Expert Forecast Opinion

101
FXUS63 KDTX 091834
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
234 PM EDT Fri May 9 2025

.KEY MESSAGES...

- Clear again tonight but not as cold. Weak cold front crosses
daytime Saturday offering a slight chance for an isolated shower
though the vast majority remain dry.

- Much above average temperatures arrive Monday and persist through
the week. Scattered shower/storm chances arrive midweek.

&&

.DISCUSSION...

Region remains under the influence of fairly strong high pressure
centered over the western Great Lakes. Active subsidence combined
with an extremely dry resident airmass- 09.12Z KDTX RAOB sounding
only shows a PW value of 0.17" (this is only a few hundreths from
the daily climo minima), has kept skies cloud-free. This as aided in
a healthy thermal recovery after the cold morning start with all of
SE MI now sitting around 60. Ridge axis begin to cross the state
tonight allowing the warmer upper Midwest airmass (850mb temps near
11C vs our local 1-2C currently in place) to fold into the area.
While this warm advection remains largely elevated atop the
nocturnal boundary layer, it in combination with late night arrival
of mid/high cloud limits radiational cooling efficiency to prevent a
repeat of last night`s frost/freeze. Instead, lows are expected to
only fall towards the lower 40s to upper 30s.

Aforementioned clouds are associated with a weak cold front dropping
out of northern Ontario that is set to cross SE MI daytime Saturday.
Moisture pooling in advance pushes surface dewpoints into the mid-
upper 40s which could offer a shot for an isolated shower with
fropa. Overall potential for this are low given the front`s
detachment from the parent wave over the James Bay with model
guidance gradually backing off on advertised coverage. Will maintain
the running slight chance (15%) PoPs during the late morning-
afternoon though do expect the vast majority of the area to remain
dry. Main impact from the front is a north-south gradient in high
temps with areas north of M-59 topping out in the 60s to lower 70s
and areas south reaching the mid to upper 70s.

Stronger high pressure then follows to close out the weekend as
broad upper ridging develops across the central CONUS. This ridge
slowly crosses the Great Lakes for the bulk of next week bringing
much above normal temps with highs in the 70s to lower 80s. A
southern stream mid-upper trough is progged to lift out of the Gulf
coast and undercut the ridge midweek offering chances to see
scattered showers and thunderstorms.

&&

.MARINE...

High pressure to bring dry weather through the weekend, with the
exception of late tonight into tomorrow morning across northern
Lake Huron, with a spotty shower possible along an elevated front. A
cold front is then set to pass over the Great Lakes through tomorrow
morning and afternoon, which will veer wind direction from southwest
to north-northeast. Winds generally remain light behind the passage
of the front, but more favorable fetch through the Saginaw Bay will
bring some sustained wind potential near 20 knots. It is borderline
at this time for both winds and waves, but a Small Craft Advisory
may eventually be needed through the Saginaw Bay for tomorrow.
Otherwise, high pressure is again reinforced tomorrow through
Sunday, continuing dry weather and maintaining lighter winds to end
the weekend.

&&

.PREV DISCUSSION...
Issued at 1243 PM EDT Fri May 9 2025

AVIATION...

High pressure has full control of conditions across SE Mi this
afternoon and evening. A cloudless sky is evidence of the cool and
very dry air mass slightly reinforced by light northerly wind. A
late day lake breeze component veers wind direction toward the east
and southeast although land temperatures are slightly too cool for
pronounced development. This leads to light SW wind as the upper
Midwest and northern Great Lakes cold front moves in late tonight. A
stray high based shower is possible in the limited moisture axis
along and ahead of the front is it moves slowly NW to SE during the
morning into Saturday afternoon.

For DTW/D21 Convection... No thunderstorms are in the forecast
tonight and Saturday.

THRESHOLD PROBABILITIES...

* None.


&&

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

$$

DISCUSSION...KDK
MARINE.......AM
AVIATION.....BT


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