Alert archive / Pennsylvania / Areal Flood Advisories in 2021

Areal Flood Advisory 8, NWS Philadelphia/Mount Holly

April 10, 2021New Castle County, Delaware; 5 counties in Pennsylvania; 4 counties in New Jersey

NWS Philadelphia/Mount Holly issued this areal flood advisory at Apr 10, 2021, 3:22 AM EDT for New Castle County, Delaware; 5 counties in Pennsylvania; 4 counties in New Jersey. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 10, 2021, 3:22 AM EDT (07:22 UTC)
Expired
Apr 10, 2021, 5:49 AM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 98 km from the middle of the area, began a volume at 07:22 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 00:00Z, 7.4 hours before the alert went out and 187 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 00:00Z on 2021-04-10Temperature 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 00:00Z on 2021-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 161 square meters per square second.193958Sfc1 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
537 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
161 m²/s²
0-3 km storm-relative helicity
238 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

335 
WGUS81 KPHI 100722
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
322 AM EDT Sat Apr 10 2021

DEC003-NJC005-007-015-033-PAC017-029-045-091-101-101030-
/O.NEW.KPHI.FA.Y.0008.210410T0722Z-210410T1030Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Burlington NJ-Camden NJ-Gloucester NJ-Salem NJ-Bucks
PA-Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
322 AM EDT Sat Apr 10 2021

The National Weather Service in Mount Holly has issued a

* Flood Advisory for...
  Northern New Castle County in northern Delaware...
  Northwestern Burlington County in southern New Jersey...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Northwestern Salem County in southern New Jersey...
  South Central Bucks County in southeastern Pennsylvania...
  Southeastern Chester County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...

* Until 630 AM EDT.

* At 322 AM EDT, Doppler radar indicated heavy rain due to showers 
  and thunderstorms. Minor flooding is ongoing or expected to begin 
  shortly in the advisory area as these showers and storms are 
  putting down a quick inch to inch and a half of rain as they move 
  through.

* Some locations that will experience flooding include...
  Philadelphia, Camden, Wilmington, Newark, West Chester, Gloucester 
  City, Cherry Hill, Bensalem, Mount Laurel, Norristown, Chester, 
  and Willingboro.

This includes the following highways...
	New Jersey Turnpike between exits 1 and 4.
	Pennsylvania Turnpike between exits 324 and 346.
	Interstate 95 in Pennsylvania between mile markers 0 and 36.
	Interstate 95 in Delaware between mile markers 0 and 23.
	Interstate 76 in Pennsylvania between mile markers 327 and 351.
	Interstate 76 in New Jersey between mile markers 0 and 3.
	Interstate 295 in New Jersey between mile markers 0 and 44.
	Interstate 676 in Pennsylvania between mile markers 0 and 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3972 7588 3987 7592 3994 7584 4020 7513
      4011 7495 3995 7483 3958 7554 3963 7579
      3972 7579

$$

Fitzsimmons
1 follow-up statement
686 
WGUS81 KPHI 100949
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
549 AM EDT Sat Apr 10 2021

DEC003-NJC005-007-015-033-PAC017-029-045-091-101-100959-
/O.CAN.KPHI.FA.Y.0008.000000T0000Z-210410T1030Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Burlington NJ-Camden NJ-Gloucester NJ-Salem NJ-Bucks
PA-Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
549 AM EDT Sat Apr 10 2021

...FLOOD ADVISORY IS CANCELLED FOR NORTHERN NEW CASTLE, NORTHWESTERN 
BURLINGTON, NORTHWESTERN CAMDEN, NORTHWESTERN GLOUCESTER, 
NORTHWESTERN SALEM, SOUTH CENTRAL BUCKS, SOUTHEASTERN CHESTER, 
DELAWARE, SOUTHEASTERN MONTGOMERY, AND PHILADELPHIA COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

LAT...LON 3972 7588 3987 7592 3994 7584 4020 7513
      4011 7495 3995 7483 3958 7554 3963 7579
      3972 7579

$$

Fitzsimmons

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 1:19 AM EDTSpecial Weather StatementPHINew Castle56 min
Apr 10, 2:34 AM EDTSpecial Weather StatementPHIChester41 min
Apr 10, 2:35 AM EDTSpecial Weather StatementPHIDelaware40 min
Apr 10, 3:44 AM EDTSpecial Weather StatementPHIGloucester46 min
Apr 10, 4:42 AM EDTSpecial Weather StatementPHIGloucester48 min
Apr 10, 4:00 PM EDTSmall Craft AdvisoryPHI3 days

Nearby

Areal Flood Advisories in Pennsylvania, 2021Areal Flood Advisories in New Jersey, 2021Areal 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.