Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 56, NWS Grand Rapids, MI

August 24, 2021Mason County, Oceana County, Michigan

NWS Grand Rapids, MI issued this severe thunderstorm warning at Aug 24, 2021, 3:48 PM EDT for Mason County, Oceana County, Michigan. It was in force for 42 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 24, 2021, 3:48 PM EDT (19:48 UTC)
Expired
Aug 24, 2021, 4:30 PM EDT
In force
42 min
Issued by
NWS Grand Rapids, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Mason County, MI, Oceana County, MI

The radar

The Grand Rapids radar (KGRR), 118 km from the middle of the area, began a volume at 19:47 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.

What was reported inside it

TimeReportWhereRemark
Aug 24, 4:00 PM EDTTSTM WND DMG3 Se Ludington, MISEVERAL DOWNED TREES ON US-31 SHOULDER NEAR PERE MARQUETTE EXIT. TIME ESTIMATED BY RADAR.
Aug 24, 4:20 PM EDTTSTM WND GST 413 Ne Shelby, MIOCEANA COUNTY AIRPORT AWOS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 7.8 hours before the alert went out and 158 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 12:00Z on 2021-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 58 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2021-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -33 square meters per square second.1939Sfc1 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
58 J/kg
Mixed-layer CIN
-344 J/kg
Mixed-layer LCL
1387 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
-33 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

020 
WUUS53 KGRR 241948
SVRGRR
MIC105-127-242030-
/O.NEW.KGRR.SV.W.0056.210824T1948Z-210824T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Rapids MI
348 PM EDT Tue Aug 24 2021

The National Weather Service in Grand Rapids has issued a

* Severe Thunderstorm Warning for...
  Southern Mason County in west central Michigan...
  Oceana County in west central Michigan...

* Until 430 PM EDT.

* At 348 PM EDT, a severe thunderstorm was located near Silver Lake
  SP, or 10 miles west of Hart, moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Hart...                Shelby...              Scottville...
  Pentwater...           Mears SP...            Silver Lake SP...
  Weare...               Elbridge...            Colfax...
  Custer...              Walkerville...         Walhalla...
  Crystal Valley...      

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4370 8651 4375 8646 4379 8644 4386 8643
      4392 8645 4401 8604 4362 8605 4357 8651
      4362 8654 4366 8654
TIME...MOT...LOC 1948Z 247DEG 37KT 4371 8657 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

04
1 follow-up statement
869 
WWUS53 KGRR 242025
SVSGRR

Severe Weather Statement
National Weather Service Grand Rapids MI
425 PM EDT Tue Aug 24 2021

MIC105-127-242035-
/O.EXP.KGRR.SV.W.0056.000000T0000Z-210824T2030Z/
Mason MI-Oceana MI-
425 PM EDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN MASON AND OCEANA
COUNTIES WILL EXPIRE AT 430 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4370 8651 4375 8646 4379 8644 4386 8643
      4392 8645 4401 8604 4362 8605 4357 8651
      4362 8654 4366 8654
TIME...MOT...LOC 2025Z 270DEG 37KT 4385 8610 

$$

04

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 2:06 PM EDTSpecial Marine WarningGRR114 min
Aug 24, 3:52 PM EDTSpecial Marine WarningGRR98 min
Aug 24, 4:24 PM EDTSpecial Marine WarningGRR66 min
Aug 24, 4:43 PM EDTSevere Thunderstorm WarningGRRNewaygo49 min
Aug 24, 4:45 PM EDTSevere Thunderstorm WarningGRRLake45 min
Aug 24, 4:53 PM EDTSevere Thunderstorm WarningGRRNewaygo40 min
Aug 24, 5:10 PM EDTSevere Thunderstorm WarningGRRKent, Mecosta, Montcalm, Osceola50 min
Aug 24, 5:56 PM EDTSevere Thunderstorm WarningGRRClare, Isabella64 min
Aug 24, 6:06 PM EDTSevere Thunderstorm WarningGRRClinton, Gratiot, Ionia, Montcalm84 min
Aug 24, 6:13 PM EDTSpecial Marine WarningGRR92 min
Aug 24, 6:48 PM EDTSevere Thunderstorm WarningGRRBarry, Clinton, Eaton, Ingham, Ionia42 min
Aug 24, 7:38 PM EDTAreal Flood AdvisoryGRRCalhoun, Jackson, Kalamazoo, Van Buren10 hr
Aug 24, 7:41 PM EDTSpecial Marine WarningGRR54 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2021Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.