Alert archive / Delaware / Tornado Warnings in 2021

Tornado Warning 47, NWS Philadelphia/Mount Holly

September 1, 2021New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this tornado warning at Sep 1, 2021, 6:24 PM EDT for New Castle County, Delaware. It was in force for 16 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
Sep 1, 2021, 6:24 PM EDT (22:24 UTC)
Expired
Sep 1, 2021, 6:40 PM EDT
In force
16 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County New Castle County, DE

The radar

The Dover AFB radar (KDOX), 93 km from the middle of the area, began a volume at 22:27 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
Sep 1, 12:40 PM EDTTornado WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.4 hours before the alert went out and 168 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 558 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 square meters per square second.19395878Sfc1 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
558 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
575 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
223 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.6

Open this sounding in Storm Lab

The text

As transmitted.

768 
WFUS51 KPHI 012224
TORPHI
DEC003-012300-
/O.NEW.KPHI.TO.W.0047.210901T2224Z-210901T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
624 PM EDT Wed Sep 1 2021

The National Weather Service in Mount Holly NJ has issued a

* Tornado Warning for...
  Northwestern New Castle County in northern Delaware...

* Until 700 PM EDT.
    
* At 624 PM EDT, a severe thunderstorm capable of producing a tornado
  was located over Cayots, or near Middletown, moving northeast at 30
  mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Newark, New Castle, Glasgow, Bear, Pike Creek, Wilmington Manor and
  Brookside.

This includes Interstate 95 in Delaware between mile markers 1 and 9.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3974 7571 3966 7554 3963 7558 3962 7558
      3949 7577 3962 7579
TIME...MOT...LOC 2224Z 219DEG 28KT 3951 7581 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Staarmann
1 follow-up statement
404 
WWUS51 KPHI 012240
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
640 PM EDT Wed Sep 1 2021

DEC003-012250-
/O.CAN.KPHI.TO.W.0047.000000T0000Z-210901T2300Z/
New Castle DE-
640 PM EDT Wed Sep 1 2021

...THE TORNADO WARNING FOR NORTHWESTERN NEW CASTLE COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 1000 PM EDT for northern
Delaware.

LAT...LON 3974 7571 3966 7554 3963 7558 3962 7558
      3949 7577 3962 7579
TIME...MOT...LOC 2239Z 219DEG 28KT 4038 7485 

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 6:19 AM EDTAreal Flood AdvisoryPHINew Castle116 min
Sep 1, 6:49 AM EDTFlash Flood WarningPHINew Castle86 min
Sep 1, 8:03 AM EDTRiver Flood WarningPHINew Castle4 hr
Sep 1, 2:53 PM EDTFlash Flood WarningPHINew Castle9 hr
Sep 1, 4:59 PM EDTTornado WarningPHIKent, Sussex46 min
Sep 1, 5:01 PM EDTTornado WarningPHIKent, New Castle44 min
Sep 1, 5:16 PM EDTSevere Thunderstorm WarningPHIKent, Sussex44 min
Sep 1, 5:26 PM EDTFlash Flood WarningPHINew Castle9 hr
Sep 1, 5:35 PM EDTTornado WarningPHIKent, New Castle25 min
Sep 1, 6:03 PM EDTSevere Thunderstorm WarningPHIKent, Sussex42 min
Sep 1, 6:08 PM EDTRiver Flood WarningPHINew Castle18 hr
Sep 1, 6:15 PM EDTRiver Flood WarningPHINew Castle9 hr
Sep 1, 6:38 PM EDTRiver Flood WarningPHINew Castle28 hr
Sep 1, 6:57 PM EDTSevere Thunderstorm WarningPHIKent, Sussex63 min
Sep 1, 7:44 PM EDTRiver Flood WarningPHINew Castle11 hr

Nearby

Tornado Warnings in Delaware, 2021Every tornado warning in 2021Tornadoes 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.