Alert archive / Pennsylvania / Flash Flood Warnings in 2026

Flash Flood Warning 145, NWS Pittsburgh, PA

September 12, 2026Armstrong County, Butler County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Sep 12, 2026, 9:19 PM EDT for Armstrong County, Butler County, Pennsylvania. It was in force for 116 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
Sep 12, 2026, 9:19 PM EDT (01:19 UTC)
Expired
Sep 12, 2026, 11:15 PM EDT
In force
116 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Armstrong County, PA, Butler County, PA

The radar

The Pittsburgh radar (KPBZ), 58 km from the middle of the area, began a volume at 01:22 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.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 00:00Z, 1.3 hours before the alert went out and 61 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 2026-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 567 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 2026-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 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
567 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
483 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
227 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 8:27 PM EDTAreal Flood WarningPBZFayette, Greene, Washington, Westmoreland3 hr
Sep 13, 2:28 AM EDTFlash Flood WarningPBZClarion3 hr
Sep 13, 5:17 PM EDTSevere Thunderstorm WarningPBZMercer, Venango30 min
Sep 13, 5:26 PM EDTFlash Flood WarningPBZMercer3 hr
Sep 13, 5:30 PM EDTSevere Thunderstorm WarningPBZButler, Lawrence, Mercer34 min
Sep 13, 6:18 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Butler42 min
Sep 13, 5:10 PM EDTSevere Thunderstorm WarningPBZCarroll, Columbiana, Jefferson28 min
Sep 13, 6:43 PM EDTSevere Thunderstorm WarningPBZNoble47 min

Nearby

Flash Flood Warnings in Pennsylvania, 2026Every flash flood warning in 2026

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; radar from the NEXRAD Level II archive.