Area Forecast Discussion
Issued by NWS Indianapolis, IN

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030
FXUS63 KIND 211517
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1015 AM EST Tue Nov 21 2017

.UPDATE...
The Near Term 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 through Monday Night/...

Issued at 338 AM EST Tue Nov 21 2017

The influences of high pressure will keep conditions dry on
Friday.  However, a frontal system will move through the Great
Lakes Region on Friday night/Saturday, and models remain
consistent in some of its precipitation reaching the northern
portions of central Indiana as rain.  After that, high pressure
will once again strengthen over the region and bring dry
conditions through the end of the long term period. Meanwhile,
temperatures through the period will be near normal on Friday and
Saturday, then quickly plummet below normal for Sunday and Monday
behind a secondary cold front.

&&

.AVIATION /Discussion for the 21/15Z TAF Update/...

Issued at 940 AM EST Tue Nov 21 2017

Wind gusts are starting to develop in central Indiana this morning.
These will become more widespread and will be in place over all the
sites starting in the next couple of hours. Initially winds will be
out of the SW. During the afternoon a cold front will move through
the sites and switch winds around to the west and then northwest.
Ceilings will develop as the front approaches but these should
remain VFR for the most part. May see some MVFR a couple of hours
after frontal passage, but confidence in this is low and will leave
the deck as VFR for now. Could see a few light showers along the
front but these look to have little if any impact, and are low
confidence to directly fall on any of the sites. Wind gusts should
fall off tonight.

&&

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

&&

$$

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



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