Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 280600

Area Forecast Discussion
National Weather Service Indianapolis IN
200 AM EDT Tue Mar 28 2017

The SYNOPSIS...NEAR TERM and SHORT TERM Sections have been updated below.


Issued at 200 AM EDT Tue Mar 28 2017

Low pressure over Indiana will depart the area early this
morning...allowing high pressure to build across the Hoosier
state. This will result in dry weather for Central Indiana through the high moves through the region.

On late Wednesday Night...another low pressure system over the
southern plains will begin to push toward Indiana. This will bring
the best chances for rain back to Central Indiana by Thursday and
Thursday night.

At that point, the pattern will almost repeat again as High
pressure arrives with a dry period for the weekend followed by
another Low pressure system bringing rain early next work week.


.NEAR TERM /Today/...

Issued at 200 AM EDT Tue Mar 28 2017

Surface analysis early this morning shows low pressure in place
across east Central Indiana...slowly advecting eastward. Radar
shows scattered showers across our forecast area...slowly rotating
and exiting eastward. IR Images show extensive cloud cover
associated with the low across the state. Plenty of lower level
stratocu was found further upstream across Illinois...Wisconsin
and Iowa.

Models suggest deep moisture and forcing will exit the area early
this morning as the upper low and associated short wave depart.
GFS and NAM suggest ridging building aloft today and tonight as
Time heights show good mid level subsidence. However time heights
suggest that the lower level moisture will continue to linger
through today and tonight. Given Satellite trends upstream and the
lack of strong anti-cyclonic flow across the area...will trend
toward mostly cloudy skies today. Weak cold air advection is
expected within the north to northeast flow in the wake of the
departing low. A forecast builder blend will probably be suitable


.SHORT TERM /Tonight through Thursday night/...

Issued at 200 AM EDT Tue Mar 28 2017

Quiet weather will be expected at least through Wednesday across
Central Indiana. GFS and NAM show strong ridging building
across Indiana. Time heights and forecast soundings show excellent
subsidence in the mid and upper levels. However a different story
remains in play in the lower levels. Lower level moisture appears
to linger as the models suggest a dirty northeast flow across
Indiana...around the high north of the Great Lakes. THus will keep
mostly cloudy through Tonight. May trend cloud cover slightly less
on Wednesday as best ridging remains in place at that time and
lower level moisture appears to slightly dry out. Again a blend on
Temps will work just fine.

On Wednesday night and Thursday changeable weather is expected to
return. GFS shows Low pressure developing again over the souther
plains...pushing a warm front and tight baroclinic zone toward
Indiana from the southwest. Forecast soundings show lower level
saturation arriving by 12Z Thursday amid a warm air advection
inversion. Meanwhile the GFS 300K isentropic surface shows strong
up-glide arriving with specific humidities over 5 g/kg. With best
saturation not appearing until close to 12Z Thursday...will try
to minimize pops on late wednesday night as much of the night
should be dry. However By thursday all the previous mentioned
ingredients begin to come in to play...and will trend to
categorical pops then. An elevated thunderstorm will be possible
on Thursday given the advance of the warm front...however the
lower level inversion should just keep any storm isolated.

As for temps will trend lows on wednesday night warmer than a
forecast builder blend given the expected warm front and low cloud
arrival. Will trend highs on Thursday at or below a blend given
the expected rain.

Best forcing appears lost on Thursday night...however lingering
pops will need to be carried ans lower level flow looks to remain
cyclonic...with lingering lower level moisture available.


.LONG TERM /Thursday night through Monday/...

Issued at 220 PM EDT Mon Mar 27 2017

Timing of showers will be the main focus for the long term.

The general weather pattern will remain the same through the long
term with alternating Pacific upper lows and ridges. Each upper low
will dive southeast across dessert southwest and southern Plains and
then lift northeast over the Ohio Valley.

Thursday night will start off with the first upper low over the
Ozarks. It will open up and move east over the Ohio Valley on
Friday. Southerly flow along and ahead of the associated frontal
system will bring deep moisture and some instability to the area as
well as synoptic forcing. Thus, expect widespread showers and a few
thunderstorms from Thursday night through Friday. An upper ridge
will follow and should keep the weather quiet from early Saturday
through Sunday morning. Then, the next in the upper train will bring
shower chances back to central Indiana by Monday.

Low level thermal progs and expected cloud cover support slightly
above normal blend temperatures with highs in the mid 50s to mid


.AVIATION /Discussion for the 28/0300Z TAF Issuance/...

Issued at 1030 PM EDT Mon Mar 27 2017

With the update...went more pessimistic at KLAF with low MVFR/high
IFR developing already and upstream sites showing several obs with
IFR ceilings. For KIND added some light showers for the next couple
of hours but not convinced these will impact category until after 4z
or so. Rest of TAFs on track. Previous discussion follows...

Scattered rain showers will bring MVFR conditions over the next
few hours for TAF sites across Central Indiana. These scattered
showers will move out of the area by midnight leaving behind
ceilings that will lower into IFR by sunrise. Some isolated fog
will be possible, but with low confidence it will be left out at
this time. Ceilings will begin to rise by mid to late afternoon to
MVFR and will remain there through the evening. Winds will remain
less than 10 knots and generally be north to northeasterly
through the period.




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