Alert archive / Pennsylvania / Flash Flood Warnings in 2009
Flash Flood Warning 1, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at May 7, 2009, 1:08 AM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 6 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
- May 7, 2009, 1:08 AM EDT (05:08 UTC)
- Expired
- May 7, 2009, 7:00 AM EDT
- In force
- 6 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 05:11 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, 5.1 hours before the alert went out and 192 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
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 465 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 257 m²/s²
- 0-3 km storm-relative helicity
- 364 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
000
WGUS51 KPHI 070508
FFWPHI
PAC029-091-071100-
/O.NEW.KPHI.FF.W.0001.090507T0508Z-090507T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
108 AM EDT THU MAY 7 2009
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLASH FLOOD WARNING FOR...
CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
THIS INCLUDES THE CITY OF WEST CHESTER...
MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
THIS INCLUDES THE CITY OF WILLOW GROVE...
* UNTIL 700 AM EDT
* AT 105 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
ADDITIONAL HEAVY RAIN MOVING UP FROM NORTHEASTERN MARYLAND. A
HALF INCH TO AN INCH OF RAIN HAS ALREADY FALLEN IN THE AREA
TONIGHT. AN ADDITIONAL ONE TO TWO INCHES OF RAIN IS POSSIBLE AT
SOME LOCATIONS BEFORE 400 AM.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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 3973 7615 3978 7607 3987 7601 3997 7600
4012 7593 4024 7570 4044 7553 4013 7502
4006 7515 4009 7523 4005 7527 4002 7523
3999 7529 4006 7537 4005 7542 3999 7545
3987 7562 3984 7559 3982 7570 3973 7578
$$
IOVINOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 6, 9:01 PM EDT | Flood Watch | PHI | Delaware, Philadelphia | 19 hr |
| May 7, 1:43 AM EDT | Flash Flood Warning | PHI | Bucks | 5 hr |
| May 7, 1:51 AM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 5 hr |
| May 7, 10:15 AM EDT | Areal Flood Warning | PHI | Montgomery | 3 hr |
| May 7, 1:42 PM EDT | Areal Flood Advisory | PHI | Bucks, Montgomery | 4 hr |
| May 7, 2:34 PM EDT | Areal Flood Advisory | PHI | Bucks, Delaware, Montgomery, Philadelphia | 3 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2009Every flash 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.