Alert archive / Pennsylvania / Flash Flood Watches in 2020

Flash Flood Watch 7, NWS State College, PA

August 6, 20204 counties in Pennsylvania

NWS State College, PA issued this flash flood watch at Aug 6, 2020, 1:59 PM EDT for 4 counties in Pennsylvania. It took effect at Aug 6, 2020, 3:00 PM EDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued: Aug 6, 2020, 1:59 PM EDT (17:59 UTC)
In effect from: Aug 6, 2020, 3:00 PM EDT
Expired: Aug 6, 2020, 10:25 PM EDT
In force: 7 hr
Issued by: NWS State College, PA
Flood severity: None

Counties Adams County, PA, Franklin County, PA, Lancaster County, PA, York County, PA

The radar

The Sterling radar (KLWX), 116 km from the middle of the area, began a volume at 17:59 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.0 hours before the alert went out and 116 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: 182 J/kg
Mixed-layer CIN: -149 J/kg
Mixed-layer LCL: 750 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

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 6, 1:39 PM EDT, 20 minutes earlier.

Area forecast discussion, Aug 6, 1:39 PM EDT, 20 minutes before

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Hazardous weather outlook, Aug 6, 5:04 AM EDT, 8 hours 55 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 6, 6:31 PM EDT	Areal Flood Advisory	CTP	Adams	119 min
Aug 6, 7:32 PM EDT	Special Weather Statement	CTP	York	43 min

Nearby

Flash Flood Watches in Pennsylvania, 2020 Every flash flood watch 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.