Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 250639

Area Forecast Discussion
National Weather Service Indianapolis IN
239 AM EDT Mon Sep 25 2017

The SYNOPSIS...NEAR TERM and SHORT TERM Sections have been updated


Issued at 237 AM EDT Mon Sep 25 2017

A weak frontal system is expected to move through the area towards
the middle of week, otherwise high pressure is expected.


.NEAR TERM /Today/...
Issued at 237 AM EDT Mon Sep 25 2017

Strong mid level ridging aloft should result in dry and warm weather
today. Low level thicknesses suggest the GFS MOS highs for today
look a little on the cool side. Will bump up the guidance numbers
about a category.


.SHORT TERM /Tonight through Wednesday night/...
Issued at 237 AM EDT Mon Sep 25 2017

Model data suggest the upper ridge will get suppressed to the south
by the middle of the week as the northern end of the Rockies trough
shears out across the Great Lakes. An associated weakening cold
front is expected to pass through the area around Wednesday.

Forcing in the vicinity of the front looks quite weak, but enough
lift may be present to keep a small chance PoP in the forecast for
Wednesday as the front moves through. Will continue to keep the rest
of the short term dry.

Progged low level thicknesses suggest the GFS MOS temperature
guidance is probably too cool. Will raise the guidance about 2-5
degrees each period.


.LONG TERM /Thursday through Sunday/...

Issued at 225 AM EDT Mon Sep 25 2017

Cooler and more active weather expected during this period. ECMWf
suggests a pattern change aloft as compared to the past week. By
Thursday...Cooler air is expected to arrive across Central Indiana
as High pressure over the western Great Lakes sags southward.
Aloft...a quick more zonal flow pushes Wednesday
s cold front farther east along with the rest of the hot air that
have been over Indiana for much of the  past week. Thus dry and
cooler will work for Thursday.

The ECMWF Suggests a quick moving cold front and weak low pressure
system moving through the great lakes on Friday. However the gulf
fails to open ahead of this system and Pacific moisture is
limited. Thus the forecast builder blend has gone dry...which
seems reasonable as confidence for precip remains low.

Stronger and cool high pressure over the upper midwest is then
expected to build across Indiana on Saturday and
Sunday...providing more dry and cool weather to start October. The
next best chance for rain looks like Monday as the ECMWF shows a
negatively tilted upper trough pushing toward Indiana from the
plains states...but again...moisture may be limited.


.AVIATION /Discussion for 250600z TAF issuance/...

Issued at 1139 PM EDT Sun Sep 24 2017

May see an hour or two of MVFR visibilities near daybreak at the
outlying sites, but otherwise VFR expected. Winds should be light
and variable overnight. May see some cu during the afternoon hours
but they shouldn`t impact the flight category.




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