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Office: IND

FXUS63 KIND 180237
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1037 PM EDT Tue Jul 17 2018

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

&&

.SYNOPSIS...
Issued at 218 PM EDT Tue Jul 17 2018

High pressure is going to dominate Indiana weather through
Thursday. A warm front should cross the Hoosier state Thursday
night, and a cold front should do so Saturday. Another high
pressure system is predicted to slowly build in from the west
behind the cold front.

&&

.NEAR TERM (Tonight)...

Issued at 218 PM EDT Tue Jul 17 2018

There is excellent model agreement we will have a clear night under
high pressure.

Withe the guidance close, consensus temperatures should mostly be
accurate to within 2 degrees.  A few spots could see higher errors
depending whether there is a light wind or no wind at all.

&&

.SHORT TERM (Wednesday through Friday)...

Issued at 218 PM EDT Tue Jul 17 2018

Until Thursday, there is good model agreement we will be dry with
some diurnal cumulus. The main forecast issue is POPs Thursday
night and Friday.

The models differ about whether rain will be possible at all
Thursday night. For now, the low chance POPs from consensus are
reasonable.

The prospect for rain will definitely be better Friday as a front
moves in. However, given the nature of fronts in the last half of
summer, the consensus is right: precipitation Friday is likely,
but not yet certain.

Consensus temperatures should mostly be accurate to within 3 degrees
through Thursday night considering basic model agreement.
Temperatures Friday are less certain. A lot will depend on how
much rain there is. While there is no reason to change the
consensus, temperatures Friday could be off by as much as 5
degrees.

&&

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

Issued at 225 PM EDT Tue Jul 17 2018

An upper level low will sink southeast through the Midwest into the
Ohio valley during the long term period. This will lead to chances
for showers and thunderstorms until Monday night, when the upper low
finally gets east enough of the area that its influence has moved
off. A surface cold front will move through Friday night into
Saturday morning and then models indicate its associated surface low
will slowly meander along it as it stalls out to the east. There are
model differences on the timing of the exit of the upper low and
front with some runs moving things along more quickly (by Sunday
night) and others holding PoPs through the day on Monday and keeping
dry air off until at least Monday night. Thus will make no big
changes from the initialization for middle of the road solution.
Highest confidence in precip is on Friday night. After that moderate
confidence scattered precip occurs from time to time Saturday
through Sunday, but low confidence in timing/placement/amounts.
Temperatures with this upper pattern should run near to just below
normal, and have moderate to high confidence in this.

&&

.AVIATION /Discussion for the 18/03Z TAF Update/...

Issued at 1035 PM EDT Tue Jul 17 2018

Update...
Will keep winds at 13 kts through Wed 04Z at KIND.

Previous Discussion...
VFR conditions are expected for the duration of the TAF period.
Dew point depressions should be large enough to inhibit any fog
formation. Meanwhile, winds will start out northerly this evening
at 10 to 12 kts, decreasing and becoming variable by late evening.

&&

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

$$

SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....CP
AVIATION...TDUD



Office: IWX FXUS63 KIWX 172336 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 736 PM EDT Tue Jul 17 2018 .SYNOPSIS... Issued at 226 PM EDT Tue Jul 17 2018 High pressure will provide fair weather and low humidity through Thursday. Lows will generally be in the 50s with afternoon highs near 80 degrees. A low pressure system will then stall over the region Friday into the weekend with periodic chances for showers and thunderstorms. && .SHORT TERM...(This Evening through Thursday) Issued at 226 PM EDT Tue Jul 17 2018 Tonight through Thursday will feature mainly clear skies, low humidity and comfortable temps as sfc high pressure builds in under rising heights aloft. Associated dry/stable airmass should promote decent diurnal temp trends with lows in the 50s and highs near 80 degrees. && .LONG TERM...(Thursday Night through Tuesday) Issued at 226 PM EDT Tue Jul 17 2018 An unusual large scale pattern for late July will emerge Friday into the weekend as a shortwave in northwest flow closes off and stalls over the Midwest/Great Lakes. This system will bring pretty good chances for showers/embedded storms through these periods, especially Friday into Friday evening as leading frontal occlusion and surge of moisture under diffluent flow aloft translates east into the local area. There may even be an opportunity for stronger storms Friday afternoon, though extensive cloudiness and lacking deep layer shear should preclude a more widespread severe threat. Medium range guidance is then in decent agreement in stalling the then vertically stacked low in the vicinity of the southern Great Lakes on Saturday. Showery weather should result, especially during the afternoon hours as lapse rates steepen under cold pocket aloft. Locally heavy rainfall will likely be the primary threat on Saturday. Chances for showers/iso thunder then persist into Sunday and possibly Monday on the backside of this broadening circulation as additional smaller scale vorts rotate through. Temps will generally remain closer to seasonal norms through the long term period. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 734 PM EDT Tue Jul 17 2018 VFR conditions expected through the TAF cycle Wed as a dry air mass remains over the region. North winds near 10 knots initially will drop off overnight to light and variable. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement until 10 PM CDT this evening for INZ003. MI...Beach Hazards Statement until 11 PM EDT this evening for MIZ077. OH...NONE. LM...Small Craft Advisory until 11 PM EDT this evening for LMZ043-046. && $$ SYNOPSIS...Steinwedel SHORT TERM...Steinwedel LONG TERM...Steinwedel AVIATION...MF Visit us at www.weather.gov/iwx Follow us on Facebook...Twitter...and YouTube at: www.facebook.com/NWSNorthernIndiana www.twitter.com/nwsiwx www.youtube.com/NWSNorthernIndiana