Alert archive / New Hampshire / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 208

May 26, 20214 states

The Storm Prediction Center issued this severe thunderstorm watch at May 26, 2021, 3:56 PM EDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
May 26, 2021, 3:56 PM EDT (19:56 UTC)
Expired
May 26, 2021, 9:12 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 21 counties

Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT, Essex County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Worcester County, MA, Cumberland County, ME, Oxford County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Coos County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH

The radar

The Portland,ME radar (KGYX), 79 km from the middle of the area, began a volume at 19:59 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 26, 4:51 PM EDTSevere Thunderstorm WarningGYXCoos, Grafton54 min
May 26, 5:07 PM EDTSevere Thunderstorm WarningGYXGrafton, Merrimack, Sullivan53 min
May 26, 5:14 PM EDTSevere Thunderstorm WarningGYXCheshire, Hillsborough, Merrimack, Sullivan46 min
May 26, 5:47 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampshire, Worcester58 min
May 26, 5:52 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll, Grafton, Merrimack, Strafford53 min
May 26, 5:58 PM EDTSevere Thunderstorm WarningGYXBelknap, Cheshire, Hillsborough, Merrimack, Rockingham, Strafford and 1 more62 min
May 26, 6:13 PM EDTSevere Thunderstorm WarningBOXFranklin, Middlesex, Worcester62 min
May 26, 6:30 PM EDTSevere Thunderstorm WarningGYXCumberland, Oxford, York60 min
May 26, 6:39 PM EDTSevere Thunderstorm WarningBOXFranklin, Hampden, Hampshire, Worcester66 min
May 26, 6:59 PM EDTSevere Thunderstorm WarningGYXYork61 min
May 26, 7:05 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region55 min
May 26, 7:16 PM EDTSevere Thunderstorm WarningGYXCumberland, York22 min
May 26, 7:40 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region65 min
May 26, 7:45 PM EDTSevere Thunderstorm WarningBOXCapitol Planning Region, Northeastern Connecticut Planning Region60 min
May 26, 8:22 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region38 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 7.9 hours before the alert went out and 78 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, Gray, ME at 12:00Z on 2021-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Gray, ME at 12:00Z on 2021-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 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
9 J/kg
Mixed-layer CIN
-211 J/kg
Mixed-layer LCL
1555 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
140 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

664 
WWUS20 KWNS 261954
SEL8  
SPC WW 261954
CTZ000-MAZ000-MEZ000-NHZ000-270300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 208
NWS Storm Prediction Center Norman OK
355 PM EDT Wed May 26 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northern Connecticut
  Central Massachusetts
  Western Maine
  New Hampshire

* Effective this Wednesday afternoon and evening from 355 PM
  until 1100 PM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms over New York and Vermont will track
eastward across the watch area this afternoon and evening.  Hot and
humid conditions, coupled with strong winds aloft, will pose a risk
of locally damaging wind gusts in the strongest cells.

The severe thunderstorm watch area is approximately along and 45
statute miles east and west of a line from 25 miles northeast of
Berlin NH to 25 miles east southeast of Windsor Locks CT. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 205...WW 206...WW 207...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 450. Mean storm motion vector
26035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 26, 12:59 PM EDTSevere Thunderstorm WatchSPCNorthwest Hills Planning Region7 hr
May 26, 2:48 PM EDTSevere Thunderstorm WatchSPCGreater Bridgeport Planning Region7 hr
May 26, 3:21 PM EDTMesoscale DiscussionSPC54 min
May 26, 4:41 PM EDTMesoscale DiscussionSPC64 min
May 26, 6:07 PM EDTMesoscale DiscussionSPC113 min
May 26, 12:16 PM EDTMesoscale DiscussionSPCAddison, Bennington, Rutland, Washington, Windsor119 min

Nearby

Severe Thunderstorm Watches in New Hampshire, 2021Severe Thunderstorm Watches in Massachusetts, 2021Severe Thunderstorm Watches in Connecticut, 2021Every severe thunderstorm watch 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.