Alert archive / Iowa / Heat Advisories in 2020

Heat Advisory 4, NWS La Crosse, WI

July 26, 2020Crawford County, Grant County, Richland County, Wisconsin; 4 counties in Iowa

NWS La Crosse, WI issued this heat advisory at Jul 26, 2020, 2:53 AM CDT for Crawford County, Grant County, Richland County, Wisconsin; 4 counties in Iowa. It took effect at Jul 26, 2020, 12:00 PM CDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Jul 26, 2020, 2:53 AM CDT (07:53 UTC)
In effect from
Jul 26, 2020, 12:00 PM CDT
Expired
Jul 26, 2020, 7:00 PM CDT
In force
7 hr
Issued by
NWS La Crosse, WI

Counties Allamakee County, IA, Clayton County, IA, Fayette County, IA, Winneshiek County, IA, Crawford County, WI, Grant County, WI, Richland County, WI

The radar

The La Crosse radar (KARX), 79 km from the middle of the area, began a volume at 07:54 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

Minneapolis, MN (KMPX), launched 00:00Z, 7.9 hours before the alert went out and 272 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, Minneapolis, MN at 00:00Z on 2020-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1584 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, Minneapolis, MN at 00:00Z on 2020-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 229 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
1584 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
935 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
229 m²/s²
0-3 km storm-relative helicity
363 m²/s²
Significant tornado parameter
1.5
Supercell composite
12.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this heat advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS La Crosse, WI wrote its last area forecast discussion before this heat advisory went out at Jul 25, 11:14 PM CDT, 3 hours 39 minutes earlier.

Area forecast discussion, Jul 25, 11:14 PM CDT, 3 hours 39 minutes before
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Hazardous weather outlook, Jul 25, 3:57 AM CDT, 22 hours 56 minutes before
Hazardous Weather Outlook
National Weather Service La Crosse WI
357 AM CDT Sat Jul 25 2020

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-261200-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
357 AM CDT Sat Jul 25 2020

This Hazardous Weather Outlook is for portions of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...Today and Tonight

Very warm temperatures and increasing humidity will push heat
index values to around 100 to 105 degrees this afternoon. A Heat
Advisory is in effect for most of the area this afternoon into
early evening. Warm and muggy conditions will persist into
tonight, offering limited relief from the heat.

Thunderstorm chances will increase this afternoon into tonight
across the entire area. Isolated strong storms with damaging winds
as the main threat will be possible this afternoon into early
evening, mainly from southeast Minnesota to north-central
Wisconsin. In addition, any storms today into tonight will be
capable of producing torrential rainfall that could lead to
localized flooding, especially if storms repeat over the same
areas.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Thunderstorms will diminish Sunday morning, followed by scattered
to numerous storms redeveloping in the afternoon, continuing
through Sunday night. Isolated strong storms with damaging winds
as the main threat will be possible anywhere within the forecast
area. Any storms will be capable of producing very heavy rainfall.

Very warm and oppressively humid conditions on Sunday will again
yield afternoon heat index readings around 100 degrees for some
areas.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening from
southeast Minnesota to north-central Wisconsin. Activation may
be needed again Sunday afternoon and evening in some areas.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Kurz

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 25, 9:34 PM CDTFlash Flood WatchARXBuffalo, Jackson, Trempealeau12 hr
Jul 26, 3:18 PM CDTSpecial Weather StatementARXRichland42 min
Jul 26, 3:39 PM CDTSpecial Weather StatementARXRichland36 min
Jul 26, 5:11 PM CDTSpecial Weather StatementARXGrant34 min
Jul 26, 4:56 PM CDTSpecial Weather StatementARXDubuque19 min

Nearby

Heat Advisories in Iowa, 2020Heat Advisories in Wisconsin, 2020Every heat advisory in 2020

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.