Alert archive / Pennsylvania / Areal Flood Warnings in 2009
Areal Flood Warning 21, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 11, 2009, 9:41 AM EDT for Chester County, Pennsylvania. It was in force for 82 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Sep 11, 2009, 9:41 AM EDT (13:41 UTC)
- Expired
- Sep 11, 2009, 11:03 AM EDT
- In force
- 82 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
County Chester County, PA
The radar
The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 13:41 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.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 1.7 hours before the alert went out and 208 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.
- Mixed-layer CAPE
- 5 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 447 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- -100 m²/s²
- 0-3 km storm-relative helicity
- -74 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
WGUS41 KPHI 111341
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
941 AM EDT FRI SEP 11 2009
PAC029-111630-
/O.NEW.KPHI.FA.W.0021.090911T1341Z-090911T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-
941 AM EDT FRI SEP 11 2009
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLOOD WARNING FOR SMALL STREAMS IN...
EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 1230 PM EDT
* AT 935 AM EDT...OBSERVATIONS FROM THE VALLEY FORGE GAGE ON VALLEY
CREEK INDICATED THAT WATER LEVELS HAVE RISEN ABOVE FLOOD STAGE.
ADDTIONAL RAIN, CURRENTLY OVER SOUTHERN NEW JERSEY, WILL MOVE OVER
THE WARNED AREA IN THE NEXT HOUR.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLOOD WARNING MEANS FLOODING IS OCCURRING OR IS IMMINENT. 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.
&&
LAT...LON 4015 7551 4013 7551 4013 7548 4011 7547
4009 7545 4010 7543 4007 7542 4007 7539
4007 7538 3997 7552 4007 7564
$$
KRUZDLO1 follow-up statement
000
WGUS81 KPHI 111503
FLSPHI
FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1103 AM EDT FRI SEP 11 2009
PAC029-111511-
/O.CAN.KPHI.FA.W.0021.000000T0000Z-090911T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-
1103 AM EDT FRI SEP 11 2009
...THE FLOOD WARNING HAS BEEN CANCELLED FOR SMALL STREAMS IN EAST
CENTRAL CHESTER COUNTY...
OBSERVATIONS FROM THE VALLEY FORGE GAGE ON VALLEY CREEK INDICATED
THAT WATER LEVELS HAVE FALLEN BELOW FLOOD STAGE.
MORE RAIN IS EXPECTED THROUGH THE AFTERNOON. RENEWED RISES ARE
POSSIBLE.
LAT...LON 4015 7551 4013 7551 4013 7548 4011 7547
4009 7545 4010 7543 4007 7542 4007 7539
4007 7538 3997 7552 4007 7564
$$
KRUZDLOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 11, 8:41 AM EDT | Areal Flood Advisory | PHI | Berks, Chester, Delaware, Montgomery, Philadelphia | 3 hr |
Nearby
Areal Flood Warnings in Pennsylvania, 2009Every areal flood warning in 2009
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.