Alert archive / Pennsylvania / Flash Flood Watches in 2014

Flash Flood Watch 15, NWS State College, PA

August 12, 201415 counties in Pennsylvania

NWS State College, PA issued this flash flood watch at Aug 12, 2014, 10:52 PM EDT for 15 counties in Pennsylvania. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Aug 12, 2014, 10:52 PM EDT (02:52 UTC)
Expired
Aug 13, 2014, 3:54 AM EDT
In force
5 hr
Issued by
NWS State College, PA
Flood severity
None

Counties Adams County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lycoming County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Union County, PA, York County, PA

The radar

The State College radar (KCCX), 106 km from the middle of the area, began a volume at 02:55 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 00:00Z, 2.9 hours before the alert went out and 186 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, Washington/Dulle, VA at 00:00Z on 2014-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 571 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 00:00Z on 2014-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.19395878Sfc1 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
571 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
726 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.1

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 10:08 PM EDTAreal Flood AdvisoryCTPDauphin, Lebanon112 min
Aug 12, 10:20 PM EDTAreal Flood AdvisoryCTPWarren3 hr
Aug 12, 11:06 PM EDTAreal Flood AdvisoryCTPCentre, Clinton, Lycoming, Snyder, Tioga, Union4 hr
Aug 12, 11:52 PM EDTAreal Flood AdvisoryCTPColumbia, Lycoming, Montour, Northumberland, Snyder, Sullivan and 1 more3 hr
Aug 13, 3:01 AM EDTAreal Flood AdvisoryCTPCentre, Clinton, Columbia, Juniata, Lycoming, Mifflin and 5 more3 hr

Nearby

Flash Flood Watches in Pennsylvania, 2014Every flash flood watch in 2014

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.