National Weather Service United States Department of Commerce


519
FXUS63 KDTX 311938
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
338 PM EDT Sun May 31 2026

.KEY MESSAGES...

- Dry weather with plentiful sunshine continues through mid week.

- Near normal temperatures early week become warmer and more humid
Thursday and Friday.

- The next chance of rain develops Friday into next weekend.

&&

.DISCUSSION...

Except for a fringe of cirrus, another cloudless day is unfolding
across Lower Mi with low humidity and temperatures right around
normal to finish off the weekend and the month of May. Temperatures
rising into the mid 70s, combined with broad and flat surface high
pressure, is promoting a typical lake breeze pattern to keep
readings cooler near the shorelines.

Afternoon satellite observations indicate an energetic mid level
short wave still moving down from the James Bay region on a
meridional track over the eastern Great Lakes tonight and early
Monday. This system carves some height falls into the eastern flank
of the larger scale blocking ridge while pulling a weak surface
trough/backdoor front through southern Ontario. The pressure feature
washes out quickly but is effective at reinforcing the dry air mass
without much change expected to high temperatures during the early
week period.

Consensus of 12Z deterministic models shows the 500 mb ridge
rebuilding over the western Great Lakes by Wednesday and maintains
good timing consistency from over the last few model cycles. This is
the first stage of omega block unraveling as the upper jet picks up
strength across both the north Pacific and north Atlantic. There can
often be some predictability issues during the transition, however
the timing and shape of the 500 mb structure look good compared to
ensemble means over the last few forecast cycles. A warming trend is
the associated weather highlight in the Great Lakes tied to the
increasing height field while humidity remains in check through
Thursday.

The current Rockies closed low component of the blocking pattern
becomes the focus of rain potential returning by Friday. The
circulation is kicked eastward during the larger scale zonal flow
transition while interacting with broad lee side surface troughing
across the Plains. Increasing POPs in blended guidance looks
reasonable across the Great Lakes as pent up Gulf moisture returns
northward into the region ahead of the low pressure system.

&&

.MARINE...

Light and variable winds observed this afternoon across the Great
Lakes as high pressure weakens overhead. A weak backdoor cold front
drops through the area tonight, causing winds to flip to the
northeast as high pressure expands in from Ontario. Northeast flow
along Saginaw Bay leads to breezy conditions Monday afternoon,
prompting the issuance of a Small Craft Advisory for Inner Saginaw
Bay. Elsewhere, gusts are capped below 20 knots. Extended stretch of
dry and overall favorable marine weather persists through much of
the work week.

&&

.PREV DISCUSSION...
Issued at 126 PM EDT Sun May 31 2026

AVIATION...

Stable and dry conditions held within broad high pressure across the
region maintain light wind and VFR through the period. The bulk of
SE MI sees wind veer to NW this afternoon, but the Metro Detroit
sites look to hold out of the SE due to the lake breeze influence.
Nearly calm winds overnight emerge from the NE on Monday with weak
instability possibly introducing high based cumulus by the afternoon.

D21/DTW Convection...No thunderstorms through Monday.

DTW THRESHOLD PROBABILITIES...

* None.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory from noon to 10 PM EDT Monday for LHZ422.

Lake St Clair...None.

Michigan waters of Lake Erie...None.

&&

$$

DISCUSSION...BT
MARINE.......MV
AVIATION.....TF


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