Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 231948

National Weather Service Northern Indiana
248 PM EST Thu Feb 23 2017

Issued at 1228 PM EST Thu Feb 23 2017

It will remain unseasonable warm today into Friday. A frontal
boundary will cool the lakeshore area today where temperatures
will remain in the upper 40s to around 50. Well inland highs
today will push well into the 50s with even lower to middle 60s
south of route 24 expected. Rain chances will increase later this
afternoon and especially tonight as low pressure develops in the
Plains. Severe weather remains a possibility Friday afternoon and
evening as a cold front moves through the area. High on Friday
will be in the middle 60s to the lower 70s in spots, then plummet
back to seasonable levels for the weekend along with a chance for
snow showers.


.SHORT TERM...(This Evening through Friday)
Issued at 248 PM EST Thu Feb 23 2017

Cold front in association with sw disturbance crossing srn ON this
aftn stalling now through cntrl IL/IN and will quickly reverse this
evening in response to upstream cyclone spinning up through wrn KS.
Fairly vigorous low level theta-e surge expected mid to late evening
in concert with nwd spread of ramping low level flow although better
implied forcing exists through wrn OH late evening.

Warm front mixes rapidly north into lower MI late tonight as sfc low
lifts into ern IA. Capping inherent to steep elevated mixed layer
likely to squash any warm sector convective development until mid
aftn at the earliest tied to prospects of arrival of better low
level moisture and upticking sfc based destabilization. Conditional
severe risk based on moisture availability appears greatest along
prefrontal trough feature through ern IN/wrn OH late aftn/early
evening where best overlap of 0-3km shear/MLCAPE ~1200 j/kg exists
suggesting a discrete supercell threat and all modes of severe wx
possible. Secondary concerns would lie along strongly forced cold
frontal zone farther west Fri evening through nrn IN/srn MI as more
unidirectional flow here indicates primarily a wind threat...
sweeping ewd through wrn OH late evening. Otherwise given as yet
still considerable spread present in highres solutions will follow
blended pops Fri aftn/eve.


.LONG TERM...(Friday Night through Thursday)
Issued at 248 PM EST Thu Feb 23 2017

Trailing H7-5 deformation zone will wrap ewd late Fri night/early
Sat morning along with brief lake enhancement as strong low level
cold advection wing follows in. Some minimal accums possible
northwest Sat am however rapid liftout of parent cyclone into se
Canada along with loss of mid level moisture plume along with
collapsing lake MI thermal trough Sat evening warrant an aggressive
cut to prior gridded pops.

Thereafter flow backs quickly Sun downstream of renewed broad
troughing through the wrn US which leads to rapid temp moderation
and returning rain chances by Tue.


.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1237 PM EST Thu Feb 23 2017

Low clouds have sunk into KSBN with leading edge showing some
potential signs of eroding. For the time being have had to go with
MVFR conditions until marine layer may mix out somewhat. At KFWA
mainly high clouds through 00z. Tonight, showers will move in in
the 3 to 6Z window with best chance of impacts at KSBN. Can`t rule
out thunder at either location but again best shot will be KSBN so
maintained prob 30 for now.

Front should race north Friday morning and bring gusty southerly
winds and somewhat improving cigs. Convective chances (including
wind gust potential of 50 kts or higher) will arrive outside the
current period for both locations.





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