Alert archive / Michigan / Mesoscale Discussions in 2021

Mesoscale Discussion 741

May 25, 2021Delta County, Menominee County, Michigan; Marinette County, Oconto County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 25, 2021, 8:56 PM EDT for Delta County, Menominee County, Michigan; Marinette County, Oconto County, Wisconsin. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
May 25, 2021, 8:56 PM EDT (00:56 UTC)
Expired
May 25, 2021, 10:30 PM EDT
In force
94 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 203

Counties Delta County, MI, Menominee County, MI, Marinette County, WI, Oconto County, WI

The radar

The Green Bay radar (KGRB), 88 km from the middle of the area, began a volume at 00:55 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 0.9 hours before the alert went out and 90 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, Green Bay/Straub, WI at 00:00Z on 2021-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1008 joules per kilogram.LCLEL10008507005003002001001 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, Green Bay/Straub, WI at 00:00Z on 2021-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.1939587897Sfc1 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
1008 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.4
Supercell composite
4.4

Open this sounding in Storm Lab

The text

As transmitted.

098 
ACUS11 KWNS 260057
SWOMCD
SPC MCD 260056 
MIZ000-WIZ000-260230-

Mesoscale Discussion 0741
NWS Storm Prediction Center Norman OK
0756 PM CDT Tue May 25 2021

Areas affected...Upper Fox River Valley vicinity into southern Upper
Peninsula of Michigan

Concerning...Severe Thunderstorm Watch 203...

Valid 260056Z - 260230Z

The severe weather threat for Severe Thunderstorm Watch 203
continues.

SUMMARY...Strong to locally severe gusts possible in the near-term,
particularly for southern portions of the Upper Peninsula.

DISCUSSION...The 00Z GRB sounding showed mid-level lapse rates of
around 7 C/km with 42 kts of effective shear. The portion of the
line moving into the Upper Peninsula is moving at around 40-45 kts.
This would suggest that even marginal enhancement of the winds by
the convection would result in strong to perhaps locally severe
gusts. Within the past 20-30 minutes, KIMT ASOS measured 44 kts.
These gusts will remain possible until the line encounters greater
MLCIN with the marine layer.

..Wendt.. 05/26/2021

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

ATTN...WFO...MQT...GRB...

LAT...LON   45478818 46028775 46148683 45808687 44988765 44738788
            44478820 44638859 45058868 45478818

Nearby

Mesoscale Discussions in Michigan, 2021Mesoscale Discussions in Wisconsin, 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.