Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 061046

Area Forecast Discussion
National Weather Service Indianapolis IN
546 AM EST Tue Dec 6 2016

The AVIATION section has been updated below.


Issued at 310 AM EST Tue Dec 6 2016

An area of low pressure will move from the Tennessee Valley into the
Upper Ohio Valley today, bringing rain to much of central Indiana.
Colder air will move in mid-week, bringing a chance for some light
snow. A couple of systems will bring additional precipitation
chances for the latter half of the weekend into early next week.


.NEAR TERM.../Today/
Issued at 310 AM EST Tue Dec 6 2016

Regional radar shows patchy rain developing across central Indiana
early this morning as isentropic lift increases, but it`s having a
hard time reaching the ground yet due to dry low levels. More
widespread rain was across southern Illinois and western Kentucky.

Rain should continue to develop and move northeast into the area
this morning as lift increases. The best forcing and moisture will
be across the southeastern forecast area, as this area is closer to
a surface low and upper trough.

Given the above went likely to categorical PoPs across the southeast
half of the forecast area, with chance PoPs northwest.

Forcing quickly moves through the area, so that by 18Z all but the
southeast third of the area will be dry. The east will then be dry
by 21Z.

(A cold front will also move through this afternoon, but it won`t
have much forcing or moisture to work with.)

A model blend looks good for high temperatures today given expected


.SHORT TERM.../Tonight through Thursday night/
Issued at 310 AM EST Tue Dec 6 2016

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

High pressure will build in behind the cold front bringing dry
but cooler conditions tonight into Wednesday.

Another surge of colder air will move into the area Wednesday night
into Thursday. An upper trough will move in as well. These will
bring some forcing, but moisture is lacking, especially in the lower
levels of the atmosphere.

Only the NAM and Canadian models generate any QPF with this setup.
However, have seen in the past these cold advection setups squeeze
out what limited moisture is available. Thus will keep the slight
chance PoPs in the area for Wednesday night.

Wouldn`t be surprised to see some flurries on Thursday with the cold
advection continuing, but for now will keep the initialization`s dry


.LONG TERM.../Friday Through Monday/
Issued at 310 AM EST Tue Dec 6 2016

Ensembles suggest a rather zonal and progressive upper flow over the
country during this period. Main weather feature during this period
looks to be a short wave trough that is expected to push across the
Great Lakes around Sunday and Monday. There are still some
differences in the location of the associated surface low track, but
at this time, all ensembles suggest a track across northern Indiana
or farther north.

Will go with chance PoPs starting Saturday night and continue them
through next Monday to cover this feature. Ensembles thicknesses and
expected track of surface low suggests a mixed precipitation event.

Appears the best chance for light accumulations will be Saturday
night, with lesser chances by Sunday and Monday as warmer air
advects into the system.


.AVIATION (Discussion for the 061200Z TAF Issuance)...
Issued at 546 AM EST Tue Dec 6 2016

MVFR conditions expected at times through much of the first half of
the TAF valid period. IFR possible mainly at KIND/KLAF during the
same period. VFR returns this evening.

Widespread rain will quickly move into the KIND/KBMG sites, with more
scattered rain at the other sites. With the widespread rain will
come MVFR ceilings and visibilities, with the potential for IFR
ceilings at times before 18Z. Other sites will see VFR with some
MVFR possible.

Rain will exit by 18Z, but a cold front will bring more MVFR
ceilings along with a wind shift this afternoon. VFR returns this
evening as drier air moves in.




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