Alert archive / Delaware / Flash Flood Warnings in 2017

Flash Flood Warning 41, NWS Philadelphia/Mount Holly

August 3, 2017Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 3, 2017, 4:17 PM EDT for Kent County, Sussex County, Delaware. 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: Aug 3, 2017, 4:17 PM EDT (20:17 UTC)
Expired: Aug 3, 2017, 8:15 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 17 km from the middle of the area, began a volume at 20:17 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 8.3 hours before the alert went out and 116 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: 204 J/kg
Mixed-layer CIN: -106 J/kg
Mixed-layer LCL: 1338 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 23 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

452 
WGUS51 KPHI 032017
FFWPHI
DEC001-005-040015-
/O.NEW.KPHI.FF.W.0041.170803T2017Z-170804T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
417 PM EDT THU AUG 3 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  North central Sussex County in southern Delaware...
  Southeastern Kent County in central Delaware...

* Until 815 PM EDT

* At 415 PM EDT...Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to three 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...
  Milford, Bowers, Big Stone Beach, Frederica and Riverview. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3891 7548 3905 7554 3907 7537 3905 7537
      3901 7533 3893 7529 3888 7522

$$

CMS

2 follow-up statements

170 
WGUS71 KPHI 032229
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
629 PM EDT THU AUG 3 2017

DEC001-005-040015-
/O.CON.KPHI.FF.W.0041.000000T0000Z-170804T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-Kent DE-
629 PM EDT THU AUG 3 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT FOR
NORTH CENTRAL SUSSEX AND SOUTHEASTERN KENT COUNTIES...

At 627 PM EDT...Doppler radar indicated that the heavy rain had 
ended. However, rapid runoff continues from the heavy rainfall that 
occurred earlier this afternoon. Flash flooding is likely to 
continue for the next couple of hours.

Some locations that could experience flooding include...
Milford, Bowers, Big Stone Beach, Frederica and Riverview. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 3891 7548 3905 7554 3907 7537 3905 7537
      3901 7533 3893 7529 3888 7522

$$

CMS

588 
WGUS71 KPHI 032337
FFSPHI

Flash Flood Statement
National Weather Service MOUNT HOLLY NJ
737 PM EDT THU AUG 3 2017

DEC001-005-032343-
/O.CAN.KPHI.FF.W.0041.000000T0000Z-170804T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-Kent DE-
737 PM EDT THU AUG 3 2017

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL SUSSEX AND SOUTHEASTERN
KENT COUNTIES IS CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3891 7548 3905 7554 3907 7537 3905 7537
      3901 7533 3893 7529 3888 7522

$$

amc

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 3, 1:54 PM EDT	Special Weather Statement	PHI	Sussex	21 min
Aug 3, 2:12 PM EDT	Special Weather Statement	PHI	Sussex	33 min
Aug 3, 2:15 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	45 min
Aug 3, 2:26 PM EDT	Special Weather Statement	PHI	Sussex	49 min
Aug 3, 2:59 PM EDT	Special Weather Statement	PHI	Kent, Sussex	46 min
Aug 3, 3:46 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	4 hr
Aug 3, 5:01 PM EDT	Special Weather Statement	PHI	Kent	29 min
Aug 3, 5:20 PM EDT	Special Weather Statement	PHI	Sussex	25 min
Aug 3, 5:33 PM EDT	Areal Flood Advisory	PHI	Kent	4 hr
Aug 3, 5:49 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Aug 3, 6:12 PM EDT	Areal Flood Advisory	PHI	Sussex	3 hr
Aug 3, 6:31 PM EDT	Special Weather Statement	PHI	Sussex	29 min
Aug 3, 7:02 PM EDT	Flash Flood Warning	PHI	Sussex	3 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.