Alert archive / Vermont / Mesoscale Discussions in 2021

Mesoscale Discussion 1131

June 30, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jun 30, 2021, 1:52 PM EDT for 4 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Jun 30, 2021, 1:52 PM EDT (17:52 UTC)
Expired
Jun 30, 2021, 3:15 PM EDT
In force
83 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 326...327
All 22 counties

Androscoggin County, ME, Cumberland County, ME, Oxford County, ME, Belknap County, NH, Carroll County, NH, Coos County, NH, Grafton County, NH, Merrimack County, NH, Sullivan County, NH, Fulton County, NY, Montgomery County, NY, Saratoga County, NY, Schenectady County, NY, Warren County, NY, Washington County, NY, Bennington County, VT, Caledonia County, VT, Orange County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT

The radar

The Burlington radar (KCXX), 103 km from the middle of the area, began a volume at 17:55 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

Albany, NY (KALY), launched 12:00Z, 5.9 hours before the alert went out and 146 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, Albany, NY at 12:00Z on 2021-06-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 113 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, Albany, NY at 12:00Z on 2021-06-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 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
113 J/kg
Mixed-layer CIN
-257 J/kg
Mixed-layer LCL
1162 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

505 
ACUS11 KWNS 301752
SWOMCD
SPC MCD 301752 
MEZ000-NHZ000-VTZ000-NYZ000-301915-

Mesoscale Discussion 1131
NWS Storm Prediction Center Norman OK
1252 PM CDT Wed Jun 30 2021

Areas affected...Portions of eastern NY into VT...NH...and southern
ME

Concerning...Severe Thunderstorm Watch 326...327...

Valid 301752Z - 301915Z

The severe weather threat for Severe Thunderstorm Watch 326, 327
continues.

SUMMARY...The greatest short-term threat for damaging wind gusts and
severe hail should focus across parts of eastern New York into
Vermont, New Hampshire, and southern Maine.

DISCUSSION...As of 1750Z, multiple supercells and short line
segments have developed across parts of central/eastern NY into VT.
Surface temperatures have mostly warmed into the upper 80s and low
90s, with dewpoints holding in the mid 60s to low 70s. Around
1500-2000 J/kg of MLCAPE has already developed across this region.
Enhanced westerly low to mid-level flow (30-40 kt at 700 mb and
45-50 kt at 500 mb) will remain over the Northeast this afternoon,
and 40-50 kt of effective bulk shear will be favorable for organized
severe storms. Current expectations are for ongoing storms to
continue posing a threat for both scattered damaging winds and
isolated severe hail. There appears to be some potential for storms
to gradually congeal into one or more small bowing clusters, with a
potentially greater damaging wind threat into parts of VT/NH and
southern ME later this afternoon.

..Gleason.. 06/30/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GYX...BTV...ALY...BGM...

LAT...LON   43087498 43817333 44527269 44747148 44697013 43837011
            43337110 42787275 42817475 43087498

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 30, 11:04 AM EDTMesoscale DiscussionSPCAndroscoggin, Cumberland, Franklin, Hancock, Kennebec, Knox and 8 more116 min
Jun 30, 12:06 PM EDTSevere Thunderstorm WatchSPCAndroscoggin, Cumberland, Franklin, Hancock, Kennebec, Knox and 9 more7 hr
Jun 30, 4:16 PM EDTMesoscale DiscussionSPCAndroscoggin, Cumberland, Hancock, Kennebec, Knox, Lincoln and 4 more89 min
Jun 30, 11:47 AM EDTSevere Thunderstorm WatchSPCAlbany, Allegany, Broome, Cattaraugus, Cayuga, Chautauqua and 27 more7 hr
Jun 30, 2:16 PM EDTMesoscale DiscussionSPCAlbany, Columbia, Dutchess, Greene, Orange, Putnam and 2 more119 min
Jun 30, 3:21 PM EDTSevere Thunderstorm WatchSPCColumbia, Dutchess, Greene, Orange, Putnam, Rockland and 3 more7 hr
Jun 30, 4:48 PM EDTMesoscale DiscussionSPCAlbany, Columbia, Delaware, Greene, Schoharie, Sullivan and 1 more87 min
Jun 30, 6:58 PM EDTMesoscale DiscussionSPCBronx, Orange, Putnam, Rockland, Westchester92 min

Nearby

Mesoscale Discussions in Vermont, 2021Mesoscale Discussions in New Hampshire, 2021Mesoscale Discussions in New York, 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.