612
FXUS63 KIND 071629
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1229 PM EDT Mon Jul 7 2025

.KEY MESSAGES...

- Scattered thunderstorms possible this afternoon focused over the
  southeast half of central Indiana

- Torrential downpours will again be the primary concern

- Following a mainly dry day Tuesday daily shower/t-storm chances
  will persist through the week amid humid and very warm conditions

&&

.FORECAST UPDATE...
Issued at 1053 AM EDT Mon Jul 7 2025

No significant changes required to today`s forecast but did tighten
up PoPs this morning. A cold front is moving through the forecast
area today, from NW to SE, with chances for showers and some
thunderstorms as it moves through. Best chances will be along and
south of the I-70/I-69 corridor through the evening.

High temperatures today will be in the mid 80s.

&&

.SHORT TERM (Today and Tonight)...
Issued at 305 AM EDT Mon Jul 7 2025

Conditions had settled down across the forecast area early this
morning after the convection from Sunday afternoon and evening. Most
of the cloud debris from earlier storms had diminished but lower
stratus was expanding southeast across the northern Wabash Valley.
06Z temperatures were predominantly in the low to mid 70s.

The frontal boundary that served as a catalyst for the Sunday
afternoon and evening storms was just now moving into far northern
portions of the forecast area. The front will gradually shift south
through the region later today with renewed convective development
expected to focus across the southeast half of the forecast area
nearest to the boundary. Weak high pressure will build in tonight as
the front moves closer to the Ohio River bringing a slightly drier
airmass into the area.

While an isolated shower remains possible through mid morning with
the front moving into the region...much of the airmass has been
worked over from the earlier storms with mesoanalysis highlighting a
fair amount of CIN across central Indiana. The primary focus over
the next several hours will be more with the expansion of the lower
ceilings across the forecast area and the potential for patchy fog
to develop with near calm winds and moisture becoming trapped
beneath a shallow inversion. Any fog will dissipate shortly after
sunrise but the lower stratus will take its time lifting...likely
not fully mixing out into a cu field until early afternoon.

The boundary will move into the southern half of the forecast area
this afternoon and will serve as the focal point for scattered
convective development. PWATs remain near 2 inches and with light
winds...storms will be slow moving again. Torrential downpours
producing localized flooding will be the main concern. Stronger
cells may again produce gusty winds but low level lapse rates are
weaker today than Sunday and little shear is present. Expect a
disorganized multicellular storm mode as a result.

Convection will move southeast out of the forecast area by early
evening with dry conditions expected tonight as weak high pressure
builds into the region. Potential exists for patchy fog to develop
predawn Tuesday but the arrival of drier air with light northerly
flow should be enough of a deterrent from keeping fog coverage
minimal.

Temps...after 3 to 4 days of highs near or just above 90...
temperatures will be cooler today in the low and mid 80s. Lows
tonight will be in the 60s.

&&

.LONG TERM (Tuesday through Sunday)...
Issued at 305 AM EDT Mon Jul 7 2025

A progressive weather pattern develops over much of the country
through next week featuring several weak shortwaves and associated
surface features bringing several chances for thunderstorms across
Central Indiana.

On Tuesday, Surface high pressure and low level ridging behind
Monday`s front briefly bring drier conditions to the state with
seasonal temperatures in the mid to upper 80s. Despite several
weather systems passing through this week, the surface airmass will
remain relatively unchanged with high humidity, dew points around
70, and seasonal temperatures in the mid 80s to near 90 each day.

A digging trough and associated shortwave dive southeastward from the
Dakotas and into the Great Lakes Tuesday night bringing the next
chance for showers and storms to the region. The surface feature
associated with this synoptic system is fairly weak and diffuse, so
expect mid range models to struggle with the evolution of the
surface pattern and placement of areas of greatest convective
activity.  This will likely be a set up where micro to mesoscale
features develop Tuesday in the Central Plains then propagate
eastward into the state along and just ahead of the upper trough
axis. This far out, lower resolution guidance is not able to handle
the finer details, so confidence is low on the exact timing in
placement of convective activity. For now, higher confidence exists
in showers and storms approaching from the west late Tuesday night
into Wednesday morning. Depending on how quickly the environment can
recover Wednesday afternoon, there may be a second round of storms
that develops as the weak surface feature will be directly overhead
within a warm,humid, and likely unstable environment. Widespread
severe weather is not a concern in this set up due to weak shear
through the column. However any storm will have the potential to
produce brief periods of strong winds as well as very heavy rain and
lightning. Will fine tune timing of storms, specific locations, and
threats in future forecast issuances as confidence increases. Areas
that see repeated rounds of heavy thunderstorms this week will be at
a greater risk for flash flooding on any given day.

While uncertainty increases through the rest of the week regarding
timing and placement of these weak features passing through the
area, a similar weather pattern likely persists featuring seasonal
temperatures during the day and high humidity with daily chances for
scattered storms. Longer range guidance shows another frontal
boundary approaching the region Friday into Saturday bringing
additional chances for more widespread storms. Nothing too
concerning is in the forecast for the long term period as the
current weather pattern should result in seasonable July weather for
the region. Lower confidence does exists in the finer details of
each passing system, that lower resolution guidance is not able to
resolve this far out. Mesoscale details of each system will become
clearer in time as smaller mesoscale to microscale boundaries will
likely have just as much impact on the evolution of the daily
weather pattern as larger synoptic features. Details such as
mesoscale boundaries, outflow boundaries, upstream storm complexes,
etc may all have impacts on how each day unfolds, bringing with it
unique complexities that can really only be forecasted within the
near term.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1229 PM EDT Mon Jul 7 2025

Impacts:

- MVFR ceilings this afternoon
- Return to VFR conditions by late afternoon
- Scattered convection possible this afternoon near KBMG.


Discussion:

As a upper trough and cold front work across Central Indiana, GOES16
shows low clouds across the TAF sites slowly moving northeast. A
left over boundary from yesterday`s convection was found across
southern Indiana, and radar shows some TSRA development at across
the southern parts of the state.

Clouds are expected to take a slow progression eastward this
afternoon and continue to mix out. This will lead to a gradual
transition from MVFR cigs to VFR Cigs until no Cigs arrive this
evening. Given the location of the front near BMG, a TSRA could be
possible this afternoon at that location. Have used VCTS to account
for that at the moment.

High pressure will build in from the north overnight, leading to VFR
conditions and light north winds. A few CU will be possible on
Tuesday as heating and mixing resumes by late morning.

&&

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

$$

UPDATE...KF
SHORT TERM...Ryan
LONG TERM...CM
AVIATION...Puma