Alert archive / Pennsylvania / Flash Flood Warnings in 2023
Flash Flood Warning 16, NWS Pittsburgh, PA
NWS Pittsburgh, PA issued this flash flood warning at Jul 20, 2023, 11:02 PM EDT for 5 counties in Pennsylvania. It was in force for 3 hr. 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 20, 2023, 11:02 PM EDT (03:02 UTC)
- Expired
- Jul 21, 2023, 2:15 AM EDT
- In force
- 3 hr
- Issued by
- NWS Pittsburgh, PA
- Area
- Storm-based polygon
- Flood severity
- None
Counties Allegheny County, PA, Fayette County, PA, Indiana County, PA, Washington County, PA, Westmoreland County, PA
The radar
The Pittsburgh radar (KPBZ), 51 km from the middle of the area, began a volume at 03:04 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, 3.0 hours before the alert went out and 37 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.
- Mixed-layer CAPE
- 1429 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 1189 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 160 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 6.2
What forecasters said that day
The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Pittsburgh, PA wrote its last area forecast discussion before this flash flood warning went out at Jul 20, 10:43 PM EDT, 19 minutes earlier.
Area forecast discussion, Jul 20, 10:43 PM EDT, 19 minutes before
Area Forecast Discussion National Weather Service Pittsburgh PA 1043 PM EDT Thu Jul 20 2023 .SYNOPSIS... Strong strong will continue to move through late this evening into early Friday morning. Damaging winds and flash flooding will be the main concern. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A line of strong to severe storms will continue to move through the region early Friday morning. Damaging winds with remain the main concern for areas south of Pittsburgh. Therefore, the Severe Thunderstorm Watch will continue through 3am. Heavy rain with training storms will be the main concern for the next few hours as 1-2 inch rainfall rate have been observed and bulk wind shear vectors continue to move parallel with the frontal boundary. Urban areas have the highest chance in experiening problems. At the moment, precipitation and thunderstorms chances are expected to diminish between 06-08Z. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/... Northwest flow behind a cold front will keep this period seasonably cool. Friday will maintain a few shower chances with lingering low level moisture in a shallow mixed layer. Higher moisture and closer proximity to lift in cyclonic flow around an occluded low will mean a slight chances of isolated showers, greatest north and east of the Pittsburgh metro. Otherwise, morning fog/stratus will give way to fair weather cumulus, decreasing in coverage throughout the day. Clouds and precipitation will drop off overnight with a loss of mixing with patchy fog possible in mostly clear skies. Highs on Saturday will remain near to slightly above average. Conditions will likely remain dry with fair weather cumulus but shallow, capped instability mean a shower or two could not be ruled out. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... The long term will be defied with a persistent upper trough gradually weakening in amplitude. All clusters agree in this; there is high confidence that near average temperature will gradually and steadily trend above average. Positioning on the southeast side of the axis will lend to occasional precipitation chances, but no sizable QPF in widespread rainfall is likely. By late next week, clusters diverge into three camps. First, one solution resolves to a building eastern ridge which would mean well above average temperatures. Second, zonal flow is possible with temperatures a few ticks above average. Third, a central/western CONUS ridge would keep temperatures more near to slightly above average locally. Any way you cut the cake, the take-home message is increased probability of above average temperatures. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... A broken line of thunderstorms, ahead of an approaching cold front, is expected to track southeast across the region this evening. Along with tempo IFR conditions, large hail and damaging wind gusts are possible with these storms. Will and tafs as needed as they approach specific airports. For now, included strong wind gusts and IFR at all sites. After the storms end later this evening, deterioration to IFR stratus is expected with low level moisture pooling along the advancing front. These ceilings should lift to MVFR as mixing begins in the morning, with a return to VFR cigs expected by the afternoon. .OUTLOOK... Other than early morning patchy river valley fog, VFR is expected through Sunday night under high pressure. Restrictions are possible again Monday through early Tuesday with a crossing cold front. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && SYNOPSIS...Hefferan NEAR TERM...Hefferan/Milcarek SHORT TERM...Milcarek LONG TERM...Milcarek AVIATION...WM
Hazardous weather outlook, Jul 20, 10:54 PM EDT, 8 minutes before
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Local storm report, Jul 20, 10:38 PM EDT, 24 minutes before
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</html>The office that day
Everything else NWS Pittsburgh, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 8:02 PM EDT | Tornado Warning | PBZ | Mercer, Venango | 28 min |
| Jul 20, 8:18 PM EDT | Flash Flood Warning | PBZ | Mercer, Venango | 3 hr |
| Jul 20, 8:22 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Beaver, Butler, Clarion, Lawrence, Mercer and 1 more | 53 min |
| Jul 20, 8:25 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Clarion, Forest, Indiana, Jefferson, Venango | 50 min |
| Jul 20, 8:39 PM EDT | Severe Thunderstorm Warning | PBZ | Beaver, Lawrence | 66 min |
| Jul 20, 9:02 PM EDT | Flash Flood Warning | PBZ | Butler, Lawrence, Mercer | 3 hr |
| Jul 20, 9:12 PM EDT | Severe Thunderstorm Warning | PBZ | Allegheny, Armstrong, Beaver, Butler, Clarion, Lawrence and 2 more | 63 min |
| Jul 20, 9:14 PM EDT | Severe Thunderstorm Warning | PBZ | Armstrong, Clarion, Indiana, Jefferson | 44 min |
| Jul 20, 9:42 PM EDT | Flash Flood Warning | PBZ | Armstrong, Beaver, Butler, Lawrence | 3 hr |
| Jul 20, 10:03 PM EDT | Special Weather Statement | PBZ | Allegheny, Washington | 27 min |
| Jul 20, 10:29 PM EDT | Flash Flood Warning | PBZ | Allegheny, Armstrong, Beaver, Butler, Indiana, Washington and 1 more | 3 hr |
| Jul 20, 10:29 PM EDT | Special Weather Statement | PBZ | Westmoreland | 31 min |
| Jul 20, 10:58 PM EDT | Special Weather Statement | PBZ | Fayette | 32 min |
| Jul 20, 11:31 PM EDT | Special Weather Statement | PBZ | Fayette, Greene, Westmoreland | 44 min |
| Jul 20, 9:28 PM EDT | Special Weather Statement | PBZ | Hancock | 62 min |
| Jul 20, 10:44 PM EDT | Special Weather Statement | PBZ | Ohio | 31 min |
| Jul 20, 10:54 PM EDT | Special Weather Statement | PBZ | Marshall | 36 min |
| Jul 21, 12:17 AM EDT | Special Weather Statement | PBZ | Marion, Monongalia, Preston | 58 min |
| Jul 21, 12:18 AM EDT | Special Weather Statement | PBZ | Marion, Monongalia, Preston | 57 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2023Every flash flood warning in 2023
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.