Alert archive / Pennsylvania / Flash Flood Warnings in 2019

Flash Flood Warning 52, NWS Philadelphia/Mount Holly

July 17, 2019Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 17, 2019, 7:21 PM EDT for Chester County, Pennsylvania. It was in force for 97 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: Jul 17, 2019, 7:21 PM EDT (23:21 UTC)
Expired: Jul 17, 2019, 8:58 PM EDT
In force: 97 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 113 km from the middle of the area, began a volume at 23:25 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, 11.4 hours before the alert went out and 196 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: 237 J/kg
Mixed-layer CIN: -90 J/kg
Mixed-layer LCL: 1666 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

314 
WGUS51 KPHI 172321
FFWPHI
PAC029-180215-
/O.NEW.KPHI.FF.W.0052.190717T2321Z-190718T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
721 PM EDT Wed Jul 17 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern Chester County in southeastern Pennsylvania...

* Until 1015 PM EDT.

* At 719 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the northern portions of the county. Rainfall 
  rates over 2 inches per hour will result in flash flooding in some 
  locations within the warned area. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

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 4004 7593 4011 7594 4024 7570 4024 7565
      4022 7561 4024 7560 4020 7557 4021 7556
      4015 7553 4015 7550 3990 7579 4000 7597

$$

JJM

1 follow-up statement

284 
WGUS71 KPHI 180058
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
858 PM EDT Wed Jul 17 2019

PAC029-180106-
/O.CAN.KPHI.FF.W.0052.000000T0000Z-190718T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
858 PM EDT Wed Jul 17 2019

...THE FLASH FLOOD WARNING FOR NORTHERN CHESTER COUNTY IS
CANCELLED...

The heavy rain has ended. Any residual flooding from earlier rain is 
expected to end without additional problems.

Please continue to heed any remaining road closures.

LAT...LON 4004 7593 4011 7594 4024 7570 4024 7565
      4022 7561 4024 7560 4020 7557 4021 7556
      4015 7553 4015 7550 3990 7579 4000 7597

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 9:15 PM EDT	Special Weather Statement	PHI	Philadelphia	45 min
Jul 17, 3:54 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	19 hr
Jul 17, 1:26 PM EDT	Special Weather Statement	PHI	Pike	34 min
Jul 17, 1:50 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	80 min
Jul 17, 2:05 PM EDT	Special Weather Statement	PHI	Lehigh	25 min
Jul 17, 3:14 PM EDT	Excessive Heat Watch	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more	24 hr
Jul 17, 5:05 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	40 min
Jul 17, 5:14 PM EDT	Special Weather Statement	PHI	Lehigh	46 min
Jul 17, 5:44 PM EDT	Special Weather Statement	PHI	Monroe	46 min
Jul 17, 5:46 PM EDT	Areal Flood Advisory	PHI	Monroe	119 min
Jul 17, 5:49 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	41 min
Jul 17, 6:24 PM EDT	Special Weather Statement	PHI	Berks	51 min
Jul 17, 6:35 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	40 min
Jul 17, 6:51 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	54 min
Jul 17, 6:52 PM EDT	Areal Flood Advisory	PHI	Berks	113 min
Jul 17, 7:06 PM EDT	Flash Flood Warning	PHI	Berks	3 hr
Jul 17, 7:15 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	45 min
Jul 17, 7:31 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	44 min
Jul 17, 7:36 PM EDT	Flash Flood Warning	PHI	Bucks, Lehigh, Montgomery	3 hr
Jul 17, 7:44 PM EDT	Special Weather Statement	PHI	Lehigh	31 min
Jul 17, 7:56 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery, Philadelphia	64 min

Nearby

Flash Flood Warnings in Pennsylvania, 2019 Every flash flood warning in 2019

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.