Alert archive / Pennsylvania / Flash Flood Warnings in 1997

Flash Flood Warning 21, NWS State College, PA

September 11, 1997Adams County, Pennsylvania

NWS State College, PA issued this flash flood warning at Sep 11, 1997, 12:20 AM EDT for Adams County, Pennsylvania. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 11, 1997, 12:20 AM EDT (04:20 UTC)
Expired
Sep 11, 1997, 4:30 AM EDT
In force
4 hr
Issued by
NWS State College, PA
Area
Whole counties

County Adams County, PA

The radar

The Sterling radar (KLWX), 102 km from the middle of the area, began a volume at 04:21 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, 4.3 hours before the alert went out and 104 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 1997-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 534 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 1997-09-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 square meters per square second.193958Sfc1 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
534 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
816 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
272 m²/s²
Significant tornado parameter
0.2
Supercell composite
3.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCTP 110420
FFWCTP
PAC001-110830-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1220 AM EDT THU SEP 11 1997

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL 430 AM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...

IN SOUTH CENTRAL PENNSYLVANIA

   ...ADAMS COUNTY
 
AT 1215 AM EDT...DOPPLER RADAR FROM STATE COLLEGE SHOWED THAT
ANOTHER BATCH OF VERY HEAVY RAINFALL WAS MOVING INTO ADAMS COUNTY
FROM MARYLAND AND NORTHERN VIRGINIA. RAINFALL SINCE YESTERDAY
MORNING HAS TOTALED OVER 4 INCHES IN PARTS OF ADAMS COUNTY. RUNOFF
FROM THE RECENT RAINFALL AND ADDITIONAL HEAVY RAINFALL OVERNIGHT
WILL LIKELY CAUSE FLOODING OF STREAMS AND CREEKS IN ADAMS COUNTY
DURING THE EARLY MORNING HOURS.

IN ADDITION... URBAN AND POOR DRAINAGE AREAS WILL BE VERY
SUSCEPTIBLE TO FLOODING PROBLEMS THROUGH THE OVERNIGHT.
 
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE
THE DANGERS OF FLASH FLOODING.

IF FLASH FLOODING IS OBSERVED...ACT QUICKLY.  MOVE TO ESCAPE FLOOD
WATERS.  DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS
RISING.

NICOSIA/WINTHER

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 10, 11:30 PM EDTFlash Flood WarningCTPCumberland, Franklin, Perry4 hr
Sep 11, 12:57 AM EDTFlash Flood WarningCTPSnyder, Union4 hr
Sep 11, 12:57 AM EDTFlash Flood WarningCTPJuniata4 hr
Sep 11, 3:27 AM EDTFlash Flood WarningCTPAdams, Cumberland, Perry5 hr
Sep 11, 4:00 AM EDTFlash Flood WarningCTPLancaster4 hr
Sep 11, 4:57 AM EDTFlash Flood WarningCTPJuniata, Snyder3 hr
Sep 11, 7:46 AM EDTFlash Flood WarningCTPCumberland, Perry3 hr
Sep 11, 10:41 AM EDTFlash Flood WarningCTPCumberland, Perry3 hr
Sep 11, 6:19 PM EDTSevere Thunderstorm WarningCTPYork56 min

Nearby

Flash Flood Warnings in Pennsylvania, 1997Every flash flood warning in 1997

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.