Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 260811

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

Aviation section updated


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 332 AM EDT Fri Aug 26 2016

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 260900z IND Taf update/...

Radar shows a few isolated tsra/shra drifting east mainly just
north of i-70. Have included VCTS the next several hours in case
a rumble of thunder is heard at the IND taf site.
Otherwise...ongoing tafs in good shape.

Previous discussion below.

/Discussion for the 260600Z TAFS/...
Issued at 1220 AM EDT Fri Aug 26 2016

Diffuse frontal system sagging through central Indiana combined with
15-20 kts of enhanced flow at 850mb may result in widely scattered
convection overnight. Short term model guidance suggest a upper
vorticity center near KSTL may enhance the convective threat
towards/after sunrise on Friday, but confidence in direct impacts
remain low at this time.

Crossover temperatures are within reach overnight, so fog is a concern.
Presence of some cloud cover should help to limit potential for
widespread or prolonged IFR visibility restrictions. As a result, will
keep visibilities above IFR.

Weak lift in the vicinity of the frontal zone should help keep some cloud
cover around 035-045 for most of the night. Surface winds below 7 kts
expected through midday Friday.


.IND Watches/Warnings/Advisories...


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