Alert archive / New Hampshire / Tornado Watches in 2023

Tornado Watch 497

July 16, 20236 states

The Storm Prediction Center issued this tornado watch at Jul 16, 2023, 8:21 AM EDT for 6 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jul 16, 2023, 8:21 AM EDT (12:21 UTC)
Expired: Jul 16, 2023, 3:00 PM EDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 50 kt

All 30 counties

Capitol Planning Region, CT, Greater Bridgeport Planning Region, CT, Lower Connecticut River Valley Planning Region, CT, Naugatuck Valley Planning Region, CT, Northeastern Connecticut Planning Region, CT, Northwest Hills Planning Region, CT, Southeastern Connecticut Planning Region, CT, Berkshire County, MA, Essex County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Worcester County, MA, Cumberland County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Nassau County, NY, Putnam County, NY, Suffolk County, NY, Westchester County, NY, Providence County, RI

The radar

The Boston radar (KBOX), 107 km from the middle of the area, began a volume at 12:21 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: 30%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 5%
Ten or more severe hail reports: 5%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 16, 8:22 AM EDT	Flash Flood Warning	ALY	Northwest Hills Planning Region	2 hr
Jul 16, 8:22 AM EDT	Flash Flood Warning Considerable damage threat	GYX	Hillsborough, Merrimack, Rockingham	3 hr
Jul 16, 8:22 AM EDT	Flash Flood Warning	OKX	Suffolk	2 hr
Jul 16, 8:29 AM EDT	Tornado Warning	GYX	Hillsborough, Merrimack, Rockingham	31 min
Jul 16, 8:43 AM EDT	Tornado Warning	BOX	Middlesex	22 min
Jul 16, 9:01 AM EDT	Tornado Warning	GYX	Hillsborough, Rockingham	16 min
Jul 16, 9:15 AM EDT	Severe Thunderstorm Warning	BOX	Capitol Planning Region	45 min
Jul 16, 9:23 AM EDT	Flash Flood Warning	BOX	Capitol Planning Region	3 hr
Jul 16, 9:30 AM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	45 min
Jul 16, 9:34 AM EDT	Severe Thunderstorm Warning	GYX	Rockingham	41 min
Jul 16, 9:43 AM EDT	Flash Flood Warning	OKX	Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region	3 hr
Jul 16, 9:51 AM EDT	Tornado Warning	GYX	Rockingham, Strafford	24 min
Jul 16, 10:10 AM EDT	Tornado Warning	BOX	Middlesex, Worcester	20 min
Jul 16, 10:16 AM EDT	Severe Thunderstorm Warning	BOX	Northeastern Connecticut Planning Region	44 min
Jul 16, 10:16 AM EDT	Tornado Warning	GYX	Hillsborough	29 min
Jul 16, 10:32 AM EDT	Flash Flood Warning	GYX	Belknap, Carroll, Coos, Grafton, Merrimack, Strafford	6 hr
Jul 16, 10:49 AM EDT	Flash Flood Warning	BOX	Northeastern Connecticut Planning Region	3 hr
Jul 16, 10:53 AM EDT	Flash Flood Warning	BOX	Middlesex, Worcester	3 hr
Jul 16, 11:24 AM EDT	Flash Flood Warning Considerable damage threat	GYX	Belknap, Cheshire, Hillsborough, Merrimack, Rockingham	7 hr
Jul 16, 11:33 AM EDT	Flash Flood Warning	GYX	Belknap, Carroll, Merrimack, Strafford	6 hr
Jul 16, 12:23 PM EDT	Flash Flood Warning	OKX	Greater Bridgeport Planning Region, Naugatuck Valley Planning Region	3 hr
Jul 16, 12:31 PM EDT	Flash Flood Warning	GYX	Cumberland, Oxford	5 hr
Jul 16, 12:56 PM EDT	Flash Flood Warning	OKX	Greater Bridgeport Planning Region	88 min
Jul 16, 1:01 PM EDT	Flash Flood Warning Considerable damage threat	GYX	Belknap, Carroll, Strafford	5 hr
Jul 16, 1:36 PM EDT	Flash Flood Warning	BOX	Northeastern Connecticut Planning Region	6 hr
Jul 16, 2:19 PM EDT	Flash Flood Warning	BOX	Bristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk and 1 more	5 hr
Jul 16, 2:22 PM EDT	Flash Flood Warning Considerable damage threat	GYX	Cumberland, Oxford, York	6 hr
Jul 16, 2:42 PM EDT	Flash Flood Warning Considerable damage threat	GYX	Cumberland, Oxford	3 hr

Discussions around it

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 0.4 hours before the alert went out and 134 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: 236 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 766 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 193 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 6.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Lasted
Jul 16, 7:07 AM EDT	Mesoscale Discussion	SPC	2 hr
Jul 16, 10:40 AM EDT	Mesoscale Discussion	SPC	95 min
Jul 16, 1:31 PM EDT	Mesoscale Discussion	SPC	89 min

Nearby

Tornado Watches in New Hampshire, 2023 Tornado Watches in Connecticut, 2023 Tornado Watches in Massachusetts, 2023 Every tornado watch in 2023

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.