831
FXUS63 KMPX 160636
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
136 AM CDT Thu Jul 16 2026

.KEY MESSAGES...

- Dense wildfire smoke is creating hazardous air quality and
  reduced visibility for much of the coverage area, lasting
  into Friday morning.

- Dangerous heat expected to persist into Friday, despite a
  small respite for all areas outside of the Twin Cities metro
  for today. This is a long duration and cumulative threat due
  to highs in the low-mid 90s and heat indices from the mid 90s
  to near 100 degrees.

- Only main likelihood for rain comes Sunday night into Monday
  morning, otherwise mainly dry conditions through late next
  week.

&&

.DISCUSSION...
Issued at 131 AM CDT Thu Jul 16 2026

Fairly widespread visibility reductions and significant increases
in airborne particulates (per MPCA) have been observed from
last evening into the early morning hours as a wide swath of
wildfire smoke has been dragged south with a frontal boundary
over central-southern MN through southern WI. At a minimum, AQI
values into the Moderate category have been observed as far
south as the IA/MN border, while Hazardous values (the worst of
the AQI categories) have been observed throughout the Twin
Cities metro and as far west as Kandiyohi County, and also
includes the Alexandria, Brainerd and Duluth areas up through
the MN Arrowhead region and over much of western WI. The smoke
will reach as far south as the front sags, which looks to reach
as far south as a line roughly Morris-Hutchinson-Rochester.
Though the front will have very little upper level support as
the upper heat ridge remains over the region, a few isolated
showers are possible in eastern MN into western WI, similar to
what developed late Wednesday afternoon. Nothing heavy or enough
to appreciably clear out the hazardous wildfire smoke from the
air, but still a small chance of precip nonetheless. MPCA has
opted to place the majority of our coverage area in the Maroon
category, the worst of the 6 categories for air quality, with
the air quality listed as being Hazardous. To the south of the
Maroon area is a line of counties in Red category, Unhealthy
(4th out of 6 categories), from roughly Montevideo-Mankato-
Rochester. The Air Quality Alert remains in place through late
Friday morning.

The next issue is the prolonged dangerous heat. Per observations of
temperatures, heat indices and WBGT levels, the smoke and frontal
boundary are having appreciable impacts by diminishing the
temperature and dewpoints and limiting the combination needed to
produce Advisory or Warning-level heat index and WBGT values. With
the front and smoke expected to have their peak daytime impacts on
Thursday, highs will only range from the upper 80s to lower 90s. In
turn, heat index values will be limited to no higher than the mid-
90s. In addition, low temperatures this morning and again early
Friday morning will range from the mid 60s to lower 70s. Therefore,
we have opted to cancel all Heat Advisories for today and only
maintain the Extreme Heat Warning for the TC metro counties due to
the more prolonged urban heat island effects, the likelihood of lows
remaining in the lower 70s and the lower threshold of heat index
values in the mid 90s. Otherwise, heat index values are expected to
run no higher than the mid 90s in all other counties for today.

Once past today, the smoke will retreat northward in tandem with the
surface front sliding back north in response to an area of low
pressure developing over the western Dakotas. The upper ridge will
also flatten out and have its axis retreat westward in response to a
large upper low developing over Hudson Bay which will shift slightly
south. This will allow for weak shortwaves to drop southeast from
central Canada towards the Great Lakes, helping drag the
aforementioned low pressure center eastward. As it progresses, the
WFO MPX coverage area will become warm-sectored on Friday, leading
to a return of high temperatures into the mid 90s and heat index
values to the 95-100 degree range for much of the area. A final day
of broad heat headlines is looking more likely for Friday, but
confidence is not there to issue at this time, plus more time to
evaluate the impacts and location of the smoke swath is desired.

The upper ridge will break down more completely over the weekend
into early next week, allowing for a more organized frontal system
to push through the region late Sunday into early Monday. This will
be the best chance for fairly widespread precipitation across our
coverage area through the end of next week. Chances have been upped
to the Likely category with QPF potentially nearing 0.25". Yes, that
isn`t much, but given the lack of rain and prolonged heat, we shall
take what we can get. Once past that system, precipitation will be
decidedly lacking but the tradeoff is noticeably lower temperatures.
Highs drop to the upper 80s to lower 90s Saturday-Monday, then fall
to the lower 80s Tuesday-Thursday. In addition, overnight lows will
drop to the upper 50s to mid 60s Monday night through Thursday
night.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 105 AM CDT Thu Jul 16 2026

Worst of the smoke is impacting most sites at this current time
with either IFR or MVFR visibilities. Did include a short 2hr
tempo for LIFR this morning at RNH where another pocket of dense
smoke potentially blankets the field. Otherwise, sites should
begin to observe improvements back into MVFR around sunrise this
morning then reaching VFR come mid morning. Smoke will linger
through the rest of this morning for MN sites before retreating
back east. RNH and EAU can expect smoke retreat after 00z.

Aside from smoke, fog development is possible especially for
MKT. Currently forecasting MVFR but additional reductions
maybe necessary based on trends and fog extent.

KMSP...Hazy/Smoke conditions expect to improve by 11z this
morning back into MVFR category. By mid morning, VFR vsby should
return although some lingering smoke can be expected until
around 21z. At that time smoke should retreat east.

/OUTLOOK FOR KMSP/
FRI...VFR. Wind SW 10-15kts.
SAT...VFR. Wind N 10-15kts.
SUN...VFR. Chc -TSRA. Wind S 5-10kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Extreme Heat Warning until 9 PM CDT Friday for Anoka-Carver-
     Dakota-Hennepin-Ramsey-Scott-Washington.
WI...None.

&&

$$

DISCUSSION...JPC
AVIATION...Dunleavy