Alert archive / New Hampshire / Mesoscale Discussions in 2021
Mesoscale Discussion 753
The Storm Prediction Center issued this mesoscale discussion at May 26, 2021, 6:07 PM EDT for Cumberland County, Oxford County, York County, Maine; 4 counties in Massachusetts; 6 counties in New Hampshire. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- May 26, 2021, 6:07 PM EDT (22:07 UTC)
- Expired
- May 26, 2021, 8:00 PM EDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 208
Counties 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, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH
The radar
The Boston radar (KBOX), 114 km from the middle of the area, began a volume at 22:10 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 nearest sounding before it
Gray, ME (KGYX), launched 12:00Z, 10.1 hours before the alert went out and 155 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.
- 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
The text
As transmitted.
187
ACUS11 KWNS 262208
SWOMCD
SPC MCD 262207
MEZ000-MAZ000-NHZ000-RIZ000-CTZ000-270000-
Mesoscale Discussion 0753
NWS Storm Prediction Center Norman OK
0507 PM CDT Wed May 26 2021
Areas affected...Portions of New England
Concerning...Severe Thunderstorm Watch 208...
Valid 262207Z - 270000Z
The severe weather threat for Severe Thunderstorm Watch 208
continues.
SUMMARY...Damaging gust potential will continue in WW 208 for at
least another hour. As daytime heating ceases, the boundary layer
will cool and stabilize. Convective intensity may decrease as it
approaches the coast.
DISCUSSION...Though temperatures have started to cool slightly,
upper 80s to low 90s F observations are still present across parts
of southern New England into southwestern Maine. Low-level lapse
rates should continue to support damaging gusts with a
semi-organized line from central New Hampshire into central
Massachusetts for at least another hour. With the line back-building
farther southwest into more of Massachusetts, it is possible that
the southern flank of the line will end up impacting the Boston area
within the next 1.5-2 hours. The main uncertainty will be how
intense the line will be as temperatures slowly decrease with the
loss of daytime heating.
..Wendt.. 05/26/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...
LAT...LON 43107206 44707111 44947040 44037019 42807072 42487107
42077165 41747203 41807247 42047279 42157293 43107206SPC 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, 3:21 PM EDT | Mesoscale Discussion | SPC | 54 min | |
| 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 |
Nearby
Mesoscale Discussions in New Hampshire, 2021Mesoscale Discussions in Massachusetts, 2021Mesoscale Discussions in Maine, 2021Every 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.