Alert archive / Pennsylvania / Flash Flood Warnings in 1996

Flash Flood Warning 17, NWS Philadelphia/Mount Holly

April 1, 1996Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Apr 1, 1996, 11:55 PM EST for Chester County, Montgomery County, Pennsylvania. It was in force for 7 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: Apr 1, 1996, 11:55 PM EST (04:55 UTC)
Expired: Apr 2, 1996, 7:00 AM EST
In force: 7 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 04:54 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, 4.9 hours before the alert went out and 203 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 461 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 136 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.

000 
TTAA00 KPHL 020455
FFWPHL
PAC029-091-021200-

BULLETIN - EAS ACTIVATION REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
1155 PM EST MON APR 1 1996

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE FLOOD
WARNING FOR CHESTER COUNTY IN PENNSYLVANIA UNTIL 500 AM...AND FOR
MONTGOMERY COUNTY IN PENNSYLVANIA UNTIL 700 AM.

THE HEAVY RAIN IN SOUTHEASTERN PENNSYLVANIA WILL CONTINUE TO LESSEN
IN INTENSITY DURING THE NEXT FEW HOURS...HOWEVER...AREA STREAMS AND
CREEKS WILL CONTINUE TO RISE.  RAINFALL TOTALS OF 1 TO 2 INCHES WERE
COMMON THIS EVENING...WITH THE HEAVIEST RAIN FALLING IN THE NORTHERN
AND WESTERN SECTIONS OF MONTGOMERY COUNTY...WHERE 2 TO 3 INCHES OF
RAIN MAY HAVE FALLEN.

AT 1155 PM...THE PERKIOMEN CREEK IN MONTGOMERY COUNTY CONTINUED TO
RISE RAPIDLY...AND IT IS EXPECTED TO CREST NEAR...OR SLIGHTLY ABOVE
...THE FLOOD STAGE OF 11 FEET AT GRATERFORD AROUND 4 OR 5 AM.  AT
1155 PM...THE LEVEL OF THE CREEK AT GRATERFORD WAS 9.4 FEET.

IN ADDITION TO THE PERKIOMEN CREEK...THERE WILL LIKELY CONTINUE TO BE
MINOR FLOODING ALONG OTHER SMALL STREAMS AND CREEKS IN CHESTER AND
MONTGOMERY COUNTIES DURING MUCH OF THE NIGHT...DUE TO RUNOFF FROM THE
HEAVY RAIN.  THERE WILL ALSO CONTINUE TO BE FLOODING PROBLEMS IN
AREAS OF POOR DRAINAGE.

REMEMBER...DO NOT ATTEMPT TO DRIVE THROUGH FLOOD WATERS.  THE WATER
MAY BE DEEPER THAN YOU THINK.

STAY TUNED TO NOAA WEATHER RADIO...AND TO YOUR LOCAL TELEVISION AND
RADIO STATIONS FOR ADDITIONAL INFORMATION ON THE FLOOD WARNINGS.

IOVINO

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 1, 8:21 PM EST	Flash Flood Warning	PHI	Chester, Montgomery	4 hr
Apr 2, 12:35 AM EST	Flash Flood Warning	PHI	Lehigh	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 1996 Every flash flood warning in 1996

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.