Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 280232

Area Forecast Discussion
National Weather Service Indianapolis IN
1030 PM EDT Mon Mar 27 2017

The Aviation Section has been updated below.


Issued at 327 PM EDT Mon Mar 27 2017

An active forecast period is expected for Central Indiana as
several troughs and ridges rotate through the area. The first
system is currently approaching the forecast area and is expected
to produce showers and thunderstorms this evening and tonight.
After that, weak ridging will result in dry conditions for mid-
week, but another system will approach from the southwest on
Wednesday night. This will keep high rain chances in the forecast
through the end of the week along with the threat for additional
thunderstorms. At that point, the pattern will almost repeat again
with a dry period for the weekend followed by another system late
in the extended period.


.NEAR TERM /Rest of tonight/...

Issued at 1001 PM EDT Mon Mar 27 2017

Radar mosaic shows an area of showers across much of central
Indiana at 10 pm. Currently no lightning showing up across the
area. However HRRR and RAP continue to show some elevated
instability available over the next few hours across the southern
half or so of the area, so kept a slight chance for thunderstorms
going for that part of the area until 6z. Rain will continue over
much of the area until moving out from west to east starting
around 6z during the overnight, with dry conditions expected
everywhere around daybreak. Cloudy skies will be the rule with low
center moving through the area and being in the wake of the low
after it moves east. Could see a decent gradient in low
temperatures as the northwest could drop into the mid 40s before
daybreak as the low moves east (currently a couple obs of mid 40s
in northeast Illinois and northwest Indiana), but most of the
area should stay in the low to mid 50s.


.SHORT TERM /Tomorrow through Thursday/...

Issued at 327 PM EDT Mon Mar 27 2017

Rain showers will end from west to east very early tomorrow
morning, and then dry conditions will prevail through Wednesday
evening as ridging strengthens aloft.

Focus then turns to the next system, which will start impacting
Central Indiana on Wednesday night. This system will take almost
the same exact path as the near term system, approaching from the
southwest. Inserted mention of thunderstorms with this forecast
issuance starting Wednesday night across the southwestern
counties, spreading northeast across the forecast area on
Thursday. As of now, any severe threat with this system is
expected to stay south, but this could change quickly with any
shifts in the path.

Temperatures through the period will be in the 60s, increasing to
the low 70s by Thursday as warm advection increases with
aforementioned system. Meanwhile, overnight lows will generally be
in the 40s with some 50s across the southern counties.


.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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