Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 170900
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
400 AM EST Fri Nov 17 2017

.UPDATE...
The SYNOPSIS...NEAR TERM...SHORT TERM
and AVIATION Sections have been updated below.

&&

.SYNOPSIS...
Issued at 306 AM EST Fri Nov 17 2017

The most active part of the forecast will be early in the period
when the upper ridge breaks down and a frontal system impacts
central Indiana. The highest precipitation chances will be tonight
through Saturday as the associated cold front moves through the
forecast area. After that, much cooler and drier air will follow
in the wake of the cold front on Sunday. Another cold front early
in the week will supply an additional shot of reinforcing cold
air, but the best dynamics should keep any precipitation chances
north of the forecast area.

&&

.NEAR TERM /Today/...

Issued at 306 AM EST Fri Nov 17 2017

Central Indiana will be under the influence of high pressure for
most of the near term period. So, dry conditions can be expected
through the afternoon. Meanwhile, partly cloudy skies will all
prevail through the morning and early afternoon hours.
Nonetheless, time cross sections indicate rapid saturation in the
low and mid levels by Sat 00Z as low pressure approaches from the
Missouri Valley. Meanwhile, a leading warm front will help to
increase temperatures above normal this afternoon with highs
topping off in the low to mid 50s.

&&

.SHORT TERM /Tonight through Sunday Night/...

Issued at 306 AM EST Fri Nov 17 2017

The main focus of the short term period will be shower and
thunderstorm chances early in the period.

As mentioned above, showers will infiltrate central Indiana from
the west by late afternoon as a frontal system approaches from the
west. As upward vertical motion increases after Sat 06Z per time
cross sections, so will the chances for thunderstorm development.
As a result, will include mention of thunderstorms in the forecast
at that point and continuing through Saturday along and ahead of
the associated cold front. SPC Day 2 convective outlook does
highlight an area of marginal risk for severe weather across the
southern third of central Indiana as the cold front encounters
some instability. Daytime highs for Saturday are progged to top
off in the upper 50s to mid 60s with dewpoints in the mid to upper
50s.

Instability and dynamics will begin to wane by Saturday evening
though, and convection will quickly taper off. Forecast soundings
indicate that any lingering moisture on Saturday night will be in
the form of rain, but it looks like moisture will be limited
anyway after Sun 06Z.

Sunday, much cooler and drier air will prevail in the wake of the
aforementioned cold front with highs only in the 30s and lows
dipping into the 20s.

&&

.LONG TERM /Monday through Thursday/...
Issued at 237 AM EST Fri Nov 17 2017

Ensembles in good agreement in suggesting a rather quiet weather
pattern during this period, with little threat for precipitation.

A short wave trough is expected to push across the Great Lakes
around Tuesday, but it appears the better dynamics and deeper
moisture will remain to the north of the forecast area. Will
continue with a dry forecast.

&&

.AVIATION /Discussion for the 17/09Z TAF Update/...

Issued at 306 AM EST Fri Nov 17 2017

Update...
Lower ceilings will clear out by FRI 10Z.

Previous Discussion...
Expect the low clouds to scour out near or shortly after 06z as
surface high pressure shifts east of the terminals and an upper
ridge moves overhead. That said, confidence in exact timing is low
but confidence in the overall trend regarding flying conditions is
good.

Much or all of the daylight hours are expected to feature just high
and mid clouds well ahead of a central Plains system. However, a
warm front will move in from the west with MVFR overrunning rain
likely after 03z.

Light and variable wind will become southeast and south to near 10
knots after 15z. Should  start to see gusts to around 20 knots after
03z Saturday.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....JAS
AVIATION...MK/JAS



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