674
FXUS63 KDTX 160353
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1153 PM EDT Sat Jun 15 2024

.KEY MESSAGES...

- Dry with seasonable temperatures through tonight before abnormally
  warm conditions commence late Sunday and continue through next week.

- Temperatures likely peak in the mid 90s early next week with heat
  indices topping out near 100F at times.

- Low confidence in periodic widely scattered thunderstorms that could
  offset some of the warming, depending on coverage and timing.

&&

.AVIATION...

Thicker high clouds overhead at forecast issuance shift northward
late tonight leaving mostly clear sky in the morning. At the same
time, surface high pressure positioned over southern Ontario begins
an exit toward the New England coast while still supplying dry
easterly boundary layer wind that gradually veers toward the south
by afternoon. The still dry low level air mass inhibits any cumulus
development while another round of mid and high clouds arrives ahead
of a warm front strengthening along the MS valley region. These
clouds are associated with showers and thunderstorms ongoing across
the Midwest which are projected on a track into the northern Great
Lakes through the afternoon into Sunday evening.

For DTW/D21 Convection...No thunderstorms are expected late tonight
through Sunday evening.

 DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 305 PM EDT Sat Jun 15 2024

DISCUSSION...

The area will remain under the influence of surface high pressure as
it shifts off to the east tonight. Light easterly flow will maintain
pleasant conditions with lows dropping into the 50s area-wide (which
is average for this time of year). Southeasterly flow will increase
on Sunday as this high continues to the east coast. As upper level
high pressure centered over North Carolina begins to intensify, this
flow will draw warmer air north into the region with highs reaching
the mid/upper 80s by afternoon. A shortwave trough is still progged
to race east along the northern periphery of this expanding upper
level ridge late Sunday and a few showers may brush the northern
edge of the forecast area from Sunday into Sunday night.

Once this shortwave passes east through Ontario into Quebec (and
beyond), the upper ridge will build north and northwest into the
region and bring a rapid expansion of hot and modestly humid air
into the area on Monday as H5 heights build to near 590 dam as the
upper high over North Carolina expands to 595 dam. This air mass
change will bring high temperatures into the mid (to locally upper)
90s with heat indices topping out in the upper 90s to around 100
degrees. With the influx of more humidity, isolated showers and
thunderstorms will also be possible late in the day, especially
along lake breeze boundaries.

The hot weather will then continue on through much/all of the week
as the upper high re-orients such that the western lobe pivots into
the Tennessee and Ohio Valley regions and upper heights remain quite
high over the area. Overall, it appears lower 90s will be common
with occasional temperatures into the mid 90s. As such, messaging
remains the same as impacts from the heat compound which each
successive day.

Some combination of a Heat Advisory and/or Excessive Heat Warning
will be likely with the eventual configuration likely determined by
the degree to which the upper ridge builds north into the area by
midweek. Medium range models vary in the degree of shortwave energy
traversing the northern edge of the ridge. This will impact the
eventual northward expanse and also the coverage and frequency of
isolated to scattered mainly late day showers and thunderstorms
which will be possible at times throughout the week.

MARINE...

A warm and humid airmass will set up over the Great Lakes late
tomorrow through early Monday and will last through the end of the
week. This will produce relatively stable over-lake conditions.
Prior to the arrival of this airmass, the leading warm front will
provide the chance for showers and thunderstorms over portions of
Lake Huron tomorrow. Additional isolated to scattered shower and
storm chances will exist Monday and Tuesday over the Great Lakes as
an upper-level disturbance moves over the region. Otherwise, south
to southwest flow will become established through early next week
after the passage of the warm front. Some breezy conditions with
gusts to 20-25 knots will be likely Sunday as flow transitions from
southeast to south-southwest, but otherwise gusts stay aob 20 knots
through the early week with the stable conditions in place.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

AVIATION.....BT
DISCUSSION...DG
MARINE.......AM


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