Alert archive / Delaware / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 73, NWS Philadelphia/Mount Holly

June 22, 2020New Castle County, Delaware; Chester County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 22, 2020, 7:25 PM EDT for New Castle County, Delaware; Chester County, Pennsylvania; Cecil County, Maryland. It was in force for 22 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 22, 2020, 7:25 PM EDT (23:25 UTC)
Expired
Jun 22, 2020, 7:47 PM EDT
In force
22 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), 106 km from the middle of the area, began a volume at 23:26 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, 11.4 hours before the alert went out and 145 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 2020-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 333 joules per kilogram.LCLLFCEL10008507005003002001001 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 2020-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 square meters per square second.1939Sfc1 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
333 J/kg
Mixed-layer CIN
-93 J/kg
Mixed-layer LCL
968 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

862 
WUUS51 KPHI 222325
SVRPHI
DEC003-MDC015-PAC029-230000-
/O.NEW.KPHI.SV.W.0073.200622T2325Z-200623T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
725 PM EDT Mon Jun 22 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 800 PM EDT.

* At 724 PM EDT, a severe thunderstorm was located over Charlestown,
  or 7 miles west of Elkton, moving north at 15 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, Homeville, Glen Roy, Zion, Blake, Barksdale, Glasgow,
  Bear, West Nottingham, Brantwood, Mount Vernon, Fair Hill, Glen
  Westover and Bay View.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 4.
 Interstate 95 in Maryland between mile markers 92 and 109.

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.

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3978 7606 3981 7603 3983 7604 3983 7602
      3986 7601 3987 7598 3959 7561 3940 7594
      3947 7600 3952 7598 3955 7603 3955 7606
      3961 7612
TIME...MOT...LOC 2324Z 196DEG 12KT 3959 7595 

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

Davis
2 follow-up statements
942 
WWUS51 KPHI 222339
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
739 PM EDT Mon Jun 22 2020

DEC003-MDC015-PAC029-230000-
/O.CON.KPHI.SV.W.0073.000000T0000Z-200623T0000Z/
New Castle DE-Cecil MD-Chester PA-
739 PM EDT Mon Jun 22 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR WEST CENTRAL NEW CASTLE...NORTHEASTERN CECIL AND SOUTHWESTERN
CHESTER COUNTIES...

At 739 PM EDT, a severe thunderstorm was located over Bay View, or
near Elkton, moving north at 15 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,
Homeville, Glen Roy, Zion, Blake, Barksdale, Glasgow, Bear, West
Nottingham, Brantwood, Mount Vernon, Fair Hill, Glen Westover and Bay
View.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 4.
 Interstate 95 in Maryland between mile markers 95 and 109.

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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3978 7606 3981 7603 3983 7604 3983 7602
      3986 7601 3987 7598 3959 7561 3946 7584
      3952 7597 3964 7609
TIME...MOT...LOC 2339Z 196DEG 12KT 3964 7593 

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

Davis
977 
WWUS51 KPHI 222347
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
747 PM EDT Mon Jun 22 2020

DEC003-MDC015-PAC029-222357-
/O.CAN.KPHI.SV.W.0073.000000T0000Z-200623T0000Z/
New Castle DE-Cecil MD-Chester PA-
747 PM EDT Mon Jun 22 2020

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL NEW CASTLE...
NORTHEASTERN 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, heavy rain and 
minor flooding is still possible with this thunderstorm.

LAT...LON 3978 7606 3981 7603 3983 7604 3983 7602
      3986 7601 3987 7598 3959 7561 3946 7584
      3952 7597 3964 7609
TIME...MOT...LOC 2344Z 196DEG 12KT 3967 7592 

$$

Davis

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 22, 7:01 PM EDTSpecial Weather StatementPHISussex44 min
Jun 22, 7:08 PM EDTSevere Thunderstorm WarningPHIKent, Sussex15 min
Jun 22, 7:52 PM EDTAreal Flood AdvisoryPHIChester109 min
Jun 22, 5:37 PM EDTSpecial Weather StatementPHITalbot38 min
Jun 22, 7:08 PM EDTSpecial Weather StatementPHICecil37 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2020Severe Thunderstorm Warnings in Pennsylvania, 2020Severe Thunderstorm Warnings in Maryland, 2020Every 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.