Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 181714

Area Forecast Discussion
National Weather Service Indianapolis IN
114 PM EDT Sun Mar 18 2018

The AVIATION Section has been updated below.


Issued at 312 AM EDT Sun Mar 18 2018

High pressure will provide a picturesque day for central Indiana
today with a return to above normal temperatures. This will be short-
lived, however as a series of low pressure systems will bring
chances of rain or snow to the area early next week and late next
week and weekend. There are several chances for light snow
accumulation starting Monday night over northeast counties.

Temperatures will fall back below normal by Tuesday and briefly
return to near normal by next Saturday.


.NEAR TERM /This afternoon/...

Issued at 944 AM EDT Sun Mar 18 2018

Surface analysis late this morning shows broad high pressure
across Indiana. GOES16 fails to show any clouds in the sky across
the forecast area. Winds were light and from the northeast.

Forecast soundings and time heights show a dry column this
afternoon...with unreachable convective temperatures.
Aloft...ridging was in place across the Plains...which was
resulting in lee side subsidence across the Ohio Valley. Thus we
will look for mostly sunny skies this afternoon. Given the
plentiful sunshine expected today and weak warm air
advection...we have trended the high temperatures closer to the


.SHORT TERM /Tonight through Tuesday night/...
Issued at 312 AM EDT Sun Mar 18 2018

Precipitation timing and type will be the primary issues in the
short term.

Today will start off with a weak east coast trough, a high amplitude
Missouri Valley ridge and a western trough. Models in generally good
agreement that an upper low will form within the western trough as
it moves to the Rockies and southern Plains tonight and Ohio Valley
Monday and Monday night. The blend brings increasing clouds with
this system from southwest to northeast tonight. In addition, the
blend has small PoPs after 09z across our extreme southwestern
sections. This has been the case the last several runs, so left the
small PoPs in there. Models then bring higher PoPs in Monday
afternoon and night which looks reasonable. Precipitation type will
be liquid until the low passes tonight. The result will be the rain
will change to snow from north to south tonight. Northeastern
sections could see minor accumulation of less than an inch per the

The precipitation should briefly end Tuesday morning but return
during the afternoon and night over all but the far northwestern
counties as upper system follows the first. Model soundings and low
level thicknesses suggest it will start as rain Tuesday afternoon
before changing to snow Tuesday night. Could see another minor snow
accumulation. Regardless, daytime heating will melt any snow during
the afternoon hours.


.LONG TERM /Wednesday through Saturday/...

Issued at 250 AM EDT Sun Mar 18 2018

The forecast looks mainly dry to start the long term with an upper
trough over the eastern U.S. making its way east. Could see a little
rain/snow mix still hanging around the southeastern counties
Wednesday morning as the system impacting the short term moves off.
High pressure will slide through on Thursday with small chances for
precipitation returning Thursday night. Greater chances will expand
over the area on Friday and into the weekend as a warm front makes
its way toward and across the area. Models show differences in
timing in the arrival of the aforementioned front, but all seem to
indicate this feature is coming near the end of the week or
beginning of the weekend, so made no changes to the blended
initialization. With the temperature profiles forecast, still
looking at rain being the main precip type during the day and then
adding a mix of rain and snow and finally over to snow at times
during the overnight hours.


.AVIATION /Discussion for the 181800Z Tafs/...

Issued at 114PM EDT Sun Mar 18 2018

VFR Conditions are expected this TAF period.

Models suggest dry air will remain in place tonight and much of
monday morning as High pressure over Indiana departs eastward.
Some High and mid cloud may invade the area after 18Z
time heights and forecast soundings suggest saturation aloft with
favorable lift within the column...however CIGS at that points
still look to be VFR...except within a scattered shower that could
occur late in the day.




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