Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 261028

Area Forecast Discussion
National Weather Service Indianapolis IN
628 AM EDT FRI AUG 26 2016

The AVIATION Section has been updated below.


Issued at 332 AM EDT Fri Aug 26 2016

Active weather pattern continues with chances for thunderstorms
most days through the period. Temperatures will run above normal
through the period as well with highs in the mid 80s to around 90
and lows in the mid 60s to lower 70s.


.NEAR TERM /Today/...

Issued at 530 AM EDT Fri Aug 26 2016

Quick update to increase pops and change wording to scattered
thunderstorms across the northwestern counties for the next couple
of hours. Previous discussion follows...

Radar mosaic shows scattered showers and thunderstorms from
central Ohio through central Indiana and central Illinois
generally along a weak stalled-out warm frontal boundary. Rapid
update models show these dissipating over the next hour or so but
think this may be too quick as they haven`t been handling this
convection well. Thus kept scattered and isolated storms going in
that area for a few hours before dropping pops to a slight chance
and going dry in the west. During the morning looks like there
could be a few showers and storms across the northern half or so
of the area before high pressure builds in from the north and
ushers in dry air. Across the south could see a few showers and
storms in the afternoon with the front settling near there as the
high builds from the north. For highs used a consensus in the mid
80s north to upper 80s south.


.SHORT TERM /Tonight through Sunday night/...

Issued at 332 AM EDT Fri Aug 26 2016

Focus for the short term is on thunderstorm chances...but with
model variability and weak waves moving through the edges of an
upper ridge generally lower than average confidence forecast.
There potential for a wave to move in tonight, but it doesn`t look
very strong and there is big model disagreement on precip so
brought in low to mid chance pops in the west on the outskirts of
the ridge. Saturday better model agreement on a shortwave bringing
thunderstorm chances but no agreement on timing so tried to
compromise among solutions. Again the best chances will be in the
northwest closest to the upper forcing and furthest from the
subsidence of the ridge. Chances continue through Sunday with the
lowest chance on Sunday night with less forcing. High temperatures
will generally run in the mid 80s to around 90, but could wind up
a little lower if precip is more widespread or long lived than
currently thinking.


.LONG TERM /Monday through Thursday/...

Issued at 237 AM EDT Fri Aug 26 2016

ECMWF suggests High pressure in place much of this period as NW
flow develops aloft ahead of an amplifying upper ridge upstream
over the central plains states. NE surface flow is suggest through
much of the period. Nonetheless...superblend suggests daily low
chc pops as even though there appears to be little forcing.
Superblend suggests the continuation of high dew points throughout the upper 60s and lower 70s...and this may resulting
the blend putting in daily chances for diurnal convection. Still
dew points in the upper 60s and lower 70s seem high given the
expected northeast surface flow. This being said...confidence is
low. Followed superblend precip chances look to
mainly be afternoon convection.


.AVIATION /Discussion for the 261200/...

Issued at 620 AM EDT Fri Aug 26 2016

Main VFR Conditions expected today...with MVFR/IFR fog possible on
Early Saturday morning.

TSRA will pass over LAF within the first 1-2 hours of the taf
period...associated with an upper wave approaching from the
southwest. The tropical plume in place over the Mississippi Valley
will trend farther north today...keeping best forcing north of the
forecast area. Forecast soundings show convective temps in the
middle 80s...which should be reached. Some sct convection will
also be possible within the warm and humid air amass across the
area...however...confidence on location and time too low for a
mention at this point.

Better confidence in precip and fog chances overnight and
forecast soundings suggest and overruning set beginning to take
shape and yet another wave aloft pushing toward central Indiana.
Given this set up...and the expected NE flow...have trended toward
some MVFR fog overnight and dew point depressions will be 0-1
degrees overnight. Forecast soundings also hint at becoming
saturated as do the time height sections. Thus have included a
vcsh mention also.


.IND Watches/Warnings/Advisories...


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