782
FXUS63 KIND 092027
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
327 PM EST Mon Feb 9 2026

.KEY MESSAGES...

- Patchy fog possible late tonight into Tuesday morning.

- Mostly dry through midweek with mix of rain and snow chances
  returning late Thursday.

- Rain is likely late Saturday into Sunday although uncertainty
  remains on the exact timing and amounts.

- Ice Jam development remains a concern this week with milder
  temperatures expected.

- Generally near seasonal temperatures this week, except Tuesday and
  again early next week when highs are expected to be in the 40s and
  50s.

&&

.SHORT TERM (This evening through Tuesday)...
Issued at 327 PM EST Mon Feb 9 2026

Satellite imagery shows stratus associated with broad isentropic
lift exiting to our northeast. Simultaneously, high cirrus is
advancing in from the northwest ahead of a shortwave ejecting from
the northern Rockies. This shortwave is modeled to progress eastward
and interact with an existing low over south central Canada.

A potent low-level jet is expected to develop late tonight in
response to the developing system. Guidance shows strong
southwesterly flow in the 925mb to 850mb layer between 45 to 55
knots. Impressive warm air advection takes hold after about 06z,
though mainly above the surface. Within the boundary layer,
radiational cooling combined with warm air advection aloft will help
strengthen a sharp near-surface inversion. Limited momentum transfer
is expected overnight with only light winds at ground level.

As mentioned above, temperatures tonight should be dominated by
radiative effects with limited impact from ongoing warm air
advection. Guidance may be a bit too warm for lows, as model snow
depth seems to melt off too fast this afternoon. Current dew point
depressions are greater than 20 degrees, with wet bulb zero values
below freezing. Therefore, the current snow pack may be more
resilient than guidance suggests. That being said, the impact
current snow cover has on temperatures may be greater than guidance
indicates...especially during the overnight period.

During the day, however, that may not be the case. Today, for
instance, is running above guidance despite the current snow cover
and its associated high albedo. A stronger sun angle and light winds
help in this regard. Tomorrow may be similar, as high-level clouds
diminish substantially around sunrise. There is one caveat, however,
that could make tomorrow`s temperatures a bit of a challenge. That
caveat is moisture advection.

In addition to strong warm air advection, moisture will also be
lifted northward. Warm moist air over a cold dense snowpack is an
ideal setup for advection fog. We`ve included patchy fog to the
forecast for the southern half of our CWA. We maintained patchy
wording since it`s uncertain as to how much fog develops or lifts
into a low stratus layer. The southern edge of the current snowpack
is well to our southwest. It`s not unreasonable to think that fog
develops further southwest, and lifts with northward extent as it
encounters the deeper inversion over central Indiana.

Shold fog or stratus form, it will likely have a great impact on
high temperatures. Areas that remain socked in likely trend well-
below guidance and places that experience full sunshine likely trend
above guidance. For now we`ll aim more with 50th percentile
temperatures, which shows low 50s to our southwest and low 40s to
our northeast. Given the expected wind direction, the best chance of
lingering fog/stratus is across the southeastern third of our CWA.
Taking all this into consideration, forecast uncertainty is
unusually high for the short term period.

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 327 PM EST Mon Feb 9 2026

...Tuesday night through Thursday...

In the wake of a weak cold front that moves through the area Tuesday
afternoon, skies will become mostly clear except for some high
clouds that will grace the southern skies overnight originating from
the Southern Plains shortwave trough. In addition some developing
lake effect low clouds will move into the far NE towards Wed
morning. As the boundary layer flow gradually veers to more N-NW on
Wednesday, the lake cloud fetch will develop a little further west
with mostly sunny skies expected in the far W-SW portions of central
Indiana. A weak clipper system (remnants of an upper low presently
moving into B.C Canada) will move SE into the Upper MS valley and
western Great Lakes by Thursday. Have gone more bullish with cloud
cover Thursday in anticipation of the WAA forced mid-high cloud
cover increasing in the NW flow aloft.

...Thursday Night through Friday....

Weak FGEN will support the potential for a narrow band of precip
associated with clipper. Big questions relate to the degrees of dry
air in the BL noted on forecast soundings, owing to the close
proximity of surface high pressure forecast centered over Ohio.  For
now, have upped the PoPs into the slight chance range. As the
clipper moves SE, expect drier and and subsidence to help end PoP
chances Friday morning in the south with skies mostly clear in the
north by afternoon.

...Friday Night through Saturday Night...

A strong shortwave trough moving into the Rockies Friday will push
into the MS valley by Sunday. Deterministic models and ensembles are
in reasonable agreement central Indiana will see some rainfall with
this system. However, recent Euro/EPS model tendencies have been to
slow down and go further south with the track of the surface-upper
low. The compact nature and furthest south track of the operational
GFS was considered an outlier with the lack of a blocking pattern
over the Canadian border. The net result to the forecast was to
delay the onset of precip until mainly Saturday Night. QPF amounts
will need to be watched especially owing to the potential affects or
exacerbation of river ice jams/flooding potential from earlier week
milder weather/snowmelt.

...Sunday/Monday...

Uncertainty in the speed of the shortwave leads to gradually
reduction in precip Sunday with NBM PoPs diminishing west to east. A
broad and strong long wave trough is expected to develop along the
west coast Sunday into Monday will help force a broad upper ridge
over the plains into the MS valley. Monday looks to be the first day
of widespread well above normal temps (50s) area wide.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1241 PM EST Mon Feb 9 2026

Impacts:

- Low level wind shear after 06Z Tuesday
- Wind direction shifting from SE to SW and then NW on Tuesday

Discussion:

A potent storm system is moving east over southern Canada and will
allow a strong low-level jet to develop overnight. This jet may
reach speeds of 45 to 55 knots only 1500 feet off the ground. We`ve
included a period of low-level wind shear late tonight into Tuesday
morning.

Winds at the surface are expected to remain under 10kt today and
most of tonight. Direction quickly becomes southwesterly once
momentum from the low-level jet begins mixing downward after sunrise
Tuesday. However, winds shift abruptly yet again Tuesday afternoon
as the system`s cold front sweeps through central Indiana.

Some low stratus or advection fog may develop early Tuesday as
warmer winds from the south overspread existing snow cover. The
threat for this is low at the moment and fog will not be included in
the TAFs at this time.


&&

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

$$

SHORT TERM...Eckhoff
LONG TERM...Crosbie
AVIATION...Eckhoff