558
FXUS63 KIND 101542
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1142 AM EDT Thu Jul 10 2025

.KEY MESSAGES...

- Fog possible early this morning

- Mainly dry weather today and tonight

- Generally very warm/humid into next week; greatest rain/storm
  chances through this weekend

&&

.FORECAST UPDATE...
Issued at 910 AM EDT Thu Jul 10 2025

Surface Analysis late this morning shows broad high pressure
stretching from eastern Ontario, across MI to Indiana and then to
eastern TX and the deep south. An MCV and thunderstorm complex was
found over southern MN and IA. This system was waning upon its
eastward progression toward the high pressure system. Water vapor
showed strong subsidence in place over Indiana on the lee side of an
upper ridge over the upper midwest. Lower level flow across Indiana
was weak and variable due to the broad high pressure system. GOES16
shows clear skies across Central Indiana.

A dry afternoon is expected. The subsidence in place along with the
broad area of high pressure will provide a mostly sunny afternoon.
Forecast soundings support this showing a dry column along with
hints of CU development late this afternoon as convective
temperatures are approached. Thus a mostly sunny day is expected
with highs in the middle to upper 80s. Overall, ongoing forecast
appears in good shape.

&&

.SHORT TERM (Today and Tonight)...
Issued at 259 AM EDT Thu Jul 10 2025

Skies have largely cleared early this morning as a dirty high
pressure filters slightly drier air into the region from the north.
Have continued to see a few showers briefly developing over
southeast portions of the forecast area. 06Z temperatures were in
the upper 60s and lower 70s.

The presence of the aforementioned high pressure should aid in a
relatively dry day as weak subsidence and a developing capping
inversion should keep all but a stray shower or two from developing.
The Ohio Valley remains within a sloppy and wavy flow pattern aloft
however...which could contribute to additional precip by predawn
Friday or perhaps more likely on Friday and into Saturday with the
approach of a stronger upper level wave into the Great Lakes.

For the short term...the current showers over Jackson County will
continue to drift southeast and are likely to not last long. The
bigger issue through daybreak is the potential for areas of fog to
develop with stagnant flow through the lower levels and remnant
moisture present within the near surface layer. To this point fog
has been localized but anticipate further expansion through daybreak
before diminishing quickly.

Much of the day will be quiet with abundant sunshine...light winds
and slightly lower humidity. Model soundings do support diurnal cu
development for the afternoon and despite the much drier...subsident
layer aloft and the cap noted around 700mb...there is likely to be
just enough instability to generate a stray shower or two for a
brief period late this afternoon. Most areas will remain dry but
this is enough to warrant very low precip chances for a couple
hours.

Cu will diminish near sunset with mostly clear skies returning for
the first half of the night. Another subtle wave aloft will approach
the region in the predawn hours and while the bulk of the upper
level forcing and deeper moisture will be displaced further north
over the Great Lakes...could see a few showers approach the northern
Wabash Valley towards daybreak Friday. Leaving a dry forecast at
this time with low confidence in this solution coming to pass.

Temps...low level thermals support highs relatively similar to
Wednesday in the mid and upper 80s. Lows tonight will be in the
upper 60s and lower 70s.

&&

.LONG TERM (Friday through Wednesday)...
Issued at 259 AM EDT Thu Jul 10 2025

High humidity will continue in tandem with very warm to marginally
hot conditions into the middle of next week...as central Indiana
finds itself generally south of an somewhat active zonal flow
stretched along the Canadian border...yet north of any better-
organized portions of the subtropical ridge that will attempt to
build into the Midwest next week.  Weak boundaries on the very
southern tier of waves passing closer to the Great Lakes, will
occasionally align closer to the Ohio Valley.  Corresponding light W
to NW flow, which will be most prominent around the Sunday-Monday
timeframe should promote slightly milder readings peaking near the
mid-80s, and perhaps an overnight falling to the mid-60s for a
portion of the region.  Otherwise upper 80s should be the rule
through the long term, with several days around 90F closer to the
Ohio Valley.  Maximum afternoon heat indices should be highest on
Friday and Saturday, in the mid to upper 90s, courtesy of higher
dewpoints above 70F...and also Wednesday ahead of the long-awaited
Canadian cold front.

Daily opportunities for diurnally-driven convective scattered
showers and at least isolated storms will continue...with perhaps
more numerous coverage of showers when northern stream waves
approach the CWA both over the weekend and perhaps again at the end
of the long term ahead of possibly noticeably milder air. Associated
non-zero wind shear will introduce the potential for a few strong
storms Friday night, especially N/W of Indianapolis... before the
period`s best opportunity for stronger storms, late Saturday as a
small short wave passes, and then late Sunday when lift from the
associated boundary may combine with decent wind shear.
Expect any TRWs Monday-Tuesday to be a less-organized, typical
midsummer type.  Greatest threats from most storms will be
lightning, torrential downpours, and localized flooding...with a few
stronger cells this weekend perhaps capable of producing minor
damage.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1142 AM EDT Thu Jul 10 2025

Impacts:

- VFR this period.

Discussion:

Surface high pressure stretching from Ontario across Indiana to TX
and ridging upstream aloft will provide VFR conditions this TAF
period.

Diurnal cumulus is expected this afternoon and again on Friday
afternoon as convective temperatures are reached. CU will diminish
in the evening as heating is lost. Forecast soundings keep a dry
column through the area this afternoon and tonight along with a mid
level inversion which will inhibit tall CU growth.

&&

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

$$

UPDATE...Puma
SHORT TERM...Ryan
LONG TERM...AGM
AVIATION...Puma