Area Forecast Discussion
Issued by NWS Indianapolis, IN

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625
FXUS63 KIND 151659
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1200 PM EST Mon Jan 15 2018

.UPDATE...
AVIATION section has been updated below.

&&

.SYNOPSIS...
Issued at 244 AM EST Mon Jan 15 2018

A low pressure system will bring accumulating snow to the area
today. An upper level disturbance may result in some flurries or
light snow showers on Tuesday. High pressure is expected for the mid
to late parts of the week.

&&

.NEAR TERM /Rest of Today/...
Issued at 957 AM EST Mon Jan 15 2018

Snow has diminished quite a bit across the northwest half of our
region as drier air spreads in.  As a result additional
accumulations should be half inch or less.  Radar indicates heavier
snow will occur over southern and east central areas through at
least midday and then snow will diminish over the rest of the area.

Even though additional snow amounts appear less northwest...decided
to keep Winter Weather advisories intact for now as driving
conditions are still poor.

Lowered temperatures slightly most areas this afternoon as colder
air behind the cold front spreads in.

&&

.SHORT TERM /Tonight through Wednesday night/...
Issued at 244 AM EST Mon Jan 15 2018

Model data suggest most of the lift will have passed off to the
southeast around sunset, so will go dry tonight. An elongated area
of mid level vorticity is progged to pass over the area during the
day Tuesday and Tuesday night. This may result in some flurries or
light snow showers at times, but model data continue to be rather
conservative with QPF potential with this lobe.

Will go with a dry forecast for Wednesday and Wednesday night as
surface high pressure builds through the Ohio and Tennessee Valley.

Progged low level thicknesses suggest the GFS MOS temperature
guidance for the next couple of days looks reasonable, so only minor
adjustments planned.

Expected wind chills approach advisory criteria over parts of the
area by early Tuesday morning, so wind chill headlines are possible
at some point.

&&

.LONG TERM /Thursday through Sunday/...
Issued at 132 AM EST Mon Jan 15 2018

Moderating temperatures and weekend rain will be the main highlights
for the weekend.

Surface high pressure will start over the southern states before
moving to the southeastern states and Atlantic Friday night. This
will allow for a return flow off the Gulf of Mexico resulting in
much warmer temperatures and rain chances by Saturday with warm air
advection and any upper impulses in the southwest flow aloft. The
00z Canadian and GFS continue to be faster than the ECMWF bringing
QPF to the area overnight Friday night. The latter does not have any
precip until late Saturday. The Forecast Builder has a compromise
starting with low pops around 12z Saturday. This looks reasonable,
so will accept it. Models all agree an approaching frontal system
will be just west of the area late Sunday, when the best chances of
rain should be. Would not rule out very brief freezing rain or snow
at the very onset Saturday morning over eastern locales in the near
freezing temperatures.

Prior to the precip onset, Thursday and Friday should see a good
deal of sunshines with regional blend highs in the upper 20s and
lower 30s Thursday and middle and upper 30s Friday looking good.
Could see 50s by Saturday. Good confidence in temperatures trends if
not in precise highs.

&&

.AVIATION /Discussion for the 15/12Z TAF Issuance/...
Issued at 1200 PM EST Mon Jan 15 2018

MVFR ceilings with pockets of IFR early on...improving to VFR this
evening and back to MVFR ceilings northern sections Tuesday morning.

Low pressure over southeast Wisconsin will track east across the
great lakes as a cold front moves east across central Indiana.
Snow was ending across north and central sections and should end
in the south in a few hours. Could see flurries this afternoon and
northern areas Tuesday morning.

Southwest winds 10 to 12 knots will become west after cold front
passage and then decreasing a little late tonight.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 4 PM EST this afternoon for INZ021-
028>031-035>049-051>057-060>065-067>072.

&&

$$

SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....MK
AVIATION...JH



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