Alert archive / Pennsylvania / Flash Flood Warnings in 2017

Flash Flood Warning 12, NWS Philadelphia/Mount Holly

July 14, 2017New Castle County, Delaware; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 14, 2017, 2:53 PM EDT for New Castle County, Delaware; 4 counties in Pennsylvania. It was in force for 3 hr. 2 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 14, 2017, 2:53 PM EDT (18:53 UTC)
Expired: Jul 14, 2017, 5:45 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 18:57 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 14, 3:55 PM EDT	FLOOD	Newark, DE	SEVERAL CARS ISTUCK IN HIGH WATER. FLOODING ON RED MILL... TROPICAL TRAIL... CHRUCHMANS AND AIRPORT ROAD.
Jul 14, 3:55 PM EDT	FLOOD	Newark, DE	SEVERAL CARS STUCK IN HIGH WATER. FLOODING ON RED MILL... TROPICAL TRAIL... CHRUCHMANS AND AIRPORT ROADS.

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, 6.9 hours before the alert went out and 207 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: 403 J/kg
Mixed-layer CIN: -72 J/kg
Mixed-layer LCL: 1367 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

100 
WGUS51 KPHI 141853
FFWPHI
DEC003-PAC029-045-091-101-142145-
/O.NEW.KPHI.FF.W.0012.170714T1853Z-170714T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
253 PM EDT FRI JUL 14 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Southeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 545 PM EDT

* At 250 PM EDT...Doppler radar indicated a line of thunderstorms 
  running north to south through Chester County...moving east at 30 
  MPH. This line of thunderstorms is producing very heavy 
  rain...falling at the rate of one to two inches per hour. Expect 
  torrential downpours for brief periods of time as this line moves 
  through the warned area during the next two hours. Road flooding 
  and small stream flooding can be expected where the heaviest rain 
  happens to fall. 

* Some locations that will experience flooding include...
  Philadelphia, Camden, Wilmington, Newark, West Chester, Norristown,
  Chester, West Norriton, East Norriton, Pennsville, Yeadon,
  Westtown, Conshohocken, Palmyra, Folcroft, Ambler, Swarthmore,
  Elsmere, Paulsboro and Kennett Square.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4017 7544 4015 7503 4012 7496 4005 7498
      3998 7508 3996 7513 3990 7513 3988 7516
      3985 7525 3984 7536 3977 7546 3968 7551
      3967 7579 3972 7579 3972 7593

$$

jjm

1 follow-up statement

896 
WGUS71 KPHI 141939
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
339 PM EDT FRI JUL 14 2017

DEC003-PAC029-045-091-101-142145-
/O.CON.KPHI.FF.W.0012.000000T0000Z-170714T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Montgomery PA-Chester PA-Philadelphia PA-Delaware PA-
339 PM EDT FRI JUL 14 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT FOR
NORTHERN NEW CASTLE...SOUTHEASTERN MONTGOMERY...SOUTHEASTERN
CHESTER...SOUTHWESTERN PHILADELPHIA AND DELAWARE COUNTIES...

At 338 PM EDT...Doppler radar indicated thunderstorms producing 
heavy rain across the warned area.  Flash flooding is expected in 
the areas of heavies rain. 

Some locations that will experience flooding include...
Philadelphia, Camden, Wilmington, Newark, West Chester, Chester,
Pennsville, Yeadon, Westtown, Folcroft, Swarthmore, Elsmere,
Paulsboro, Kennett Square, New Castle, Narberth, National Park, West
Grove, East Lansdowne and Newport.

LAT...LON 4000 7563 4004 7536 4001 7505 3996 7513
      3990 7513 3985 7524 3984 7536 3977 7546
      3968 7551 3967 7579 3972 7579 3972 7593

$$

jjm

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 13, 8:09 PM EDT	Special Weather Statement	PHI	Kent	36 min
Jul 13, 8:29 PM EDT	Special Weather Statement	PHI	Kent	31 min
Jul 13, 10:03 PM EDT	Special Weather Statement	PHI	Sussex	27 min
Jul 13, 10:15 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	4 hr
Jul 13, 10:39 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	51 min
Jul 14, 9:02 AM EDT	Special Weather Statement	PHI	New Castle	28 min
Jul 14, 11:40 AM EDT	Flash Flood Watch	PHI	Kent, New Castle	11 hr
Jul 14, 12:06 PM EDT	Heat Advisory	PHI	Kent, Sussex	7 hr
Jul 14, 2:14 PM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Jul 14, 2:31 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	59 min
Jul 14, 3:18 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	12 min
Jul 14, 3:23 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	67 min
Jul 14, 3:25 PM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Jul 14, 3:34 PM EDT	Flash Flood Warning	PHI	New Castle	3 hr
Jul 14, 3:54 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	66 min
Jul 14, 5:14 PM EDT	Areal Flood Advisory	PHI	Kent	3 hr
Jul 14, 5:24 PM EDT	Special Weather Statement	PHI	Sussex	36 min
Jul 14, 5:30 PM EDT	River Flood Warning	PHI	New Castle	7 hr
Jul 14, 5:40 PM EDT	Severe Thunderstorm Warning	PHI	Kent	65 min
Jul 14, 5:51 PM EDT	Special Weather Statement	PHI	Sussex	39 min
Jul 14, 6:10 PM EDT	Flash Flood Warning	PHI	Kent	3 hr
Jul 14, 6:20 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	40 min
Jul 14, 6:32 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Jul 14, 6:48 PM EDT	Special Weather Statement	PHI	Sussex	42 min
Jul 14, 7:15 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	60 min
Jul 13, 8:17 PM EDT	Special Weather Statement	PHI	Montgomery, Philadelphia	43 min
Jul 14, 7:21 AM EDT	Areal Flood Advisory	PHI	Carbon, Monroe, Northampton	3 hr
Jul 14, 12:30 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Montgomery, Northampton	4 hr
Jul 14, 1:58 PM EDT	Special Weather Statement	PHI	Chester	62 min
Jul 14, 2:57 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2017 Flash Flood Warnings in Delaware, 2017 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.