Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

April 10, 2021Chester County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this special weather statement at Apr 10, 2021, 1:19 AM EDT for Chester County, Pennsylvania; New Castle County, Delaware. It was in force for 56 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 10, 2021, 1:19 AM EDT (05:19 UTC)
Expired
Apr 10, 2021, 2:15 AM EDT
In force
56 min
Issued by
NWS Philadelphia/Mount Holly

Counties New Castle County, DE, Chester County, PA

The radar

The Dover AFB radar (KDOX), 97 km from the middle of the area, began a volume at 05:21 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, 5.3 hours before the alert went out and 154 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°0°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.

788 
WWUS81 KPHI 100519
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
119 AM EDT Sat Apr 10 2021

DEZ001-002-MDZ012-015-020-PAZ101-102-100615-
Kent-New Castle-Queen Anne's-Kent-Caroline-Western Chester-Eastern
Chester-
119 AM EDT Sat Apr 10 2021

An area of showers with embedded thunderstorms currently over 
eastern Maryland will move northeast into western portions of the 
Delaware Valley. Locally heavy rain is possible as these showers 
move into portions of southeast Pennsylvania and northern Delaware, 
and rumbles of thunder are possible.

LAT...LON 3987 7599 3997 7599 4014 7584 3976 7561
      3931 7549 3908 7578 3936 7585 3938 7582
      3938 7577 3972 7579 3972 7603 3978 7606
TIME...MOT...LOC 0516Z 214DEG 17KT 3985 7604 3951 7584 3920 7576 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 3:22 AM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem2 hr
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
Apr 10, 2:34 AM EDTSpecial Weather StatementPHIChester41 min
Apr 10, 2:35 AM EDTSpecial Weather StatementPHIDelaware40 min

Nearby

Special Weather Statements in Pennsylvania, 2021Special Weather Statements in Delaware, 2021Every special weather statement 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.