430
FXUS63 KDTX 090715
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
315 AM EDT Wed Oct 9 2024

.KEY MESSAGES...

- Quiet weather through the rest of the work week with temperatures
near normal.

- There is another chance of frost Wednesday night in non-urban and
lakeshore areas, likely over a wider area than last night.

- Above normal temps briefly return Friday with highs well into the
70s. A cold front then crosses early Saturday bringing cooler temps
and a slight chance for widely scattered showers.

- Better precipitation chances Sunday into next week as well as
colder temperatures.

&&

.DISCUSSION...

Clear overnight skies have resulted lows north of of I-69 falling
well into the 30s early this morning supporting a healthy frost.
Areas south have held a touch warmer in the upper 30s keeping any
potential frost more patchy. Despite this cold start, surface high
pressure, still gradually becoming established over the region,
keeps skies clear or mostly clear today allowing highs to climb back
into the lower 60s. With the edge of mid-upper troughing still
lingering over the central Great Lakes, diurnal mixing will again be
able to tap into stronger flow aloft to support an afternoon breeze
with gusts topping out around 20mph for most of the area- 25mph
gusts possible in the Thumb.

Surface high is fully established and centered over lower MI by
tonight likely leading to the coldest night of the week. Both clear
skies and little to no wind brings low temps solidly in the 30s for
all but lakeshore and urban areas with near or at freezing not out
of the question in the Saginaw Valley and portions of the Thumb.
Another round of frost advisories will likely be needed.

Above normal temperatures make their brief return Friday as
collapsing central CONUS ridging spills over the Great Lakes raising
850mb to 12-14C and supporting highs well into the 70s. This is
response to the next developing trough dropping out of northern
Canada, which will draw a cold front through the area early
Saturday. Rain chances are limited along this front largely due to
being too far south and detached from the main shortwave/vorticity
pool which slides over northern Ontario. Mid-range model guidance
continues to suggest this front will stall out somewhere around the
Ohio border becoming the focal point for a stronger embedded
shortwave/rapidly developing surface low Sunday. Better rain
potential accompanies this system, with these chances likely
lingering through the first part of next week as the system becomes a
broad, stacked, closed low over the eastern US/Canada. Colder air
also can be expected during this period as deepening upper troughing
draws air out of far northern Canada dropping local 850mb temps in
the negative single digits (C) which keeps highs only in the 50s.

&&

.MARINE...

One more day of cooler northwesterly flow will maintain the elevated
mixing depths and over lake instability. Sustained northwest flow
around 20 knots with gusts of 25 knots, isolated 30 knots, will
persist through the bulk of the day tomorrow. A convergent band of l
ake effect rain showers will also be likely across the central Lake
Huron basin through the morning and afternoon hours, which will
bring a low-end chance for isolated waterspout development.

Wind direction will veer a little more northerly later this
afternoon, which will result in increasing wave heights across
portions of the Thumb. A Small Craft Advisory will go in effect from
the outer Saginaw Bay to Port Sanilac as wave heights breach the
four ft. threshold. High pressure then builds in over the Great
Lakes through tomorrow morning, relaxing wind speeds and diminishing
the higher end gust potential.

&&

.PREV DISCUSSION...
Issued at 1144 PM EDT Tue Oct 8 2024

AVIATION...

High pressure will expand across Lower Michigan from the northwest
during the course of the day Wednesday. Ample dry air associated
with this high will support mainly clear skies. There will be a
slight increase in west-northwest wind to 10 to 12 knots by
Wednesday afternoon with the growth of the daytime mixed layer.

For DTW/D21 Convection... No thunderstorms expected.

DTW THRESHOLD PROBABILITIES...

* None.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory until 9 AM EDT this morning for MIZ047-048-053-054-
     060>062.

Lake Huron...Small Craft Advisory from 4 PM this afternoon to 4 AM EDT Thursday
     for LHZ421-442.

     Small Craft Advisory from 10 AM this morning to 4 AM EDT Thursday
     for LHZ441.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

DISCUSSION...KDK
MARINE.......AM
AVIATION.....SC


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