Alert archive / Pennsylvania / Flash Flood Watches in 2007

Flash Flood Watch 1, NWS State College, PA

August 20, 200722 counties in Pennsylvania

NWS State College, PA issued this flash flood watch at Aug 20, 2007, 10:45 AM EDT for 22 counties in Pennsylvania. It took effect at Aug 20, 2007, 2:04 PM EDT. It was in force for 26 hr.

The area

The counties it named.

The facts

Issued: Aug 20, 2007, 10:45 AM EDT (14:45 UTC)
In effect from: Aug 20, 2007, 2:04 PM EDT
Expired: Aug 21, 2007, 4:00 PM EDT
In force: 26 hr
Issued by: NWS State College, PA
Flood severity: None

All 22 counties

Adams County, PA, Bedford County, PA, Blair County, PA, Cambria County, PA, Centre County, PA, Clearfield County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Mifflin County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Union County, PA, York County, PA

The radar

The State College radar (KCCX), 73 km from the middle of the area, began a volume at 14:49 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 (KAGC), launched 12:00Z, 2.8 hours before the alert went out and 221 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 572 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 172 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 watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS State College, PA wrote its last area forecast discussion before this flash flood watch went out at Aug 20, 7:30 AM EDT, 3 hours 15 minutes earlier.

Area forecast discussion, Aug 20, 7:30 AM EDT, 3 hours 15 minutes before

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Hazardous weather outlook, Aug 20, 5:33 AM EDT, 5 hours 12 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 2:15 PM EDT	Flash Flood Warning	CTP	Blair, Cambria	6 hr
Aug 20, 3:33 PM EDT	Flash Flood Warning	CTP	Somerset	5 hr

Nearby

Flash Flood Watches in Pennsylvania, 2007 Every flash flood watch in 2007

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.