Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 181940

Area Forecast Discussion
National Weather Service Northern Indiana
340 PM EDT Wed Oct 18 2017

Issued at 340 PM EDT Wed Oct 18 2017

High pressure will remain across the region through Saturday and
will maintain dry and sunny conditions. Highs will remain in the
upper 60s to mid 70s with cooler conditions near Lake Michigan on
Thursday. The next chance of rain will arrive on Sunday.


.SHORT TERM...(This Evening through Thursday)
Issued at 340 PM EDT Wed Oct 18 2017

No sensible weather concerns through the short term as behemoth
ridge and associated dry/stable airmass remain entrenched over the
eastern CONUS through Sat. High latitude trough/front will pass to
our north overnight and this will maintain a decent gradient
overnight and may support some high clouds in the morning. Main
impact of this will be milder lows tonight. Some slight warm/moist
air advection ahead of this front and persistent gradient should
keep lows in the upper 40s/around 50F. Postfrontal CAA is minimal
and confined to Michigan. Highs may be a little cooler near the lake
with weak W/NW flow but still mid 60s there and low 70s in our
south. Expect sunny skies by afternoon.


.LONG TERM...(Thursday Night through Wednesday)
Issued at 340 PM EDT Wed Oct 18 2017

Ridge rebuilds aggressively late tomorrow into Friday as next Pacific
trough crashes into the western CONUS. Dry and sunny conditions will
persist on Friday with highs creeping into the mid 70s. A few more
clouds possible by Sat but WAA/SW flow also increases with another
day in the mid 70s.

Forecast for Sunday and Monday still uncertain with Canadian and,
to a lesser extent, the 12Z ECMWF indicating a much slower/more
closed off solution. GFS and majority of its ensemble runs remain
much more progressive, similar to the 00Z ECMWF. Maintained likely
PoPs on Sunday with good CVA and theta-e advection ahead of the
front. Not enough instability to introduce thunder mention but
could see some modest (around 0.25 inches) rainfall. Forecast
confidence decreases drastically for Monday and stayed close to
concensus PoPs for now. Secondary trough digs into the Great Lakes
but question is whether or not it will arrive quick enough to
phase with lingering wave to our south. Regardless, do expect
colder temps and persistent rain chances for the middle of next


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1245 PM EDT Wed Oct 18 2017

Southerly flow this afternoon at 10 to 15 knots with gusts to 20
to 25 knots. Overnight the winds will diminish to 5 to 10 knots
and slowly shift towards out of the southwest by morning. There
may be some low level wind shear over KSBN around midnight but
left it out due to a lower confidence.


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




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