329
FXUS63 KIND 140539
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
139 AM EDT Mon Jul 14 2025

.KEY MESSAGES...

- Patchy fog possible late tonight and into tomorrow morning`s
commute

- Not quite as warm/humid through Monday, with otherwise humid and
very warm/marginally hot conditions returning Tuesday

- Daily chances of showers/t-storms next week for mainly Tuesday and
onward with isolated downpours/localized flooding possible

&&

.FORECAST UPDATE...
Issued at 139 AM EDT Mon Jul 14 2025

Observations show dense fog near/in northern Carroll County, with
fog developing to the west and northwest of central Indiana. Latest
hi-res guidance shows dense fog continuing to spread across the
northwest forecast area overnight, and this seems reasonable with
the light winds, lower cloud cover, and high moisture content of the
lower atmosphere.

Have thus issued a Dense Fog Advisory for the northwest forecast
area. Will continue to monitor for changes and if the need to adjust
the advisory arises.

&&

.SHORT TERM (This evening through Monday)...
Issued at 259 PM EDT Sun Jul 13 2025

Central Indiana is seeing cumulus clouds across the area with
approaching showers and storms just off to the west. Isolated
showers have formed in our NW as of mid-afternoon but that coverage
will continue to expand as showers and storms fill in and the system
gradually approaches.

While our NW border is already seeing a few showers as of this
issuance, our SW border should see the arrival of storms around 4 to
5pm. Main threats with storms this evening will be lightning,
localized heavy rain, and a few strong winds gusts within stronger
storms. Best threat for isolated damaging winds will be along and
south of I-74, where an expected vort max will interact with a warm,
buoyant environment, and the threat is expected to come to an end
around sunset. This system will continue progressing eastward
through the evening and into tonight. Past midnight, the best
chances for PoPs will be south of I-70.

With a moist airmass in place, calm winds, and lingering showers,
patchy fog will again be possible for late tonight and into tomorrow
morning`s commute. As the morning goes on, fog should mix out and
most of the lingering rain should have pushed eastward. However, a
boundary could stall just to the SE so our SE counties could see
rain into the afternoon or evening hours. Afternoon heating may also
work to  enhance coverage later in the day as well, but strong
storms are not expected.

Lows tonight will be near 70 and highs tomorrow will again be in the
mid 80s.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 259 PM EDT Sun Jul 13 2025

Overall forecast thoughts remain generally the same for the extended
thus an update to the discussion was not needed. Expect daily storm
chances through the period with localized flooding being the primary
threat. Weak deep-layer shear should tend to limit the severe
threat, but deep moisture and daytime heating promoting strong
instability most afternoons could support isolated strong to severe
wind gusts in loosely-organized storms mid to late week. Please
refer to the previous discussion below for additional details on the
long-term forecast...

Stagnant mid-summer synoptic pattern to continue over the Midwest
this week, as the H500 588 dm height contour to remain generally in
a zonal west-to-east alignment just north of central Indiana through
at least mid-week.  Weak surface ridging through Monday night will
suppress better deep moisture to the south, with precipitable water
values closer to only 1.50 inches over the local region.
Corresponding surface dewpoint reductions will be minor, but should
be enough to get lows Monday night into the upper 60s for much of
the region.

Light southerly breezes Tuesday afternoon will then return several
marginally hot and humid days through the mid-week.  Highs in the
upper 80s to around 90F...will combine with dewpoints in the low to
mid-70s...to yield afternoon maximum heat indices into the mid-90s
to low 100s. The return of loosely-organized diurnally-driven
convection Tuesday should increase on to numerous showers/scattered
TRWs for both Wednesday and Thursday...which should at least provide
late-day heat relief for some locations.

An increasingly-active northern jet should send several short waves
eastward along the Canadian border through the mid- to late week.
While there is so far low confidence in any of these weaknesses
plunging cooler air into the local region by the end of the long
term, they will at least encourage surface low pressure to take form
across the central Plains, with associated gradient and weak
convergence over the local CWA fueling convection with oppressive
humidity, lift...and just enough wind shear to present the potential
for stronger storms by the late workweek.

Greatest threats in any stronger mid/late week thunderstorms will be
isolated flooding from downpours and possibly strong to severe
winds. Chances for a cold frontal passage will be highest by the end
of the long term, with the periods` lowest temperatures possible as
the workweek ends.

Indianapolis` normal max/min will maintain the year`s peak values
through July 22...85/67.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 103 AM EDT Mon Jul 14 2025

Impacts:

- IFR and worse conditions at most sites in stratus and fog
  developing during the night and lasting until about 13Z
- Isolated showers around during the night with isolated storms
  mainly southern sites Monday afternoon

Discussion:

Stratus and fog will continue to develop across the sites overnight,
with most sites reaching IFR conditions. KLAF should see the lowest
visibility with lower than IFR conditions possible. Elsewhere should
see mainly MVFR visibility with IFR ceilings.

Fog and stratus will mix out during the morning, with a scattered to
broken cumulus field developing. Isolated showers and storms will be
around at times through the period, primarily at the southern sites.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM EDT this morning for INZ021-028-
029-035-036-043-044.

&&

$$

UPDATE...50
SHORT TERM...KF
LONG TERM...AGM/Melo
AVIATION...50