River Flood Warning 22, NWS Detroit, MI

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
802 PM EDT Tue May 19 2020

.AVIATION...

Drier easterly flow will allow for broken mid clouds early in the
TAF period to erode leaving just passing high cloud as the TAF
period progresses. Wind speeds will generally hold in the 10-15 knot
range overnight as a fairly tight pressure gradient remains in place
between building high pressure from the north and the departing
closed low to the south. Daytime heating allows for gusts to push 20
knots at times after 14z Wednesday.

For DTW...Mid clouds early in the period give way to passing high
cloud as high pressure builds into the region through the TAF period.

 DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 337 PM EDT Tue May 19 2020

DISCUSSION...

Remaining light rain showers pivoting through the area around upper
low now to the south will fade with the loss of daytime heating
early this evening. At the same time, the low drops even further
south and a ridge of high pressure centered to the northeast builds
settles south into the area bringing a drier low level air mass and
eventual clearing overnight.

This basic configuration holds for the balance of the week as the
low stalls to the south before weakening and shifting off to the
east as westerly flow eventually impinges on it late in the week.
The pressure ridge will also be weakening during this time frame.
Several 12z model solutions still wobble the northern fringe of this
low close enough to brush the area with light showers, but this
seems unlikely at this time.

So, dry weather can be expected from tonight on into Friday with
temperatures moderating from the current 50s and 60s today into the
60s Wednesday and upper 60s to 70s Thursday into Friday. During this
time, there should be a fair amount of sunshine as well (aside from
perhaps Friday as the upper low finally makes a move and brushes the
area with mid to higher level cloudiness.

Overall upper level pattern becomes more progressive again over the
weekend into next week as a very wavy zonal time flow becomes
established. The lead shortwave, instrumental in the ejection of the
this week's cutoff low to the south, will move into the area
Saturday into Saturday night and bring a chance of scattered
showers. It will also be riding into the Great Lakes around a
building ridging so temperatures will still moderate well into the
70s despite some cloud cover. Said ridge builds back with force on
Sunday once this shortwave passes with temperatures responding by
climbing into the 80s in most, if not all, locations as mostly sunny
skies return.

A more significant Pacific shortwave will track almost due east
through the basically zonal flow and impinge on the Great Lakes by
Monday. With ridging still in place, temperatures will once again
reach the 80s. At the same time, moisture will be returning as well
and with it a better chance of showers and thunderstorms, especially
as surface troughing associated with the upper system works into the
area to provide a mechanism to support the convection.

MARINE...

Broad area of low pressure centered south of the Great Lakes will
continue to result in easterly flow across the region. Winds and
waves have subsided enough across the Lake Huron basin to allow the
small crafts to expire there but gusts to near 20 knots across the
long axis of Lake Erie will continue to keep waves heights elevated
into the evening hours. The low will stall over the Tennessee Valley
through the mid week period while high pressure builds southward
from Ontario/Quebec which will keep easterly flow going through the
end of the week.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Lakeshore Flood Warning until 10 PM EDT this evening for MIZ070-076-
     083.

     Flash Flood Watch until 8 AM EDT Wednesday for MIZ047.

Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...Small Craft Advisory until midnight EDT tonight for LEZ444.

&&

AVIATION.....IRL
DISCUSSION...DG
MARINE.......DRK

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

Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
348 PM EDT Tue May 19 2020

MIZ047>049-053>055-060>063-068-069-075-082-200900-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Washtenaw-Lenawee-
348 PM EDT Tue May 19 2020

This hazardous weather outlook is for portions of southeast
Michigan.

.DAY ONE...This Afternoon and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

MIZ070-076-083-200900-
Macomb-Wayne-Monroe-
348 PM EDT Tue May 19 2020

This hazardous weather outlook is for portions of southeast
Michigan.

.DAY ONE...This Afternoon and Tonight

A Lakeshore Flood Warning is in effect this evening. Please see the
latest lakeshore hazard message for details.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-200900-
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-
348 PM EDT Tue May 19 2020

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

.DAY ONE...This Afternoon and Tonight

A Small Craft Advisory is in effect for the Michigan waters of Lake
Erie this evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

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

DG