Alert archive / Pennsylvania / Flash Flood Watches in 2009

Flash Flood Watch 3, NWS State College, PA

July 21, 20099 counties in Pennsylvania

NWS State College, PA issued this flash flood watch at Jul 21, 2009, 10:44 AM EDT for 9 counties in Pennsylvania. It took effect at Jul 21, 2009, 11:00 AM EDT. It was in force for 14 hr.

The area

The counties it named.

The facts

Issued: Jul 21, 2009, 10:44 AM EDT (14:44 UTC)
In effect from: Jul 21, 2009, 11:00 AM EDT
Expired: Jul 22, 2009, 1:21 AM EDT
In force: 14 hr
Issued by: NWS State College, PA
Flood severity: None

Counties Cambria County, PA, Cameron County, PA, Clearfield County, PA, Elk County, PA, McKean County, PA, Potter County, PA, Somerset County, PA, Tioga County, PA, Warren County, PA

The radar

The State College radar (KCCX), 54 km from the middle of the area, began a volume at 14:48 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, 2.7 hours before the alert went out and 169 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: 372 J/kg
Mixed-layer CIN: -28 J/kg
Mixed-layer LCL: 721 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 63 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 Jul 21, 7:51 AM EDT, 2 hours 53 minutes earlier.

Area forecast discussion, Jul 21, 7:51 AM EDT, 2 hours 53 minutes before

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Hazardous weather outlook, Jul 21, 5:54 AM EDT, 4 hours 50 minutes before

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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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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
Jul 21, 8:56 AM EDT	Areal Flood Advisory	CTP	Elk, McKean, Warren	3 hr
Jul 21, 12:16 PM EDT	Flash Flood Warning	CTP	Elk, McKean, Warren	6 hr
Jul 21, 12:32 PM EDT	Areal Flood Advisory	CTP	Columbia, Northumberland, Schuylkill	3 hr
Jul 21, 5:26 PM EDT	Special Weather Statement	CTP	Elk	64 min
Jul 21, 5:37 PM EDT	Special Weather Statement	CTP	Somerset	23 min
Jul 21, 5:57 PM EDT	Special Weather Statement	CTP	Somerset	33 min
Jul 21, 6:28 PM EDT	Special Weather Statement	CTP	Elk	47 min
Jul 21, 6:33 PM EDT	Special Weather Statement	CTP	Somerset	42 min
Jul 21, 7:09 PM EDT	Areal Flood Advisory	CTP	Cambria	111 min
Jul 21, 7:32 PM EDT	Special Weather Statement	CTP	Cambria	28 min
Jul 21, 7:55 PM EDT	Special Weather Statement	CTP	Blair	65 min

Nearby

Flash Flood Watches in Pennsylvania, 2009 Every flash flood watch in 2009

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.