Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 281821

Area Forecast Discussion
National Weather Service Indianapolis IN
220 PM EDT Tue Mar 28 2017

The LONG TERM Section has 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 /Friday night through Tuesday/...
Issued at 220 PM EDT Tue Mar 28 2017

The general weather pattern will continue through the long term. The
main focus will be on timing of showers.

Models and ensembles continue the pattern of having Pacific systems
move through the dessert southwest, Plains and then Ohio Valley with
ridging in between. One such system will be moving out of the area
Friday night. Ridging in its wake should allow for dry weather
through Sunday night. Then, the next system will be getting close
enough for pops by Monday. The system should then be on our doorstep
on Tuesday, so pops look good the rest of the long term. Instability
progs suggest some instability will be around if only weak. So, will
throw in isolated thunderstorms.

Look for below normal temperatures in the 50s on Friday but above
normal temperatures by Sunday as return flow sets up ahead of the
second system. Blend highs in the 60s look good.


.AVIATION /Discussion for the 28/1800Z TAF Issuance/...

Issued at 121 PM EDT Tue Mar 28 2017

Time cross sections continue to trend toward lingering low level
moisture. Plus, an inversion for the beginning of the TAF period
will make it tough for conditions to improve beyond MVFR levels.
As a result, a return to VFR conditions may not happen until the
very end of the TAF period. Meanwhile, winds will generally be
north/northeasterly at 5 to 10 kts.





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