Alert archive / Pennsylvania / Flash Flood Warnings in 2011

Flash Flood Warning 59, NWS State College, PA

September 11, 20116 counties in Pennsylvania

NWS State College, PA issued this flash flood warning at Sep 11, 2011, 9:38 PM EDT for 6 counties in Pennsylvania. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 11, 2011, 9:38 PM EDT (01:38 UTC)
Expired: Sep 12, 2011, 12:30 AM EDT
In force: 3 hr
Issued by: NWS State College, PA
Area: Storm-based polygon
Flood severity: None

Counties Centre County, PA, Clinton County, PA, Lycoming County, PA, Montour County, PA, Northumberland County, PA, Union County, PA

The radar

The State College radar (KCCX), 64 km from the middle of the area, began a volume at 01:41 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.

What was reported inside it

Time	Report	Where	Remark
Sep 11, 10:17 PM EDT	FLASH FLOOD	Duboistown, PA	STREET FLOODING REPORTED IN DUBOISTOWN.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.6 hours before the alert went out and 225 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: 420 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 1369 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 144 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

234 
WGUS51 KCTP 120138
FFWCTP
PAC027-035-081-093-097-119-120430-
/O.NEW.KCTP.FF.W.0059.110912T0138Z-110912T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
938 PM EDT SUN SEP 11 2011

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN MONTOUR COUNTY...
  UNION COUNTY...
  NORTHWESTERN NORTHUMBERLAND COUNTY...
  EAST CENTRAL CENTRE COUNTY...
  SOUTHERN LYCOMING COUNTY...
  SOUTHEASTERN CLINTON COUNTY...

* UNTIL 1230 AM EDT...

* AT 932 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  CLUSTERS OF VERY HEAVY RAIN OVER THE WARNING AREA. AREAS WITHIN 
  THE WARNING AREA HAVE SEEN IN EXCESS OF 2 INCHES OVER THE LAST 3
  HOURS...AND ADDITIONAL HEAVY RAIN WILL CAUSE FLASH FLOODING TO 
  BEGIN SHORTLY.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  MIFFLINBURG...LOCK HAVEN...JERSEY SHORE...MONTOURSVILLE AND
  WILLIAMSPORT. THE MONTOURSVILLE AREA HAS RECEIVED THE HEAVIEST
  RAINFALL AND IS PARTICULARLY SUSCEPTIBLE TO FLASH FLOODING FROM
  ADDITIONAL HEAVY RAINFALL. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. NEVER ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR IN AN
AUTOMOBILE. TURN AROUND DON'T DROWN!

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4087 7708 4082 7731 4082 7736 4085 7737
      4081 7748 4080 7757 4122 7751 4133 7716
      4127 7649

$$

FORECASTER: DEVOIR

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 11, 8:26 PM EDT	Areal Flood Advisory	CTP	Lycoming	2 hr
Sep 11, 8:30 PM EDT	Special Weather Statement	CTP	Lancaster	30 min
Sep 11, 8:32 PM EDT	Special Weather Statement	CTP	Cumberland	43 min
Sep 11, 9:02 PM EDT	Areal Flood Advisory	CTP	Centre, Clinton, Lycoming, Montour, Northumberland, Snyder and 1 more	118 min
Sep 11, 9:10 PM EDT	Areal Flood Advisory	CTP	Lancaster	65 min
Sep 11, 9:21 PM EDT	Flash Flood Warning	CTP	Lancaster	3 hr
Sep 11, 10:12 PM EDT	Areal Flood Advisory	CTP	Columbia, Dauphin, Juniata, Lebanon, Lycoming, Montour and 5 more	3 hr
Sep 11, 10:51 PM EDT	Special Weather Statement	CTP	Columbia	24 min
Sep 12, 12:29 AM EDT	Dense Fog Advisory	CTP	Adams, Bedford, Blair, Cambria, Cameron, Centre and 27 more	10 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2011 Every flash flood warning in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.