Alert archive / Michigan / Areal Flood Advisories in 2021

Areal Flood Advisory 21, NWS Detroit, MI

August 27, 2021Saginaw County, Michigan

NWS Detroit, MI issued this areal flood advisory at Aug 27, 2021, 8:32 AM EDT for Saginaw County, Michigan. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Aug 27, 2021, 8:32 AM EDT (12:32 UTC)
Expired
Aug 27, 2021, 11:45 AM EDT
In force
3 hr
Issued by
NWS Detroit, MI
Area
Storm-based polygon

County Saginaw County, MI

The radar

The Detroit radar (KDTX), 85 km from the middle of the area, began a volume at 12:33 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, 0.5 hours before the alert went out and 85 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 2021-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 319 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, Detroit, MI at 12:00Z on 2021-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
319 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
912 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
75 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 areal flood advisory 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 areal flood advisory went out at Aug 27, 7:13 AM EDT, 1 hour 19 minutes earlier.

Area forecast discussion, Aug 27, 7:13 AM EDT, 1 hour 19 minutes before
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Hazardous weather outlook, Aug 27, 4:52 AM EDT, 3 hours 40 minutes before
Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
452 AM EDT Fri Aug 27 2021

MIZ047-048-053>055-060>063-068>070-075-076-082-083-280900-
Midland-Bay-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
452 AM EDT Fri Aug 27 2021

This hazardous weather outlook is for portions of southeast
Michigan.

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms are expected today and tonight,
moving southwest to northeast at around 15 mph. Isolated storms may
produce strong gusts in excess of 50 mph, but the main threat will be
localized heavy rainfall as storms will likely produce rainfall
rates in excess of 1 inch per hour. This may lead to flooding of
urban, low-lying, or otherwise flood prone areas.

Hot and muggy conditions persist today with heat index values ranging
from the mid 80s to mid 90s.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

A Heat Advisory may be needed for parts of Southeast Michigan on
Saturday and Sunday as heat index values reach the upper 90s to near
100 degrees. Isolated to scattered thunderstorms are possible both
days with heavy rainfall and localized flooding the primary threat.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated today and tonight.

MIZ049-280900-
Huron-
452 AM EDT Fri Aug 27 2021

This hazardous weather outlook is for Huron County.

.DAY ONE...Today and Tonight

A Beach Hazards Statement has been issued. See the latest Coastal
Hazard Message for details.

Isolated to scattered thunderstorms are expected today and tonight,
moving southwest to northeast at around 15 mph. Isolated storms may
produce strong gusts in excess of 50 mph, but the main threat will be
localized heavy rainfall as storms will likely produce rainfall
rates in excess of 1 inch per hour. This may lead to flooding of
urban, low-lying, or otherwise flood prone areas.

Hot and muggy conditions persist today with heat index values ranging
from the mid 80s to mid 90s.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

A Heat Advisory may be needed for parts of Southeast Michigan on
Saturday and Sunday as heat index values reach the upper 90s to near
100 degrees. Isolated to scattered thunderstorms are possible both
days with heavy rainfall and localized flooding the primary threat.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated today and tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-280900-
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-
452 AM EDT Fri Aug 27 2021

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

.DAY ONE...Today and Tonight

A Small Craft Advisory is in effect. See the latest Marine Weather
Message for details.

Isolated to scattered thunderstorms are expected today and tonight,
moving southwest to northeast at around 10 kt. Isolated storms may
produce strong gusts in excess of 34 kt.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Isolated to scattered thunderstorms are possible Saturday and Sunday
as the humid and unstable air mass remains over the region.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated today and tonight.

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

TF

In the hours before

Special weather statement, Aug 27, 6:43 AM EDT, 1 hour 49 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 9:34 PM EDTSmall Craft AdvisoryDTX30 hr
Aug 27, 4:04 AM EDTBeach Hazards StatementDTXHuron18 hr
Aug 27, 6:43 AM EDTSpecial Weather StatementDTXBay, Midland, Saginaw62 min
Aug 27, 10:03 AM EDTAreal Flood AdvisoryDTXGenesee3 hr
Aug 27, 12:08 PM EDTSpecial Weather StatementDTXWayne67 min
Aug 27, 12:22 PM EDTSpecial Weather StatementDTXMacomb68 min
Aug 27, 12:47 PM EDTAreal Flood AdvisoryDTXOakland, Wayne3 hr
Aug 27, 12:57 PM EDTSpecial Weather StatementDTXMacomb63 min
Aug 27, 1:02 PM EDTSpecial Marine WarningDTX58 min
Aug 27, 1:12 PM EDTFlash Flood WarningDTXOakland, Wayne3 hr
Aug 27, 1:56 PM EDTFlash Flood WarningDTXWayne2 hr
Aug 27, 4:26 PM EDTAreal Flood WarningDTXWayne6 hr

Nearby

Areal Flood Advisories in Michigan, 2021Every areal flood advisory 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.