Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 96, NWS Gray, ME

September 15, 2021Cheshire County, Hillsborough County, Merrimack County, New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Sep 15, 2021, 5:09 PM EDT for Cheshire County, Hillsborough County, Merrimack County, New Hampshire. It was in force for 51 min. 4 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: Sep 15, 2021, 5:09 PM EDT (21:09 UTC)
Expired: Sep 15, 2021, 6:00 PM EDT
In force: 51 min
Issued by: NWS Gray, ME
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Cheshire County, NH, Hillsborough County, NH, Merrimack County, NH

The radar

The Boston radar (KBOX), 124 km from the middle of the area, began a volume at 21:11 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
Sep 15, 5:09 PM EDT	HAIL 1	2 W Dublin, NH	TIME ESTIMATED BASED ON RADAR.
Sep 15, 5:12 PM EDT	TSTM WND DMG	1 W Dublin, NH	TREES DOWN ON MCVEAGH RD. DIAMETER OF TREES UP TO 7 INCHES. TIME ESTIMATED BASED ON RADAR.
Sep 15, 5:22 PM EDT	TSTM WND DMG	2 S Peterborough, NH	TREES DOWN SOUTH OF PETERBOROUGH ALONG US HWY 202. SMALL HAIL ALSO FELL. TIME ESTIMATED BY RADAR.
Sep 15, 5:40 PM EDT	TSTM WND DMG	2 Wnw Sharon, NH	TREES DOWN IN THE TOWN OF SHARON. ONE TREE BLOCKING NH HWY 123. TIME ESTIMATED BY RADAR.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 15, 1:15 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 9.2 hours before the alert went out and 157 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: 856 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 766 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 214 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 6.3

Open this sounding in Storm Lab

The text

As transmitted.

801 
WUUS51 KGYX 152109
SVRGYX
NHC005-011-013-152200-
/O.NEW.KGYX.SV.W.0096.210915T2109Z-210915T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
509 PM EDT Wed Sep 15 2021

The National Weather Service in Gray Maine has issued a

* Severe Thunderstorm Warning for...
  Eastern Cheshire County in southern New Hampshire...
  Hillsborough County in southern New Hampshire...
  Southeastern Merrimack County in central New Hampshire...

* Until 600 PM EDT.

* At 509 PM EDT, severe thunderstorms were located along a line
  extending from Hillsborough to Dublin to 6 miles southwest of
  Richmond, moving east at 25 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...
  Manchester, Concord, Jaffrey, Henniker, Merrimack, Bedford,
  Milford, Hooksett, Amherst, Litchfield, Hollis, Peterborough,
  Hopkinton, New Boston, Epsom, Winchester, Antrim, Mont Vernon,
  Greenfield and Lyndeborough.

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 4273 7240 4289 7213 4313 7206 4325 7138
      4288 7147 4270 7167
TIME...MOT...LOC 2109Z 270DEG 23KT 4316 7196 4289 7204 4270 7235 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MEC

1 follow-up statement

599 
WWUS51 KGYX 152159 RRA
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
559 PM EDT Wed Sep 15 2021

NHC005-011-013-152209-
/O.EXP.KGYX.SV.W.0096.000000T0000Z-210915T2200Z/
Cheshire NH-Hillsborough NH-Merrimack NH-
559 PM EDT Wed Sep 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN CHESHIRE...
HILLSBOROUGH AND SOUTHEASTERN MERRIMACK COUNTIES WILL EXPIRE AT 600
PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
southern and central New Hampshire.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Gray Maine.

LAT...LON 4273 7240 4289 7213 4313 7206 4325 7138
      4288 7147 4270 7167
TIME...MOT...LOC 2159Z 270DEG 23KT 4316 7156 4289 7164 4270 7195 

$$

Legro

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 15, 7:50 AM EDT	Special Weather Statement	GYX	Coos	55 min
Sep 15, 2:18 PM EDT	Severe Thunderstorm Warning	GYX	Coos, Grafton	57 min
Sep 15, 2:31 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Coos, Grafton, Merrimack, Sullivan	59 min
Sep 15, 2:33 PM EDT	Severe Thunderstorm Warning	GYX	Coos	42 min
Sep 15, 3:04 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Grafton, Merrimack, Sullivan	56 min
Sep 15, 3:22 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Coos, Grafton, Merrimack, Sullivan	53 min
Sep 15, 4:07 PM EDT	Severe Thunderstorm Warning	GYX	Cheshire, Hillsborough, Merrimack, Sullivan	38 min
Sep 15, 4:09 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Coos, Grafton, Merrimack	51 min
Sep 15, 4:44 PM EDT	Severe Thunderstorm Warning	GYX	Belknap, Carroll, Merrimack, Strafford	46 min
Sep 15, 5:29 PM EDT	Severe Thunderstorm Warning	GYX	Carroll, Strafford	61 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.