Alert archive / Pennsylvania / Flash Flood Warnings in 2020

Flash Flood Warning 15, NWS Pittsburgh, PA

July 7, 2020Allegheny County, Beaver County, Washington County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Jul 7, 2020, 5:48 PM EDT for Allegheny County, Beaver County, Washington County, 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 7, 2020, 5:48 PM EDT (21:48 UTC)
Expired
Jul 7, 2020, 9:00 PM EDT
In force
3 hr
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

Counties Allegheny County, PA, Beaver County, PA, Washington County, PA

The radar

The Pittsburgh radar (KPBZ), 10 km from the middle of the area, began a volume at 21:51 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 12:00Z, 9.8 hours before the alert went out and 9 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 2020-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2020-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1848 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 7, 4:43 PM EDT, 1 hour 5 minutes earlier.

Area forecast discussion, Jul 7, 4:43 PM EDT, 1 hour 5 minutes before
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Hazardous weather outlook, Jul 7, 3:16 AM EDT, 14 hours 32 minutes before
Hazardous Weather Outlook
National Weather Service Pittsburgh PA
316 AM EDT Tue Jul 7 2020

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021-509>514-080730-
Garrett-Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-
Jefferson OH-Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-
Forest-Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-
Armstrong-Indiana-Washington-Greene-Westmoreland-Westmoreland Ridges-
Fayette-Fayette Ridges-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-
Monongalia-Ridges of Eastern Monongalia and Northwestern Preston-
Preston-Eastern Preston-Western Tucker-Eastern Tucker-
316 AM EDT Tue Jul 7 2020

This Hazardous Weather Outlook is for western Maryland, east
central Ohio, northwest Pennsylvania, southwest Pennsylvania,
western Pennsylvania, northern West Virginia and the northern
panhandle of West Virginia.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Special weather statement, Jul 7, 4:13 PM EDT, 1 hour 35 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
413 PM EDT Tue Jul 7 2020

PAZ020-072045-
Beaver-
413 PM EDT Tue Jul 7 2020

...A STRONG THUNDERSTORM CAPABLE OF PRODUCING SMALL HAIL AND GUSTY
WIND WILL AFFECT NORTHEASTERN BEAVER COUNTY...

At 412 PM EDT, a strong thunderstorm was located over Beaver Falls,
moving northeast at 10 mph.

Wind gusts up to 45 mph and small hail are possible with this storm.

Locations impacted include...
Beaver Falls...                   New Brighton...
Rochester...                      Patterson Township...
Big Beaver...                     West Mayfield...
Bridgewater...                    Patterson Heights...
Fallston...                       Eastvale...

This includes the following highways...
  Pennsylvania Turnpike between mile markers 14 and 20.
  Interstate 376 in Pennsylvania near mile marker 31.

This storm may intensify, so monitor local radio or television
stations for additional information and possible warnings from the
National Weather Service.

LAT...LON 4070 8029 4078 8038 4085 8024 4078 8016
TIME...MOT...LOC 2012Z 235DEG 10KT 4077 8029

CL
Special weather statement, Jul 7, 4:41 PM EDT, 1 hour 7 minutes before
Special Weather Statement
National Weather Service Pittsburgh PA
441 PM EDT Tue Jul 7 2020

PAZ020-021-072115-
Beaver-Allegheny-
441 PM EDT Tue Jul 7 2020

...A STRONG THUNDERSTORM CAPABLE OF PRODUCING SMALL HAIL AND GUSTY
WIND WILL AFFECT SOUTHEASTERN BEAVER AND NORTHWESTERN ALLEGHENY
COUNTIES...

At 441 PM EDT, a strong thunderstorm was located over Imperial, or
near Moon Township, moving northeast at 15 mph.

Wind gusts up to 45 mph and small hail are possible with this storm.

Locations impacted include...
Moon Township...                  Aliquippa...
Robinson Township...              Economy...
Kennedy Township...               Ambridge...
Coraopolis...                     Baden...
Sewickley...                      Harmony Township...
Imperial...                       Emsworth...

This includes the following highways...
  Interstate 79 in Pennsylvania between mile markers 64 and 69.
  Interstate 376 in Pennsylvania between mile markers 47 and 59.

LAT...LON 4064 8021 4051 8008 4039 8026 4041 8028
      4052 8037
TIME...MOT...LOC 2041Z 236DEG 15KT 4049 8026

CL
Local storm report, Jul 7, 4:47 PM EDT, 1 hour 1 minute before
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Special weather statement, Jul 7, 4:52 PM EDT, 56 minutes before
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Local storm report, Jul 7, 4:53 PM EDT, 55 minutes before
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Special weather statement, Jul 7, 5:47 PM EDT, 1 minute before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 4:13 PM EDTSpecial Weather StatementPBZBeaver32 min
Jul 7, 4:28 PM EDTSevere Thunderstorm WarningPBZBeaver, Butler, Lawrence32 min
Jul 7, 4:34 PM EDTSevere Thunderstorm WarningPBZButler26 min
Jul 7, 4:41 PM EDTSpecial Weather StatementPBZAllegheny34 min
Jul 7, 5:16 PM EDTSevere Thunderstorm WarningPBZWashington29 min
Jul 7, 6:04 PM EDTSpecial Weather StatementPBZFayette26 min
Jul 7, 6:20 PM EDTAreal Flood AdvisoryPBZFayette, Westmoreland3 hr
Jul 7, 7:25 PM EDTAreal Flood AdvisoryPBZFayette, Washington, Westmoreland2 hr
Jul 7, 7:31 PM EDTSpecial Weather StatementPBZJefferson14 min
Jul 7, 7:39 PM EDTSpecial Weather StatementPBZIndiana36 min
Jul 7, 7:53 PM EDTSpecial Weather StatementPBZJefferson22 min
Jul 7, 2:26 PM EDTSevere Thunderstorm WarningPBZMuskingum28 min
Jul 7, 2:49 PM EDTSevere Thunderstorm WarningPBZCoshocton26 min
Jul 7, 2:52 PM EDTSevere Thunderstorm WarningPBZCoshocton, Guernsey, Muskingum, Tuscarawas23 min
Jul 7, 3:08 PM EDTSevere Thunderstorm WarningPBZCoshocton, Guernsey, Muskingum, Tuscarawas37 min
Jul 7, 3:09 PM EDTAreal Flood AdvisoryPBZGuernsey, Muskingum, Noble3 hr
Jul 7, 3:35 PM EDTSevere Thunderstorm WarningPBZCarroll, Tuscarawas25 min
Jul 7, 3:37 PM EDTAreal Flood AdvisoryPBZCoshocton, Guernsey, Muskingum, Tuscarawas113 min
Jul 7, 3:51 PM EDTSpecial Weather StatementPBZColumbiana24 min
Jul 7, 4:19 PM EDTAreal Flood AdvisoryPBZCarroll, Harrison, Tuscarawas3 hr
Jul 7, 4:31 PM EDTFlash Flood WarningPBZCarroll, Tuscarawas119 min
Jul 7, 4:59 PM EDTAreal Flood AdvisoryPBZCarroll, Harrison, Jefferson2 hr
Jul 7, 4:52 PM EDTSpecial Weather StatementPBZHancock38 min
Jul 7, 7:11 PM EDTSpecial Weather StatementPBZTaylor34 min
Jul 7, 7:36 PM EDTAreal Flood AdvisoryPBZMarion, Monongalia, Preston3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2020Every flash flood warning in 2020

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.