Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 212231
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
531 PM EST Tue Nov 21 2017

.UPDATE...
The AVIATION Section has been updated below.

&&

.SYNOPSIS...
Issued at 233 AM EST Tue Nov 21 2017

A cold front will move through central Indiana today, bringing a
chance for rain and breezy conditions to parts of the area. Dry
weather will then rule for much of the period into early next week,
except for a chance of rain across northern parts of the area Friday
night. Temperatures will bounce around from near normal to below
normal.

&&

.NEAR TERM.../Rest of Today/
Issued at 1015 AM EST Tue Nov 21 2017

Only made some minor adjustments to push back the timing of the
arrival of the light shower chances by an hour or two based on
latest hi res guidance. Also increased high temperatures in the
south by a degree or two for the same reason. Previous discussion
follows...

The morning will be dry across the area ahead of an approaching cold
front. As the front moves in during the afternoon, there will be
decent forcing with some upper support in play. However, there will
only be a narrow band of deep moisture with the system. This should
limit rain chances.

The best forcing and moisture look to move across the northern half
or so of the area. Will go with PoPs after 19Z, spreading across the
northern forecast area through 23Z. Will keep PoPs no higher than
the chance category since moisture is limited.

Some of the stronger winds aloft will mix down and produce
wind gusts around 30 mph today.

The blend`s temperatures look reasonable given a warmer start this
morning and some warm advection ahead of the front.

&&

.SHORT TERM.../Tonight through Thursday night/
Issued at 233 AM EST Tue Nov 21 2017

Models are close enough that the model blend initialization
was accepted for most items.

Enough lingering forcing and moisture will remain across the area at
00Z to go with low PoPs across northern and eastern sections of the
area. These will end by 03Z as forcing quickly exits.

Some clearing will occur this evening, but am concerned about low
clouds sticking around, especially north and east. Will go above the
blend`s cloud cover here and keep skies partly cloudy.

High pressure will then build in and keep things dry through
Wednesday night. On Thanksgiving, a front will wash out as it
approaches the area. Thus only expect some increase in clouds. High
pressure returns for Thursday night.

Much cooler air will flow into the area tonight behind the front,
returning lows into the 20s tonight. Highs on Wednesday will only be
in the 30s most areas. Thanksgiving will be a little warmer with
highs in the 40s.

&&

.LONG TERM /Friday night through Tuesday/...

Issued at 153 PM EST Tue Nov 21 2017

As the long term begins, an upper wave and cold front are making
their way through central Indiana. With the area being dry and
these forcing mechanisms lacking moisture, at this time it looks
like only a small chance for showers late Friday night over the
eastern counties. Better forcing in the models stays north as
well, so this lends more confidence in a mostly dry forecast. High
pressure building in behind the front will keep dry weather in
place over central Indiana. Temperatures will be cooler Saturday
in the wake of the front but slowly moderate after Sunday.

&&

.AVIATION /Discussion for the 220000Z TAFS/...
Issued at 531 PM EST Tue Nov 21 2017

Narrow band of rain, with possibly some wet snow mixed in at times
based on surface observations, is expected to affect the
KLAF/KIND/KHUF terminals through about 220100Z. Brief MVFR
visibility restrictions and ceilings around 020 probable within
the precipitation area.

Expecting most of the layered cloud cover to scatter out by mid to
late evening, although some lingering cloud cover near 040
possible later tonight.

Surface winds generally 300-330 degree at 9-13 kts this evening
expected to become 320-350 degrees at 5-8 kts by pre dawn
Wednesday. Occasional surface gusts 18-20 kts possible early this
evening.

&&

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

$$

SYNOPSIS...50
NEAR TERM...50/CP
SHORT TERM...50
LONG TERM....CP
AVIATION...JAS


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