126
FXUS63 KIND 290159
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
959 PM EDT Sat Jun 28 2025

.KEY MESSAGES...

- A few showers and storms into this evening

- Patchy fog with locally dense fog early Sunday

- Scattered daily afternoon and evening showers/t-storms Sunday and
  Monday; isolated strong wind gusts are possible as well as
  localized flooding

- Drier and slightly cooler weather expected for the middle of next
  week before more humid conditions return Friday into next weekend

&&

.FORECAST UPDATE...
Issued at 959 PM EDT Sat Jun 28 2025

Convection, which has been driven more by outflow recently,
continues to weaken across much of the southern forecast area. This
is due to much of that area being worked over from earlier
convection as well as the instability beginning to decrease as the
sun sets.

Heavy rain will be the primary threat from any lingering stronger
convection. Have some slight chance to chance PoPs across areas that
are currently seeing convection/dying convection. The chances will
continue to diminish through around midnight with continued loss of
heating and no significant forcing.

However, wouldn`t be surprised if a pop up shower shows up into the
early overnight as has been seen in recent days.

Clouds from the convection will thin during the night, and winds
will be light. This will allow for the potential for patchy fog,
especially where rain has fallen. Locally dense fog is possible.
Will continue the fog mention.

Adjusted hourly temperatures based on latest observational trends.
Made some tweaks to low temperatures, but no significant changes
were made.

&&

.SHORT TERM (This Evening through Sunday)...
Issued at 238 PM EDT Sat Jun 28 2025

Ample diurnal cu field remains over the forecast area early this
afternoon and although dewpoints remain in the lower to mid
70s...temperatures are running cooler for the afternoon than they
have in 8 days with most locations in the mid and upper 80s as of
18Z. Convection has largely remained to our south and east so far
this afternoon but have noticed some enhancement to cu on recent
satellite imagery and there does appear to be a few tiny showers
trying to form.

The remnants of the frontal boundary moving slowly away to the east
and lingering moisture and instability will keep the threat for a
few storms around into this evening before the forecast area can
enjoy a brief break as drier air and weak high pressure pass by to
the north through the Great Lakes. As that passes by however...
moisture will advect back into the region from the southwest on
Sunday with a return to the recent pattern of afternoon and evening
scattered convection.

There appears to be some form of weak convergence zone extending
along I-70 west from Ohio across the forecast area and back into
south central Illinois. While the deepest moisture has already
shifted to near and south of the Ohio River...this convergence zone
may serve as a focal point for the convective development locally
over the next few hours as it drifts south. Convection will be
entirely dependent on available instability and moisture as shear is
nonexistent. A few cells may become strong enough to generate gusty
winds but the setup favors locally heavy downpours from slow moving
convection that will remain disorganized and challenged to maintain
intensity for any extended length of time. Will maintain scattered
pops until near sunset before precip chances end as slightly drier
air advects in from the north.

Cannot rule out a stray shower overnight into early Sunday morning
across far southern portions of the forecast area in closest
proximity to the deeper plume of moisture. As winds go near calm and
skies gradually clear...fog is likely to develop and may be locally
dense in spots.

As mentioned above this will be short lived as deeper moisture
returns back into the southern half of the forecast area as early as
after daybreak Sunday and gradually expanding north through the day.
There is a subtle upper level wave that combined with the deeper
moisture as PWATS climb back to 2 inches or higher that should
contribute to greater convective coverage by the afternoon focused
especially near and south of the I-70 corridor. Shear remains
virtually nil with convection moving slowly leading to locally
torrential downpours.

Temps...the 90 degree streak will break for most locations today and
low level thermals support highs remaining in the mid to upper 80s
on Sunday as well...aided by increase cu coverage and scattered
convection. Lows tonight will range from the upper 60s to lower 70s.

&&

.LONG TERM (Sunday Night through Saturday)...
Issued at 238 PM EDT Sat Jun 28 2025

Unsettled weather will continue for the early part of the week as
the combination of an upper level wave and a cold front sweep across
the Great Lakes and Ohio Valley. Once these features pass Tuesday
morning...a drier and slightly cooler airmass will build in courtesy
of broad surface high pressure and drier northwest flow aloft. Upper
level ridging will return by late next week with a likely return to
isolated to scattered diurnal convection both Friday and Saturday as
a more unstable airmass reestablishes across the Ohio Valley.

Monday and Monday Night..

The arrival of the aforementioned upper level wave with the front
and a poorly organized surface low will bring the best threat for
rain and storms throughout the extended on Monday and Monday night.
A few stronger storms are possible Monday afternoon and evening but
mitigating factors will be weak boundary layer shear and overall
poor lapse rates through the column. More than likely...torrential
rainfall and localized flooding will be the primary threats yet
again from convection along with lightning serving as a deterrent to
outdoor activities. PWATs will rise above 2 inches and storms will
be slow moving. Gusty winds are possible as downdrafts collapse
courtesy of heavy precipitation loading with the influx of rich deep
moisture.

Convection will linger Monday night before diminishing by Tuesday
morning as the front moves away to the east. Highs on Monday will
primarily reach the mid 80s with lows Monday night falling into the
mid and upper 60s as drier air begins to filter in from the west as
the front shifts east.

Tuesday through Saturday...

Mostly quiet weather conditions are increasingly expected as the day
progresses Tuesday...continuing through Thursday as high pressure
settles across the region. Dewpoints will finally fall back into the
lower and middle 60s and perhaps even down into the upper 50s in
northern portions of the forecast area for midweek...providing a
break from the recent stretch of oppressive conditions. Highs will
slide back into the mid 80s Tuesday and Wednesday before beginning
to rise on Thursday.

The arrival of ridging aloft coinciding with a weakening of the
surface high will enable deeper moisture to advect back into the
Ohio Valley by Friday with growing confidence in higher dewpoint air
at or above 70 degrees making a return for the holiday into next
weekend. Instability will increase in response with both Friday and
Saturday likely to see isolated to scattered pulse intensity...short
lived and slow moving convection develop during the afternoon and
evening. Highs will creep back up to around 90 for Friday and
Saturday.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 703 PM EDT Sat Jun 28 2025

Impacts:

- Some isolated to scattered convection is expected mainly at the
  southern sites and during the early part of the period

- Patchy fog tonight, perhaps dense in spots

Discussion:

Scattered convection along an area of convergence will persist early
in the period, mainly near KBMG. Much of the convection will
dissipate this evening, but an isolated shower or storm may persist
into the night. Will have a mention early, but odds will be too low
to mention overnight.

The other concern is the development of fog overnight. With low
level moisture and light winds, patchy fog will form. Whether it
occurs at a TAF site remains somewhat uncertain, but will continue
to keep a mention of MVFR fog for now at most sites. Locally dense
fog may form if conditions set up just right, especially near KBMG
where storms are more common this evening.


&&

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

$$

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