Plainfield, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

411
FXUS63 KIND 290645
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
245 AM EDT Mon Jun 29 2026

.KEY MESSAGES...

- Hot and humid condition expected for much of this week with
  multiple days in the 90s and heat indices over 100 degrees

- Heat Advisory in effect this afternoon through Thursday

- Thunderstorm chances will increase late week into the holiday
  weekend

&&

.DISCUSSION (Today through Sunday)...
Issued at 245 AM EDT Mon Jun 29 2026

Steamy early this morning as with leftover convective cloud debris
drifting southeast across the region on the eastern flank of the
upper ridge. 06Z temperatures were in the mid and upper 70s.

The ridge will amplify across much of the eastern part of the
country over the next several days with an extended stretch of hot
and humid conditions lasting into the upcoming weekend. This will be
easily the hottest weather of the summer to date through Thursday
with dangerous heat indices becoming a primary concern throughout
the forecast period. The ridge will flatten by the end of the week
as the jet stream drifts back south into the area. Scattered
convection largely prevalent on any waves ripping through the flow
will increase for the holiday weekend as a result.

The remnants of convection from Sunday afternoon continue to track
southeast out of lower Michigan early this morning on the east side
of the upper ridge. There remains just enough low level moisture
that a few stray showers are not entirely out of the question across
the northeast half of the forecast area through daybreak. After
that...the ridge axis will pivot across the Ohio Valley shifting any
threat of rain well to the east of central Indiana.

Despite scattered diurnal cu development today...the onset of the
dangerous heat and humidity that has been discussed for several days
now arrives over the Ohio Valley today. Today will mark the first in
an extended stretch of days with highs 90 degrees or warmer and heat
indices above 100 as the heat ridge becomes the dominant influence
for much of the next week. The Heat Advisory will go into effect at
16Z this afternoon and continue through Thursday. The hottest days
will be Tuesday and Wednesday as the core of the ridge parks over
the region with heights at 596-597dam. Highs both days will peak in
the mid 90s in some locations with limited clouds. Daytime dewpoints
remaining well into the 70s will ensure max heat indices at 105 to
109 degrees and provide an oppressive airmass that will only
exacerbate the hot temperatures.

The ridge will slowly flatten heading into the weekend as waves
aloft drift further south into the lower Great Lakes and Ohio
Valley. Moisture lifting around the back side of the ridge may be
enough to generate more cu and perhaps isolated late afternoon and
evening convection by Thursday. Convective coverage should steadily
increase Friday into the weekend as the mid level heights begin to
fall back. Locally intense slow moving storms will be a possibility
within the moist and highly unstable airmass. Very warm and humid
conditions will linger into the holiday weekend with highs slipping
back into the upper 80s by Sunday.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1202 AM EDT Mon Jun 29 2026

Impacts:

- Patchy MVFR fog possible overnight, periods of IFR possible at KBMG

Discussion:

High level convective cloud debris will continue to drift southeast
across the region over the next few hours. Still feel LAMP guidance
is underforecasting fog potential...and NBM probabilities tend to
hint at somewhat more possibility for visibility restrictions
predawn and through daybreak. Greatest potential will be at outlying
terminals and will continue with a period of tempo MVFR. At KBMG
which is both climatologically vulnerable and in one of the wetter
regions of the area in recent days...IFR visibilities will be
possible later in the overnight.

VFR conditions are expected once any fog dissipates in typical
diurnal fashion by mid morning. Diurnal cu is possible for this
afternoon before diminishing as skies clear this evening. S/SW
winds up to 10kts are possible later today.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 8 PM EDT Thursday for INZ021-
028>031-035>049-051>057-060>065-067>072.

&&

$$

AVIATION...Ryan
DISCUSSION...Ryan