Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 201931
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
331 PM EDT Tue Jun 20 2017

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

&&

.SYNOPSIS...
Issued at 330 PM EDT Tue Jun 20 2017

Some chances for storms early tonight across the northern counties
will give way to dry conditions for central Indiana for the most
part until the remainder of a tropical system interacts with a
frontal system to bring rain and thunderstorm chances across the
area for Thursday night through Friday night. The front moving
through will bring lesser chances for precip to the area until
Sunday night once it has passed. Then dry, cooler weather moves
in.

&&

.NEAR TERM /Tonight/...

Issued at 330 PM EDT Tue Jun 20 2017

An upper wave and surface front will approach the forecast area from
the northwest this evening and move into the area tonight. This
should provide sufficient forcing for shower and thunderstorm
development along/ahead of it. High resolution models are showing
activity getting into the northwest part of the forecast area
shortly before or just after 0z. As the surface front moves toward
the southeast its progress will slow drastically as it moves toward
high pressure to the southeast and more stable environment, and it
should essentially wash out about midway through the area. Thus will
bring a chance for thunderstorms into the northwestern counties just
before 0z and move the area of chances toward the southeast from
0-6z but then have it dissipate by 6z except for a slight chance
of showers in the northeast in accordance with output from the
NAM/RAP/HRRR. For temperatures used a blend for lows in the low to
mid 60s.

&&

.SHORT TERM /Wednesday through Friday/...

Issued at 330 PM EDT Tue Jun 20 2017

On Wednesday surface high pressure and weak upper ridging will be
over the area. These features currently look like they will be
sufficient to quell any chances for showers along the washed out front
during the day. For the most part dry weather will then continue
until midday Thursday. By that point could see some low chances
for thunderstorms start to move in from the south ahead of the
tropical system. By late Thursday night a cold front will move
toward the area from the northwest while the tropical remnants
approach from the south. The highest chances for precipitation
will be across the south. During the day Friday precipitation
chances and amounts will increase as the bulk of the tropical
moisture is drawn north and interacts with the aforementioned
frontal boundary making rain likely and bringing chances for
thunderstorms across most of the area. At this point bulk of model
guidance keeps the axis of heaviest rainfall to the south of the
forecast area, but this will be something to watch going forward.

Highs Wednesday will likely be a couple degrees warmer than today
with some warming at 850 mb and a mostly sunny day expected.
Thursday should again be warm with a strong flow of warm moist air
into the area. Friday though should see cloudy skies with the
tropical remnants drawing further north, and this additional cloud
cover should cap highs off in the low 80s.

&&

.LONG TERM /Friday Night through Tuesday/...
Issued at 253 PM EDT Tue Jun 20 2017

Showers and a few thunderstorms will linger into Friday night as a
front across central Indiana moves on to the south.  The front will
be far enough south Saturday for Indiana to be dry.   Models...
especially the european indicate a weather disturbance may bring
chance POPS around Sunday...then mostly dry weather will occur
Sunday night through Tuesday as high pressure over the central plains
moves towards the Ohio valley.

Temperatures will be cooler than normal...especially Sunday and
Monday.
Highs will be in the upper 70s to lower 80s Saturday and again
Tuesday and in the 70s Sunday and Monday.  Lows will be in the lower
to middle 60s Friday night...around 60 Saturday night and 50s Sunday
and Monday night.  Generally stayed close to model initialized
temperatures.

&&

.AVIATION /Discussion for 201800z TAF issuance/...

Issued at 109 PM EDT Tue Jun 20 2017

VFR through the period. Wind of 8-14 kts through the afternoon out
of the WSW with gusts of 18-24 kts at KIND and KLAF. KHUF and KBMG
could see gusts also but those may be more sporadic. For KLAF kept
at VCTS going from 23z to 2z based on line currently getting
started in southern Wisconsin along the upper wave and surface
boundary moving into that area during that time. Current output
looks like the line will have trouble making it further south due
to subsidence aloft from the high so didn`t include any thunder
mention elsewhere. Some early indications that KLAF could have
some MVFR visibilities overnight if they get some rain early
tonight and then the front stalls out just south of there, but
guidance indicates this wouldn`t develop until after 9z or so and
is too far out to include a tempo at this point with low
confidence.

Wind gusts will fall off by sunset and winds should be light
overnight.


&&

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

$$

SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...CP



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