Macomb, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

345
FXUS63 KDTX 220510
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1210 AM EST Sun Dec 22 2024

.KEY MESSAGES...

- Lake effect snow showers will continue to brush the shoreline of
Huron County tonight, bringing a chance for minor accumulations and
pockets of blowing snow.

- Cold continue into tomorrow with morning lows ranging from around
0 degrees in the Saginaw Valley to around 10 degrees in Detroit.
Daytime temperatures again will be in the 20s

- Next chance for snow and rain arrives on Monday with snow
accumulations of an inch and greater increasingly likely north of I-
69.

&&

.AVIATION...

Surface high pressure is now centered directly over northern Lower
Michigan. VFR conditions are anticipated throughout the night. The
surface anticyclone will pass into Upstate New York causing a
prevailing south wind Sunday. Expecting some diurnal low VFR cloud
development but confidence is low on the coverage. Midlevel warm
advection cloud is then expected prior to 00Z Monday.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5000 feet tonight and Sunday.

&&

.PREV DISCUSSION...
Issued at 334 PM EST Sat Dec 21 2024

DISCUSSION...

An arctic high pressure has settled over the area today along with a
lot of dry air in the mid and upper levels noted on the 12Z DTX RAOB
which also came in with a -17C temperature at 850mb. These cold
temperatures are resulting in a high Delta T over the lakes and
strong instability. This continues to support lake effect snow
showers that are clipping portions of the Thumb. Convective depths
over the lake will continue to lower into the evening, which should
limit greater snow rates. The other result is a fair degree of
clouds underneath the inversion layer streaming across the state with
the north/northwest flow this afternoon. Moisture depth is shallow,
but forecast soundings depict the cloud layer over land within the
DGZ. This affords the opportunity for maintenance of some scattered
flurry activity throughout the remainder of the afternoon.

Tonight will see the coldest temperatures associated with this cold
airmass. The arrival of a surface high pressure bringing calm winds,
fresh snow pack, and clearing skies will bring favorable conditions
for surface temperatures to plummet from the highs in the low to mid
20s this afternoon into the single digits for most areas tonight.
Temperatures across the Saginaw Valley will be the coldest with
morning lows bottoming out around zero degrees (F). Wind direction
overnight will keep potential for any lake effect snow bands
overnight to clip northern and east Huron County. This brings the
lower probability to see up to an inch of additional snowfall during
the overnight period.

A PacNW wave rounding the flattening ridge over the Rockies will
travel across the northern plains and arrive into the central Great
Lakes during the day Monday bringing the next chance at widespread
precipitation starting Monday morning. Models remain in fairly
consistent in snow being the predominant precipitation type,
especially for the northern half of the CWA. Being on the warm
advection wing of this system, some warmer low level temperatures
begin to edge into Lower Michigan. This will work to bump
temperatures near the surface into the mid 30s across the southern
CWA leading to the probability for a rain/snow mix or complete
change over to rain at times and cut into any snow accumulation
total. Latest guidance has trended higher with QPF amounts. This
brings potential snowfall amounts up more solidly in the 1 to 3
inch range north of I-69. Higher end of this range resides across
the northern Thumb. Forecast into Monday will be sensitive to the
trends of the QPF and degree of warm air nudging into Lower Michigan,
which will affect overall totals and precipitation type. South of
I-69 totals are currently to an inch or less.

High pressure settles back into the region for Tuesday bringing dry
conditions. There will not be a lot of cold air advection in the
wake of the system Monday, which will keep daytime highs in the mid
30s. A lot of uncertainty remains with the mid-week forecast as a
southern stream wave tries to release north into Michigan. Several
ensembles remain dry for Wednesday, so outgoing forecast will carry
low PoPs given the uncertainty. If it does precipitate, solution
space currently points towards rain as the main precipitation type.
Greater confidence will be for warmer than average temperatures
spreading across the region into the late week with daytime highs
likely climbing into the 40s by Friday.

MARINE...

Arctic high pressure continues to gradually become established over
the central Great Lakes this evening leading to a diminishing trend
in northerly winds. Lingering lake effect snow showers over southern
Lake Huron likewise diminishes as this occurs. High slides across
the region Sunday bringing a brief period of light flow and dry
conditions. Southerly flow then strengthens Sunday night-Monday as
compact low pressure ejects out of the Plains into the Great Lakes.
Peak gusts during the day Monday expected to reach the 25-30kt range
over Lake Huron; gusts over the southern Great Lakes likely stay
closer to 20kts. This system tracks over the area latter half of
Monday into early Tuesday generating widespread snow with winds
slowly veering from NW to NE on the backside of the system Tuesday.
High pressure is quick to build back into the region in the low`s
wake likely resulting in winds weakening once northerly flow
develops.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....CB
DISCUSSION...AA
MARINE.......KDK


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at www.weather.gov/detroit.