Alert archive / Pennsylvania / Flash Flood Warnings in 2004

Flash Flood Warning 45, NWS Philadelphia/Mount Holly

July 28, 2004Cecil County, Maryland; 5 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 28, 2004, 2:28 AM EDT for Cecil County, Maryland; 5 counties in Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 28, 2004, 2:28 AM EDT (06:28 UTC)
Expired
Jul 28, 2004, 5:30 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Counties, with a storm outline in the text

Counties Cecil County, MD, Berks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 06:27 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, 6.5 hours before the alert went out and 188 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 2004-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 685 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 2004-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 39 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
685 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
1049 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
91 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 280636
FFWPHI
MDC015-PAC011-029-045-091-101-280930-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
228 AM EDT WED JUL 28 2004

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS CONTINUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA
  NORTHEASTERN CECIL COUNTY IN NORTHEAST MARYLAND
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA

* UNTIL 530 AM EDT

* AT 223 AM EDT...FLOODING CONTINUED ALONG MANY SMALL STREAMS IN THE 
  AREA FROM RAIN THAT FELL TUESDAY AFTERNOON AND EVENING. WHILE      
  THE HEAVY RAIN HAS MOVED OUT OF THE AREA FOR THE TIME BEING,       
  FLOODING CONTINUES ON MANY SMALLER STREAMS FROM THIS EARLIER RAIN. 

SOME CREEKS WHICH WERE OVER FLOOD STAGE AS OF 215 AM INCLUDE: 
MANATAWNY CREEK AT SPANGVILLE IN SOUTHEASTERN BERKS COUNTY, AS WELL 
AS POTTSTOWN IN NORTHWESTERN MONTGOMERY COUNTY IN PENNSYLVANIA. 
ALSO, THE PENNYPACK CREEK IN PHILADELPHIA, THE CRUM CREEK IN 
DELAWARE COUNTY, AND THE WEST BRANCH BRANDYWINE CREEK AT HONEY BROOK 
IN CHESTER COUNTY.

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 4012 7509 3981 7542 3985 7554 3985 7564
      3983 7569 3972 7580 3959 7579 3966 7608
      4040 7571

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 10:44 PM EDTFlash Flood WarningPHICecil4 hr
Jul 27, 9:37 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia38 min
Jul 27, 9:39 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia36 min
Jul 28, 7:00 PM EDTFlash Flood WarningPHIMontgomery2 hr
Jul 28, 7:10 PM EDTSevere Thunderstorm WarningPHIBucks50 min
Jul 28, 7:21 PM EDTFlash Flood WarningPHIBucks114 min

Nearby

Flash Flood Warnings in Pennsylvania, 2004Flash Flood Warnings in Maryland, 2004Every flash flood warning in 2004

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.