Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 221813
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
213 PM EDT Fri Sep 22 2017

.UPDATE...
The LONG TERM section has been updated below.

&&

.SYNOPSIS...
Issued at 235 AM EDT Fri Sep 22 2017

High pressure is expected across the area through the early parts of
next week. A frontal system may affect the area towards the middle
of next week.

&&

.NEAR TERM /Rest of Today/...
Issued at 1002 AM EDT Fri Sep 22 2017

Warm and hazy morning for most as the region remains firmly under
the influence of surface high pressure and ridging aloft. 14Z
temperatures had already risen into the mid and upper 70s.

Astronomical Fall arrives later this afternoon but it will once
again feel like the middle of the summer over central Indiana as
the Ohio Valley resides under high pressure at the surface and
aloft. Expect a very similar day to Thursday as temperatures will
likely peak in the lower 90s in many locations this afternoon.
Dewpoints in the upper 60s and lower 70s will once again give max
heat indices in the mid and upper 90s. We will be in record watch
mode this afternoon with the record high of 93 from 1895 for
Indy.

While the dry forecast has been maintained for the day with high
pressure across the area and the presence of a high-based mid
level cap...cannot entirely rule out a stray shower or storm this
afternoon with a weakness in the upper ridge drifting southwest
near the Ohio River. This mid level feature likely contributed to
the isolated storm early this morning across southern Indiana and
could see it tapping into the unstable airmass this afternoon to
help produce a stray shower or storm over mainly southern
counties. Confidence and coverage too low to include a mention in
the forecast at this time but will continue to monitor.

&&

.SHORT TERM /Tonight through Sunday night/...
Issued at 235 AM EDT Fri Sep 22 2017

Model data suggest strong upper ridging aloft will hold across the
local area through the weekend. This will result in dry and warm
conditions through the period.

Progged low level thicknesses suggest the GFS MOS temperature
guidance may be on the cool side over the next couple of days. Will
raise the guidance highs and lows a category or so through the
period.

&&


.LONG TERM /Monday Night Through Friday/...
Issued at 213 PM EDT Fri Sep 22 2017

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

Warm conditions will continue early in the long term, then much
cooler will move into the area to end the work week.

Lingering upper ridging will keep the area dry Tuesday, but the cold
front with the much cooler air behind it will move through on
Wednesday bringing low chances for showers to parts of the area.
Current timing puts the front moving through when there should be
little instability, so continued to leave out any mention of thunder.

There is still some uncertainty on timing of the front which could
have impacts on rain chances if it changes. However, confidence is
high for the much cooler air moving in by late next work week.

&&

.AVIATION /Discussion for 221800Z TAF Issuance/...
Issued at 1247 PM EDT Fri Sep 22 2017

With the exception of visibility restrictions from fog near
daybreak...VFR conditions are anticipated.

The region remains under the influence of high pressure aloft and
at the surface. The result will be continued dry weather with
little in the way of clouds. Despite a mid level cap...presence of
strong surface heating and instability will generate some cu in
the afternoon today and again on Saturday. Cannot entirely rule
out an isolated shower or storm...but the threat is too low to
consider for the terminals at this time.

Will once again see brief visibility restrictions to IFR and lower
at the outlying terminals from localized fog during the predawn
hours through daybreak Saturday. Winds will be light and variable
through the period.

&&

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

&&

$$

SYNOPSIS...JAS
NEAR TERM...Ryan
SHORT TERM...JAS
LONG TERM....50
AVIATION...Ryan



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