Alert archive / Pennsylvania / Flash Flood Warnings in 2018
Flash Flood Warning 40, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 24, 2018, 1:34 AM EDT for 4 counties in Pennsylvania. It was in force for 8 hr. 1 report 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 24, 2018, 1:34 AM EDT (05:34 UTC)
- Expired
- Jul 24, 2018, 9:30 AM EDT
- In force
- 8 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Berks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 110 km from the middle of the area, began a volume at 05:34 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 24, 4:52 AM EDT | FLOOD | Gilbertsville, PA | WATER COVERING THE INTERSECTION OF RT 663 AND SWAMP PIKE. |
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 00:00Z, 5.6 hours before the alert went out and 209 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
- 791 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 722 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 115 m²/s²
- 0-3 km storm-relative helicity
- 141 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 4.2
The text
As transmitted.
586 WGUS51 KPHI 240534 FFWPHI PAC011-029-077-091-240930- /O.NEW.KPHI.FF.W.0040.180724T0534Z-180724T0930Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Mount Holly NJ 134 AM EDT TUE JUL 24 2018 The National Weather Service in Mount Holly NJ has issued a * Flash Flood Warning for... Eastern Berks County in eastern Pennsylvania... Northwestern Montgomery County in southeastern Pennsylvania... Southwestern Lehigh County in eastern Pennsylvania... Northeastern Chester County in southeastern Pennsylvania... * Until 530 AM EDT. * At 130 AM EDT, Doppler radar indicated heavy rain across the warned area. Doppler radar indicated rainfall rates of up to 2 inches per hour in the warned area. Flash flooding is expected to begin shortly in the areas of heaviest rain. * Some locations that could experience flooding include... Pottstown, Phoenixville, Downingtown, Collegeville, Kutztown, Royersford, Trappe, East Greenville, Topton, Bally, Bechtelsville, Lyons, Pughtown, Ancient Oaks, Claussville, Lionville-Marchwood, Valley Forge, Paoli, Chester Springs and Lionville. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Be especially cautious at night when it is harder to recognize the dangers of flooding. Please report flooding to your local law enforcement agency when you can do so safely. A Flash Flood Warning means that flooding is imminent or occurring. If you are in the warned area move to higher ground immediately. Residents living along streams and creeks should take immediate precautions to protect life and property. && LAT...LON 3999 7570 4061 7580 4062 7555 4002 7544 $$ MPS
4 follow-up statements
642 WGUS71 KPHI 240808 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 408 AM EDT TUE JUL 24 2018 PAC011-029-077-091-240930- /O.CON.KPHI.FF.W.0040.000000T0000Z-180724T0930Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Berks PA-Montgomery PA-Lehigh PA-Chester PA- 408 AM EDT TUE JUL 24 2018 ...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM EDT FOR EASTERN BERKS...NORTHWESTERN MONTGOMERY...SOUTHWESTERN LEHIGH AND NORTHEASTERN CHESTER COUNTIES... At 405 AM EDT, Doppler radar indicated that the heavy rain has weakened and moved out of the warned area. However, another area of heavy rain is moving up through the eastern shore of Maryland and northern and central Delaware, and will approach the warned area later this morning. Flash flooding will begin shortly. Some locations that could experience flooding include... Pottstown, Phoenixville, Downingtown, Collegeville, Kutztown, Royersford, Trappe, East Greenville, Topton, Bally, Bechtelsville, Lyons, Pughtown, Ancient Oaks, Claussville, Lionville-Marchwood, Valley Forge, Paoli, Chester Springs and Lionville. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Be especially cautious at night when it is harder to recognize the dangers of flooding. Please report flooding to your local law enforcement agency when you can do so safely. && LAT...LON 3999 7570 4061 7580 4062 7555 4002 7544 $$ MPS
321 WGUS51 KPHI 240921 FFWPHI PAC011-029-077-091-241330- /O.EXT.KPHI.FF.W.0040.000000T0000Z-180724T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Mount Holly NJ 521 AM EDT TUE JUL 24 2018 The National Weather Service in Mount Holly NJ has extended the * Flash Flood Warning for... Eastern Berks County in eastern Pennsylvania... Northwestern Montgomery County in southeastern Pennsylvania... Southwestern Lehigh County in eastern Pennsylvania... Northeastern Chester County in southeastern Pennsylvania... * Until 930 AM EDT. * At 516 AM EDT, Doppler radar indicated heavy rain over northern Delaware, lifting north into southeast Pennsylvania. This rain will move into the warned area through the morning commute. Any roads that are already flooded will experience additional flooding. Flash flooding is already occurring. * Some locations that could experience flooding include... Pottstown, Phoenixville, Downingtown, Collegeville, Kutztown, Royersford, Trappe, East Greenville, Topton, Bally, Bechtelsville, Lyons, Pughtown, Ancient Oaks, Claussville, Lionville-Marchwood, Valley Forge, Paoli, Chester Springs and Lionville. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Be especially cautious at night when it is harder to recognize the dangers of flooding. Please report flooding to your local law enforcement agency when you can do so safely. && LAT...LON 3999 7570 4061 7580 4062 7555 4002 7544 $$ MPS
125 WGUS71 KPHI 241144 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 744 AM EDT TUE JUL 24 2018 PAC011-029-077-091-241330- /O.CON.KPHI.FF.W.0040.000000T0000Z-180724T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Berks PA-Montgomery PA-Lehigh PA-Chester PA- 744 AM EDT TUE JUL 24 2018 ...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 AM EDT FOR EASTERN BERKS...NORTHWESTERN MONTGOMERY...SOUTHWESTERN LEHIGH AND NORTHEASTERN CHESTER COUNTIES... At 743 AM EDT, Doppler radar indicated the rain had begun to taper off across the warned area. However, runoff will be slow to recede, therefore the threat of flash flooding continues. Some locations that could experience flooding include... Pottstown, Phoenixville, Downingtown, Collegeville, Kutztown, Royersford, Trappe, East Greenville, Topton, Bally, Bechtelsville, Lyons, Pughtown, Ancient Oaks, Claussville, Lionville-Marchwood, Valley Forge, Paoli, Chester Springs and Lionville. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Please report flooding to your local law enforcement agency when you can do so safely. && LAT...LON 3999 7570 4061 7580 4062 7555 4002 7544 $$ SFJ
902 WGUS71 KPHI 241326 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 926 AM EDT TUE JUL 24 2018 PAC011-029-077-091-241334- /O.EXP.KPHI.FF.W.0040.000000T0000Z-180724T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Berks PA-Montgomery PA-Lehigh PA-Chester PA- 926 AM EDT TUE JUL 24 2018 ...THE FLASH FLOOD WARNING FOR EASTERN BERKS...NORTHWESTERN MONTGOMERY...SOUTHWESTERN LEHIGH AND NORTHEASTERN CHESTER COUNTIES WILL EXPIRE AT 930 AM EDT... Flood waters have receded. Flooding is no longer expected to pose a threat for now. Please continue to heed any remaining road closures. A flood watch remains in effect. Due to saturated ground, any additional heavy rain will quickly become runoff and lead to additional flooding issues. Please continue to monitor the latest forecasts. LAT...LON 3999 7570 4061 7580 4062 7555 4002 7544 $$ SFJ
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 24, 12:56 AM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more | 4 hr |
| Jul 24, 4:56 AM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more | 4 hr |
| Jul 24, 10:03 AM EDT | Areal Flood Advisory | PHI | Berks, Carbon, Chester, Lehigh, Montgomery | 2 hr |
| Jul 24, 12:50 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Jul 24, 1:02 PM EDT | Special Weather Statement | PHI | Chester | 28 min |
| Jul 24, 1:22 PM EDT | Areal Flood Advisory | PHI | Bucks, Lehigh, Monroe, Montgomery, Northampton | 3 hr |
| Jul 24, 1:24 PM EDT | Special Weather Statement | PHI | Berks, Chester | 36 min |
| Jul 24, 1:40 PM EDT | Areal Flood Advisory | PHI | Berks, Chester | 4 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2018Every flash flood warning in 2018
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.