Alert archive / Maryland / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 149, NWS Philadelphia/Mount Holly

July 21, 2020Caroline County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 21, 2020, 9:39 PM EDT for Caroline County, Talbot County, Maryland. It was in force for 51 min. 6 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 21, 2020, 9:39 PM EDT (01:39 UTC)
Expired
Jul 21, 2020, 10:30 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Caroline County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 44 km from the middle of the area, began a volume at 01:42 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.

What was reported inside it

TimeReportWhereRemark
Jul 21, 9:45 PM EDTTSTM WND DMG1 Ssw Windyhill, MDREPORTS OF DOWNED POWER LINES NEAR WINDY HILL ROAD AND BRUCEVILLE ROAD. TIME ESTIMATED FROM RADAR.
Jul 21, 9:45 PM EDTTSTM WND DMGHambleton, MDTRAINED SPOTTER REPORTS 2 LARGE TREES DOWN NEAR HIS HOME ALONG WITH MANY SMALLER TREES BLOWN OVER. SPOTTER ALSO REPORTS CONSTANT CLOUD TO GROUND LIGHTNING.
Jul 21, 9:53 PM EDTTSTM WND DMG2 Sse Tanyard, MDREPORTS OF TREES AND WIRES DOWN NEAR BETHLEHEM ROAD SOUTHEAST OF TANYARD. TIME ESTIMATED FROM RADAR.
Jul 21, 9:53 PM EDTTSTM WND DMGMatthews, MDDOWNED POWER LINES NEAR LEWISTOWN ROD IN MATTHEWS. TIME ESTIMATED FROM RADAR.
Jul 21, 9:53 PM EDTTSTM WND DMGPreston, MDDISPATCH REPORTS NUMEROUS TREES DOWN AROUND THE TOWN OF PRESTON. TIME ESTIMATED FROM RADAR.
Jul 21, 9:54 PM EDTTSTM WND DMG2 Wnw Preston, MDDISPATCH REPORTS A TREE INTO A HOUSE ON MARSH CREEK ROAD WEST OF PRESTON. TIME ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 1.7 hours before the alert went out and 98 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, Wallops Is Stn, VA at 00:00Z on 2020-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3628 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, Wallops Is Stn, VA at 00:00Z on 2020-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 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
3628 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
1027 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

473 
WUUS51 KPHI 220139
SVRPHI
MDC011-041-220230-
/O.NEW.KPHI.SV.W.0149.200722T0139Z-200722T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
939 PM EDT Tue Jul 21 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 1030 PM EDT.

* At 939 PM EDT, a severe thunderstorm was located over Windyhill, or
  7 miles northwest of Hurlock, moving northeast at 30 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Easton, Denton, Trappe, Preston, Tanyard, Harmony, Smithville,
  Agner, Matthews, Choptank, Hambleton, Griffin and Windyhill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to 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 3871 7613 3900 7574 3874 7571 3869 7580
      3871 7584 3868 7594 3863 7598 3860 7598
      3857 7604
TIME...MOT...LOC 0139Z 233DEG 24KT 3868 7599 

HAIL...0.75IN
WIND...60MPH
 
$$

Gorse
3 follow-up statements
256 
WWUS51 KPHI 220150
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
950 PM EDT Tue Jul 21 2020

MDC011-041-220230-
/O.CON.KPHI.SV.W.0149.000000T0000Z-200722T0230Z/
Talbot MD-Caroline MD-
950 PM EDT Tue Jul 21 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT
FOR SOUTHEASTERN TALBOT AND SOUTHERN CAROLINE COUNTIES...

At 950 PM EDT, a severe thunderstorm was located over Preston, or
near Hurlock, moving northeast at 30 mph.

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

SOURCE...Trained weather spotters.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Easton, Denton, Preston, Agner, Matthews, Choptank, Tanyard, Harmony,
Smithville, Griffin 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 3875 7607 3900 7574 3874 7571 3869 7580
      3871 7584 3868 7594 3863 7598
TIME...MOT...LOC 0150Z 236DEG 24KT 3871 7590 

HAIL...0.75IN
WIND...60MPH
 
$$

Gorse
556 
WWUS51 KPHI 220200
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1000 PM EDT Tue Jul 21 2020

MDC011-041-220230-
/O.CON.KPHI.SV.W.0149.000000T0000Z-200722T0230Z/
Talbot MD-Caroline MD-
1000 PM EDT Tue Jul 21 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT
FOR NORTHEASTERN TALBOT AND SOUTHERN CAROLINE COUNTIES...

At 959 PM EDT, a severe thunderstorm was located over Harmony, or 9
miles north of Hurlock, moving northeast at 25 mph.

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...Trained weather spotters.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Denton, Preston, Agner, Matthews, Harmony, Smithville and Griffin. 

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, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3880 7600 3900 7574 3874 7571 3869 7580
      3871 7584 3868 7594
TIME...MOT...LOC 0159Z 222DEG 22KT 3876 7588 

HAIL...0.75IN
WIND...70MPH
 
$$

Gorse
639 
WWUS51 KPHI 220222
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1022 PM EDT Tue Jul 21 2020

MDC011-041-220231-
/O.EXP.KPHI.SV.W.0149.000000T0000Z-200722T0230Z/
Talbot MD-Caroline MD-
1022 PM EDT Tue Jul 21 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN TALBOT AND
SOUTHERN CAROLINE COUNTIES WILL EXPIRE AT 1030 PM EDT...
                
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 will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

LAT...LON 3880 7600 3900 7574 3874 7571 3869 7580
      3871 7584 3868 7594
TIME...MOT...LOC 0221Z 233DEG 24KT 3884 7574 

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 9:16 PM EDTSpecial Weather StatementPHIKent29 min
Jul 21, 9:25 PM EDTSpecial Weather StatementPHITalbot35 min
Jul 21, 9:46 PM EDTSpecial Weather StatementPHIKent, Queen Anne's29 min
Jul 21, 10:14 PM EDTSpecial Weather StatementPHICaroline46 min
Jul 21, 10:21 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's54 min
Jul 22, 4:01 PM EDTSevere Thunderstorm WarningPHICecil22 min
Jul 22, 4:38 PM EDTSevere Thunderstorm WarningPHICecil52 min
Jul 22, 4:47 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot43 min
Jul 22, 5:13 PM EDTSevere Thunderstorm WarningPHICecil, Kent, Queen Anne's47 min
Jul 22, 5:23 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot52 min
Jul 22, 5:54 PM EDTSevere Thunderstorm WarningPHICaroline, Cecil, Kent, Queen Anne's51 min

Nearby

Severe 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.