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000
FXUS63 KDTX 231108
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
708 AM EDT Sat Sep 23 2017

.AVIATION...

Early morning light fog will burn off 13-14Z, with mainly clear
skies and very light winds through the TAF period as the upper level
ridge remains in place. Like yesterday, there remains a very low
chance of a pop up thunderstorm in late afternoon. Patchy fog likely
developing once again overnight, with YIP/DTW looking to be the most
susceptible.

//DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 405 AM EDT Sat Sep 23 2017

DISCUSSION...

High temperature records will be in jeopardy once again today,
especially in the Flint to Tri Cities region as interior sections of
lower Michigan remain capable of highs in the lower to mid 90s.
These readings, along with surface dewpoint in the mid to upper 60s
will produce another round of heat index in the mid to upper 90s for
a few hours during mid to late afternoon. These readings are again
short of the 100 degree threshold for heat advisory headlines but
remain notable for the time of year and for occurring during the
weekend with so much outdoor activity. The slightly cooler locations
near the shorelines will also make another run at 90, especially
metro Detroit with a little less influence from Lake Erie. Surface
high pressure that has been oriented southwest to northeast and
centered over Lake Erie will shift a little more over lower Michigan
during the day. This will provide more of a light and variable wind
or a later developing southeast component to allow a longer period
of surface heating before weak lake influence can occur.

Mesoscale/CAM solutions, mainly just the HRRR, have a few specks of
convective activity again this afternoon. The same was true in last
night`s runs for yesterday but with considerable uncertainty on
location. Prefer to monitor satellite trends again through the day to
pinpoint favorable locations for a possible late day shower or
thunderstorm, assuming similarly capped low levels can be overcome by
daytime heating alone.

The mid summer heat wave will continue Sunday through early next
week with a degree or two of cooling expected to occur each day.
This will be due to the core of the upper level ridge sliding
eastward along the Atlantic coast as the long wave pattern begins
some adjustment from strong amplification over the last few days.
Still, we are looking at record or near record highs again in the
lower to mid 90s Sunday, lower 90s Monday, and upper 80s Tuesday.
The Tuesday numbers could also be revised upward in later forecasts
depending on cloud cover prior to the arrival of the next cold front
due Tuesday night into Wednesday. This frontal passage will bring
the next organized chance of showers and thunderstorms along with
sharply cooler temperatures. Readings are projected to be limited to
highs in the lower half of the 60s by Friday into next weekend.

MARINE...

Extended stretch of very warm and humid conditions will exist
through the weekend as the region remains under the influence of
strong upper ridging. This pattern will support light winds - under
15 knots - and low waves during this time. These conditions will
persist into early next week. A cold front crossing the Central Great
Lakes Tuesday night will bring a low chance of shower and
thunderstorm activity, along with winds shifting to the west and
increasing to around 15 knots.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

AVIATION.....SF
DISCUSSION...BT
MARINE.......SF


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