Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 29, NWS Gray, ME

June 29, 2021Belknap County, Grafton County, Merrimack County, New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Jun 29, 2021, 6:12 PM EDT for Belknap County, Grafton County, Merrimack County, New Hampshire. It was in force for 33 min. 3 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: Jun 29, 2021, 6:12 PM EDT (22:12 UTC)
Expired: Jun 29, 2021, 6:45 PM EDT
In force: 33 min
Issued by: NWS Gray, ME
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Belknap County, NH, Grafton County, NH, Merrimack County, NH

The radar

The Burlington radar (KCXX), 122 km from the middle of the area, began a volume at 22:12 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
Jun 29, 6:15 PM EDT	TSTM WND DMG	4 Nw Canaan, NH	MULTIPLE TREES DOWN ON TALBERT HILL ROAD. TIME ESTIMATED BASED ON RADAR.
Jun 29, 6:19 PM EDT	HAIL 1.25	4 Ne Enfield, NH	HAIL FELL FOR ABOUT 5 MINUTES ON EAST SIDE OF GOOSE POND WITH THE LARGEST STONES UP TO 1.25 INCHES. TIME ESTIMATED BASED ON RADAR.
Jun 29, 6:30 PM EDT	HAIL 1	2 Nnw Orange, NH	NORTH OF CANAAN NEAR MASCOMA STATE PARK. TIME ESTIMATED BASED ON RADAR.

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 12:00Z, 10.2 hours before the alert went out and 148 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: 342 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 1242 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

743 
WUUS51 KGYX 292212
SVRGYX
NHC001-009-013-292300-
/O.NEW.KGYX.SV.W.0029.210629T2212Z-210629T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
612 PM EDT Tue Jun 29 2021

The National Weather Service in Gray Maine has issued a

* Severe Thunderstorm Warning for...
  Southwestern Grafton County in northern New Hampshire...
  Northwestern Belknap County in central New Hampshire...
  North central Merrimack County in central New Hampshire...

* Until 700 PM EDT.

* At 611 PM EDT, a severe thunderstorm was located near Enfield, or 8
  miles northeast of Lebanon, moving southeast at 30 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...
  Lebanon, Plymouth, Grafton, Hanover, Enfield, Canaan, Holderness,
  Ashland, Danbury, Groton, Bristol, Lyme, Hill, Hebron, Dorchester,
  Orange, Rumney and Campton.

This includes Interstate 93 between mile markers 77 and 81.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4375 7223 4377 7220 4377 7221 4383 7215
      4378 7162 4348 7178 4370 7228
TIME...MOT...LOC 2211Z 293DEG 26KT 4372 7212 

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

Tubbs

2 follow-up statements

138 
WWUS51 KGYX 292231
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
631 PM EDT Tue Jun 29 2021

NHC001-009-013-292300-
/O.CON.KGYX.SV.W.0029.000000T0000Z-210629T2300Z/
Grafton NH-Belknap NH-Merrimack NH-
631 PM EDT Tue Jun 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR SOUTH CENTRAL GRAFTON...NORTHWESTERN BELKNAP AND NORTH CENTRAL
MERRIMACK COUNTIES...

At 631 PM EDT, a severe thunderstorm was located over Canaan, or 14
miles east of Lebanon, moving east at 30 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...
Plymouth, Grafton, Enfield, Canaan, Holderness, Ashland, Danbury,
Groton, Bristol, Lyme, Hill, Hebron, Dorchester and Orange.

This includes Interstate 93 between mile markers 78 and 79.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4365 7214 4380 7205 4375 7165 4348 7178
TIME...MOT...LOC 2231Z 291DEG 26KT 4368 7198 

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

Tubbs

330 
WWUS51 KGYX 292245
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
645 PM EDT Tue Jun 29 2021

NHC001-009-013-292254-
/O.CAN.KGYX.SV.W.0029.000000T0000Z-210629T2300Z/
Grafton NH-Belknap NH-Merrimack NH-
645 PM EDT Tue Jun 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL GRAFTON...
NORTHWESTERN BELKNAP AND NORTH CENTRAL MERRIMACK 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 gusty winds and
heavy rain are still possible with this thunderstorm.

LAT...LON 4365 7214 4380 7205 4375 7165 4348 7178
TIME...MOT...LOC 2242Z 293DEG 26KT 4364 7185 

$$

Tubbs

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 28, 8:11 PM EDT	Special Weather Statement	GYX	Belknap	34 min
Jun 29, 2:30 PM EDT	Heat Advisory	GYX	Belknap, Carroll, Cheshire, Hillsborough, Merrimack, Rockingham and 1 more	28 hr
Jun 29, 5:41 PM EDT	Special Weather Statement	GYX	Grafton	34 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.