Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 53, NWS Gray, ME

July 20, 2021Belknap County, Carroll County, Strafford County, New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Jul 20, 2021, 10:38 PM EDT for Belknap County, Carroll County, Strafford County, New Hampshire. It was in force for 41 min. 1 report 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 20, 2021, 10:38 PM EDT (02:38 UTC)
Expired: Jul 20, 2021, 11:19 PM EDT
In force: 41 min
Issued by: NWS Gray, ME
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Belknap County, NH, Carroll County, NH, Strafford County, NH

The radar

The Portland,ME radar (KGYX), 77 km from the middle of the area, began a volume at 02:38 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

Time	Report	Where	Remark
Jul 20, 11:05 PM EDT	TSTM WND DMG	1 Wnw Brookfield, NH	TREES AND POWER LINES DOWN.

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

The nearest sounding before it

Gray, ME (KGYX), launched 00:00Z, 2.6 hours before the alert went out and 77 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: 66 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 1282 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -1.1

Open this sounding in Storm Lab

The text

As transmitted.

794 
WUUS51 KGYX 210238
SVRGYX
NHC001-003-017-210330-
/O.NEW.KGYX.SV.W.0053.210721T0238Z-210721T0330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
1038 PM EDT Tue Jul 20 2021

The National Weather Service in Gray Maine has issued a

* Severe Thunderstorm Warning for...
  Northwestern Strafford County in central New Hampshire...
  East central Belknap County in central New Hampshire...
  Southern Carroll County in northern New Hampshire...

* Until 1130 PM EDT.

* At 1038 PM EDT, severe thunderstorms were located along a line
  extending from 10 miles southeast of Woodstock to near Sandwich to
  7 miles southeast of Moultonborough to near Wolfeboro to near
  Gilmanton, moving east at 35 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Ossipee, Moultonborough, Alton, Gilmanton, Effingham, Wolfeboro,
  Tamworth, Sandwich, Gilford, Madison, Acton, Freedom, Brookfield,
  Eaton, Wakefield, Tuftonboro, Middleton, New Durham, Parsonsfield
  and Porter.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4345 7138 4356 7130 4367 7129 4379 7132
      4389 7153 4393 7103 4390 7099 4357 7097
      4355 7095 4354 7096 4351 7096 4349 7097
      4345 7097
TIME...MOT...LOC 0238Z 260DEG 29KT 4388 7153 4379 7134 4367 7131 4357
7132 4347 7138

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

Ekster

1 follow-up statement

474 
WWUS51 KGYX 210319
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
1119 PM EDT Tue Jul 20 2021

NHC001-003-017-210328-
/O.CAN.KGYX.SV.W.0053.000000T0000Z-210721T0330Z/
Strafford NH-Belknap NH-Carroll NH-
1119 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN STRAFFORD...EAST
CENTRAL BELKNAP AND SOUTHERN CARROLL COUNTIES IS CANCELLED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled.  However heavy rain is
still possible with these thunderstorms.

LAT...LON 4345 7138 4356 7130 4367 7129 4379 7132
      4389 7153 4393 7103 4390 7099 4357 7097
      4355 7095 4354 7096 4351 7096 4349 7097
      4345 7097
TIME...MOT...LOC 0315Z 260DEG 29KT 4393 7112 4384 7093 4372 7090 4362
7091 4352 7097

$$

The office that day

Everything else NWS Gray, ME issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 8:55 PM EDT	Special Weather Statement	GYX	Grafton	50 min
Jul 20, 8:58 PM EDT	Severe Thunderstorm Warning	GYX	Grafton	47 min
Jul 20, 9:15 PM EDT	Special Weather Statement	GYX	Sullivan	30 min
Jul 20, 9:24 PM EDT	Severe Thunderstorm Warning	GYX	Grafton, Sullivan	29 min
Jul 20, 9:35 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Grafton, Merrimack, Sullivan	40 min
Jul 20, 9:47 PM EDT	Special Weather Statement	GYX	Sullivan	43 min
Jul 20, 10:10 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Grafton	50 min
Jul 20, 10:14 PM EDT	Severe Thunderstorm Warning	GYX	Cheshire, Hillsborough, Merrimack, Sullivan	46 min
Jul 20, 10:15 PM EDT	Special Weather Statement	GYX	Rockingham	45 min
Jul 20, 10:33 PM EDT	Special Weather Statement	GYX	Cheshire	42 min
Jul 20, 10:36 PM EDT	Severe Thunderstorm Warning	GYX	Cheshire, Hillsborough	39 min
Jul 20, 10:57 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Cheshire, Hillsborough, Merrimack	48 min
Jul 20, 11:10 PM EDT	Special Weather Statement	GYX	Rockingham	35 min
Jul 20, 11:28 PM EDT	Severe Thunderstorm Warning	GYX	Hillsborough, Merrimack, Rockingham	47 min
Jul 20, 11:32 PM EDT	Special Weather Statement	GYX	Strafford	43 min
Jul 20, 11:42 PM EDT	Special Weather Statement	GYX	Rockingham	48 min
Jul 20, 11:55 PM EDT	Severe Thunderstorm Warning	GYX	Rockingham	25 min
Jul 21, 12:06 AM EDT	Special Weather Statement	GYX	Rockingham	24 min
Jul 21, 12:13 AM EDT	Severe Thunderstorm Warning	GYX	Rockingham, Strafford	30 min

Nearby

Severe Thunderstorm Warnings in New Hampshire, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.