Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 051437
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
937 AM EST Mon Dec 5 2016

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

&&

.SYNOPSIS...
Issued at 324 AM EST Mon Dec 5 2016

A brief break in the precipitation chances will occur today as high
pressure moves across. Precipitation returns tonight into Tuesday as
an upper system moves across the area. A potent cold front will
bring some snow chances mid week and then usher in much colder air.
Another system will bring more chances for rain and snow this
weekend.

&&

.NEAR TERM /Rest of Today/...

Issued at 926 AM EST Mon Dec 5 2016

UPDATE...
Current forecast is on track, so no changes. Widespread clouds
continue to linger across all of Central Indiana, and will
continue to do so into the afternoon hours. Best chances for some
partial clearing will still come late in the day. Current temps
across the area are generally in the low to mid 30s. Daytime highs
are still projected to top off in the low to mid 40s. Updated
grids have been sent.

PREVIOUS DISCUSSION...
The clearing line across Illinois that was moving toward the area
is no longer making good progress east. An inversion will continue
to develop across the area this morning, trapping these clouds. Thus
will go pessimistic with cloud cover this morning.

Forecast soundings show that some breaks in the clouds will develop
this afternoon as the center of high pressure moves off to the east.
Will go cautiously optimistic and allow for partly cloudy skies by
late afternoon.

Some short term models are showing fog developing early this
morning. However, they`re already overdoing fog coverage right now.
With the clouds sticking around, do not believe fog will become
significant.

With the cloud cover, went below (and in some cases well below) MOS
for highs, closer to a raw model blend.

&&

.SHORT TERM.../Tonight through Wednesday night/
Issued at 324 AM EST Mon Dec 5 2016

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

Clouds will quickly increase tonight ahead of an approaching upper
system. However, it now looks like forcing and moisture with this
system is a little slower than previously thought, so went dry most
areas this evening. During the overnight, isentropic lift ramps up
and moisture increases, so went likely PoPs far south by late
tonight with chance PoPs elsewhere.

While there could be some mixed rain/snow at precipitation onset,
feel that temperatures will rise enough that rain will be the main
type by the end of the night.

Forcing continues across the area Tuesday morning, with the best
forcing across southeast areas closer to the upper system. Kept the
blend`s likely or higher PoPs southeast half and chance PoPs
elsewhere. Forcing quickly exits, allowing most areas to be dry
Tuesday afternoon.

Colder air flows into the area for the remainder of the short term.
A weak upper system will bring some forcing Wednesday night. Models
aren`t very bullish with forcing or QPF (with the exception of the
Canadian). However feel that with the cold advection and the upper
wave, chance category PoPs are still warranted.

&&

.LONG TERM /Thursday Through Sunday/...
Issued at 324 AM EDT Mon Dec 5 2016

Ensembles suggest the system that may affect the area at the
tail end of the short term will be passing off to the east on
Thursday. Will keep some small chance PoPs for light snow over the
eastern zones on Thursday.

It appears upper flow will become zonal towards the end of the
week. There continues to be large differences with respect to the
next upper trough that is progged to move into the middle of the
country by the weekend. Slim majority of the ensembles suggest this
feature will remain progressive and weak, however there are still
quite a few that suggest a stronger trough is possible.

Ensembles are trending farther north with the potential for warm
advection snow on Saturday. Will keep some chance PoPs over the
northern zones on Saturday to cover this. Minor accumulations still
look possible over the north on Saturday. Will go with chance PoPs
for mixed precipitation by Sunday.

&&

.AVIATION (Discussion for the 051200Z TAF Issuance)...
Issued at 538 AM EST Mon Dec 5 2016

IFR conditions will give way to VFR conditions by early-mid
afternoon. However, conditions will deteriorate late
tonight back to MVFR.

Have moderate confidence that the current conditions of low MVFR at
most TAF sites will lower to IFR by valid time. These ceilings will
start to lift after a few hours and should reach VFR by mid
afternoon. Visibilities look like they will remain VFR.

During the night ceilings will start to lower again, but they should
remain VFR through most of the night. Widespread rain will move in
mainly after 12Z Tuesday.


&&

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

&&

$$

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



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