Alert archive / Wisconsin / Mesoscale Discussions in 2023

Mesoscale Discussion 1721

July 26, 20239 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2023, 5:03 AM CDT for 9 counties in Wisconsin. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
Jul 26, 2023, 5:03 AM CDT (10:03 UTC)
Expired
Jul 26, 2023, 6:30 AM CDT
In force
87 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Adams County, WI, Columbia County, WI, Green Lake County, WI, Juneau County, WI, Marquette County, WI, Portage County, WI, Sauk County, WI, Waupaca County, WI, Waushara County, WI

The radar

The La Crosse radar (KARX), 124 km from the middle of the area, began a volume at 10:03 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, 10.1 hours before the alert went out and 139 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 2023-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1348 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, Green Bay/Straub, WI at 00:00Z on 2023-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
1348 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1459 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.2

Open this sounding in Storm Lab

The text

As transmitted.

839 
ACUS11 KWNS 261003
SWOMCD
SPC MCD 261003 
WIZ000-261130-

Mesoscale Discussion 1721
NWS Storm Prediction Center Norman OK
0503 AM CDT Wed Jul 26 2023

Areas affected...Central and Eastern WI

Concerning...Severe potential...Watch unlikely 

Valid 261003Z - 261130Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated gusts may continue, but limited coverage of
severe-caliber gust will preclude the need for a downstream watch.

DISCUSSION...Convective complex continues to push across southwest
WI. This complex continues to show a well-developed rear-inflow jet,
with recent velocity data sampling 40 to 50 kt at 3 kft across a
large part of Juneau County. However, low-level stability continues
to prevent the strongest rear-inflow from reaching the surface, with
consistent gusts near 40 kt throughout its duration thus far. LSE
and VOK measured 39 and 37 kt, respectively, as the line moved
through. The overall low-level thermodynamic environment downstream
shows similar, or even stronger, stability. As such, the trend of
sub-severe gusts is expected to persist, precluding the need for a
downstream watch.

..Mosier/Edwards.. 07/26/2023

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

ATTN...WFO...GRB...MKX...ARX...

LAT...LON   44329017 44588991 44488894 43658845 43218902 43138988
            43529017 43969014 44329017

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 26, 1:10 AM CDTMesoscale DiscussionSPCBuffalo, Dunn, Pepin, Pierce, Saint Croix, Trempealeau95 min
Jul 26, 1:31 AM CDTSevere Thunderstorm WatchSPCBuffalo, Crawford, Grant, Jackson, Juneau, La Crosse and 4 more4 hr
Jul 26, 4:03 AM CDTMesoscale DiscussionSPCCrawford, Grant, Jackson, Juneau, La Crosse, Monroe and 3 more87 min
Jul 26, 7:30 AM CDTMesoscale DiscussionSPCGreen, Rock, Walworth90 min
Jul 26, 8:45 AM CDTMesoscale DiscussionSPCKenosha, Racine2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2023Every mesoscale discussion in 2023

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.