Alert archive / New Hampshire / Mesoscale Discussions in 2021
Mesoscale Discussion 1283
The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2021, 3:11 PM EDT for Cumberland County, Oxford County, York County, Maine; 10 counties in New Hampshire; Bennington County, Essex County, Windham County, Vermont. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2021, 3:11 PM EDT (19:11 UTC)
- Expired
- Jul 14, 2021, 5:45 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties 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, Bennington County, VT, Essex County, VT, Windham County, VT
The radar
The Portland,ME radar (KGYX), 124 km from the middle of the area, began a volume at 19:11 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, 7.2 hours before the alert went out and 124 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 435 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 137 m²/s²
- 0-3 km storm-relative helicity
- 172 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
508
ACUS11 KWNS 141912
SWOMCD
SPC MCD 141911
MEZ000-MAZ000-NHZ000-VTZ000-NYZ000-142145-
Mesoscale Discussion 1283
NWS Storm Prediction Center Norman OK
0211 PM CDT Wed Jul 14 2021
Areas affected...parts of New England
Concerning...Severe potential...Watch unlikely
Valid 141911Z - 142145Z
Probability of Watch Issuance...20 percent
SUMMARY...An uptick in storm coverage is expected over the next 1-2
hours, with isolated damaging gusts or small hail possible. A watch
is not anticipated due to expected isolated/marginal nature of
severe.
DISCUSSION...A low-level theta-e/instability axis currently exists
across far eastern NY and into southern New England, with impinging
west/southwest 850 mb winds aiding warm advection across VT and NH.
Winds in the low to mid levels are not particularly strong, but
sufficient to support a few longer-lived cells. Heating/favorable
time of day may further bolster updrafts, and marginal hail will be
possible with the strongest cells. Ample PWAT over 1.50" may further
support strong outflow winds. Effective SRH is currently in the
50-100 m2/s2 range, which is a bit low to support any supercell
threat. While isolated/marginal severe will be possible, coverage is
not expected to necessitate a watch.
..Jewell/Bunting.. 07/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...BTV...ALY...
LAT...LON 42777366 43247275 43817225 44347196 45037181 45337134
45347101 45097058 44257034 43437028 42877047 42727117
42667223 42697336 42777366Nearby
Mesoscale Discussions in New Hampshire, 2021Mesoscale Discussions in Maine, 2021Mesoscale Discussions in Vermont, 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.