Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 73, NWS Pittsburgh, PA

July 9, 1999Washington County, Pennsylvania

NWS Pittsburgh, PA issued this severe thunderstorm warning at Jul 9, 1999, 9:03 PM EDT for Washington County, Pennsylvania. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 9, 1999, 9:03 PM EDT (01:03 UTC)
Expired
Jul 9, 1999, 9:45 PM EDT
In force
42 min
Issued by
NWS Pittsburgh, PA
Area
Whole counties

County Washington County, PA

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 9, 8:00 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 00:00Z, 1.1 hours before the alert went out and 28 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 00:00Z on 1999-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1241 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 00:00Z on 1999-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 306 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
1241 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
1397 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
306 m²/s²
0-3 km storm-relative helicity
396 m²/s²
Significant tornado parameter
1.7
Supercell composite
15.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 8:02 PM EDTSevere Thunderstorm WarningPBZArmstrong58 min
Jul 9, 8:07 PM EDTSevere Thunderstorm WarningPBZAllegheny53 min
Jul 9, 8:22 PM EDTSevere Thunderstorm WarningPBZJefferson53 min
Jul 9, 8:26 PM EDTSevere Thunderstorm WarningPBZButler34 min
Jul 9, 8:39 PM EDTSevere Thunderstorm WarningPBZIndiana, Westmoreland66 min
Jul 9, 8:50 PM EDTSevere Thunderstorm WarningPBZAllegheny55 min
Jul 9, 8:32 PM EDTSevere Thunderstorm WarningPBZMuskingum58 min
Jul 9, 8:54 PM EDTSevere Thunderstorm WarningPBZJefferson51 min
Jul 9, 9:31 PM EDTSevere Thunderstorm WarningPBZBelmont44 min
Jul 9, 8:58 PM EDTSevere Thunderstorm WarningPBZBrooke, Hancock32 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1999Every severe thunderstorm warning in 1999

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.