118
FXUS63 KIND 241142
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
642 AM EST Tue Dec 24 2024

.KEY MESSAGES...

- Cloudy and dreary today

- Rain returns late tonight into tomorrow, amounts less than a
  tenth of an inch

- Warming trend through the weekend with additional rain likely
  Friday into Saturday

&&

.SHORT TERM (Today through Wednesday)...
Issued at 207 AM EST Tue Dec 24 2024

Today.

A dreary Christmas Eve is expected for today with mostly cloudy to
cloudy skies continuing through the day as broad high pressure
persists across the Ohio Valley. Pockets of patchy fog are
possible through morning hours as winds drop to near calm but as
temperatures begin to slowly rise into the 40s by the early
afternoon, dewpoint depressions will rise enough to bring an end
to any remaining fog. The weak subsidence associated with the
ongoing high pressure will gradually begin to break down late
today ahead of the rain producing system for late tonight into
Christmas morning.

Tonight through Wednesday.

The aforementioned system will gradually track from the Southern
Plains into Arkansas late tonight with broad isentropic lift
extending northeastward into the Lower Ohio Valley.  Confidence has
increased in the northeastward extent of the better lift reaching
into Indiana especially into Wednesday morning when moisture
transfer vectors show good moisture flux into the southwestern
counties.

Thus will gradually ramp up POPs late tonight with highest
chances mid to late morning tomorrow. Total QPF still looks to be
around a tenth of an inch with high confidence in rain being the
only precipitation type as temperatures remain in the upper 30s to
mid 40s. Rain chances will gradually drop off into the later
afternoon hours as the LLJ has a more north to south orientation and
cuts off the moisture flow into Indiana. During periods without rain
late tonight, fog looks likely with the near calm winds and near
surface saturation.

&&

.LONG TERM (Wednesday Night through Monday)...
Issued at 207 AM EST Tue Dec 24 2024

Wednesday Night Through Saturday.

Any rain should come to an end by the early overnight hours as the
system that will bring rain on Christmas continues to dissipate
across the Gulf states. Flow across the Midwest then begins to
stagnate Thursday with cloudy skies across much of the area along
with periods of light rain/drizzle likely for much of Thursday.
Focus then shifts to the next low pressure system as it exits the
Four Corners region and begins to track northeastwards.

Over the last 12 hours models have begun to better hone in on the
development and track of this system with increasing confidence in a
period of moderate rain Friday with total QPF likely in the 0.25-
0.75 inch range. A secondary low then quickly develops behind the
initial low pressure system with the potential in heavier rain
impacting portions of the Ohio Valley, but there is a lot more
uncertainty as to where this axis of heavier rain looks to set up.
Current ensemble guidance is hinting that the heavier axis will be
south of the Ohio River but details remain quite uncertain. Where
confidence is higher is that the some of the warmest temperatures of
the month look likely for Saturday as highs climb into the mid to
upper 50s as moisture rich air from the Gulf of Mexico advects into
the area.

Sunday Through Monday.

Drier conditions look likely for Sunday into Monday with some low
rain chances being associated with the uncertainty in timing for the
Saturday system. Surface flow will become more easterly as a surface
low begins to deepen across Kansas which will moderate temperatures
to around 50 for Monday.  Looking towards the middle of the week
that aforementioned low looks to bring another round of rain with a
brief cooldown likely to end the week.

These periods of rain through next week are expected to bring rises
to the main stem rivers of central Indiana, but only in the highest
end of rainfall amount scenarios is minor flooding expected. This
lines up with MMEFS probabilities that show the lower White and
Wabash Valleys seeing a lass than 10 percent chance of flooding
through the new year.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 642 AM EST Tue Dec 24 2024

Impacts:

- Cigs lowering to MVFR this morning then to IFR tonight

- Rain returns late tonight with IFR conditions

Discussion:

Lower stratus deck across northern Indiana is slowly working south
behind weak boundary. Cigs expected to lower to MVFR this morning as
this cloud deck moves in. Light winds expected through the period,
becoming northeasterly behind this boundary.

Tonight, moisture surge from southwest to northeast to bring light
rain back to the terminals with cigs lowering to IFR as this
moisture works in overnight.

&&

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

$$

SHORT TERM...White
LONG TERM...White
AVIATION...Lashley