Alert archive / Maryland / Tornado Watches in 2020

Tornado Watch 515

November 30, 20205 states

The Storm Prediction Center issued this tornado watch at Nov 30, 2020, 1:07 PM EST for 5 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Nov 30, 2020, 1:07 PM EST (18:07 UTC)
Expired
Nov 30, 2020, 7:00 PM EST
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 44 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA, Accomack County, VA, King George County, VA, Lancaster County, VA, Northumberland County, VA, Richmond County, VA, Westmoreland County, VA

The radar

The Dover AFB radar (KDOX), 69 km from the middle of the area, began a volume at 18:09 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Nov 30, 1:28 PM ESTSevere Thunderstorm WarningLWXAnne Arundel, Calvert, Charles, Prince George's28 min
Nov 30, 1:38 PM ESTSevere Thunderstorm WarningAKQEssex, King and Queen, Richmond, Westmoreland22 min
Nov 30, 2:22 PM ESTSevere Thunderstorm WarningLWXCecil, Harford38 min
Nov 30, 2:36 PM ESTTornado WarningLWXCecil, Harford9 min
Nov 30, 2:41 PM ESTSevere Thunderstorm WarningPHINew Castle49 min
Nov 30, 2:50 PM ESTTornado WarningLWXCecil25 min
Nov 30, 3:01 PM ESTSevere Thunderstorm WarningPHINew Castle44 min
Nov 30, 3:04 PM ESTSevere Thunderstorm WarningPHIKent, New Castle56 min
Nov 30, 3:11 PM ESTTornado WarningPHICaroline, Queen Anne's17 min
Nov 30, 3:21 PM ESTTornado Warning Tornado observedPHIKent24 min
Nov 30, 3:43 PM ESTSevere Thunderstorm WarningPHIHunterdon, Warren47 min
Nov 30, 3:47 PM ESTTornado WarningPHIKent28 min
Nov 30, 3:53 PM ESTTornado WarningPHIHunterdon13 min
Nov 30, 4:49 PM ESTSevere Thunderstorm WarningPHICamden, Cumberland, Gloucester, Salem41 min
Nov 30, 5:29 PM ESTSevere Thunderstorm WarningPHIMercer, Middlesex, Somerset46 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 6.1 hours before the alert went out and 163 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 12:00Z on 2020-11-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2020-11-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 326 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
2 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
524 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
326 m²/s²
0-3 km storm-relative helicity
630 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

248 
WWUS20 KWNS 301802
SEL5  
SPC WW 301802
DEZ000-MDZ000-NJZ000-PAZ000-VAZ000-CWZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 515
NWS Storm Prediction Center Norman OK
105 PM EST Mon Nov 30 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Delaware
  Eastern Maryland
  Central and Southern New Jersey
  Southeast Pennsylvania
  Eastern Virginia
  Coastal Waters

* Effective this Monday afternoon and evening from 105 PM until
  700 PM EST.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are intensify along an axis from eastern
Virginia into southeast Pennsylvania.  This activity may become
severe, posing a risk of damaging wind gusts and a few tornadoes
through the afternoon.

The tornado watch area is approximately along and 50 statute miles
east and west of a line from 25 miles northeast of Trenton NJ to 45
miles south of Patuxent River MD. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 23040.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 30, 12:26 PM ESTMesoscale DiscussionSPCKent, New Castle, Sussex3 hr
Nov 30, 3:02 PM ESTMesoscale DiscussionSPCKent, New Castle, Sussex88 min
Nov 30, 4:37 PM ESTMesoscale DiscussionSPCKent, Sussex53 min

Nearby

Tornado Watches in Maryland, 2020Tornado Watches in New Jersey, 2020Tornado Watches in Virginia, 2020Every tornado watch 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.