Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 221041

Area Forecast Discussion
National Weather Service Northern Indiana
641 AM EDT Sun Oct 22 2017

Issued at 350 AM EDT Sun Oct 22 2017

Another unseasonably warm day is expected today with highs into
the 70s. Chances for rain will increase west of Interstate 69
later today into tonight along a frontal boundary. Rain will
likely engulf the entire forecast area Monday into Monday evening
as low pressure develops into the Great Lakes region. Rainfall
amounts between 1 and 3 inches will be possible in northeast
Indiana, northwest Ohio, and south-central Lower Michigan. Much
cooler and showery weather is expected behind this system into
Tuesday and Wednesday, with highs on Wednesday likely struggling
to get out of the 40s.


.SHORT TERM...(Today and Tonight)
Issued at 350 AM EDT Sun Oct 22 2017

Mild and somewhat brisk southwest flow will yield another unusually
warm late October day with highs once again well into the 70s.
Clouds and chances for rain will increase into nw IN/sw Lower MI
later today into this evening, and toward the I-69 corridor tonight,
as a frontal boundary and associated deep moisture plume slows east
into the local area. These features exist on the leading edge of a
deep central US upper trough. Energy within the trough will split
with southern piece toward the Lower MS Valley and northern stream
jet energy northeast through the Northern Great Lakes and Ontario.
The result will be a weakening/slowing trend to the aforementioned
frontal circulation once it reaches our area. With that said, at
least light rain should accompany the front by tonight into areas
mainly west of I-69 given ample moisture, weak height falls, and
right entrance upper jet associated with the northern stream


.LONG TERM...(Monday through Saturday)
Issued at 350 AM EDT Sun Oct 22 2017

A pattern change to a much more active/wet/cooler regime the story
next week/weekend...

A powerhouse Northeast Pacific jet will eventually help to carve out
a rather impressive negative height anomaly over the Eastern US by
Tuesday and Wednesday. Phase of this jet energy with leftover
southern stream wave, a coupled jet structure, and surge of gulf
moisture should allow a deepening sfc cyclone to track northeast
along frontal boundary Monday into Monday night in this
transition. Favor the stronger/farther west/wetter solutions of
ECMWF/GEM/UKMET over the GFS/NAM at this time resulting in a bump
to QPF/PoPS...especially across ne IN/sc Lower MI/nw OH near
deformation pivot. Rainfall totals in the 1-3 inch range appear
possible here.

Strong cold advection wing wraps in under low pressure on Tuesday
with breezy/sharply colder conditions. Should also see scattered
to numerous rain showers given expected lake enhancement and moist
cyclonic flow within deep trough axis. Additional trailing
shortwave energy into the upper trough may support additional lake
enhanced shower activity into Wednesday. High temperatures on
Wednesday are not expected to get out of the 40s in most locations
(10-15 degrees below normal).

Fair wx and brief warming is expected into Thursday and possibly
Friday as shortwave ridging works through in between systems. The
next upper trough is modeled to amplify into the Central US by later
Friday and next weekend. Models differ on timing of a strengthening
baroclinic zone on the leading edge. Covered with broadbrush chance
PoPs for rain and cooling temps for now.


.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 640 AM EDT Sun Oct 22 2017

Conditions still on track for an initially slow deterioration
this evening at KSBN and during the overnight hours of Monday for
KFWA. While KSBN will likely drop into IFR near/after 6Z Monday.
Have continued a downward trend, but not introduced that low quiet
yet. At KFWA, flight condition impacts may not occur until closer
to the end of the period with slow arrival of the precip. Have
kept VFR conditions through the period, but will likely need to
drop further with next forecast.




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

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