Alert archive / Delaware / Areal Flood Advisories in 2021

Areal Flood Advisory 2, NWS Philadelphia/Mount Holly

February 28, 2021Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this areal flood advisory at Feb 28, 2021, 5:20 PM EST for Kent County, New Castle County, Delaware. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Feb 28, 2021, 5:20 PM EST (22:20 UTC)
Expired
Feb 28, 2021, 8:18 PM EST
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Kent County, DE, New Castle County, DE

The radar

The Dover AFB radar (KDOX), 85 km from the middle of the area, began a volume at 22:23 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, 10.3 hours before the alert went out and 173 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, Washington/Dulle, VA at 12:00Z on 2021-02-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2021-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 174 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
801 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
149 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

001 
WGUS81 KPHI 282220
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
520 PM EST Sun Feb 28 2021

DEC001-003-010130-
/O.NEW.KPHI.FA.Y.0002.210228T2220Z-210301T0130Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent DE-New Castle DE-
520 PM EST Sun Feb 28 2021

The National Weather Service in Mount Holly has issued a

* Flood Advisory for...
  Kent County in central Delaware...
  New Castle County in northern Delaware...

* Until 830 PM EST.

* At 520 PM EST, Doppler radar indicated heavy rain. Minor flooding 
  is ongoing or expected to begin shortly in the advisory area. 
  Between 0.5 and 1.5 inches of rain have fallen.

Some locations that may experience flooding include...
  Wilmington, Dover, Newark, Middletown, Smyrna, Carneys Point, 
  Elsmere, New Castle, Penns Grove, Harrington, Camden, and Clayton.

This includes the following highways...
	Interstate 95 in Delaware between mile markers 1 and 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Advisory means river or stream flows are elevated, or 
ponding of water in urban or other areas is occurring or is imminent.

&&

LAT...LON 3974 7577 3982 7566 3983 7548 3979 7542
      3979 7541 3977 7545 3974 7547 3961 7559
      3957 7551 3954 7553 3950 7552 3947 7555
      3927 7536 3903 7538 3886 7572 3972 7579
      3972 7577

$$

Davis
1 follow-up statement
372 
WGUS81 KPHI 010118
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
818 PM EST Sun Feb 28 2021

DEC001-003-010128-
/O.CAN.KPHI.FA.Y.0002.000000T0000Z-210301T0130Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent DE-New Castle DE-
818 PM EST Sun Feb 28 2021

...FLOOD ADVISORY IS CANCELLED FOR KENT AND NEW CASTLE COUNTIES...

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

LAT...LON 3974 7577 3982 7566 3983 7548 3979 7542
      3979 7541 3977 7545 3974 7547 3961 7559
      3957 7551 3954 7553 3950 7552 3947 7555
      3927 7536 3903 7538 3886 7572 3972 7579
      3972 7577

$$

Davis

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 28, 3:14 PM ESTWind AdvisoryPHINew Castle, Sussex42 hr
Feb 28, 5:20 PM ESTAreal Flood AdvisoryPHINew Castle3 hr

Nearby

Areal Flood Advisories in Delaware, 2021Every areal flood advisory in 2021

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.