Alert archive / Maryland / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 228, NWS Philadelphia/Mount Holly

July 29, 2021Caroline County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2021, 11:48 AM EDT for Caroline County, Talbot County, Maryland. It was in force for 45 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 29, 2021, 11:48 AM EDT (15:48 UTC)
Expired: Jul 29, 2021, 12:33 PM EDT
In force: 45 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Caroline County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 50 km from the middle of the area, began a volume at 15:51 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 3.8 hours before the alert went out and 97 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: 581 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 863 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

200 
WUUS51 KPHI 291548
SVRPHI
MDC011-041-291645-
/O.NEW.KPHI.SV.W.0228.210729T1548Z-210729T1645Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1148 AM EDT Thu Jul 29 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Talbot County in eastern Maryland...
  Southwestern Caroline County in eastern Maryland...

* Until 1245 PM EDT.

* At 1148 AM EDT, a severe thunderstorm was located over Hambleton,
  or near Easton, 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...
  Trappe, Preston, Hambleton, Choptank and Windyhill. 

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.

&&

LAT...LON 3864 7612 3871 7613 3875 7589 3870 7589
      3870 7590 3868 7593 3867 7594 3866 7596
      3865 7596 3862 7598
TIME...MOT...LOC 1548Z 273DEG 6KT 3868 7607 

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

Robertson

2 follow-up statements

623 
WWUS51 KPHI 291611
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1211 PM EDT Thu Jul 29 2021

MDC011-041-291645-
/O.CON.KPHI.SV.W.0228.000000T0000Z-210729T1645Z/
Talbot MD-Caroline MD-
1211 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 PM EDT
FOR SOUTHEASTERN TALBOT AND SOUTHWESTERN CAROLINE COUNTIES...

At 1211 PM EDT, a severe thunderstorm was located over Windyhill, or
7 miles southeast of Easton, moving east at 5 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...
Preston, Choptank and Windyhill. 

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.

&&

LAT...LON 3863 7603 3872 7607 3875 7589 3870 7589
      3870 7590 3868 7593 3867 7594 3866 7596
      3865 7596 3863 7597
TIME...MOT...LOC 1611Z 273DEG 6KT 3868 7602 

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

PO

850 
WWUS51 KPHI 291633
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1233 PM EDT Thu Jul 29 2021

MDC011-041-291642-
/O.CAN.KPHI.SV.W.0228.000000T0000Z-210729T1645Z/
Talbot MD-Caroline MD-
1233 PM EDT Thu Jul 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN TALBOT AND
SOUTHWESTERN CAROLINE COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. 

LAT...LON 3863 7603 3872 7607 3875 7589 3870 7589
      3870 7590 3868 7593 3867 7594 3866 7596
      3865 7596 3863 7597
TIME...MOT...LOC 1632Z 273DEG 6KT 3868 7597 

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 11:35 AM EDT	Special Weather Statement	PHI	Talbot	55 min
Jul 29, 12:12 PM EDT	Areal Flood Advisory	PHI	Caroline, Talbot	84 min
Jul 29, 5:59 PM EDT	Special Weather Statement	PHI	Queen Anne's	31 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2021 Every severe thunderstorm warning 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.