Alert archive / Delaware / Flash Flood Warnings in 2017

Flash Flood Warning 38, NWS Philadelphia/Mount Holly

August 2, 2017New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 2, 2017, 1:44 PM EDT for New Castle County, Delaware. It was in force for 4 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: Aug 2, 2017, 1:44 PM EDT (17:44 UTC)
Expired: Aug 2, 2017, 5:45 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County New Castle County, DE

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 17:44 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
Aug 2, 3:46 PM EDT	FLOOD	Wilmington, DE	UNION STREET FLOODED WITH AN ESTIMATED 1-2 FEET OF WATER.

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, 5.7 hours before the alert went out and 183 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: 378 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 1469 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

850 
WGUS51 KPHI 021744
FFWPHI
DEC003-022145-
/O.NEW.KPHI.FF.W.0038.170802T1744Z-170802T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
144 PM EDT WED AUG 2 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  North central New Castle County in northern Delaware...

* Until 545 PM EDT

* At 144 PM EDT...Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Wilmington, Elsmere, New Castle, Newport, Arden, Greenville,
  Stanton, Talleyville, Wilmington Manor, Bellefonte, Ardentown,
  Ardencroft and Edgemoor.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3983 7548 3974 7551 3967 7555 3970 7565
      3983 7561

$$

Kruzdlo

2 follow-up statements

731 
WGUS71 KPHI 022048
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
448 PM EDT WED AUG 2 2017

DEC003-022145-
/O.CON.KPHI.FF.W.0038.000000T0000Z-170802T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
448 PM EDT WED AUG 2 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT FOR
NORTH CENTRAL NEW CASTLE COUNTY...

At 444 PM EDT...Doppler radar indicated that 3 to 4 inches of rain 
had fallen this afternoon. While only some showers remain across the 
warned area, runoff will continue. The flash flood warning remains 
in effect through 545 pm. 

LAT...LON 3983 7548 3974 7551 3967 7555 3970 7565
      3983 7561

$$

Kruzdlo

132 
WGUS71 KPHI 022139
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
539 PM EDT WED AUG 2 2017

DEC003-022147-
/O.EXP.KPHI.FF.W.0038.000000T0000Z-170802T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
539 PM EDT WED AUG 2 2017

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL NEW CASTLE COUNTY WILL
EXPIRE AT 545 PM EDT...

The heavy rain has ended and water is receding. The flash flood 
warning will be allowed to expire.

LAT...LON 3983 7548 3974 7551 3967 7555 3970 7565
      3983 7561

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 2, 12:28 PM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Aug 2, 3:16 PM EDT	Areal Flood Advisory	PHI	Kent	7 hr
Aug 2, 6:27 PM EDT	Special Weather Statement	PHI	Kent	33 min
Aug 2, 7:58 PM EDT	Severe Thunderstorm Warning	PHI	Kent	47 min

Nearby

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.