Alert archive / Pennsylvania / Flash Flood Warnings in 2017

Flash Flood Warning 32, NWS Philadelphia/Mount Holly

July 24, 2017Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 24, 2017, 9:44 PM EDT for Philadelphia County, Pennsylvania. It was in force for 4 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
Jul 24, 2017, 9:44 PM EDT (01:44 UTC)
Expired
Jul 25, 2017, 1:45 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 59 km from the middle of the area, began a volume at 01:48 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

Brookhaven, NY (KOKX), launched 00:00Z, 1.7 hours before the alert went out and 211 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-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2017-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2017-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -105 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
608 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
-105 m²/s²
0-3 km storm-relative helicity
-14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

545 
WGUS51 KPHI 250144
FFWPHI
PAC101-250545-
/O.NEW.KPHI.FF.W.0032.170725T0144Z-170725T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
944 PM EDT MON JUL 24 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Central Philadelphia County in southeastern Pennsylvania...

* Until 145 AM EDT

* At 941 PM EDT...Doppler radar and automated rain gauges indicated
  thunderstorms had produced heavy rain across the warned area. Up to
  three inches of rain has fallen. Flash flooding is expected to begin 
  shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  Philadelphia.

Flood waters are moving down Frankford Creek and the flood crest is 
expected to exceed 7 feet.

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 4003 7510 4001 7507 3999 7509 4001 7512

$$
1 follow-up statement
701 
WGUS71 KPHI 250326
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1126 PM EDT MON JUL 24 2017

PAC101-250336-
/O.CAN.KPHI.FF.W.0032.000000T0000Z-170725T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Philadelphia PA-
1126 PM EDT MON JUL 24 2017

...THE FLASH FLOOD WARNING FOR CENTRAL PHILADELPHIA COUNTY IS
CANCELLED...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 4003 7510 4001 7507 3999 7509 4001 7512

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 8:08 PM EDTSevere Thunderstorm WarningPHIChester, Delaware52 min
Jul 24, 8:19 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery, Philadelphia116 min
Jul 24, 8:59 PM EDTAreal Flood AdvisoryPHIChester, Delaware, Montgomery, Philadelphia2 hr
Jul 24, 9:01 PM EDTSpecial Weather StatementPHIPhiladelphia59 min
Jul 24, 9:06 PM EDTAreal Flood AdvisoryPHIPhiladelphia114 min
Jul 24, 10:01 PM EDTAreal Flood AdvisoryPHIPhiladelphia119 min
Jul 24, 11:11 PM EDTAreal Flood WarningPHIMontgomery4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2017Every flash flood warning in 2017

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.