Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 270504

Area Forecast Discussion
National Weather Service Northern Indiana
103 AM EDT Tue Sep 27 2016

Issued at 755 PM EDT Mon Sep 26 2016

Clear and seasonably cool conditions will persist through Tuesday.
Rain chances will return Tuesday night and persist through the end
of the week as a stalled upper level system sets up over the
region. Lows tonight will be in the middle to upper 40s...except
warmer near Lake Michigan. Highs on Tuesday will generally range
from 65 to 70.


.SHORT TERM...(This Evening through Tuesday)
Issued at 310 PM EDT Mon Sep 26 2016

Strong negative theta-e advection bringing an abrupt end to cloud
cover from west to east this afternoon. Deep postfrontal mixing and
a modest pressure gradient supporting a few wind gusts around 30 mph
this afternoon with a corresponding bump in afternoon temps.
Gradient stays up overnight but CAA will allow overnight lows to
drop into the upper 40s for the first time since June. This will
certainly feel cool after recent conditions but is only a few
degrees below average for this time of year. Skies expected to
remain mostly clear given depth and magnitude of dry air advecting
into the area. Dry conditions will then persist through Tuesday with
mostly sunny skies. Another day of relatively deep mixing will push
afternoon highs well into the mid to upper 60s and low 70s not out
of the question. Westerly winds also expected to gust near 30 mph
again tomorrow afternoon. Wind profiles aloft just a few knots lower
than today so expect conditions will be similar. May even flirt
with red flag criteria in our S/SW zones, similar to today, with
surface dewpoints in the 30s yielding RH values near/below 30


.LONG TERM...(Tuesday Night through Monday)
Issued at 310 PM EDT Mon Sep 26 2016

Dry and sunny conditions will be short-lived though. Latest models
continued earlier noted trend of developing cutoff upper low in our
region through the second half of the week. This will support cool
and cloudy conditions with periodic chances for light rain. Initial
PV filament and associated low level trough axis will rotate into
our NW CWA Tuesday night. Delayed the arrival just a bit based on
latest guidance. Suspect Tuesday will remain entirely dry through
the day with precip not entering our NW until after sunset Tuesday
evening. Healthy CVA and low level convergence will be further aided
by theta-e flux from relatively warm Lake Michigan to generate
numerous showers in our NW counties. Chances for rain much lower for
counties along and south of US-24 but wouldn`t rule out a stray
shower. Wednesday will likely be the coolest day of the week. Could
struggle to reach the lower 60s with cool thermal profiles, abundant
clouds, and SCT showers for much of the day.

Forecast for the rest of the week remains much the same with upper
low set to wobble around the region. Continued trend from previous
shift of increased clouds, higher PoP`s, and reduced diurnal temp
ranges. After Wednesday, precip forecast becomes more muddled with
timing of better precip chances dependent on exact evolution of
meandering upper low and embedded shortwaves rotating around its
center. Maintained concensus broad-brushed low chance PoP`s with
temps very slowly moderating through next weekend. Some hope for
better weather by early next week.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 103 AM EDT Tue Sep 27 2016

VFR conditions will persist through this period yet big changes in
store thereafter. Insolation will again drive strong wswly gusts by
late morning through late afternoon...sfc gusts aoa 25 knots.


LM...Small Craft Advisory until 11 PM EDT Wednesday for LMZ043-046.




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