Alert archive / Delaware / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 138, NWS Philadelphia/Mount Holly

July 6, 2020New Castle County, Delaware; Cecil County, Maryland; Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 6, 2020, 6:13 PM EDT for New Castle County, Delaware; Cecil County, Maryland; Chester County, Pennsylvania. It was in force for 48 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
Jul 6, 2020, 6:13 PM EDT (22:13 UTC)
Expired
Jul 6, 2020, 7:01 PM EDT
In force
48 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), 117 km from the middle of the area, began a volume at 22:17 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.

IssuedProductOfficeLasted
Jul 6, 1:38 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.2 hours before the alert went out and 153 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 2020-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1250 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 2020-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
1250 J/kg
Mixed-layer CIN
-133 J/kg
Mixed-layer LCL
1150 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

312 
WUUS51 KPHI 062213
SVRPHI
DEC003-MDC015-PAC029-062315-
/O.NEW.KPHI.SV.W.0138.200706T2213Z-200706T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
613 PM EDT Mon Jul 6 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 715 PM EDT.

* At 613 PM EDT, a severe thunderstorm was located over Mount Vernon,
  or 16 miles northwest of Newark, moving east at 10 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, Kennett Square, Oxford, Parkesburg, West
  Grove, Rising Sun, Homeville, Glen Roy, Zion, Blake, Barksdale,
  Cochranville, North Star, West Nottingham, Mount Vernon, Pike
  Creek, Fair Hill and Glen Westover.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 2.
 Interstate 95 in Maryland between mile markers 101 and 109.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3973 7610 3974 7610 3976 7606 3981 7603
      3983 7604 3983 7602 3985 7602 3987 7599
      3995 7599 3997 7575 3976 7564 3960 7577
      3968 7616 3972 7616
TIME...MOT...LOC 2213Z 270DEG 8KT 3980 7603 

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

BAH
2 follow-up statements
887 
WWUS51 KPHI 062232
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
632 PM EDT Mon Jul 6 2020

DEC003-MDC015-PAC029-062315-
/O.CON.KPHI.SV.W.0138.000000T0000Z-200706T2315Z/
New Castle DE-Cecil MD-Chester PA-
632 PM EDT Mon Jul 6 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHWESTERN NEW CASTLE...NORTHEASTERN CECIL AND SOUTHWESTERN
CHESTER COUNTIES...

At 631 PM EDT, a severe thunderstorm was located over Oxford, or 14
miles northwest of Newark, moving east at 10 mph.

HAZARD...60 mph wind gusts and half dollar 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, Kennett Square, Oxford, Parkesburg, West
Grove, Rising Sun, Homeville, Glen Roy, Zion, Blake, Barksdale,
Cochranville, North Star, West Nottingham, Mount Vernon, Pike Creek,
Fair Hill and Glen Westover.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 2.
 Interstate 95 in Maryland between mile markers 101 and 109.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
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 3973 7610 3974 7610 3976 7606 3981 7603
      3983 7604 3983 7602 3985 7602 3987 7599
      3995 7599 3997 7575 3976 7564 3960 7577
      3968 7616 3972 7616
TIME...MOT...LOC 2231Z 270DEG 8KT 3980 7598 

HAIL...1.25IN
WIND...60MPH
 
$$

BAH
707 
WWUS51 KPHI 062301
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
701 PM EDT Mon Jul 6 2020

DEC003-MDC015-PAC029-062311-
/O.CAN.KPHI.SV.W.0138.000000T0000Z-200706T2315Z/
New Castle DE-Cecil MD-Chester PA-
701 PM EDT Mon Jul 6 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN NEW CASTLE...
NORTHEASTERN CECIL AND SOUTHWESTERN CHESTER COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...northeastern Maryland...and southeastern
Pennsylvania.

LAT...LON 3973 7610 3974 7610 3976 7606 3981 7603
      3983 7604 3983 7602 3985 7602 3987 7599
      3995 7599 3997 7575 3976 7564 3960 7577
      3968 7616 3972 7616
TIME...MOT...LOC 2259Z 270DEG 8KT 3980 7589 

$$

BAH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 3:16 AM EDTHeat AdvisoryPHINew Castle12 hr
Jul 6, 12:52 PM EDTFlash Flood WatchPHINew Castle8 hr
Jul 6, 5:43 PM EDTAreal Flood AdvisoryPHINew Castle3 hr
Jul 6, 6:00 PM EDTSevere Thunderstorm WarningPHINew Castle60 min
Jul 6, 6:37 PM EDTSevere Thunderstorm WarningPHINew Castle53 min
Jul 6, 7:41 PM EDTSevere Thunderstorm WarningPHIKent, New Castle, Sussex64 min
Jul 6, 7:48 PM EDTAreal Flood AdvisoryPHIKent, New Castle117 min
Jul 6, 4:49 PM EDTSpecial Weather StatementPHICecil56 min
Jul 6, 5:14 PM EDTSevere Thunderstorm WarningPHICecil61 min
Jul 6, 7:03 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's42 min
Jul 6, 7:23 PM EDTTornado WarningPHICaroline, Kent, Queen Anne's19 min
Jul 6, 12:34 PM EDTSpecial Weather StatementPHIPhiladelphia26 min
Jul 6, 12:45 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia60 min
Jul 6, 12:57 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia2 hr
Jul 6, 1:08 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Jul 6, 1:15 PM EDTSevere Thunderstorm WarningPHIBucks60 min
Jul 6, 1:20 PM EDTSpecial Weather StatementPHIMontgomery25 min
Jul 6, 1:24 PM EDTSpecial Weather StatementPHIMonroe36 min
Jul 6, 1:43 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia62 min
Jul 6, 1:44 PM EDTSpecial Weather StatementPHIMontgomery31 min
Jul 6, 1:50 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery4 hr
Jul 6, 1:50 PM EDTSevere Thunderstorm WarningPHIMonroe40 min
Jul 6, 2:02 PM EDTAreal Flood AdvisoryPHIBucks118 min
Jul 6, 2:04 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery41 min
Jul 6, 2:10 PM EDTAreal Flood AdvisoryPHIMonroe2 hr
Jul 6, 2:18 PM EDTSpecial Weather StatementPHIMontgomery27 min
Jul 6, 2:27 PM EDTSevere Thunderstorm WarningPHIMontgomery48 min
Jul 6, 2:28 PM EDTSevere Thunderstorm WarningPHIMonroe28 min
Jul 6, 2:39 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Montgomery4 hr
Jul 6, 2:39 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia66 min
Jul 6, 2:41 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery49 min
Jul 6, 2:48 PM EDTAreal Flood AdvisoryPHIPhiladelphia4 hr
Jul 6, 2:51 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery24 min
Jul 6, 2:57 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Jul 6, 3:00 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton45 min
Jul 6, 3:11 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia49 min
Jul 6, 3:38 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Northampton52 min
Jul 6, 3:52 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia38 min
Jul 6, 3:56 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton64 min
Jul 6, 4:06 PM EDTSevere Thunderstorm WarningPHILehigh24 min
Jul 6, 4:07 PM EDTFlash Flood WarningPHIChester, Delaware, Montgomery4 hr
Jul 6, 4:31 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Monroe, Northampton44 min
Jul 6, 4:51 PM EDTAreal Flood AdvisoryPHICarbon, Monroe114 min
Jul 6, 5:00 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton45 min
Jul 6, 5:01 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton119 min
Jul 6, 5:17 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton43 min
Jul 6, 5:20 PM EDTSevere Thunderstorm WarningPHIChester, Delaware42 min
Jul 6, 5:29 PM EDTSevere Thunderstorm WarningPHIChester46 min
Jul 6, 5:53 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery52 min
Jul 6, 6:14 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery3 hr
Jul 6, 6:18 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery35 min
Jul 6, 6:54 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery109 min
Jul 6, 7:18 PM EDTSevere Thunderstorm WarningPHIMonroe36 min
Jul 6, 7:36 PM EDTSevere Thunderstorm WarningPHIChester69 min

Nearby

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