Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 241020

Area Forecast Discussion
National Weather Service Northern Indiana
620 AM EDT Mon Oct 24 2016

Issued at 335 AM EDT Mon Oct 24 2016

A frontal boundary tracking southward across the Ohio Valley will
bring cooler conditions to the region today. Some low clouds are
possible this morning, especially across northern Indiana and
southwest lower Michigan due to lake effect. Dry conditions are
expected to continue today into Tuesday. Rain chances will
increase once again Tuesday night, and especially late Wednesday
afternoon into Wednesday night. A few thunderstorms are also
possible Wednesday and Wednesday night. High temperatures today
will range from 55 to 60. Low temperatures tonight will drop into
the mid to upper 30s.


.SHORT TERM...(Today and Tonight)
Issued at 335 AM EDT Mon Oct 24 2016

A return to seasonable temps will characterize the short term
period, with dry conditions persisting today and tonight.

A cold frontal boundary will continue to exit east central Indiana
over the next few hours. Patchy stratocu should continue to build
southward from Michigan/east central Wisconsin this morning
although some low confidence in the details regarding coverage as
far south as the southern Great Lakes given increasing large scale
subsidence behind yesterday`s short wave. The best chance of more
substantial low cloud coverage this morning will be probably end
up being in association with lake effect clouds and downwind of
Lake Michigan. Still expecting a diminishing trend to any morning
stratocu this afternoon however. With cold air advection rather
shallow in nature, lake induced convective cloud depths still
appear to be on the marginal side to support lake effect rain
showers and will continue to keep PoPs just below mentionable
levels this morning, with any precip likely to be of the trace
variety. High pressure will settle across the area tonight with
primarily clear skies and light winds. Setup does appear favorable
for lows in the 35 to 40 degree range and some patchy frost.


.LONG TERM...(Tuesday through Sunday)
Issued at 335 AM EDT Mon Oct 24 2016

Tuesday will be a transition day as low level thermal troughing
slowly exits to the east and as next eastern Pacific upper PV
anomaly begins to emerge across the lee of the Rockies. The
amplitude of the southeast Canadian negative height anomaly should
result in only stubborn eastward progression of the low level
ridge axis across northwest Ohio and south central lower Michigan,
with primary axis of WAA/moisture transport confined well to the
west across the Corn Belt. The low level jet axis will shift
eastward by Tuesday night/early Wednesday with what appears to be
a favorable setup for narrow band of warm advection/isentropic
lift induced rain showers Tuesday night into Wednesday morning.
There could be just enough elevated instability and enough low
level mass convergence with the nose of the low level jet to
support an isolated storm during this period, but will hold off on
a mention at this time. Have not added significant detail yet to
weather grids but some possibility for brief lull in rain shower
chances is possible later Wednesday morning into the early
afternoon between strongest warm advection forcing and stronger
synoptic forcing late Wednesday afternoon/Wednesday night.
Previous weather grids appear to be in good shape with likely PoPs
Wednesday night diminishing from west to east Thursday morning.

By Thursday, a broad baroclinic zone should extend from the northern
Plains to the southern Great Lakes which may act as a favorable
path for additional northwest flow waves to amplify along in the
Thursday night-Friday night period. A good deal of run to run
volatility/inconsistency noted among deterministic solutions with
overall low confidence in refining rain chances. From a consensus
view point, guidance is overall trending a bit more aggressive in
the suggestion of another short wave impacting the area for
Friday/Friday night, and have thus nudged chances up a bit for
this period. Uncertainty in short wave pattern Friday-Sunday and
potential for wavering baroclinic zone is contributing to lower
than normal confidence in temp forecast for next weekend also, but
the overall idea of near normal temps still appears to be


.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
Issued at 615 AM EDT Mon Oct 24 2016

VFR/dry conditions expected through the period. Post-frontal
BKN/OVC stratocu deck in 3-6 kft range expected through early-mid
afternoon, especially at KSBN given shallow lake response in
veered nnw flow. Mainly clear skies and light winds then by late
afternoon/tonight as high pressure builds in.


LM...Small Craft Advisory until 8 PM EDT this evening for LMZ043-046.



SHORT TERM...Marsili
LONG TERM...Marsili

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