Alert archive / New Hampshire / Mesoscale Discussions in 2021

Mesoscale Discussion 750

May 26, 20214 states

The Storm Prediction Center issued this mesoscale discussion at May 26, 2021, 3:21 PM EDT for 4 states. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: May 26, 2021, 3:21 PM EDT (19:21 UTC)
Expired: May 26, 2021, 4:15 PM EDT
In force: 54 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch likely
Chance of a watch: 80%

Counties 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, Providence County, RI

The radar

The Portland,ME radar (KGYX), 128 km from the middle of the area, began a volume at 19:22 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 208May 26, 3:55 PM EDT

The nearest sounding before it

Gray, ME (KGYX), launched 12:00Z, 7.4 hours before the alert went out and 128 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: 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.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 26, 12:59 PM EDT	Severe Thunderstorm Watch	SPC	Northwest Hills Planning Region	7 hr
May 26, 2:48 PM EDT	Severe Thunderstorm Watch	SPC	Greater Bridgeport Planning Region	7 hr
May 26, 3:56 PM EDT	Severe Thunderstorm Watch	SPC	Capitol Planning Region, Northeastern Connecticut Planning Region	5 hr
May 26, 4:41 PM EDT	Mesoscale Discussion	SPC		64 min
May 26, 6:07 PM EDT	Mesoscale Discussion	SPC		113 min

Nearby

Mesoscale Discussions in New Hampshire, 2021 Mesoscale Discussions in Massachusetts, 2021 Mesoscale Discussions in Maine, 2021 Every mesoscale discussion 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.