Wonder Lake, Indiana Weather Forecast Discussion

766
FXUS63 KIND 170529
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
129 AM EDT Wed Sep 17 2025
.KEY MESSAGES...
- Dry and hot conditions persist for the rest of the work week
- Drying fuels and low RH values each afternoon through Friday may
lead to elevated fire threat, but light winds should limit overall
concerns
- Next chance of rain and slightly cooler temperatures arrives
  this weekend and early next week
&&
.FORECAST UPDATE...
Issued at 926 PM EDT Tue Sep 16 2025
Temperatures have been dropping rapidly after sunset due to ideal
radiative cooling conditions (light winds, clear skies, low
humidity). In fact, cooling has been so efficient it is hard to
capture it using various model blends. Incorporating NBM 10th
percentile still doesn`t fully capture how quickly temperatures have
dropped since sunset, especially in rural areas where low 60s are
already being reported. With time, the rate of cooling should level
off. For now, we used a blend of NBM10, hi-res guidance, and
observations to get a representative near term forecast (the next
3 hours or so).
Some patchy ground fog may be possible by morning. Given the dry
atmosphere in place, fog should be limited with the best chance
being confined to near rivers and in agricultural/rural areas.
&&
.SHORT TERM (This evening through Wednesday)...
Issued at 247 PM EDT Tue Sep 16 2025
Hot and dry weather continues this week the entire region as high
pressure remains the dominant weather influence and keeps the dry
airmass in place.
Latest satellite imagery shows mainly clear skies over Indiana due
to subsidence under the high pressure. Local ACARs soundings verify
this well showing the subsidence inversion at 800mb and an
environment too dry to support afternoon cumulus for the northern
2/3rd of the state. Upper troughing over the Mid Atlantic states is
advecting upper level moisture into the state, but the only result
of this will be cirrus clouds through tonight.
Expect another tranquil night across Indiana as clearing skies,
light winds, and dry conditions allow for optimal conditions for
radiational cooling. Temperatures quickly fall after sunset with
lows bottoming out in the mid 50s to near 60 degrees.
Very similar set up for tomorrow with high pressure keeping the same
abnormally dry and hot airmass in place. The upper trough from the
previous day pushes northward, switching upper level flow to the
north and shutting off any moisture advection aloft. Expect sunny
skies and highs a few degrees warmer than on Tuesday with highs
reaching the upper 80s to near 90 degrees.
&&
.LONG TERM (Wednesday night through Tuesday)...
Issued at 247 PM EDT Tue Sep 16 2025
The persistent Omega blocking pattern over the area keeping us
summer-like and dry in recent days will continue to be the dominant
force over the area through at least the end of the work week,
gradually beginning to shift orientation and then break down later
this week and into the weekend. This process will allow for
moderation of temperatures back to near seasonal normals this
weekend into early next week, as well as at least low chances for
some scattered showers and perhaps isolated thunderstorms at times
as early as Friday night onward.
Guidance has slowly but steadily trended slower with the demise of
the block, which is fairly typical of both blocking patterns and
NWP`s handling of them, so uncertainty is a bit higher than desired,
even for the long range, with respect to precipitation chances,
particularly over the weekend, but at least low PoPs are merited.
As the block erodes, a couple of upper level lows will eventually
push eastward and exert influence on the region over the weekend
into next week, again allowing for moderation of temperatures and
potential for rainfall.
Abnormally dry or moderate drought antecedent conditions over the
area, along with surface high pressure at least partially inhibiting
moisture return from the Gulf, additionally add uncertainty to the
rain potential. The old maxim of "drought begets drought" may be in
play. GFS Integrated Water Vapor Transport progs (IVT) are quite
poor to non-existent through at least Saturday evening, but
gradually improve with time, particularly by late Sunday onward,
though moisture transport is maximized just to our west/northwest.
Significant uncertainty will remain through the end of the period
and beyond as global models begin to differ significantly toward the
end of the forecast period on the strength and persistence of the
second upper level low, which will have significant impacts upon
both the degree of cooldown and PoPs/persistence of precipitation
chances.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 129 AM EDT Wed Sep 17 2025
Impacts:
- Brief patchy ground fog possible at KBMG tonight
Discussion:
VFR conditions are expected to continue over central Indiana
terminals through Wednesday night...although lower visibility is
possible in some patchy ground fog tonight, especially at KBMG.
Otherwise, a weakening upper level ridge will persist over Indiana
while high cloud will continue to spin off of a Mid-Atlantic trough
into the region while decreasing in coverage.  Diurnal cumulus is
expected again this afternoon.
Light and variable winds will continue early this morning, with a
residual northeasterly component over some locations. Speeds will
pick up later this morning...sustained to around 7KT or less and
from the east to southeast.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...Eckhoff
SHORT TERM...CM
LONG TERM...Nield
AVIATION...AGM

NWS IND Office Area Forecast Discussion