Windfall, Indiana Weather Forecast Discussion

632
FXUS63 KIND 290700
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
300 AM EDT Mon Sep 29 2025
.KEY MESSAGES...
- Dry with unseasonably warm afternoons this week
- Patchy fog possible during the overnights
&&
.SHORT TERM (Today and tonight)...
Issued at 259 AM EDT Mon Sep 29 2025
Be prepared for much of the same weather, as large
synoptic ridge with the width the size of the CONUS has rooted
itself aloft, of which will be reinforced by warm-core lows over the
atlantic and strong AVA over the Eastern Canadian Provinces. This
large upper level ridge is the primary culprit for the well above
normal temperatures we have been experiencing, especially in
combination with weak surface flow and 1020-1025mb surface high
pressure. Expect highs this afternoon to once again push well into
the upper 80s with 850mb temperatures remaining around 15C. A few
locations may reach or exceed 90 for brief periods this afternoon if
the near surface layer can become super dry-adiabatic.
Also continuing is the diurnal patchy dense fog threat due to the
same dry, clear and calm conditions creating large diurnal curves.
However, without a synoptically induced low level moisture source,
fog should be confined to near rivers and in agricultural areas /
farm fields.
For tomorrow, a slight cool down is possible as northeasterly
surface winds develop. Even so temps will still be well above normal
with highs in the mid 80s.
&&
.LONG TERM (Tuesday through Sunday)...
Issued at 259 AM EDT Mon Sep 29 2025
Confidence is increasing in a dry and warm mid to late week with
latest guidance presenting a stronger and broader upper subtropical
ridge over much of the central/eastern CONUS...including a H500
center drifting from northern Illinois to the lower Ohio Valley
while occasionally reaching a 588 dm height.  Meanwhile an equally
massive 1032 mb ridge of Canadian surface high pressure will slowly
follow a circular path around the top and eastern side of the upper
high, from northeastern Ontario to the Mid-Atlantic by Sunday.
Earlier forecast uncertainty surrounding the lingering trough over
southeastern states possibly nosing into the CWA`s far-southern
zones...has shifted to a noticeably lower-humidity solution with
both upper and lower ridges suppressing this feature down the
Appalachians to the Gulf coast through the mid-week.  Next upstream
mid-latitude wave is not expected to approach Indiana until the end
of the weekend...when possibly ample mid-level RH / column
precipitable water will struggle to get through the antecedent dry
boundary layer.
This will all translate to continued rain-free conditions amid warm
afternoons more closely resembling early September normals. Expect
another unseasonably warm day Tuesday with widespread mid-80s. Low
80s the rule for the remainder of the long term period, with the
surface high`s establishment along the eastern seaboard facilitating
light/moderate southerly breezes by the late week.  Generally mostly
clear skies will flank SCT/BKN decks through the Wednesday-Thursday
timeframe when the Canadian air mass first builds into the CWA while
sliding around the upper ridge...with highs perhaps only reaching
the upper 70s for several eastern zones on Thursday.  Morning lows
consistently in the 50s...should include early mornings around 50F
for northeastern counties through the midweek.  The normal max/min
at Indianapolis through the long term falls from 73/52 to 71/50.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 1219 AM EDT MON Sep 29 2025
Impacts:
- Brief MVFR/IFR conditions in fog possible at KHUF/KLAF/KBMG late
tonight
Discussion:
VFR conditions are expected through the TAF period at KIND, with
brief MVFR/IFR conditions expected at KHUF/KLAF/KBMG early this
morning with patchy shallow fog.
The patchy shallow fog at KHUF/KLAF/KBMG will dissipate quickly
after sunrise, ending by 13Z. Diurnal cumulus is expected
tomorrow afternoon similar to today. Winds will be light and
variable overnight and into tomorrow morning before settling on a
northeasterly direction tomorrow afternoon while remaining under
8kt.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
SHORT TERM...Updike
LONG TERM...AGM
AVIATION...Updike

NWS IND Office Area Forecast Discussion