Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171855

Area Forecast Discussion
National Weather Service Northern Indiana
255 PM EDT Thu Aug 17 2017

Issued at 255 PM EDT Thu Aug 17 2017

Drier and less humid air will overspread the region tonight into
Friday. Lows tonight will drop into the low to mid 60s, with highs
on Friday into the upper 70s to near 80 degrees. An upper level
disturbance then brings chances for rain and perhaps a few
thunderstorms back into the forecast later Friday night into
Saturday. Dry and warmer conditions are expected behind this
system Sunday into Monday.


.SHORT TERM...(This Evening through Friday)
Issued at 255 PM EDT Thu Aug 17 2017

Line of showers/storms near an active pre-frontal trough will
continue to shift off to the east leaving mainly dry conditions
for the remainder of the afternoon and evening. The main sfc
trough, tied to filling low lifting northeast through nrn WI/UP of
MI, will pivot through from nw to se late this afternoon into
early this evening. Not expecting much more than a stray shower
with this feature given dwindling moisture/instability in wake of
pre- frontal trough/warm conveyor belt and weak convergence. Wrap
around moisture likely clips areas mainly north of US 30 later
tonight through early Friday afternoon with a period of
broken/overcast stratocumulus possible, especially in our MI
counties. Moisture profile looks really shallow which should
preclude any light shower development. Dry/less humid/somewhat
breezy otherwise into Friday as deep layer subsidence overspreads
in between waves.


.LONG TERM...(Friday Night through Thursday)
Issued at 255 PM EDT Thu Aug 17 2017

Rain/embedded thunder chances return later Friday night into
Saturday morning as a more compact trop undulation digs through
underneath leftover trough axis. Moisture and unfavorable diurnal
timing continue to bring some question into rain chances locally.
However, relatively strong dynamic forcing (for mid August Standards)
looking more likely with each new model suite for a period of rain
and perhaps some embedded thunder with this wave as it moves
through. 12z model consensus populated with mid chance PoPs which
seems reasonable at this fcst range.

Sunday into Monday will be characterized by dry/warmer conditions
as the flow pattern flattens and sfc high pressure migrates through.
Upper troughing then looks to become reestablished into southeast
Canada/northeast US by the middle of next week. This transition will
send a seasonably strong cold front through around Tuesday/Tuesday
night with renewed shower/storm chances. Cooler/drier condition then
to follow mid-late week.


.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 125 PM EDT Thu Aug 17 2017

Vigorous shortwave continues on its northeast track into South-
central Canada with plenty of moisture in the column across the
region today. As a prefrontal trough moves east, it should take
most of the thunder ingredients with it leaving the area
thunderstorm free this afternoon. Drier air begins to funnel in
just out ahead of the cold front this afternoon so the area may be
able to dry out should the clouds break up. CIGs will start around
MVFR across the region, but feel the diurnal trend may be able to
keep the TAF sites in VFR. Winds will be able to be gusty this
afternoon as a result of a low level jet nearby and mixing down to
the surface. This low level jet will be able to stick around into
the overnight so feel that stratus would be a better bet than fog
overnight tonight. Should that drying occur, stratus may not form
at all.


IN...Beach Hazards Statement from 5 PM CDT this afternoon through
     Friday afternoon for INZ003.

MI...Beach Hazards Statement from 6 PM EDT this evening through
     Friday afternoon for MIZ077.

LM...Small Craft Advisory from 6 PM this evening to 5 PM EDT Friday
     for LMZ043-046.



SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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