Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 260142
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
942 PM EDT Sat May 25 2019

.UPDATE...
The NEAR TERM Section has been updated below.

&&

.SYNOPSIS...
Issued at 336 PM EDT Sat May 25 2019

An active weather pattern will remain in place with chances for
showers and thunderstorms and above normal temperatures for much
of the next week.

&&

.NEAR TERM /Overnight/...

Issued at 942 PM EDT Sat May 25 2019

Surface analysis this evening shows high pressure in place across
the deep south with warm and humid SW flow streaming across
Indiana. A cluster of thunderstorms had developed over SE Iowa and
NE Missouri. Skies across Central Indiana were continuing to clear
as convection related to the heating of the day continued to
diminish.

850mb-300mb model thicknesses suggest propagation of the Iowa
thunderstorms to reach Central Indiana late overnight. HRRR is
also in agreement...pushing showers/storms across the northern
parts of the forecast area after 09Z...persisting until nearly
14-15Z. Time heights and forecast soundings suggest ample moisture
and lift...thus have trended pops higher overnight than the
previous forecast.

Also given the expected clouds and rain...trended overnight low at
or above the model blends.

&&

.SHORT TERM /Sunday through Monday Night/...

Issued at 336 PM EDT Sat May 25 2019

Forecast focus is on timing for rain and storms for the remainder
of the holiday weekend. Unfortunately models are still not in good
agreement on timing of QPF over the area, so medium confidence is
going to be the best this forecaster can offer. That said, for
those with outdoor plans contingent on dry weather, here it goes.
An upper wave moving through during the late overnight/early
morning hours will have rain ongoing across much of northern and
central Indiana as Sunday morning begins. Expect this first wave
to move off to the east and allow for a few dry hours, starting
late morning (9-11 am) and ending in the early afternoon (1-3
pm), depending on your location. In the hourly forecast, show
this in the form of PoPs of 20-30 percent during the "most likely
to be dry" hours.

The potential problems with this timing is where the front sets
up. Fairly confident on the timing of the upper waves (early
morning, then arriving early to mid afternoon), but not confident
on the exact location of the front. This could again serve as a
focusing mechanism for convection and increase severe potential,
and it could legitimately set up anywhere in Indiana depending on
what happens with the first wave of convection in the early
morning.

Sunday night the upper wave will move out and convection will end,
bu the front possibly moving north through the area during the
day on Monday could prompt some showers and storms for the
holiday. Those chances are lower at this time due to uncertainty
regarding the frontal position, but the upper forcing looks far
less impressive than Sunday afternoon.

All of these waves over the same general area raises the concern
for flooding, and will have to monitor this closely going forward.
At this time not expecting a widespread threat, so will forgo any
flood headlines.

High tempertures Sunday will be highly dependent on cloud cover
and the aforementioned precipitation that develops. Went toward
the middle of guidance in the lower to mid 80s, with high humidity
as well. Monday should be a few degrees warmer.

&&

.LONG TERM /Tuesday through Saturday/...

Issued at 336 PM EDT Sat May 25 2019

Temperatures will run slightly above normal through the long term,
and an active weather pattern with a trough over the western U.S.
spitting out shortwaves that will bring thunderstorm chances to
central Indiana Tuesday night through Thursday. The pattern will
become flatter and more progressive toward the end of the week.

&&

.AVIATION /Discussion for the 250000Z Tafs/...

Issued at 700 PM EDT Sat May 25 2019

VFR Conditions are expected for much of the next taf period.

Convection is not expected across the Taf sites through at least
06Z as diurnal heating wanes. A short wave is expected to arrive
after 06Z...and showers and isolated storms are expected after
09Z-10Z. Any shower that does strike a taf site may produce brief
MVFR to IFR conditions. Models then suggest this short wave will
depart the area near 12Z before another short wave arrives after
15Z. Ample moisture and forcing appear present. Thus will trend
toward VFR conditions with prevailing SHRA/vcts after 20Z-21Z.
Again...any shower or storm that strikes a taf site may result in
brief IFR conditions.


&&

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

$$

SYNOPSIS...CP
NEAR TERM...Puma
SHORT TERM...CP
LONG TERM....CP
AVIATION...JP


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