Area Forecast Discussion
Issued by NWS Indianapolis, IN

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710
FXUS63 KIND 220820
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
420 AM EDT Fri Jun 22 2018

.UPDATE...
The AVIATION Section has been updated below.

&&

.SYNOPSIS...
Issued at 240 AM EDT Fri Jun 22 2018

A slow moving upper level low and associated surface low will keep
chances for rain in the area through the weekend. After a brief
break on Monday, a frontal system will bring more rain chances for
next week. Temperatures will return to near normal by the end of the
weekend and then to above normal during next week.

&&

.NEAR TERM.../Today/
Issued at 240 AM EDT Fri Jun 22 2018

Early this morning an upper level low was near St. Louis. Bands of
scattered showers and isolated thunderstorms were moving north
across central Indiana.

Expect coverage of rain to diminish through sunrise as the
atmosphere continues to stabilize.

As the upper low moves toward central Indiana today, eventually
arriving by early evening, forcing will increase. The atmosphere
will destabilize with daytime heating (albeit limited due to cloud
cover). Moisture remains plentiful, with precipitable water values
running 130-140 percent of normal.

With the upper low moving in, feel that most areas will see some
rain today. Will go likely PoPs all areas, with the highest PoPs
during the afternoon most areas when forcing and instability are
maximized.

With the high moisture content of the atmosphere today, locally
heavy rain will continue to be a threat. Can`t rule out a strong
storm this afternoon, but feel that instability will be limited
enough that severe storms are not a threat.

Cloud cover will help keep temperatures down again today, and the
model blend captures this well.

&&

.SHORT TERM.../Tonight through Sunday night/
Issued at 240 AM EDT Fri Jun 22 2018

Models are close enough that the model blend initialization
was accepted for most items.

The upper low will drift northeast across the area tonight. With
instability waning and forcing focused mainly across northern
Indiana ahead of the upper low, feel that chance category PoPs
should cover it tonight. PoPs will diminish during the night as the
forcing and instability weaken. Locally heavy rain will remain a
threat, mainly during the evening hours.

On Saturday there is some lingering weak forcing behind the exiting
upper system, so will keep some low PoPs across the area.

Saturday night into Sunday, an upper wave moving through the lower
Ohio Valley will bring some weak forcing to mainly the southern half
of central Indiana. Will go with some low PoPs.

Upper heights will rise Sunday night, and high pressure will nudge
into the area at the surface. Thus will keep the forecast dry then.

Clouds will keep temperatures down again Saturday, but more sunshine
will allow readings to return to near normal values on Sunday.

&&

.LONG TERM (Monday through Thursday)...

Issued at 150 AM EDT Fri Jun 22 2018

Forecast confidence is high. The GFS and European models have come
into good alignment, which has not always been true recently.

In particular, both models have high pressure controlling Indiana
weather into Monday night. After that agreement is not quite so
strong, but they both indicate a chance or slight chance of rain
most of the time.  Errors from consensus should be mainly 10 percent
or less for POPs and 3 degrees or less for temperatures.

&&

.AVIATION (Discussion for 220900Z TAF update)...

Issued at 420 AM EDT Fri Jun 22 2018

LIFR in fog and stratus will be common early in the period in very
moist air.

Conditions should mostly recover to VFR by afternoon. However there
will an ongoing threat of much lower conditions in showers and
storms as vertically stacked low pressure crosses the area.

Winds will be variable less than 10KT throughout the period.

&&

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

$$

SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....JK
AVIATION...Nield/JK



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