Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 202333

Area Forecast Discussion
National Weather Service Northern Indiana
633 PM EST Sat Jan 20 2018

Issued at 320 PM EST Sat Jan 20 2018

Mild and moist air will continue to spread over the area through
Sunday. Expect highs from the upper 30s to to mid 40s, and around
50 Monday. Areas of fog are drizzle are expected to develop tonight,
and persist through Sunday. Rain is then expected to develop
Sunday night and continue into Monday. Some flooding is possible.


.SHORT TERM...(This Evening through Sunday)
Issued at 306 PM EST Sat Jan 20 2018

Mild and moist air will continue to spread north over snow covered
ground. Areas of fog and drizzle are expected to develop tonight
as these conditions persist. For now, have not mentioned dense
fog; however, concern for the ability of increasing moisture over
snow cover to produce dense fog. Lows tonight will be much above
normal around or just above freezing. Highs should top 40 Sunday
with the foggy conditions continuing.


.LONG TERM...(Sunday Night through Saturday)
Issued at 306 PM EST Sat Jan 20 2018

Multiple concerns will unfold early this upcoming week beyond the
onset, density and duration of fog. An upper level system with
favorable dynamics will move across the forecast area and bring a
good chance for heavy rain, especially over northwest areas.
Given the likelihood of melting snow over frozen ground to enhance
flood potential, have issued an Hydrologic Outlook. Please see
this outlook and the Hydrology section below for more
information. Rain should mix with snow and possibly change over to
snow late Monday night and early Tuesday. At this time, travel
issues Tuesday morning appear marginal; however, light snow
accumulations with temps falling below freezing could cause
elevated travel concerns. Otherwise, temperatures will not be
nearly as cold as after the past several cold fronts; highs
Wednesday should be around freezing, and then rise much above
normal into the 40s by next weekend.


.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 633 PM EST Sat Jan 20 2018

Conditions will continue to deteriorate through the overnight as
warm/moist air convergence increases. Model guidance in good
agreement on LIFR conditions by morning but still some differences
on how fast lower cigs/vis arrive. Latest obs suggest surface
saturation still struggling a bit and latest RAP and HRRR are
catching on to this trend and suggest IFR will not arrive until
after midnight with LIFR potentially holding off until 12Z. Some
improvement possible at times during the day tomorrow given
modest wind and lack of good snowpack but confidence in timing and
degree of improvement are too low to include at this range.



Snowmelt with snow water equivalent near 1 inch across northwest
CWA along with forecast rainfall amounts of 1 to 1.25 inches early
next week will result in increased runoff/increased streamflow.
Lesser rainfall amounts (0.50-0.75 inches) in the Maumee/Wabash
River Basins, along with lesser antecedent snow water equivalent
values, will lessen response in these basins. Caveat will be ice jam
formation potential that brings all basins onto a similar plain with
respect to flooding potential. Heightened awareness for potential
highlighted in latest hydrologic outlook/ESF and sitrep to core




SHORT TERM...Skipper
LONG TERM...Skipper

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