Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 180650

Area Forecast Discussion
National Weather Service Indianapolis IN
250 AM EDT Sun Mar 18 2018

The LONG TERM Section has been updated below.


Issued at 252 PM EDT Sat Mar 17 2018

A weakening upper low is expected to pass through the area later
this afternoon and evening. Another low pressure system is expected
to affect the area early next week. In the wake of this system, high
pressure will build into the area for the middle and later parts of
next week.


.NEAR TERM /Overnight/...
Issued at 1238 AM EDT Sun Mar 18 2018

Had to hasten the clearing per satellite trends as the clearing line
has made it all the way south to IND at 04z.

Previous discussion follows...
Issued at 916 PM EDT Sat Mar 17 2018

Radar indicates that the patches of light rain have ended or will
end shortly or the forecast area. Will take the precipitation out
of the forecast for the rest of the night.

Previous discussion follows.

Weakening upper low currently over Illinois will be passing over the
local area later this afternoon and into the evening hours. Radar
indicates there is still some patches of light rain and drizzle
associated with this feature, so will keep some PoPs going into the
evening hours until the upper low passes off to the east. Most of
the lingering precipitation should be in the form of rain, but there
could be a light mix at times over some of the northern zones.

Short term model data suggest the low clouds should start scattering
out from the north around sunset, with the clearing line slowly
dropping south tonight, although the clearing line may not reach the
far southern zones until well after midnight.

There may be some fog development, especially later tonight, as
skies clear with a light gradient and residual moisture.

Low level thicknesses suggest the GFS MOS lows for tonight look
reasonable, so little if any adjustments planned.


.SHORT TERM /Sunday through Tuesday/...
Issued at 252 PM EDT Sat Mar 17 2018

Next upper trough is expected to move into the Midwest by Monday,
with an associated surface low passing near of south of the Ohio
River. Warm advection begins Sunday night, so will bring PoPs back
into the southern zones Sunday night, and spread them northward into
the rest of the area on Monday and Monday night. The highest PoPs at
this time appear to be Monday afternoon and evening over the
southern zones, coinciding with the best lift.

Thicknesses suggest rain will be the predominate precipitation type
Sunday night and Monday, however thicknesses are expected to lower
Monday night, allowing for more of a mixed precipitation threat by
that time. Some light accumulations are possible over parts of the
area Monday night.

Will keep some chance PoPs for mixed precipitation into Tuesday
morning as the system passes off to the east, however some of the
ensembles suggest the precipitation threat may linger longer
into the day Tuesday.

Progged low level thicknesses suggest the GFS MOS highs for Sunday
may be a bit on the warm side. Will nudge the guidance highs down a
category. The remainder of the periods look OK at this time.


.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 180600z TAF issuance/...

Issued at 1248 AM EDT Sun Mar 18 2018

GOES-East loop shows cloud deck has moved south of KIND and KLAF
as of 5z and should shortly be south of KHUF. May take another
hour or two to clear KBMG, so will start with MVFR ceilings there.
Could see them bounce between MVFR and IFR ceilings for the first
two hours, but after that they should clear out. SREFS show
potential for some fog at KIND and KLAF, but RAP shows the
potential for lower visibilities at KHUF and KBMG near the lower
cloud deck, and boundary layer dewpoint depressions may be making
the difference here. Thus will put MVFR fog near daybreak at all
sites but KBMG, where it could start and last a bit longer. Expect
improvement to VFR at all the sites by 14-15z. NAM MOS shows some
potential for much lower fog in the hours around daybreak, but
with it being an outlier generally disregarded it.




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