Alert archive / Pennsylvania / Flash Flood Warnings in 2004

Flash Flood Warning 20, NWS Philadelphia/Mount Holly

July 12, 2004Chester County, Delaware County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 12, 2004, 6:51 PM EDT for Chester County, Delaware County, Pennsylvania; Cecil County, Maryland. It was in force for 78 days. 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 12, 2004, 6:51 PM EDT (22:51 UTC)
Expired: Sep 28, 2004, 9:45 PM EDT
In force: 78 days
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Cecil County, MD, Chester County, PA, Delaware County, PA

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.9 hours before the alert went out and 60 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: 76 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 902 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 143 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 
WGUS51 KPHI 122253
FFWPHI
MDC015-130145-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
651 PM EDT MON JUL 12 2004

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS CONTINUED A

* FLASH FLOOD WARNING FOR...
  CECIL COUNTY IN NORTHEAST MARYLAND

* UNTIL 945 PM EDT

* AT 646 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  5 TO 8 INCHES OF RAIN HAD FALLEN OVER PORTIONS OF CECIL COUNTY     
  SINCE THE MORNING HOURS. WHILE THE RAIN IS TAPERING OFF...
  FLOODING WILL CONTINUE INTO THE LATE EVENING HOURS. 

EXCESSIVE RUNOFF FROM HEAVY RAINFALL HAS PRODUCED FLOODING OF 
SMALL CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND 
UNDERPASSES AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

DO NOT DRIVE THROUGH FLOODED ROADWAYS. THE WATER MAY BE DEEPER THAN  
YOU THINK.

LAT...LON 3970 7615 3940 7612 3941 7579 3969 7583

$$

JJM

1 follow-up statement

000 
WGUS51 KPHI 282251
FFWPHI
PAC029-045-290145-
/X.NEW.KPHI.FF.W.0020.040928T2247Z-040929T0145Z/
/0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
647 PM EDT TUE SEP 28 2004

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING CONTINUED FOR...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA

* UNTIL 945 PM EDT

* AT 642 PM EDT...HEAVY RAIN CONTINUES ACROSS THE AREA. MORE RAIN IS 
  ON THE WAY. EXPECT FLOODING ALONG SMALL STREAMS AND EVEN ALONG     
  THE BRANDYWINE EIVER. 


EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. TURN AROUND, DONT DROWN.

LAT...LON 3995 7531 4025 7568 4008 7591 3974 7610
      3975 7593 3975 7582 3983 7574 3989 7561
      3984 7544

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 7:26 AM EDT	Flash Flood Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	68 days
Jul 12, 7:50 AM EDT	Flash Flood Warning	PHI	Chester	68 days
Jul 12, 8:28 AM EDT	Flash Flood Warning	PHI	Montgomery	78 days
Jul 12, 9:31 AM EDT	Flash Flood Warning	PHI	Berks, Chester, Delaware	78 days
Jul 12, 12:10 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	78 days
Jul 12, 4:33 PM EDT	Flash Flood Warning	PHI	Carbon, Monroe	78 days
Jul 12, 4:49 PM EDT	Flash Flood Warning	PHI	Philadelphia	78 days
Jul 12, 4:50 PM EDT	Special Marine Warning	PHI		70 min
Jul 12, 7:32 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	78 days
Jul 12, 1:09 PM EDT	Severe Thunderstorm Warning	PHI	Cecil	51 min
Jul 12, 1:17 PM EDT	Tornado Warning	PHI	Cecil	43 min
Jul 12, 2:52 PM EDT	Flash Flood Warning	PHI	Cecil	78 days
Jul 12, 5:26 PM EDT	Severe Thunderstorm Warning	PHI	Talbot	49 min
Jul 12, 5:45 PM EDT	Flash Flood Warning	PHI	Caroline, Cecil, Kent, Queen Anne's, Talbot	78 days

Nearby

Flash Flood Warnings in Pennsylvania, 2004 Flash Flood Warnings in Maryland, 2004 Every 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.