021
FXUS63 KIND 131130
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
630 AM EST Tue Jan 13 2026

.KEY MESSAGES...

- Gusty winds between 30-40mph today and Wednesday.

- Scattered rain showers tonight, changing to snow showers on
  Wednesday

- Minor snowfall accumulations from a dusting to around 1 inch
  possible.

- Well-below normal temperatures later this week into early next week

&&

.SHORT TERM (Today and tonight)...
Issued at 306 AM EST Tue Jan 13 2026

Strong ridge-building over the eastern Pacific will allow a trough
to dig southward over the Midwest later today and tomorrow.
Cyclogenesis associated with this trough is taking shape well to our
north over central Canada. The resulting low then progresses
eastward along a path north of the Great Lakes. Though far to our
north, the system will drive a cold front southward with cold air
advection reinforced by the digging trough.

First, however, a period of strong warm air advection is anticipated
as the MSLP gradient tightens ahead of the low. Gusty southwest
winds between 30-40 mph will help pump temperatures into the 40s
and low 50s today. Additionally, modest frontogenesis along the
approaching front allows rain showers to develop after sunset.
These rain showers should be light, and confined mainly across the
southern half of our CWA.

Once the aforementioned cold front arrives early Wednesday morning,
temperatures begin to fall quickly despite it being daytime. In
fact, high temperatures on Wednesday should occur before sunrise,
with temps falling into the 20s during the afternoon. Any lingering
rain showers should begin to change to snow Wednesday morning as
well. Guidance shows low-level instability within the post-frontal
environment, which should promote a scattered/cellular
characteristic to the snow showers.

Winds look to be out of the north, which will help maximize the
fetch off Lake Michigan. A more coherent snow shower or snow band
may develop which could extend southward enough to bring
accumulating snow to parts of central Indiana. The best chance of
this would be from Lafayette to the north suburbs of the Indy metro
and points northeast. As much as an inch of snow is possible within
this band. Elsewhere, a dusting is the most probable scenario.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 306 AM EST Tue Jan 13 2026

A pattern shift is expected in the long range with a trend towards
colder than average temperatures. As mentioned in the short term
discussion, strong ridge-building is occurring over the eastern
Pacific. Ensemble guidance show this ridge becoming a dominant
feature while evolving into a classic Rex Block. Ridging over the
West Coast then reinforces troughing over the Midwest and Eastern
US. The developing blocking pattern then locks it in for at least a
week.

Global teleconnections support the developing pattern, with a
positive Pacific North American Pattern (PNA) and an Arctic
Oscillation (AO) quickly trending negative. A negative AO favors a
highly amplified jet stream while the positive phase PNA favors
ridging over the western US and troughing over the east. The
combination of the two will help prolong deep troughing over the
Midwest and eastern US. Troughing in turn promotes colder than
average temperatures.

Scaling down a bit, guidance is in good agreement showing a series
of vort maxes diving southeast within the broad northwesterly flow
on the eastern flank of the Pacific ridge. Each likely has an
attendant cold front with a reinforcing shot of cold air. Though
potent, these systems lack moisture. Given the cold air mass likely
to be in place, snow is favored over rain this weekend onward.
Guidance differs regarding the timing and stretch of each wave, so
we`ll keep PoPs broad and prolonged through the weekend.

Temperatures through the period, as alluded to above, look to be
well-below normal...except Friday, where a shortwave ridge is
modeled to pass through with a brief period of modest warm air
advection. Guidance is in good agreement showing sub-freezing highs
from Saturday to the end of the period. Sunday looks to be the
coldest day, with highs in the teens/low 20s and lows in the single
digits. Wind chills likely dip below zero for a good chunk of the
weekend into early next week.

Days 8-14...ensemble guidance is hinting at another pattern shift
late next week where ridging shifts eastward and flattens somewhat.
Such a pattern may allow for a trend towards warmer (but still below
normal) temperatures and greater precipitation chances. An east-west
oriented baroclinic zone may develop which will help determine the
eventual storm track. Ensemble guidance tends to keep the AO
strongly negative while allowing the PNA to trend negative as well,
which adds weight to the potential pattern described above. However,
ensemble guidance diverges considerably adding to forecast
uncertainty. That said, take individual models runs / deterministic
guidance with a grain of salt.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 629 AM EST Tue Jan 13 2026

Impacts:

- Winds gusts between 25-35kt today
- Marginal LLWS this morning possible
- Rain showers developing after 00z with MVFR ceilings possible
- Snow showers after 10z Wednesday

Discussion:

Winds will be the primary impact to aviation today, with gusty
southwesterly winds between 15-20kt gusting 25-35kt at times. The
boundary layer may be stable enough this morning to promote a brief
period of marginal low-level wind shear (30-40kt at 1500ft), mainly
from 12z to 15z. Boundary layer mixing will then allow this to
diminish and surface gustiness to increase.

Mid/high-level clouds are streaming in from the northwest signaling
the arrival of a weak storm system. Mid/high ceilings are expected
to develop this morning and continue into the evening. By tonight,
continued lowering may allow for a period of MVFR ceilings.
Additionally, a period of rain showers is likely along and ahead of
an approaching cold front, mainly from 04z onward.

A transition to snow showers is expected after about 10z Wednesday,
once the front moves through. Winds become northwesterly while
increasing to between 10-15kt gusting to 20-25kt. Ceilings continue
to drop becoming MVFR early Wednesday morning, continuing through
the day.

&&

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

$$

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