Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 41, NWS Gray, ME

July 7, 2021Hillsborough County, Rockingham County, New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Jul 7, 2021, 4:36 PM EDT for Hillsborough County, Rockingham County, New Hampshire. It was in force for 11 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: Jul 7, 2021, 4:36 PM EDT (20:36 UTC)
Expired: Jul 7, 2021, 4:47 PM EDT
In force: 11 min
Issued by: NWS Gray, ME
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Hillsborough County, NH, Rockingham County, NH

The radar

The Boston radar (KBOX), 89 km from the middle of the area, began a volume at 20:37 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 7, 4:38 PM EDT	HAIL 1.25	Pelham, NH	SHREDDED LEAVES AND COVERED PARTS OF LAWNS.
Jul 7, 4:40 PM EDT	HAIL 1	2 E Pelham, NH
Jul 7, 4:45 PM EDT	TSTM WND DMG	1 S Pelham, NH	DOWNED TREES HIGHWAY 38.

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, 8.6 hours before the alert went out and 150 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1184 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

009 
WUUS51 KGYX 072036
SVRGYX
NHC011-015-072100-
/O.NEW.KGYX.SV.W.0041.210707T2036Z-210707T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
436 PM EDT Wed Jul 7 2021

The National Weather Service in Gray Maine has issued a

* Severe Thunderstorm Warning for...
  Southwestern Rockingham County in southern New Hampshire...
  Southeastern Hillsborough County in southern New Hampshire...

* Until 500 PM EDT.

* At 435 PM EDT, a severe thunderstorm was located over Pelham, or
  near Salem, moving southeast at 40 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Salem, Pelham, Atkinson and Windham. 

This includes Interstate 93 between mile markers 1 and 5.
 
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 4272 7137 4284 7123 4281 7116 4279 7119
      4274 7118 4275 7122 4274 7125 4270 7129
      4270 7134
TIME...MOT...LOC 2035Z 302DEG 36KT 4274 7127 

HAIL...1.25IN
WIND...60MPH
 
$$

Ekster

1 follow-up statement

373 
WWUS51 KGYX 072047
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
447 PM EDT Wed Jul 7 2021

NHC011-015-072056-
/O.CAN.KGYX.SV.W.0041.000000T0000Z-210707T2100Z/
Rockingham NH-Hillsborough NH-
447 PM EDT Wed Jul 7 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN ROCKINGHAM AND
SOUTHEASTERN HILLSBOROUGH COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. Large hail likely fell in 
the Pelham New Hampshire area.

LAT...LON 4272 7137 4284 7123 4281 7116 4279 7119
      4274 7118 4275 7122 4274 7125 4270 7129
      4270 7134
TIME...MOT...LOC 2045Z 302DEG 36KT 4268 7114 

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 8:00 PM EDT	Special Weather Statement	GYX	Carroll	30 min
Jul 7, 4:21 PM EDT	Special Weather Statement	GYX	Rockingham	24 min
Jul 7, 6:08 PM EDT	Special Weather Statement	GYX	Hillsborough	37 min
Jul 7, 7:53 PM EDT	Special Weather Statement	GYX	Cheshire, Hillsborough	37 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.