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000
FXUS63 KIND 091353
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
953 AM EDT Fri Jun 9 2023

.Forecast Update...
Issued at 952 AM EDT Fri Jun 9 2023

Canadian wildfire smoke continues to appear upstream of Indiana in
this morning`s satellite imagery, and the northerly upper level
winds depicted in this morning`s ACARS soundings should advect this
smoke into the area this afternoon. Due to otherwise clear
conditions, diurnal warming and diurnal mixing processes are primed
to take effect throughout the course of the day.

Surface observations indicate that temperatures have been slightly
over-performing the forecast this morning, and it is plausible that
high temperatures may reach the 80 degree mark in southern and
western portions of the forecast area this afternoon. Afternoon
highs were slightly raised in accordance with this thinking.

The combination of warmer temperatures, the potential for diurnal
mixing, a thicker plume of smoke aloft in Michigan and Northern
Indiana, and northerly flow in the column may cause air quality to
deteriorate into unhealthy thresholds for sensitive populations
later today. As a reminder, an Air Quality Alert (issued by the
Indiana Department of Environmental Management) remains in effect
today.

&&

.Short Term...(Today and tonight)
Issued at 202 AM EDT Fri Jun 9 2023

The weather pattern will change little in the short term. Periods of
smoke and haze from wildfires in Canada will continue since mean
northerly flow will prevail. For today, the mean flow should back
some to more northwesterly shifting trajectories of smoke from
Quebec fires mostly east of us. However, additional wildfires over
Ontario may contribute to at least a modest amount of smoke
continuing. For more information on potential air
quality impacts, please refer to the Indiana Department of
Environmental Management Air Quality Alert Message (AQAIND).

An upstream shortwave trough over southern Canada won`t have much
impact during the short term period, except for perhaps enhancing
high-level moisture flow and resultant cirrus by tonight. Lower
tropospheric flow will remain modest with stronger response
relegated to the Ozarks and central Plains. This, along with
midlevel height trends generally being neutral and still overall
negative anomalies, suggest maybe a degree or two warmer today at
best. Upper 70s will be common for maximum temperatures.

Tonight, broad transient surface high will be optimally placed for
light/calm winds, and as long as cirrus is minimal, good radiative
conditions are likely. This may push us down below current forecast,
and we have lowered temperatures slightly.

&&

.Long Term...(Saturday through Thursday)
Issued at 202 AM EDT Fri Jun 9 2023

Saturday Through Monday.

The pattern will begin to shift Saturday into Sunday as the
persistent high pressure and upper level ridging will begin to break
down ahead of the most robust low pressure system across the area
in the last few weeks.  Models have been fairly consistent in both
timing and strength of the upper level closed low and associated
surface front that will move through the area late Sunday into
Sunday night with widespread rain amounts up to a half inch and
mesoscale banding of up to 1.5 inches.

Model soundings show little to no instability with a stable layer
through the lowest 10kft and saturation up the column which should
limit the thunder potential. Dry air will quickly move in behind the
frontal passage with much cooler air for Monday as skies begin to
clear.

Tuesday Through Thursday.

Dry conditions are expected for much middle portions of the week
with westerly flow at the surface and northwesterly flow aloft as
the weekend low pressure system continues to slowly spin across
eastern Michigan as it slowly moves into the Eastern Great Lakes
region. Some northwesterly flow Tuesday may allow for precipitation
across the northeastern counties with some lift noted in the mid
levels, but not expecting much when it comes to QPF. Temperatures
will gradually begin to warm back up Wednesday into Thursday but
should remain near normal both for the daytime highs and overnight
lows.

&&

.Aviation...(12Z TAF Issuance)
Issued at 539 AM EDT Fri Jun 9 2023

Impacts:

* Haze and smoke may periodically reduce visibility slightly

Discussion:

While VFR conditions will prevail most likely, minimal reductions of
visibility due to haze resulting from Canadian wildfire smoke is
possible through the TAF periods. Light northerly winds are expected
to continue.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Update...Marcus
Short Term...BRB
Long Term...White
Aviation...BRB