659
FXUS63 KDTX 281923
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
323 PM EDT Sun Jun 28 2026
.KEY MESSAGES...
- Hot and humid conditions arrive Monday with highs in the low-mid
90s and heat indices nearing or briefly exceeding 100 degrees.
- Extreme Heat Watch now in effect Tuesday to Thursday with highs to
reach mid-upper 90s to 100 degrees and heat indices in excess of
105 degrees each day. There will be little nighttime relief with
lows in the mid 70s each night.
- Hot and humid conditions extending to Friday into the holiday
weekend with potential for showers and thunderstorms.
&&
.DISCUSSION...
Main story remains the extreme heat that is expected over the
upcoming week. Ridge amplification gets underway today into tonight.
Locally today, surface high pressure will maintain stable conditions
through the remainder of the day as heights build leading to the jump
in temperatures this afternoon into the mid 80s. The light E-SE wind
holds dewpoints generally in the 60s today.
Heat and humidity increase further Monday as the 594 dam upper level
ridge builds across Great Lakes with the center nearing 600 dam
centering across the Ohio Valley and Mid Mississippi Valley regions
Tuesday through Thursday. While Monday will be noticeably warmer and
more humid, early day clouds bring lower confidence in reaching heat
indices of 100 degrees or more. Clouds and potentially light
scattered shower/thunderstorm activity are associated with a passing
mid level wave on the northern periphery of the inbound ridge. Data
would suggest the locations with the best chance to achieve heat
index values would be west of I-75 if enough clearing can happen
early enough or greater coverage of clouds doesn`t pan out. Have
opted to hold off on any Heat Advisory for Monday given the lower
confidence in occurrence and duration of Heat Advisory criteria.
Tuesday through Thursday and potentially into Friday will be the
time period of most concern for extreme heat. Thus, have hoisted an
Extreme Heat Watch starting Tuesday afternoon given the expected
multi-day cumulative heat stress. An impressive airmass settles over
the region as 850mb temps climb to 20+C and 700mb temps to 10+C and
hold over the mid-week period translating to high temperatures in the
mid to upper 90s. Wednesday and Thursday could possibly see urban
areas of Detroit Metro region reaching 100 degrees as well. Combine
that with the expected dewpoints in the low to mid 70s and heat index
values should reach around or exceed 105 degrees across most of the
area over several days. These forecast temperatures will be making a
run at daily record highs and record warm minimums (see Climate
section below). Positioning of the ridge at this time for the mid-
week period should keep much convective potential out of southeast
Michigan and confined to the north/northwest, which also increases
confidence in the extreme heat. Convection potential is still worth
monitoring in case conditions change.
Hot and humid conditions are likely to continue Friday into the
holiday weekend. There is some data that suggests we could see an
eventual broadening and flattening of the ridge over the Great Lakes
by a series of shortwaves that could open the door to convective
activity in the Friday time frame. Barring any widespread convective
event, we could still be looking at temperatures in the 90s and
dewpoints holding in the 70s.
&&
.MARINE...
High pressure at the surface will keep the light northeasterly flow
around through this evening. An approaching warm front will cause
winds to increase slightly while veering to southeasterly tonight.
This will hold through Monday as gusts reach 20 knots across Lake
Huron. There is a chance of showers and thunderstorms to accompany
the front especially across the north half of Lake Huron. By Tuesday
morning, winds will have become southwesterly while again topping
out around 20 knots. Though the gradient increases, stability also
increases under a very warm airmass which will limit gust
potential.
&&
.CLIMATE...
.Daily Records for the Upcoming Week...
Detroit
Record High Record Warm Minimum
Mon June 29 96 (1933) 77 (1945)
Tue June 30 96 (1931) 76 (2018)
Wed July 1 98 (1931) 80 (1931)
Thu July 2 99 (2011) 76 (2018)
Fri July 3 100 (1911) 78 (1911)
Sat July 4 102 (2012) 79 (1921)
Flint
Record High Record Warm Minimum
Mon June 29 100 (1934) 75 (1945)
Tue June 30 98 (1933) 76 (2018)
Wed July 1 102 (1931) 72 (2018)
Thu July 2 100 (1931) 73 (2002)
Fri July 3 99 (1921) 73 (1983)
Sat July 4 102 (1921) 76 (1999)
Saginaw
Record High Record Warm Minimum
Mon June 29 100 (1971) 75 (1971)
Tue June 30 99 (1964) 77 (2018)
Wed July 1 103 (1931) 78 (1931)
Thu July 2 100 (1931) 73 (2002)
Fri July 3 99 (1966) 76 (1974)
Sat July 4 97 (2012) 75 (2012)
&&
.PREV DISCUSSION...
Issued at 137 PM EDT Sun Jun 28 2026
AVIATION...
Broad high pressure extending into the northern Great Lakes migrates
eastward before becoming centered over the St. Lawrence Valley by
Monday morning. A slight increase in heat and humidity this
afternoon produces weak instability, enough for a high based SCT to
BKN cumulus deck through the rest of the afternoon. These clouds
wane this evening while high cloud from a remnant convective system
arrives overhead. Prevailing east to southeast wind remains 10 kt or
less through tonight. A warm front will then lift into the region
from the southwest on Monday, marking the arrival of a much warmer
and more humid air mass. There is the potential for a decaying
cluster of showers and thunderstorms to ride in from NW to SE along
this boundary mid to late morning - most favorable in the MBS
vicinity where a PROB30 was introduced. Not enough confidence exists
to include in the remaining TAFs at this time.
D21/DTW Convection... No thunderstorms are forecast through Monday
morning.
DTW THRESHOLD PROBABILITIES...
* None
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Extreme Heat Watch from Tuesday afternoon through Thursday evening
for MIZ047>049-053>055-060>063-068>070-075-076-082-083.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...AA
MARINE.......DRK
CLIMATE......MV
AVIATION.....TF
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