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-- Discussion containing changed information from previous version are highlighted. --
562
FXUS61 KILN 011939
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
339 PM EDT Sat Oct 1 2016

.SYNOPSIS...
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An upper low will drift slowly northeast through the Great Lakes
this weekend. Under the influence of this upper low expect cool
temperatures and a chance for showers through Sunday. A warmer
and drier airmass will build into the region through the middle
part of next week.
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&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Water vapor loop shows an upper low spinning over northern
Indiana this afternoon. Much of the shower activity up to 19Z has
been near the upper low, a few of which have been brushing our
extreme northwest CWA. Still expect isolated to scattered shower
development further east and south into the CWA given vort max in
southwest flow and minimal daytime heating. Highest
coverage/probability would be across the northwest CWA not only
closer to the low but also where there is some instability. This
is also the area that would be most vulnerable for isolated
thunderstorms into early evening as well.

Pops will trend downward after sunset, with low chances continuing
across the northern portion of the CWA as the low treks into
southeast Michigan. Clouds will hang tough throughout the CWA as
guidance suggests a decent stratus deck developing, perhaps with
some local visibility restrictions in fog too and therefore have
patchy late night fog in the grids.
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&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
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Upper low drifts across the eastern Great Lakes and into the
Northeast states through Monday.

Influence from the upper low is expected to be less on Sunday.
After morning stratus, there may be some breaks in the clouds by
afternoon. Still can`t rule out a few showers, but coverage
should be more sparse and mainly in the isolated category on
Sunday. Dry weather and more sunshine are then expected for
Monday as the flow becomes increasingly anticyclonic.

Warming trend should also begin with highs near 70 Sunday and in
the lower to possibly mid 70s for Monday. Lows will be slightly
above average, favoring lower to mid 50s both Sunday night and
Monday night.
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&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
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Upper level ridge extending from New England into the Gulf of Mexico
will keep dry and warm conditions across the region into Thursday. A
trough will move from the Plains into the Great Lakes and Ohio
Valley late in the week. 12Z models continue to show discrepancies
in timing which may be related to the handling of Hurricane Matthew
off the Atlantic coast. Have leaned toward ECMWF for timing which
would push a cold front through the region on Friday with a chance
of post-frontal showers. This will bring temperatures down closer to
normal by Saturday.
-- End Changed Discussion --

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
An upper level low continues to rotate slowly north and is
currently located near Fort Wayne. Almost all TAF sites are VFR
this afternoon with many breaks in the clouds. Latest suite of
high res models have continued to back off on the chance of
precipitation this afternoon as the area broadly remains in a weak
sinking motion (due to NVA). Later this afternoon there still
remains a chance of shower development as the NAM shows another
wedge of upper level lift (PVA) swinging across the area. Forecast
soundings during this time have weak/skinny but sufficient CAPE
for isolated shower formation.

Sunday morning, most guidance and forecast soundings again point
to widespread IFR/ MVFR cigs. SREF/ ARW/ NMM all show this with
scattered IFR. Given the low level moisture being trapped this
makes sense. Lower visibilities though aren`t as certain. Have
only brought vsbys down to IFR at the normal problem sites. As the
sun comes up cigs and vsbys will slowly rise and most likely
remain MVFR through the morning. The upper level low will finally
depart Sunday along will the chances of rain. Forecast soundings
show drier mid and upper level air working into the area pushing
PWATs down to around 0.8". This also decreases instability to
near zero.

OUTLOOK...No impacts to aviation expected.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...BPP
LONG TERM...
AVIATION...Haines