Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 151835

Area Forecast Discussion
National Weather Service Northern Indiana
135 PM EST Wed Feb 15 2017

Issued at 130 PM EST Wed Feb 15 2017

Colder air will continue to filter into the region through the
evening hours. The cold air and northwest winds will result in
scattered snow showers or flurries over southwest Michigan and
northwest and north central Indiana. High pressure will move
across our area Thursday providing fair weather. An unseasonably
warm airmass will move into the area Friday, and linger over the
weekend and into early next week, providing much above normal
temperatures and dry weather.


.SHORT TERM...(Today and Tonight)
Issued at 301 AM EST Wed Feb 15 2017

Shrtwv dropping se across our cwa early this morning accompanied by
rather strong CAA which should persist until about midday resulting
in seasonably cold highs ranging from the lwr 30s nw to the upr 30s
se. Some clearing behind initial strato cu deck along the frontal
boundary, but caa and some wk lake induced instability with nw flow,
should allow strato cu to fill back in resulting in partly to
mostly cloudy skies across the area with a few snow showers
downwind of Lake Michigan. NW flow will cont tonight, though
will be weakening as sfc ridge approaches. Combination of wk waa
aloft and an apchg wk shrtwv in the nw flow should keep skies
partly to mostly cloudy with again a few snow showers possible
near Lake Michigan. Cloudiness should limit radiational cooling,
but a rather cold airmass will allow temps to fall to 18-25F
range by morning.


.LONG TERM...(Thursday through Tuesday)
Issued at 301 AM EST Wed Feb 15 2017

Warming trend will begin Thu as sfc ridge crosses the area while upr
level ridging approaches from the plains. This ridge will move into
the Midwest late this week providing unseasonably warm temps. A wk
shrtwv and accompanying sfc cdfnt will top the ridge and move
across our area Sat/Sat ngt. Wk forcing and lack of moisture will
keep fropa dry. An even stronger upr ridge will be building back
into the area from the srn plains Sunday in response to troughing
moving into wrn U.S., so, any post-frontal cooling should be
limited and brief. This strong upr ridge movg across the the
Midwest Monday should result in near record temps with lows mainly
in the 40s and highs in the 60s across our area (about 25F above
normal). Another shrtwv/cdfnt expected to top the ridge Tue.
Forcing with this system should be a little stronger with some
gulf moisture advecting n-ne into our area ahead of it providing
potential for showers along the frontal zone.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 130 PM EST Wed Feb 15 2017

VFR stratocu will continue to affect terminals this forecast
period as favorable lake induced instability profiles remain.
Scattered snow showers/flurries cannot be ruled out at KSBN
through early evening but larger scale low/mid level subsidence
and entrainment of drier air lends low confidence to any
mentionable precip for the 18Z TAFS. Did include TEMPO mention of
MVFR cigs in the 2500-3000 ft range at KSBN through the late
afternoon hours, although with low/mid level subsidence and slight
lowering of inversion heights, potential of some higher end MVFR
cigs may persist into this evening. An upper vort max will be
departing to the east this evening but would suspect VFR stratocu
or higher end MVFR cigs will be locked in place through much of
this forecast valid period. Continued cold advection this
afternoon and steep low level lapse rates will result in continued
gusts into the 20 to 25 knot range, but will subside early
evening as low level ridge axis approaches from the west. VFR low
clouds may persist into Thursday across terminals as backing low
level winds with approach of this ridge will help to advect some
increased low level moisture eastward. Outside of lingering iso-
sct snow showers/flurries through the evening, dry conditions are
expected to persist through this forecast valid period.


LM...Small Craft Advisory until 4 AM EST Thursday for LMZ043-046.




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