Alert archive / Michigan / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 63, NWS Grand Rapids, MI

August 26, 2020Mason County, Oceana County, Michigan

NWS Grand Rapids, MI issued this severe thunderstorm warning at Aug 26, 2020, 4:09 AM EDT for Mason County, Oceana County, Michigan. It was in force for 66 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 26, 2020, 4:09 AM EDT (08:09 UTC)
Expired
Aug 26, 2020, 5:15 AM EDT
In force
66 min
Issued by
NWS Grand Rapids, MI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Mason County, MI, Oceana County, MI

The radar

The Grand Rapids radar (KGRR), 123 km from the middle of the area, began a volume at 08:10 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, 8.2 hours before the alert went out and 156 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 2020-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2020-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1794 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Grand Rapids, MI wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 26, 3:22 AM EDT, 47 minutes earlier.

Area forecast discussion, Aug 26, 3:22 AM EDT, 47 minutes before
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Hazardous weather outlook, Aug 25, 9:35 PM EDT, 6 hours 34 minutes before
Hazardous Weather Outlook
National Weather Service Grand Rapids MI
935 PM EDT Tue Aug 25 2020

MIZ037>040-043>046-050>052-056>059-064>067-071>074-262015-
Mason-Lake-Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon-
Montcalm-Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-
Ingham-Van Buren-Kalamazoo-Calhoun-Jackson-
935 PM EDT Tue Aug 25 2020

This hazardous weather outlook is for portions of southwest Lower
Michigan.

.DAY ONE...Tonight

Thunderstorms are expected to develop over Southwest Lower Michigan
overnight and continue through Wednesday morning. The main threats
from storms tonight will be locally heavy rainfall and lightning.
Some of the stronger storms may contain wind gusts to in excess of
40 mph.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Thunderstorms will likely continue into Wednesday morning. The main
threat will remain locally heavy rainfall.

Rounds of thunderstorms are then expected from Thursday through
Friday night. There is a risk for severe weather and heavy rainfall
with each round of storms. Localized flooding is possible,
especially late Thursday night through Friday night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

LMZ844>849-262015-
St Joseph to South Haven MI-South Haven to Holland MI-
Holland to Grand Haven MI-Grand Haven to Whitehall MI-
Whitehall to Pentwater MI-Pentwater to Manistee MI-
935 PM EDT Tue Aug 25 2020

This hazardous weather outlook is for portions of southwest Lower
Michigan.

.DAY ONE...This Afternoon and Tonight

Scattered thunderstorms will develop over Lake Michigan overnight
and continue into Wednesday morning.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Thunderstorms are likely into Wednesday morning with lightning being
the main threat to boaters. Rounds of thunderstorms are then
expected from Thursday through Friday night. There is a risk for
severe weather and heavy rainfall with each round of storms.

Conditions may become hazardous to both swimmers and boaters from
Wednesday evening through early Thursday afternoon.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

DUKE

The office that day

Everything else NWS Grand Rapids, MI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 26, 3:20 AM EDTBeach Hazards StatementGRRAllegan, Mason, Muskegon, Oceana, Ottawa, Van Buren34 hr
Aug 26, 3:20 AM EDTSpecial Marine WarningGRR85 min
Aug 26, 4:11 AM EDTSpecial Marine WarningGRR49 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2020Every severe thunderstorm warning 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.