Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 241145

Area Forecast Discussion
National Weather Service Indianapolis IN
645 AM EST Fri Feb 24 2017

The AVIATION Section has been updated below.


Issued at 259 AM EST Fri Feb 24 2017

A rather potent system and its associated cold front will sweep
across Central Indiana today and this evening. As a result, the
threat for severe thunderstorms continues this afternoon and
evening across the majority of the forecast area. With this system
will also come an end to the warm temperatures as cooler air
filters in behind it. As a result, snow showers will filter into
the region tonight and tomorrow on the back side of the
aforementioned system. After that, dry conditions will return from
Saturday night through Sunday, followed by a wetter pattern early
in the week.


.NEAR TERM /Today and Tonight/...

Issued at 259 AM EST Fri Feb 24 2017

The main focus of the near term period will be severe threat with
potent system.

Latest Day 1 SPC convective outlook continues to have the eastern
two-thirds of central Indiana under an enhanced risk for severe
weather with a slight risk over the remaining third.

Currently, the surface low is situated over northern Missouri with
some convective development along its associated warm front
stretching across the lower Midwest. Any further convective
development is expected to be minimal this morning, but winds will
start out gusty across central Indiana as a 50 plus low level jet
accompanies the warm sector. Expect south winds to be sustained at
10 to 15 mph with gusts to around 35 mph. As a result, trended
above guidance for today`s highs, topping them off in the low to
mid 70s.

With temps in the low to mid 70s and dewpoints in the 50s, there
will be decent instability for the associated cold front to work
with when it moves through this afternoon and evening. Best
forcing with the front should be during the Fri 21Z-Sat 02Z time
frame, which is a high confidence forecasted time frame. Main
threats are expected to be damaging winds and isolated tornadoes.
Confidence waivers a bit though on tornadic development because
storms could take on a more linear form.

As mentioned above the severe threat will quickly diminish by Sat
02Z as much cooler air filters in on the back side. At that point,
there will be a transition to some snow showers late in the night.
But, no accumulations are expected.


.SHORT TERM /Saturday through Sunday Night/...

Issued at 259 AM EST Fri Feb 24 2017

Snow showers will initially impact the northern counties early in
the period on the back side of aforementioned system. However, no
accumulations are expected, and it will quickly taper off by the
afternoon hours. After that, dry conditions will prevail from
Saturday night through Sunday before the next round of
precipitation enters on Sunday night. Much cooler temperatures by
then could result in some snow showers across the northern
portions of the area on Sunday night, and rain showers across the
southern counties.

Highs will take a dip on Saturday and Sunday with readings in the
30s and 40s, respectively. Meanwhile, overnight lows will be in
the 20s and 30s on Saturday night and Sunday night, respectively.


.LONG TERM /Monday through Thursday/...
Issued at 222 AM EST Fri Feb 24 2017

Models in general agreement that a frontal system will be moving
over the area Tuesday night into Wednesday. Good return flow ahead
of this system supports the widespread superblend pops Monday night
into Wednesday morning. Model instability progs warrant thunder
mention Tuesday afternoon and evening.

Prior to that, an upper wave could generate a few showers Monday.
Partial thicknesses and model soundings suggest some snow could mix
in during the morning, mainly north.

Temperatures will return to above normal ahead of the midweek
frontal system, but then fall back to seasonable by Thursday in its
wake. Superblend handles this well. Will not make any changes.


.AVIATION /Discussion for the 24/12Z TAF Issuance/...

Issued at 641 AM EST Fri Feb 24 2017

Conditions will generally be at VFR levels for most of the TAF
period. However, there is the potential for severe storms during
Fri 21Z - Sat 02Z. So, there could be some reduced visibilities in
the strongest storms. The main threat for most of the TAF period
will be the gusty W/SW winds. Sustained speeds will range between
12 to 14 kts with gusts up to 30 kts.





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