Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 231742

Area Forecast Discussion
National Weather Service Northern Indiana
142 PM EDT Fri Sep 23 2016

Issued at 952 AM EDT Fri Sep 23 2016

Scattered showers and isolated thunderstorms are possible early
this afternoon, mainly north of US 30. Otherwise, expect partly to
mostly cloudy skies and highs in the upper 70s and 80s. Temperatures
will remain above normal, but trend a little cooler this weekend
behind a weak cold front. A low pressure system will bring chances
for showers back into the forecast later Sunday into Tuesday, with
cooler and mainly dry weather anticipated by late next week.


Issued at 952 AM EDT Fri Sep 23 2016

I did a quick short term update to increase pops/coverage given
the rain showers entering into the northwestern CWA-a bit earlier
and slightly more expansive than originally forecast. A few
rumbles of thunder are also possible. Otherwise,expect a
diminishing trend towards the latter part of the day (after 2 pm)
as weak upper level forcing exits the area. Most showers should
remain north of US 30.


.SHORT TERM...(Today through Sunday Morning)
Issued at 325 AM EDT Fri Sep 23 2016

Round of height falls through the Northeast US will force a
weakening front south into areas north of Route 6 this morning,
toward the US 30 corridor by later this afternoon, and then
washing out south of the local area by later this evening. The
passage of this feature will be marked by a veering wind to the
north-northeast, cooler temps into mainly northern portions of the
forecast area, and increasing clouds. Little mid-upper support
amid subtle height rises on leading edge of a northeast building
Mid-Upper MS upper ridge should preclude much of a shower risk
along this increasingly shallow front. With that said cannot
completely rule out a few sprinkles/light showers into areas
mainly north of US 30 today given decent moisture within
associated low-mid level theta-e ridge folding through.

Mainly dry/quiet weather is expected to persist tonight through
Sunday morning as amplified upper ridge axis becomes better
established into the western/lower Great Lakes. Could see stratus
develop tonight and linger into Saturday morning as moisture
possibly gets caught in strengthening low level inversion.
Improvement to mostly/partly sunny skies is then expected into
Saturday afternoon as drier air tied to low level anticyclone
dropping southeast through eastern Ontario/eastern Great Lakes
filters in.


.LONG TERM...(Sunday afternoon through Thursday)
Issued at 325 AM EDT Fri Sep 23 2016

Chance for showers Sunday Night/Monday followed by cooler/seasonable

Deep upper low now over UT/NV will eventually team up with Northeast
Pacific energy into the North-Central US Sunday and Ontario/Great
Lakes by early next week. Models continue to suggest the best
opportunity for showers with eastward progressing frontal boundary
to work through Sunday night into Monday. Medium range guidance
diverges in handling of this system into the middle of next week
(00z GFS more showery/unsettled with upper low lingering over the
Great Lakes, while the ECMWF is progressive/open with upper trough
exiting and high pressure building in). Given the
differences/uncertainties made no changes from the 00z model


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 142 PM EDT Fri Sep 23 2016

Weak backdoor cold front slowly pushing through the area. Very dry
low levels will limit impacts through the afternoon but boundary
layer will gradually cool and moisten overnight in E/NE flow and
expect at least MVFR ceilings to develop. Surface obs already
showing fuel alternate immediately upstream (aided by theta-e
flux from Lake Michigan) that may clip KSBN during the early
evening. IFR possible at KFWA by early Saturday morning but
not enough confidence to go quite that low with this TAF package.
Slow improvement anticipated Saturday morning.




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

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