407
FXUS63 KDTX 150353
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1153 PM EDT Fri Jun 14 2024

.KEY MESSAGES...

- Seasonable temperatures are expected again Saturday before heat
  begins to build late Sunday.

- An extended period of hot weather will then set up next week with
  temperatures in the mid 90s to occasionally upper 90s and maximum
  heat indices near 100 degrees.

&&

.AVIATION...

Clear sky and light NE wind are produced by tranquil high pressure
extending southward from Ontario. These conditions continue through
the morning with a slight uptick in wind speed toward noon as the
boundary layer deepens. Clear sky is followed by a gradual cirrus
increase while lake breeze enhanced easterly wind redevelops in the
afternoon into Saturday evening.

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

 DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 345 PM EDT Fri Jun 14 2024

DISCUSSION...

Upper level ridging over the central/southern plains translates east
through the area this weekend and then expands to cover much of the
eastern seaboard/northeast CONUS on into the deep south early next
week with the western periphery of this upper system encompassing
the eastern Great Lakes into lower Michigan. After another pleasant
day on Saturday with high temperatures in the 70s to around 80 and
relatively low humidity, this ridging will bring the beginning of an
expanding area of heat Sunday with highs in the mid 80s to around 90.

While the center of this upper ridge will be positioned off to the
east and southeast, its magnitude/expansion will ensure it has a
strong influence over the region as an increasingly hot airmass
works into the Ohio Valley and Great Lakes. High temperatures will
build into the mid 90s (and in some cases upper 90s) on Monday with
humidity levels edging up to some degree as well.

A similar prospect is in store for Tuesday as well. However, one
potential complication in the forecast has developed as medium range
models now bring an upper level wave northward around the western
edge of this ridge into the area. This system will originate from
the area of disturbed weather currently positioned from far south
Florida into western Cuba. This will bring a chance of scattered,
mainly afternoon, showers and thunderstorms with in on Tuesday. The
additional cloud cover/moisture with this system may limit the high
temperatures somewhat, but still expect most locations to exceed 90
degrees.

In the wake of this upper wave, the upper ridge will re-orient such
that the western lobe will pivot into the Ohio and Tennessee Valley
regions as opposed to the deep south with the northwestern periphery
of the system remaining solidly over the forecast area. This will
lead to a continuation of hot weather through the mid to late week
period. Model differences as to how much shortwave energy traverse
the edge of this ridge begin to crop up by this time frame and this
will have an impact on the extremity of eventual heat and also the
potential for periodic scattered convection late in forecast period.

As it stands, headlines for this period of hot weather will no doubt
be needed for much of next week with the eventual degree/duration of
heat determining the exact hazard. High temperatures in the mid 90s
with heat indices of around 100 at times are consistent with Heat
Advisory criteria, but the cumulative impacts from a more extended
period of hot weather may very well warrant a Excessive Heat Warning
in time. The degree of expansion of the ridge back into the area by
the middle of next week will be the main player in this distinction.
Also, one "relative" positive during this upcoming heat wave will be
modest humidity levels. This lack of significant moisture will allow
temperatures to edge back into the 70-75 degree range each night.

MARINE...

High pressure in control this weekend, bringing gentle winds across
Lake Huron. Conditions hold through the weekend ahead of a warm
front moving across the area Sunday evening. Southeasterly winds
will veer southwesterly and strengthen to 10-15 knots. Chances for
showers and storms exist with this event, mainly over northern Lake
Huron. Winds are expected to remain gentle to moderate through the
rest of the week along with chances for unorganized showers to move
across the area.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

&&

$$

AVIATION.....BT
DISCUSSION...DG
MARINE.......BC


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at www.weather.gov/detroit.