Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 33, NWS Philadelphia/Mount Holly

July 9, 19905 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 9, 1990, 5:19 PM EDT for 5 counties in Pennsylvania. It was in force for 56 min. 3 reports 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
Jul 9, 1990, 5:19 PM EDT (21:19 UTC)
Expired
Jul 9, 1990, 6:15 PM EDT
In force
56 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
Jul 9, 5:20 PM EDTThunderstorm Wind 0Chester, PA
Jul 9, 5:25 PM EDTThunderstorm Wind 0Montgomery, PA
Jul 9, 5:40 PM EDTThunderstorm Wind 0Montgomery, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 9.3 hours before the alert went out and 102 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 12:00Z on 1990-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 684 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, Atlantic City In, NJ at 12:00Z on 1990-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 114 square meters per square second.1939Sfc1 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
684 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
614 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
114 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 092122
SVRPHL
PAC017-029-045-091-101-092215-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
519 PM EDT MON JUL 9 1990
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  615 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...BUCKS COUNTY...CHESTER COUNTY...DELAWARE COUNTY
   ...MONTGOMERY COUNTY...PHILADELPHIA COUNTY
 
WEATHER SERVICE RADAR AT 520 PM INDICATED SEVERE THUNDERSTORMS IN
WESTERN SECTIONS OF BUCKS...MONTGOMERY AND CHESTER COUNTIES OF
SOUTHEASTERN PENNSYLVANIA. THESE THUNDERSTORMS WERE MOVING SOUTHEAST
AT 40 MILES AN HOUR...AND WILL MOVE THROUGH THE WARNED COUNTIES AND
INTO SOUTHWESTERN PORTIONS OF NEW JERSEY SHORTLY AFTER 600 PM.
 
THESE ARE DANGEROUS STORMS.  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.
 
A SEVERE THUNDERSTORM WATCH CONTINUES FOR SOUTHEASTERN
PENNSYLVANIA UNTIL 900 PM...AND FOR SOUTHERN NEW JERSEY UNTIL 1000 PM
EDT.  REMEMBER SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES WITH LITTLE OR NO ADVANCED WARNING.
 
WERT

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 3:45 PM EDTSevere Thunderstorm WarningPHIBucks60 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1990Every severe thunderstorm warning in 1990

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.