Alert archive / New Hampshire / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 52, NWS Gray, ME

July 20, 2021Cheshire County, Hillsborough County, New Hampshire

NWS Gray, ME issued this severe thunderstorm warning at Jul 20, 2021, 10:36 PM EDT for Cheshire County, Hillsborough County, New Hampshire. It was in force for 39 min. 2 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 20, 2021, 10:36 PM EDT (02:36 UTC)
Expired
Jul 20, 2021, 11:15 PM EDT
In force
39 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

The radar

The Albany radar (KENX), 138 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

TimeReportWhereRemark
Jul 20, 10:50 PM EDTHAIL 1.252 E Hinsdale, NH
Jul 20, 11:05 PM EDTTSTM WND DMG1 Se Peterborough, NHCORRECTS PREVIOUS TSTM WND DMG REPORT FROM 1 SE PETERBOROUGH. SEVERAL TREES DOWN AROUND INTERSECTION OF 202 AND 101.

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

The nearest sounding before it

Albany, NY (KALY), launched 00:00Z, 2.6 hours before the alert went out and 117 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-pSkew-T log-p diagram, Albany, NY at 00:00Z on 2021-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1226 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 00:00Z on 2021-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 89 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1226 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1198 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
89 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.4
Supercell composite
4.6

Open this sounding in Storm Lab

The text

As transmitted.

210 
WUUS51 KGYX 210236
SVRGYX
NHC005-011-210315-
/O.NEW.KGYX.SV.W.0052.210721T0236Z-210721T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Gray ME
1036 PM EDT Tue Jul 20 2021

The National Weather Service in Gray Maine has issued a

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

* Until 1115 PM EDT.

* At 1036 PM EDT, severe thunderstorms were located along a line
  extending from near Roxbury to Chesterfield to near Hinsdale,
  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...
  Keene, Jaffrey, Swanzey, Peterborough, Winchester, Greenfield,
  Dublin, Richmond, Harrisville, Nelson, Marlborough, Rindge,
  Hancock, Sharon, Westmoreland, Hinsdale, Roxbury, Fitzwilliam, Troy
  and Chesterfield.

This also includes...
  Mount Monadnock.
 
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 4288 7255 4290 7253 4296 7252 4297 7248
      4299 7247 4298 7188 4271 7195 4273 7246
      4277 7249 4277 7252 4278 7251 4281 7254
TIME...MOT...LOC 0236Z 255DEG 29KT 4297 7223 4290 7247 4274 7259 

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

Ekster
2 follow-up statements
325 
WWUS51 KGYX 210300
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
1100 PM EDT Tue Jul 20 2021

NHC005-011-210315-
/O.CON.KGYX.SV.W.0052.000000T0000Z-210721T0315Z/
Cheshire NH-Hillsborough NH-
1100 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT
FOR SOUTHEASTERN CHESHIRE AND WEST CENTRAL HILLSBOROUGH COUNTIES...

At 1100 PM EDT, severe thunderstorms were located along a line
extending from near Hancock to near Marlborough to near Richmond,
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...
Keene, Jaffrey, Swanzey, Peterborough, Rindge, Winchester, Dublin,
Richmond, Harrisville, Nelson, Marlborough, Fitzwilliam, Hancock,
Troy and Roxbury.

This also includes...
  Mount Monadnock.
 
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 4298 7193 4272 7213 4272 7216 4273 7240
      4295 7220 4298 7210
TIME...MOT...LOC 0300Z 258DEG 31KT 4301 7201 4287 7213 4274 7234 

HAIL...1.00IN
WIND...60MPH
 
$$
674 
WWUS51 KGYX 210309
SVSGYX

Severe Weather Statement
National Weather Service Gray ME
1109 PM EDT Tue Jul 20 2021

NHC005-011-210319-
/O.EXP.KGYX.SV.W.0052.000000T0000Z-210721T0315Z/
Cheshire NH-Hillsborough NH-
1109 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CHESHIRE AND WEST
CENTRAL HILLSBOROUGH COUNTIES WILL EXPIRE AT 1115 PM EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with these thunderstorms.

LAT...LON 4298 7193 4272 7213 4272 7216 4273 7240
      4295 7220 4298 7210
TIME...MOT...LOC 0309Z 255DEG 29KT 4302 7193 4288 7205 4275 7226 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 8:55 PM EDTSpecial Weather StatementGYXGrafton50 min
Jul 20, 8:58 PM EDTSevere Thunderstorm WarningGYXGrafton47 min
Jul 20, 9:15 PM EDTSpecial Weather StatementGYXSullivan30 min
Jul 20, 9:24 PM EDTSevere Thunderstorm WarningGYXGrafton, Sullivan29 min
Jul 20, 9:35 PM EDTSevere Thunderstorm WarningGYXBelknap, Grafton, Merrimack, Sullivan40 min
Jul 20, 9:47 PM EDTSpecial Weather StatementGYXSullivan43 min
Jul 20, 10:10 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll, Grafton50 min
Jul 20, 10:14 PM EDTSevere Thunderstorm WarningGYXCheshire, Hillsborough, Merrimack, Sullivan46 min
Jul 20, 10:15 PM EDTSpecial Weather StatementGYXRockingham45 min
Jul 20, 10:33 PM EDTSpecial Weather StatementGYXCheshire42 min
Jul 20, 10:38 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll, Strafford41 min
Jul 20, 10:57 PM EDTSevere Thunderstorm WarningGYXBelknap, Cheshire, Hillsborough, Merrimack48 min
Jul 20, 11:10 PM EDTSpecial Weather StatementGYXRockingham35 min
Jul 20, 11:28 PM EDTSevere Thunderstorm WarningGYXHillsborough, Merrimack, Rockingham47 min
Jul 20, 11:32 PM EDTSpecial Weather StatementGYXStrafford43 min
Jul 20, 11:42 PM EDTSpecial Weather StatementGYXRockingham48 min
Jul 20, 11:55 PM EDTSevere Thunderstorm WarningGYXRockingham25 min
Jul 21, 12:06 AM EDTSpecial Weather StatementGYXRockingham24 min
Jul 21, 12:13 AM EDTSevere Thunderstorm WarningGYXRockingham, Strafford30 min

Nearby

Severe Thunderstorm Warnings in New Hampshire, 2021Every 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.