Alert archive / Delaware / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 63, NWS Philadelphia/Mount Holly

June 3, 2020New Castle County, Delaware; Chester County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 3, 2020, 8:52 PM EDT for New Castle County, Delaware; Chester County, Pennsylvania; Cecil County, Maryland. It was in force for 24 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: Jun 3, 2020, 8:52 PM EDT (00:52 UTC)
Expired: Jun 3, 2020, 9:16 PM EDT
In force: 24 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties New Castle County, DE, Cecil County, MD, Chester County, PA

The radar

The Dover AFB radar (KDOX), 108 km from the middle of the area, began a volume at 00:52 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 3, 3:52 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.9 hours before the alert went out and 143 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: 577 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 2240 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 138 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

842 
WUUS51 KPHI 040052
SVRPHI
DEC003-MDC015-PAC029-040130-
/O.NEW.KPHI.SV.W.0063.200604T0052Z-200604T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
852 PM EDT Wed Jun 3 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern New Castle County in northern Delaware...
  Cecil County in northeastern Maryland...
  Southwestern Chester County in southeastern Pennsylvania...

* Until 930 PM EDT.

* At 851 PM EDT, a severe thunderstorm was located over Holtwood, or
  11 miles south of Willow Street, moving southeast at 40 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Newark, Elkton, Calvert, Oxford, North East, Rising Sun,
  Charlestown, Glen Roy, Zion, Blake, Barksdale, Glasgow, Bear,
  Bohemias Mills, West Nottingham, Octoraro, Brantwood, Mount Vernon,
  Fair Hill and Glen Westover.

This includes the following highways...
 Interstate 95 in Maryland between mile markers 91 and 109.
 Interstate 95 in Delaware between mile markers 0 and 10.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3972 7614 3974 7612 3973 7610 3974 7610
      3976 7606 3981 7603 3983 7604 3983 7602
      3970 7559 3940 7582 3950 7599 3953 7598
      3956 7610 3965 7616 3972 7623
TIME...MOT...LOC 0051Z 294DEG 36KT 3982 7630 

HAIL...1.00IN
WIND...60MPH
 
$$

Fitzsimmons

1 follow-up statement

062 
WWUS51 KPHI 040116
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
916 PM EDT Wed Jun 3 2020

DEC003-MDC015-PAC029-040126-
/O.CAN.KPHI.SV.W.0063.000000T0000Z-200604T0130Z/
New Castle DE-Cecil MD-Chester PA-
916 PM EDT Wed Jun 3 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN NEW CASTLE...
CECIL AND SOUTHWESTERN CHESTER COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
northern Delaware...northeastern Maryland...and southeastern
Pennsylvania.

LAT...LON 3972 7614 3974 7612 3973 7610 3974 7610
      3976 7606 3981 7603 3983 7604 3983 7602
      3970 7559 3940 7582 3950 7599 3953 7598
      3956 7610 3965 7616 3972 7623
TIME...MOT...LOC 0114Z 294DEG 36KT 3972 7600 

$$

Fitzsimmons

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 4, 6:06 AM EDT	Coastal Flood Advisory	PHI	Kent, New Castle, Sussex	22 hr
Jun 4, 5:39 PM EDT	Severe Thunderstorm Warning	PHI	Berks	81 min
Jun 4, 6:42 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	63 min
Jun 4, 7:47 PM EDT	Special Weather Statement	PHI	Bucks	43 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2020 Severe Thunderstorm Warnings in Pennsylvania, 2020 Severe Thunderstorm Warnings in Maryland, 2020 Every severe thunderstorm warning in 2020

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.