Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 240311
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1000 PM EST Sun Feb 23 2020

.UPDATE...
The AVIATION and Near Term Section has been updated below.

&&

.SYNOPSIS...
Issued at 245 PM EST Sun Feb 23 2020

A low pressure system is expected to affect the area starting
tonight, and lingering into the midweek period. In the wake of this
system, high pressure is expected to move into the area for the
later parts of the week.

&&

.NEAR TERM /Rest of Tonight/...
Issued at 1000 PM EST Sun Feb 23 2020

Pushed back timing of PoPs over the northern half of the forecast
area based on hi res output and current trends. Previous discussion
follows...

Models suggest an upper low, currently over the southern Rockies,
will move into the southern Plains by sunrise Monday. Appears most
of tonight may end up being dry, with some lift and deeper moisture
not expected to move into the area until the pre dawn hours of
Monday. Lift doesn`t look particularly strong late tonight, with
the main 850mb jet located well off to the southwest, over the
southern Plains. Will start to bring in chance PoPs for rain from
the southwest after 240600Z.

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

&&

.SHORT TERM /Monday through Wednesday/...
Issued at 245 PM EST Sun Feb 23 2020

Unsettled weather is expected during most of the short term. Initial
upper low will eject across the local area Monday night, before
being absorbed by a larger trough that will reach the Midwest by
Wednesday.

Will gradually increase the PoPs during the day Monday, as models
suggest the best area of lift may not pass through the local area
until Monday afternoon and evening. As a result, the highest PoPs
may be at that time.

PoPs will continue through Wednesday, given the sharpening upper
trough moving into the area. The more widespread precipitation may
become more intermittent in nature by Tuesday night and Wednesday,
as the intensifying surface low will lift off to the northeast by
that time.

Thicknesses look high enough for mostly rain through Tuesday. By
Tuesday night into Wednesday, the approaching upper trough should
allow for thicknesses to fall enough for more of a mix or a change
over to snow during those periods. Potential still exists for some
light accumulations over parts of the area Tuesday night or
Wednesday.

Given the expected precipitation during the period, will narrow the
diurnal range of the MOS guidance by about 3-5 degrees from Monday
onward.

&&

.LONG TERM (Wednesday Night Through Sunday)...
Issued at 307 PM EST Sun Feb 23 2020

Models are close enough that the National Blend of Models
initialization was accepted for most items.

A large upper trough will keep cold conditions across central
Indiana through much of the long term period. Some moderation will
occur next Sunday.

Some lingering light snow is possible Wednesday night before forcing
exits the area. Can`t rule out some light precipitation at times
afterward as both the GFS and ECMWF have light precipitation at
differing times with impulses in the upper flow.

However, with very low confidence with these features, will stick
with the dry NBM forecast for Thursday and beyond.

&&

.AVIATION /Discussion for 240300z TAF issuance/...

Issued at 1000 PM EST Sun Feb 23 2020

Updated current conditions. Previous discussion follows...

Sites will start out VFR and stay that way through around 8-10z or
so when MVFR cloud deck overspreads the area due to a front
settling in. The approach of the frontal system will also bring
rain to the area a few hours after ceilings fall. MVFR could be
brief, with ceilings rapidly falling to IFR and lower. Low
ceilings of 500 ft or lower will then be the rule throughout the
day on Monday. Winds will shift from southwesterly around 4 to 8
kts tonight to southeasterly around the same speed on Monday.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...JAS
NEAR TERM...JAS/CP
SHORT TERM...JAS
LONG TERM....50
AVIATION...CP


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