER STATEMENT - THUNDERSTORMS
NATIONAL WEATHER SERVICE PHILADELPHIA PA
915 PM EDT WED JUL 14 1993

...SEVERE THUNDERSTORM WATCH EXPIRED AS OF 900 PM...
...THUNDERSTORMS WITH LOCALLY HEAVY RAIN MOVING INTO NORTHERN CHESTER
AND MONTGOMERY COUNTIES...

THE SEVERE THUNDERSTORM WATCH THAT HAD BEEN IN EFFECT FOR THE ENTIRE
PHILADELPHIA METROPOLITAN AREA EXPIRED AS OF 900 PM. HOWEVER...SCATTERED
SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE AREA.

AT 910 PM...NATIONAL WEATHER SERVICE RADAR SHOWED THE STRONGEST STORM IN
SOUTHERN BERKS COUNTY NEAR READING. THIS STORM WAS MOVING TOWARD THE
EAST-SOUTHEAST AT ABOUT 20 MPH...INTO NORTHERN CHESTER AND MONTGOMERY
COUNTIES.

THIS STORM WAS LIKELY DROPPING LOCALLY HEAVY RAIN...AND COULD PRODUCE
WIND GUSTS OF NEAR 40 MPH AS WELL AS SMALL HAIL. IF IT HOLDS TOGETHER...
IT WILL MOVE THROUGH MONTGOMERY AND NORTHERN CHESTER COUNTIES BY 1000
PM...AND COULD APPROACH WESTERN SECTIONS OF PHILADELPHIA.

IF THREATENING WEATHER IS SIGHTED...SEEK SHELTER IMMEDIATELY.  IF YOU
SEE LARGE HAIL OR WIND DAMAGE...NOTIFY YOUR LOCAL LAW ENFORCEMENT AGENCY
AND ASK THEM TO RELAY THE REPORTS TO THE LOCAL NATIONAL WEATHER SERVICE
OF~FICE.  STORM SPOTTERS...PLEASE CALL IN ANY REPORTS OF SEVERE WEATHER.

KRAUS
Special weather statement, Jul 14, 9:30 PM EDT, 27 minutes before
NJZ003-004-006-501-DEZ501-150245-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE ATLANTIC CITY NJ
930 PM EDT WED JUL 14 1993

...THE SEVERE THUNDERSTORM WATCH HAS BEEN ALLOW TO EXPIRE...

AT 930 PM...OUR WEATHER SEARCH RADAR SHOWED THUNDERSTORMS WITH VERY HEAVY
RAIN...GUSTY WINDS...FREQUENT LIGHTNING AND POSSIBLE SMALL HAIL FROM THE
NORTHERN SECTIONS OF MARYLAND AND DELAWARE UP TO BOYERSTOWN AND ALLENTOWN.
OTHER SHOWERS AND THUNDERSTORMS WERE LOCATED ACROSS PARTS OF NEW JERSEY
SOUTHEAST MARYLAND...SOUTHERN NEW YORK AND OFF-SHORE.

MOVEMENT WAS EAST TO EASTSOUTHEAST AT 25 MILES AN HOUR.

IF THREATENING WEATHER APPROACHES...BE PREPARED TO SEEK SHELTER
IMMEDIATELY.

LISTEN FOR LATER STATEMENTS OR WARNINGS FROM THE NATIONAL WEATHER
SERVICE ATLANTIC CITY NEW JERSEY.

MCDONALD
Special weather statement, Jul 14, 9:34 PM EDT, 23 minutes before
DEZ003-002-001-150230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON DE
935 PM EDT WED JUL 14 1993

...SEVERE THUNDERSTORM WATCH EXPIRED AT 9 PM...
...THUNDERSTORMS MOVING THROUGH DELAWARE...

THE SEVERE THUNDERSTORM WATCH FOR DELAWARE AND ADJACENT COASTAL WATERS
EXPIRED AT 9 PM.  SCATTERED THUNDERSTORMS CONTINUE TO MOVE THROUGH THE
FIRST STATE THIS EVENING.

AT 920 PM RADAR SHOWED THUNDERSTORMS WITH LOCALLY HEAVY RAIN SCATTERED
OVER NEW CASTLE AND KENT COUNTIES.  OTHER THUNDERSTORMS WERE OVER QUEEN
ANNES COUNTY MARYLAND AND WOULD BE MOVING INTO KENT COUNTY DELAWARE
SHORTLY.  THESE STORMS ARE WEAKENING AS THE MOVE EAST AT ABOUT 30 MPH
AND WILL APPROACH THE COASTAL WATERS AROUND 10 PM.

PERSONS IN THE PATH OF THE APPROACHING STORMS SHOULD FIND SHELTER UNTIL
THE STORMS PASS OR DISSIPATE.  MOTORIST SHOULD USE CAUTION WHEN DRIVING
AND ALLOW EXTRA TIME FOR REACHING DESTINATIONS.

STAY TUNED TO THE NOAA WEATHER RA|DIO AND LOCAL TV AND RADION STATIONS
FOR FURTHER UPDATES.

LYLES
Special weather statement, Jul 14, 9:35 PM EDT, 22 minutes before
DEZ003-002-001-150230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON DE
935 PM EDT WED JUL 14 1993

...SEVERE THUNDERSTORM WATCH EXPIRED AT 9 PM...
...THUNDERSTORMS MOVING THROUGH DELAWARE...

THE SEVERE THUNDERSTORM WATCH FOR DELAWARE AND ADJACENT COASTAL WATERS
EXPIRED AT 9 PM.  SCATTERED THUNDERSTORMS CONTINUE TO MOVE THROUGH THE
FIRST STATE THIS EVENING.

AT 920 PM RADAR SHOWED THUNDERSTORMS WITH LOCALLY HEAVY RAIN SCATTERED
OVER NEW CASTLE AND KENT COUNTIES.  OTHER THUNDERSTORMS WERE OVER QUEEN
ANNES COUNTY MARYLAND AND WOULD BE MOVING INTO KENT COUNTY DELAWARE
SHORTLY.  THESE STORMS ARE WEAKENING AS THE MOVE EAST AT ABOUT 30 MPH
AND WILL APPROACH THE COASTAL WATERS AROUND 10 PM.

PERSONS IN THE PATH OF THE APPROACHING STORMS SHOULD FIND SHELTER UNTIL
THE STORMS PASS OR DISSIPATE.  MOTORIST SHOULD USE CAUTION WHEN DRIVING
AND ALLOW EXTRA TIME FOR REACHING DESTINATIONS.

STAY TUNED TO THE NOAA WEATHER RADIO AND LOCAL TV AND RADION STATIONS
FOR FURTHER UPDATES.

LYLES
Special weather statement, Jul 14, 9:48 PM EDT, 9 minutes before
NJZ003-004-006-501-DEZ501-150245-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE ATLANTIC CITY NJ
930 PM EDT WED JUL 14 1993

...THE SEVERE THUNDERSTORM WATCH HAS BEEN ALLOW TO EXPIRE...

AT 930 PM...OUR WEATHER SEARCH RADAR SHOWED THUNDERSTORMS WITH VERY HEAVY
RAIN...GUSTY WINDS...FREQUENT LIGHTNING AND POSSIBLE SMALL HAIL FROM THE
NORTHERN SECTIONS OF MARYLAND AND DELAWARE UP TO BOYERSTOWN AND ALLENTOWN.
OTHER SHOWERS AND THUNDERSTORMS WERE LOCATED ACROSS PARTS OF NEW JERSEY
SOUTHEAST MARYLAND...SOUTHERN NEW YORK AND OFF-SHORE.

MOVEMENT WAS EAST TO EASTSOUTHEAST AT 25 MILES AN HOUR.

IF THREATENING WEATHER APPROACHES...BE PREPARED TO SEEK SHELTER
IMMEDIATELY.

LISTEN FOR LATER STATEMENTS OR WARNINGS FROM THE NATIONAL WEATHER
SERVICE ATLANTIC CITY NEW JERSEY.

MCDONALD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 14, 10:06 PM EDTSevere Thunderstorm WarningPHIBucks54 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1993Every severe thunderstorm warning in 1993

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.