979
FXUS63 KIND 020518
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
118 AM EDT Sat Aug 2 2025

.KEY MESSAGES...

- Pleasant conditions through much of the weekend with highs in the
  upper 70s and overnight lows in the 50s

- Smoke aloft will keep skies hazy at times through Saturday

- Scattered diurnal threats for rain and storms return Monday and
  persist through late next week

- Temperatures will return to seasonal levels next week with the
  possibility of a hotter and more humid airmass by late next week
  into next weekend

&&

.FORECAST UPDATE...
Issued at 928 PM EDT Fri Aug 1 2025

Forecast is in good shape this evening. Cumulus continue to quickly
dissipate, leaving behind some cirrus and elevated smoke. Satellite
shows that cirrus will be on the increase as they flow in from the
west. Made some tweaks to sky cover as needed.

Much drier air is allowing temperatures to fall nicely, especially
in rural areas. Adjusted hourly forecasts as needed, but no changes
were needed to low temperatures.

Model forecasts of near surface smoke show a general decrease across
the area overnight. Thus do not expect any significant impact from
smoke and have left mention out of the forecast.

&&

.SHORT TERM (This Evening through Saturday)...
Issued at 214 PM EDT Fri Aug 1 2025

Beautiful first day of August in progress as high pressure settles
across the Great Lakes and Ohio Valley. The heat and humidity so
prevalent across the region over the last 7-10 days has been shoved
well to our southeast and been replaced by the coolest airmass since
the second week of June. Temps were in the mid and upper 70s at 18Z.

The short term through Saturday will be quiet as high pressure
centered over the western Great Lakes serves as the dominant
influence across central Indiana. Diurnal cu has formed this
afternoon with a noted axis streaming southwest from the western
Lake Erie basin...in effect Lake Effect clouds. As the airmass
continues to dry out through the remainder of the afternoon and
dewpoints fall through the 50s...expect cu to gradual diminish by
late day leaving largely cloudless skies tonight outside of some
thin passing cirrus. Breezy northeast winds will diminish towards
sunset with winds dropping to 5-10mph overnight. Abundant sunshine
is expected Saturday with winds veering slightly to a more E/NE
direction at 10-15mph. Deeper subsidence will advect south into the
region but model soundings continue to show potential for some
diurnal cu development in the afternoon.

The one primary issue in the short term is on the continued
potential for smoke from the Canadian wildfires to drift across
parts of the forecast area and the attendant haze likely to
accompany the smoke aloft. Smoke density has diminished from earlier
this morning as predominant northeast flow has pushed it in to the
northern half of Illinois. The Canadian smoke model shows the bulk
of the higher densities to remain north and west of the forecast
area for the rest of the day and much of tonight...but a renewed
surge of thicker smoke aloft will advect south from lower Michigan
and may once again overspread the northern half of central Indiana
on Saturday. This will largely not limit sunshine but manifest again
with slightly diminished visibilities in haze. As previous shifts
have done...will continue to keep cloud coverage percentages
generally no lower than 30% for the rest of the afternoon and then
again on Saturday.

Temps...the entire forecast area should fall into the 50s tonight...
something that has not occurred in nearly two months. Low level
thermals for Saturday support highs close to what is expected this
afternoon if not a degree or two warmer in the upper 70s to around
80.

&&

.LONG TERM (Saturday Night through Friday)...
Issued at 214 PM EDT Fri Aug 1 2025

Pleasant weather will continue through the second half of the
weekend as high pressure drifts slowly east across the Great Lakes.
Moisture return will commence by Monday on the back side of the
departing high and as low level flow transitions back to a more
southerly direction. Expect an increase in temperatures and humidity
levels back to seasonal norms while reintroducing daily threats for
scattered convection. This will persist through much of next week as
ridging aloft remains anchored over the southern Rockies and High
Plains while a weakness in the flow lingers further east across the
Ohio and Tennessee Valleys. The eastward expansion of the ridge by
late next week will enable a more oppressive airmass to return to
the area after a week long or so sabbatical.

Saturday Night through Monday Night

Dry air and subsidence will remain over the region with high
pressure centered to the north. This will maintain dry and
comfortable conditions through the end of the weekend with a subtle
warming trend back into the lower 80s for Sunday. A broader return
flow on the back side of the surface ridge will arrive on Monday
bringing deeper moisture back into the Ohio Valley from the south.
While temperatures will not be much warmer than Sunday...the
increased amounts of low level moisture will bring the potential for
isolated to scattered afternoon convection focused especially across
the southern half of the area. After cooler nights through the
weekend...lows will rise back into the mid and upper 60s by Monday
night.

Tuesday through Friday

A weak but persistent level of troughiness aloft on the lee side of
the ridge to the west will combine with a steady increase in
instability and low level moisture to support a daily threat for
mainly afternoon and evening isolated to scattered convection
throughout the remainder of next week. There is really no signal for
a period of more widespread coverage to rain and storms but the
potential will be present through Friday with the overall weakness
in the mid and upper level flow lingering. This sort of a modest
instability/low shear/deep moisture environment will support slow
moving localized soakers that generally remain subsevere. However
any stronger cell with a collapsing core will carry a localized
gusty wind threat.

Highs will return to closer to seasonal levels for early August in
the mid 80s by the middle of next week but as mentioned above...
heights aloft will respond to an expansion of the ridging to our
west with highs by Friday pushing 90 degrees and dewpoints returning
to levels near or above 70 degrees. This pattern likely continues
through much of next weekend before the potential for another cool
down early in the second week of August.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 118 AM EDT Sat Aug 2 2025

Impacts:

- Wind gusts of 15-20kt range possible again this afternoon
- Brief upper level haze possible from Canadian wildfire smoke

Discussion:

VFR conditions expected through the weekend at all TAF sites across
Central Indiana. Surface high pressure over the Great Lakes is the
dominant weather influence locally, keeping surface conditions
relatively benign. Expect another day with a diurnal wind trend with
light northeasterly flow this morning and gusts within the 15-20 kt
range 15z-00z due to low level mixing. A few afternoon cumulus are
possible, with cigs remaining VFR. Upper level haze is possible from
Canadian Wildfire smoke and is not expected to impact surface
visibility.

&&

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

$$

UPDATE...50
SHORT TERM...Ryan
LONG TERM...Ryan
AVIATION...CM