Alert archive / Michigan / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 47, NWS Detroit, MI

September 20, 2018Lenawee County, Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Sep 20, 2018, 6:59 PM EDT for Lenawee County, Michigan. It was in force for 41 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
Sep 20, 2018, 6:59 PM EDT (22:59 UTC)
Expired
Sep 20, 2018, 7:40 PM EDT
In force
41 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Lenawee County, MI

The radar

The Detroit radar (KDTX), 102 km from the middle of the area, began a volume at 22:59 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

Detroit, MI (KDTX), launched 12:00Z, 11.0 hours before the alert went out and 106 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, Detroit, MI at 12:00Z on 2018-09-20Temperature 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, Detroit, MI at 12:00Z on 2018-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 189 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
774 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
189 m²/s²
0-3 km storm-relative helicity
191 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Detroit, MI wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 20, 3:43 PM EDT, 3 hours 16 minutes earlier.

Area forecast discussion, Sep 20, 3:43 PM EDT, 3 hours 16 minutes before
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Hazardous weather outlook, Sep 20, 3:49 PM EDT, 3 hours 10 minutes before
Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
349 PM EDT Thu Sep 20 2018

MIZ047>049-053>055-060>063-068>070-075-076-082-083-212000-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
349 PM EDT Thu Sep 20 2018

This hazardous weather outlook is for portions of southeast
Michigan.

.DAY ONE...This Afternoon and Tonight

There is a Marginal Risk for severe weather today across southeast
Michigan. An isolated thunderstorm producing damaging winds will be
possible now through this evening. Greatest severe threat will be
during the afternoon hours.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Very windy conditions on Friday as a strong cold front moves through
the region. Gusts to around 40 mph will be possible.

.SPOTTER INFORMATION STATEMENT...

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-212000-
Lake St Clair-
Michigan Waters of Lake Erie from Detroit River to North Cape MI-
Lake Huron from 5NM east of Mackinac Bridge to Presque Isle Lt
beyond 5 NM off shore-
Lake Huron from Presque Isle Light to Sturgeon Point MI beyond 5NM
off shore-
Lake Huron from Sturgeon Point to Alabaster MI beyond 5NM off shore-
Outer Saginaw Bay SW of Alabaster to Port Austin MI to Inner Saginaw
Bay-Inner Saginaw Bay SW of Point Au Gres to Bay Port MI-
Port Austin to Harbor Beach MI-Harbor Beach to Port Sanilac MI-
Port Sanilac to Port Huron MI-
Lake Huron from Port Austin to Harbor Beach beyond 5NM Off Shore-
Lake Huron from Harbor Beach to Port Sanilac beyond 5NM Off Shore-
Lake Huron from Port Sanilac to Port Huron beyond 5NM Off Shore-
349 PM EDT Thu Sep 20 2018

This hazardous weather outlook is for portions of Lake Erie, Lake
Huron and Lake St Clair.

.DAY ONE...This Afternoon and Tonight

There is a Marginal Risk for severe weather today across southeast
Michigan. An isolated thunderstorm producing damaging winds will be
possible now through this evening. Greatest severe threat will be
during the afternoon hours.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Gale Warnings in effect Friday through Friday night. Please refer to
Lake Huron forecast for additional information.

.SPOTTER INFORMATION STATEMENT...

You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.

TF

In the hours before

Local storm report, Sep 20, 2:23 PM EDT, 4 hours 36 minutes before
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Local storm report, Sep 20, 3:12 PM EDT, 3 hours 47 minutes before
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Local storm report, Sep 20, 4:09 PM EDT, 2 hours 50 minutes before
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Local storm report, Sep 20, 6:22 PM EDT, 37 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 4:14 AM EDTGale WarningDTX48 hr
Sep 20, 4:14 AM EDTSmall Craft AdvisoryDTX56 hr
Sep 20, 4:25 AM EDTBeach Hazards StatementDTXHuron, Sanilac40 hr
Sep 20, 9:36 AM EDTSpecial Weather StatementDTXWayne24 min
Sep 20, 11:52 AM EDTSpecial Weather StatementDTXShiawassee38 min
Sep 20, 12:31 PM EDTSpecial Weather StatementDTXShiawassee44 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2018Every severe thunderstorm warning in 2018

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.