National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KIND 281122
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
722 AM EDT WED SEP 28 2016

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

&&

.SYNOPSIS...
Issued at 301 AM EDT Wed Sep 28 2016

An upper level low will loiter in the area into the weekend, keeping
cooler than average temperatures and chances for rain in the
forecast. Warmer and drier conditions return next week.

&&

.NEAR TERM.../Today/
Issued at 301 AM EDT Wed Sep 28 2016

An upper low will move into the forecast area today. In addition, a
surface low will move into Ohio and drag a front through central
Indiana. Q-vector convergence progs show decent forcing with this
system today.

Rain will continue to develop this morning as the system approaches,
and currently it looks like the southern and eastern forecast area
will see the highest chances for rain as the front moves through the
area. Will go likely PoPs there later this morning into early
afternoon. (Hi Res Rapid Refresh has higher coverage of rain early
this morning across the northern forecast area. Will have to watch
for development and may up PoPs there early).

After the front passes, the upper low will be moving in with cold
air aloft. The steep lapse rates could lead to additional scattered
convection developing, so will keep chance PoPs going most areas mid
to late afternoon to account for this.

It now appears that there will be enough instability to go with a
thunderstorm mention everywhere across the area this afternoon. The
southeastern forecast area looks to perhaps have some brief
sunshine, which could lead to higher instability.

SPC has placed the southeastern forecast area in Marginal Risk, and
this looks reasonable given the expected instability and cold air
aloft moving in (creating a hail threat). Will mention hail in the
Hazardous Weather Outlook.

MAV MOS and model blend look cool with some potential for occasional
breaks in the clouds today. Went warmer, but not quite as warm as
the MET MOS.

&&

.SHORT TERM.../Tonight through Friday night/
Issued at 301 AM EDT Wed Sep 28 2016

Focus remains on chances for rain through the period. Models are
close enough that a blend was used.

As the upper low meanders out of and then back into Indiana, chances
for rain will continue through the Short Term. For much of the
period, PoPs will be in slight chance to chance category, with
highest PoPs generally across the eastern areas, closer to the upper
low.

Higher chances of rain will move in Thursday night into Friday, as
more potent energy rotates into the area from the northeast. Will go
high end chance category to low likely PoPs across the north during
that period, with chance PoPs south.

There is still some uncertainty on the path of the upper low and
thus locations and timing of better forcing, so some changes in the
forecast remain a good possibility through the next couple of days.

Generally stayed close to a model blend for temperatures, as MAV MOS
is too cool for highs at times.

&&

.LONG TERM /Saturday through Tuesday night/...

Issued at 334 AM EDT Wed Sep 28 2016

Light rain showers will continue to affect portions of central
Indiana, mainly northern, through Sunday morning due to an upper
low. At that point, GFS and Euro agree on the upper low moving off
to the northeast and into eastern Canada. Dry conditions will then
return and persist through the end of the extended period as high
pressure strengthens over the region. Latest initialization is
representative of this pattern, so no changes were needed.

Below normal temperatures can be expected on Saturday with highs
only in the upper 60s/low 70s. A weak warming trend will quickly
commence by Sunday though, and temperatures will climb back to
normal for the beginning of the week.

&&

.AVIATION /Discussion for the 28/12Z TAF Issuance/...

Issued at 712 AM EDT Wed Sep 28 2016

A large upper low will keep scattered rain showers in the forecast
at times throughout the TAF period. Conditions will generally be
at VFR levels though during most precipitation. Isolated
thunderstorms also cannot be ruled out this afternoon, but
confidence is not high enough to insert mention in TAFS at this
time.

Expect deterioration to MVFR or even IFR tonight as ceilings and
visibilities drop. Meanwhile, winds will generally be northerly at
5 to 10 kts.

&&

.IND Watches/Warnings/Advisories...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....TDUD
AVIATION...TDUD