Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 210141
AFDIND

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

.UPDATE...
The NEAR TERM Section has 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 /Overnight/...

Issued at 941 PM EDT Tue Jun 20 2017

A weak trough of low pressure was push across Central Indiana this
evening. Weak instability along with the effects from daytime
heating have allowed a few light rain showers and isolated
thunderstorms to push across the area.

HRRR shows a gradual dissipation of the showers and storms over
the next few hours as heating is lost and best forcing is lost.
Furthermore good subsidence remains in place near the Ohio
River...which also should hamper further development and
progression. Thus based upon radar trends have trendy pops high
downstream of the echos...but have trended toward a dry forecast
overnight as the forcing and instability is lost.

Trended lows slightly cooler than the previous forecast...mainly
across the northern areas that have seen some light rain fall.

&&

.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 the 210000Z TAFS/...
Issued at 636 PM EDT Tue Jun 20 2017

Upper level disturbance currently dropping southeast from the
Great Lakes resulting in scattered convection over northern
Illinois. Short term model guidance suggests this feature will
pass over the terminals through about 210400Z. Instability axis
runs from northern Indiana back into west central Illinois, with
the air mass locally still fairly stable, so threat for lightning
strikes should diminish with time this evening, but some
scattered showers may linger longer into the evening. Best threat
for lightning strikes at this time appears to be in the KLAF/KHUF
vicinity, closest to instability axis. CB bases around 060.
Briefly gusty and shifting winds possible near shower activity.

Otherwise, scattered to broken clouds above 050 tonight. Surface
winds 220-250 degrees at 8-12 kts early this evening expected to
diminish to 6 kts or less late tonight.


&&

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

$$

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



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