Alert archive / Pennsylvania / Flash Flood Warnings in 2020
Flash Flood Warning 13, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 6, 2020, 4:07 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 4 hr. 8 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 6, 2020, 4:07 PM EDT (20:07 UTC)
- Expired
- Jul 6, 2020, 8:00 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 20:10 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 6, 4:20 PM EDT | FLASH FLOOD | 1 Ssw Trooper, PA | WATER RESCUE ON DRIFTWOOD DRIVE WITH WATER ENTERING AT LEAST ONE HOME. |
| Jul 6, 4:30 PM EDT | FLASH FLOOD | 2 Ese Valley Forge, PA | WATER RESCUE NEAR THE INTERSECTION OF RICHARDS ROAD AND GLENHARDIE ROAD. TIME ESTIMATED FROM RADAR. |
| Jul 6, 4:30 PM EDT | FLASH FLOOD | 2 W King Of Prussia, PA | WATER RESCUE ON RICHARDS RD IN WAYNE. |
| Jul 6, 4:40 PM EDT | FLASH FLOOD | 2 Ese Valley Forge, PA | WATER RESCUE ON RICHARDS RD. |
| Jul 6, 4:59 PM EDT | FLASH FLOOD | Paoli, PA | ROCKS SWEPT ONTO VALLEY ROAD NEAR LANCASTER PIKE FROM FLOOD WATERS. TIME ESTIMATED FROM RADAR. |
| Jul 6, 4:59 PM EDT | FLASH FLOOD | Paoli, PA | ROCKS SWEPT ONTO VALLEY ROAD NEAR LANCASTER PIKE IN PAOLI FROM FLOOD WATERS. TIME ESTIMATED FROM RADAR. |
| Jul 6, 5:20 PM EDT | FLASH FLOOD | Malvern, PA | PLANDBROOK ROAD AT US ROUTE 202 NEAR IMMACULATA CLOSED FROM FLOODING. |
| Jul 6, 5:45 PM EDT | FLASH FLOOD | 1 Ssw Trooper, PA | A PORTION OF EGYPT RD WAS WASHED OUT FROM FLOODING. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.1 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
- 1250 J/kg
- Mixed-layer CIN
- -133 J/kg
- Mixed-layer LCL
- 1150 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 62 m²/s²
- 0-3 km storm-relative helicity
- 57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
759
WGUS51 KPHI 062007
FFWPHI
PAC029-045-091-070000-
/O.NEW.KPHI.FF.W.0013.200706T2007Z-200707T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
407 PM EDT Mon Jul 6 2020
The National Weather Service in Mount Holly NJ has issued a
* Flash Flood Warning for...
Southwestern Montgomery County in southeastern Pennsylvania...
Northeastern Chester County in southeastern Pennsylvania...
North central Delaware County in southeastern Pennsylvania...
* Until 800 PM EDT.
* At 406 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Up to three inches of rain have
already fallen. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar indicated.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other
drainage and low lying areas.
* Some locations that could experience flooding include...
Phoenixville, West Norriton, Royersford, Trout Lake, Radnor
Township, Lionville-Marchwood, Valley Forge, Broomall, Paoli,
Chester Springs, Newtown Square, Lionville, King Of Prussia, Nether
Providence Township, Spring City, Malvern, Morton, Springfield,
Devon-Berwyn and Exton.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Protecting yourself from immediate threats to life and safety shall
take priority. Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.
Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4013 7537 3991 7533 4004 7572 4025 7560
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
CMS2 follow-up statements
281
WGUS71 KPHI 062046
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
446 PM EDT Mon Jul 6 2020
PAC029-045-091-070000-
/O.CON.KPHI.FF.W.0013.000000T0000Z-200707T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Chester PA-Delaware PA-
446 PM EDT Mon Jul 6 2020
...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 800 PM EDT FOR
SOUTHWESTERN MONTGOMERY...NORTHEASTERN CHESTER AND NORTH CENTRAL
DELAWARE COUNTIES...
At 445 PM EDT, law enforcement reported flash flooding in Wayne and
Norristown, with several water rescues in progress. Heavy rainfall
from thunderstorms is drifting southward into Chester County. Up to
three inches of rain have already fallen in the past one to two
hours. This is a dangerous situation. Flash flooding is expected to
continue.
HAZARD...Life threatening flash flooding. Heavy rain producing flash
flooding.
SOURCE...Law enforcement.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets and underpasses.
Some locations that could experience flooding include...
Phoenixville, West Norriton, Royersford, Trout Lake, Radnor Township,
Lionville-Marchwood, Valley Forge, Broomall, Paoli, Chester Springs,
Newtown Square, Lionville, King Of Prussia, Nether Providence
Township, Spring City, Malvern, Morton, Springfield, Devon-Berwyn and
Exton.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Protecting yourself from immediate threats to life and safety shall
take priority. Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.
Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets, and underpasses
as well as other drainage areas and low lying spots.
&&
LAT...LON 4013 7537 3991 7533 4004 7572 4025 7560
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
CMS294 WGUS71 KPHI 062351 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 751 PM EDT Mon Jul 6 2020 PAC029-045-091-070001- /O.EXP.KPHI.FF.W.0013.000000T0000Z-200707T0000Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Montgomery PA-Chester PA-Delaware PA- 751 PM EDT Mon Jul 6 2020 ...THE FLASH FLOOD WARNING FOR SOUTHWESTERN MONTGOMERY...NORTHEASTERN CHESTER AND NORTH CENTRAL DELAWARE COUNTIES WILL EXPIRE AT 800 PM EDT... The heavy rain has ended. Flood waters are beginning to recede. Flooding is no longer expected to pose a threat. Please continue to heed any remaining road closures. LAT...LON 4013 7537 3991 7533 4004 7572 4025 7560 $$ CMS
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 6, 3:16 AM EDT | Heat Advisory | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 12 hr |
| Jul 6, 12:34 PM EDT | Special Weather Statement | PHI | Philadelphia | 26 min |
| Jul 6, 12:45 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 60 min |
| Jul 6, 12:52 PM EDT | Flash Flood Watch | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 8 hr |
| Jul 6, 12:57 PM EDT | Areal Flood Advisory | PHI | Bucks, Delaware, Montgomery, Philadelphia | 2 hr |
| Jul 6, 1:08 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 6, 1:15 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 60 min |
| Jul 6, 1:20 PM EDT | Special Weather Statement | PHI | Montgomery | 25 min |
| Jul 6, 1:24 PM EDT | Special Weather Statement | PHI | Monroe | 36 min |
| Jul 6, 1:43 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 62 min |
| Jul 6, 1:44 PM EDT | Special Weather Statement | PHI | Montgomery | 31 min |
| Jul 6, 1:50 PM EDT | Areal Flood Advisory | PHI | Berks, Chester, Montgomery | 4 hr |
| Jul 6, 1:50 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 40 min |
| Jul 6, 2:02 PM EDT | Areal Flood Advisory | PHI | Bucks | 118 min |
| Jul 6, 2:04 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery | 41 min |
| Jul 6, 2:10 PM EDT | Areal Flood Advisory | PHI | Monroe | 2 hr |
| Jul 6, 2:18 PM EDT | Special Weather Statement | PHI | Montgomery | 27 min |
| Jul 6, 2:27 PM EDT | Severe Thunderstorm Warning | PHI | Montgomery | 48 min |
| Jul 6, 2:28 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 28 min |
| Jul 6, 2:39 PM EDT | Areal Flood Advisory | PHI | Bucks, Chester, Montgomery | 4 hr |
| Jul 6, 2:39 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 66 min |
| Jul 6, 2:41 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery | 49 min |
| Jul 6, 2:48 PM EDT | Areal Flood Advisory | PHI | Philadelphia | 4 hr |
| Jul 6, 2:51 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery | 24 min |
| Jul 6, 2:57 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 6, 3:00 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Northampton | 45 min |
| Jul 6, 3:11 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 49 min |
| Jul 6, 3:38 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Northampton | 52 min |
| Jul 6, 3:52 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 38 min |
| Jul 6, 3:56 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 64 min |
| Jul 6, 4:06 PM EDT | Severe Thunderstorm Warning | PHI | Lehigh | 24 min |
| Jul 6, 4:31 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Monroe, Northampton | 44 min |
| Jul 6, 4:51 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 114 min |
| Jul 6, 5:00 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 45 min |
| Jul 6, 5:01 PM EDT | Areal Flood Advisory | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 119 min |
| Jul 6, 5:14 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 61 min |
| Jul 6, 5:17 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Lehigh, Montgomery, Northampton | 43 min |
| Jul 6, 5:20 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 42 min |
| Jul 6, 5:29 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 46 min |
| Jul 6, 5:43 PM EDT | Areal Flood Advisory | PHI | Chester, Delaware | 3 hr |
| Jul 6, 5:53 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Chester, Lehigh, Montgomery | 52 min |
| Jul 6, 6:13 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 48 min |
| Jul 6, 6:14 PM EDT | Areal Flood Advisory | PHI | Berks, Chester, Montgomery | 3 hr |
| Jul 6, 6:18 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 35 min |
| Jul 6, 6:54 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Montgomery | 109 min |
| Jul 6, 7:18 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 36 min |
| Jul 6, 7:36 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 69 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2020Every flash flood warning in 2020
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.