Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 33, NWS Gray, ME

June 30, 20215 counties in New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Jun 30, 2021, 4:01 PM EDT for 5 counties in New Hampshire. It was in force for 27 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: Jun 30, 2021, 4:01 PM EDT (20:01 UTC)
Expired: Jun 30, 2021, 4:28 PM EDT
In force: 27 min
Issued by: NWS Gray, ME
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Belknap County, NH, Carroll County, NH, Grafton County, NH, Merrimack County, NH, Strafford County, NH

The radar

The Portland,ME radar (KGYX), 85 km from the middle of the area, began a volume at 20:05 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.

Issued	Product	Office	Lasted
Jun 30, 12:06 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 8.0 hours before the alert went out and 84 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: 906 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 1312 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

360 
WUUS51 KGYX 302001
SVRGYX
NHC001-003-009-013-017-302045-
/O.NEW.KGYX.SV.W.0033.210630T2001Z-210630T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
401 PM EDT Wed Jun 30 2021

The National Weather Service in Gray Maine has issued a

* Severe Thunderstorm Warning for...
  Northwestern Strafford County in central New Hampshire...
  Southeastern Grafton County in northern New Hampshire...
  Belknap County in central New Hampshire...
  North central Merrimack County in central New Hampshire...
  Southern Carroll County in northern New Hampshire...

* Until 445 PM EDT.

* At 400 PM EDT, a severe thunderstorm was located near Laconia,
  moving east at 50 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Laconia, Franklin, Moultonborough, Meredith, Ossipee, Plymouth,
  Farmington, Alton, Gilmanton, Holderness, Ashland, Effingham,
  Wolfeboro, Belmont, Gilford, Bristol, Acton, Andover, Alexandria
  and Freedom.

This includes Interstate 93 between mile markers 57 and 77.
 
This also includes...
  Lake Winnipesaukee.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Lake Winnipesaukee or any other lake in the warning, 
get away from the water and move indoors or inside a vehicle. 
Remember, lightning can strike out to 15 miles from the parent 
thunderstorm. If you can hear thunder, you are close enough to be 
struck by lightning. Move to safe shelter now!  Do not be caught on 
the water in a thunderstorm.

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

&&

LAT...LON 4371 7181 4381 7099 4357 7097 4355 7095
      4354 7096 4349 7097 4344 7096 4342 7099
      4340 7099 4346 7182
TIME...MOT...LOC 2000Z 270DEG 44KT 4358 7154 

HAIL...0.88IN
WIND...60MPH
 
$$

1 follow-up statement

466 
WWUS51 KGYX 302028
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
428 PM EDT Wed Jun 30 2021

NHC001-003-009-013-017-302038-
/O.CAN.KGYX.SV.W.0033.000000T0000Z-210630T2045Z/
Strafford NH-Grafton NH-Belknap NH-Merrimack NH-Carroll NH-
428 PM EDT Wed Jun 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN STRAFFORD...
SOUTHEASTERN GRAFTON...BELKNAP...NORTH CENTRAL MERRIMACK AND SOUTHERN
CARROLL COUNTIES IS CANCELLED...
                
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 has been cancelled.  However heavy rain is
still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 700 PM EDT for
western and southwestern Maine...and central and northern New
Hampshire.

LAT...LON 4371 7181 4381 7099 4357 7097 4355 7095
      4354 7096 4349 7097 4344 7096 4342 7099
      4340 7099 4346 7182
TIME...MOT...LOC 2025Z 270DEG 44KT 4358 7107 

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 2:39 PM EDT	Special Weather Statement	GYX	Grafton	36 min
Jun 30, 3:02 PM EDT	Severe Thunderstorm Warning	GYX	Grafton, Sullivan	43 min
Jun 30, 3:10 PM EDT	Severe Thunderstorm Warning	GYX	Carroll, Coos, Grafton	17 min
Jun 30, 3:42 PM EDT	Special Weather Statement	GYX	Belknap	48 min
Jun 30, 3:43 PM EDT	Special Weather Statement	GYX	Cheshire	47 min
Jun 30, 4:05 PM EDT	Severe Thunderstorm Warning	GYX	Cheshire, Sullivan	35 min
Jun 30, 4:11 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Merrimack, Strafford	49 min
Jun 30, 4:25 PM EDT	Severe Thunderstorm Warning	GYX	Cheshire, Hillsborough	50 min
Jun 30, 4:44 PM EDT	Special Weather Statement	GYX	Merrimack	46 min
Jun 30, 4:53 PM EDT	Special Weather Statement	GYX	Rockingham	37 min
Jun 30, 4:58 PM EDT	Severe Thunderstorm Warning	GYX	Rockingham	32 min
Jun 30, 5:12 PM EDT	Severe Thunderstorm Warning	GYX	Hillsborough, Rockingham	33 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.