Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 101, NWS Pittsburgh, PA

September 2, 1990Somerset County, Westmoreland County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Sep 2, 1990, 4:45 PM EDT for Somerset County, Westmoreland County, Pennsylvania. It was in force for 75 min. 4 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
Sep 2, 1990, 4:45 PM EDT (20:45 UTC)
Expired
Sep 2, 1990, 6:00 PM EDT
In force
75 min
Issued by
NWS Pittsburgh, PA
Area
Whole counties

Counties Somerset County, PA, Westmoreland 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
Sep 2, 5:05 PM EDTHail 0.75Somerset, PA
Sep 2, 5:30 PM EDTThunderstorm Wind 0Somerset, PA
Sep 2, 5:35 PM EDTThunderstorm Wind 0Westmoreland, PA
Sep 2, 5:40 PM EDTThunderstorm Wind 0Westmoreland, 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

Pittsburgh, PA (KPIT), launched 12:00Z, 8.8 hours before the alert went out and 78 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, Pittsburgh, PA at 12:00Z on 1990-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 692 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, Pittsburgh, PA at 12:00Z on 1990-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.19395878Sfc1 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
692 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
944 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPIT 022045
SVRPIT
PAC059-111-129-WVC069-022200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
445 PM EDT SUN SEP 2 1990

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 600 PM EDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES OF

WESTERN PENNSYLVANIA...GREENE...SOMERSET AND WESTMORELAND
PANHANDLE OF WEST VIRGINIA...OHIO

AT 443 PM RADAR SHOWED A PAIR OF SEVERE THUNDERSTORMS. ONE WAS IN
SOUTHEASTERN JEFFERSON COUNTY OHIO...JUST NORTHWEST OF THE VILLAGE
OF TILTONSVILLE OHIO. AND THE OTHER SEVERE THUNDERSTORM WAS A FEW
MILES SOUTH OF LATROBE PENNSYLVNIA IN WESTMORELAND COUNTY. BOTH
STORMS ARE MOVING SOUTHEAST AT 30 MPH.

A SEVERE THUNDERSTORM WARNING MEANS SEVERE THUNDERSTORMS ARE
IMMINENT OR IN PROGRESS. THESE STORMS WILL HAVE DAMAGING WIND..HAIL
..HEAVY RAIN..AND DANGEROUS LIGHTNING.

IF THREATENING WEATHER APPROACHES..GO TO A SAFE PLACE IMMEDIATELY.

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 2, 3:35 PM EDT, 1 hour 10 minutes before
PAZ015-WVZ001-022200-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE PITTSBURGH PA
330  PM EDT SUN SEP 02 1990

...SLOW MOVING THUNDERSTORMS WITH HEAVY DOWNPOURS OVER SOUTHWEST
PENNSYLVANIA AND THE NORTHERN PANHANDLE OF WEST VIRGINIA...

AT 325 PM WEATHER SERVICE RADAR SHOWED A LINE OF SHOWERS AND
EMBEDDED THUNDERSTORMS EXTENDING...IN PENNSYLVANIA...FROM
VANDERGRIFT TO THE NORTH HILLS OF PITTSBURGH TO HANCOCK
WEST VIRGINIA AND WESTWARD INTO OHIO.

THESE STORMS ARE MOVING VERY SLOWLY AND WILL DROP ALOT OF RAIN IN
A SHORT PERIOD OF TIME. AN INCH OF RAIN IN AN HOUR IS POSSIBLE.
MOVEMENT IS TO THE SOUTHEAST AT ONLY 20 MPH.

IN ADDITION TO HEAVY DOWNPOURS AND DANGEROUS LQIGHTNING...THESE STORMS
MAY ALSO PRODUCE STRONG WIND AND SMALL HAIL.
ALL THOSE OUTDOORS SHOULD MOVE INSIDE. IT IS LIKELY THAT
WATER WILL POND ON ROADWAYS. REMEMBER...NEVER EVER DRIVE
THROUGH FLOODED ROADWAYS.

STAIRS/DRZAL
Special weather statement, Sep 2, 3:41 PM EDT, 1 hour 4 minutes before
PAZ015-WVZ001-022200-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY...CORRECTED TO ADD
NATIONAL WEATHER SERVICE PITTSBURGH PA          HANCOCK COUNTY
330  PM EDT SUN SEP 02 1990

...SLOW MOVING THUNDERSTORMS WITH HEAVY DOWNPOURS OVER SOUTHWEST
PENNSYLVANIA AND THE NORTHERN PANHANDLE OF WEST VIRGINIA...

AT 325 PM WEATHER SERVICE RADAR SHOWED A LINE OF SHOWERS AND
EMBEDDED THUNDERSTORMS EXTENDING...IN PENNSYLVANIA...FROM
VANDERGRIFT TO THE NORTH HILLS OF PITTSBURGH TO HANCOCK COUNTY
WEST VIRGINIA AND WESTWARD INTO OHIO.

THESE STORMS ARE MOVING VERY SLOWLY AND WILL DROP ALOT OF RAIN IN
A SHORT PERIOD OF TIME. AN INCH OF RAIN IN AN HOUR IS POSSIBLE.
MOVEMENT IS TO THE SOUTHEAST AT ONLY 20 MPH.

IN ADDITION TO HEAVY DOWNPOURS AND DANGEROUS LIGHTNING...THESE STORMS
MAY ALSO PRODUCE STRONG WIND AND SMALL HAIL.
ALL THOSE OUTDOORS SHOULD MOVE INSIDE. IT IS LIKELY THAT
WATER WILL POND ON ROADWAYS. REMEMBER...NEVER EVER DRIVE
THROUGH FLOWODED ROADWAYS.

STAIRS/DRZAL

The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 2, 4:45 PM EDTSevere Thunderstorm WarningPBZGreene75 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.