Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 300546
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
146 AM EDT Fri Sep 30 2016

.SYNOPSIS...
A large area of low pressure will remain in place over the Ohio Valley
through the rest of the week, providing cool and occasionally rainy
conditions. Chances for rain will begin to diminish on Saturday,
as the low gradually begins to move to the northeast. Drier and
warmer conditions are expected for Sunday and Monday, with surface
high pressure building in from the west.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Upper level low pressure system will continue to influence the
weather pattern overnight. More widespread shower activity will
work into the region during the overnight hours. This activity has
already developed just southeast of the region and is beginning to
move into the area. Due to this have increased precipitation
chances for the overnight hours. There is some limited instability
and therefore have isolated thunder in the forecast overnight as
well. Temperatures will not drop much overnight with cloud cover
therefore have low temperatures in the low to middle 50s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
During the day Friday the upper level jet at 250 mb will
strengthen over the eastern zones with the main low level
convergence occurring over the northern part of the CWA. As the
low rotates north Friday lower PWAT air that has wrapped around
the low (0.75") will pull over the CWA with greater than 1.00"
PWATs confined to the southwest and northern parts of the CWA.
Have further refined PoPs to have the highest chances towards the
north with slightly lower values across the central parts of the
CWA. There also is instability present in both the GFS and NAM
forecast soundings (between 500 and 1000 J/kg of ML CAPE) Friday
afternoon which means thunder will be a possibility. Any slight
wobble in the upper low can easily change the eventual location of
higher precipitation totals.

On Saturday the upper level low will head north towards the
Indiana/ Michigan border with low level convergence and PVA
increasing over the area. PWATs for Saturday aren`t impressive
with values only around 1.00". Have gone ahead and increased PoPs
for Saturday to account for the upper level lift mentioned above.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
The general consensus of the models is to start to lift the upper
low off to the northeast through the day on Sunday. This should
allow for a deceasing chance of pcpn by the start of the long term
period and will just linger some slight chance pops across the area
through Sunday afternoon. Highs on Sunday will generally be in the
lower 70s.

The 12Z ECMWF and the 12Z CMC are now maintaining a closed upper low
through a good part of next week as it shifts off to the east, with
the 12Z CMC slower pushing it east and even retrograding it some
back across Pennsylvania through mid week. Meanwhile, the 12Z GFS
continues it trend to weaken the upper low as it moves northeast
while building some ridging across our area through the rest of the
long term period. Likely as a result, there is also quite a bit of
variability on the track of Matthew with it possibly riding up off
the east coast through mid week. This all spells out some
uncertainty in our sensible weather as we progress through the
upcoming week. At this point will discount the CMC and lean toward
more of a blend of the ECMWF and GFS, which would keep us mainly dry
through mid week along with a gradual warming trend each day. The
ECMWF is faster than the GFS with a possible front moving in through
late week. Will again go with a blend and allow for some lower
chance pops to work in from the west through the day on Thursday.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Slow moving low pressure in the upper atmosphere coupled with a
surface trough and persistent moisture will continue to produce
less than ideal flight conditions. Showers are generally moving
north of TAF sites for now. However, IFR ceilings will likely form
early in the forecast, probably increasing to MVFR and then VFR
by the end of the forecast period.

Shower activity will stay mainly around the periphery of the upper
low as it travels toward CVG. This will allow the somewhat drier
period with higher ceilings, though thunderstorms may develop
this afternoon near northern sites DAY CMH and LCK, while showers
linger in the vicinity of other sites.

Winds will stay light in the weak surface pressure gradient, with
direction shifting from northeast.

OUTLOOK...MVFR ceilings and visibilities possible with showers
through Saturday. IFR ceilings possible Sunday morning.

&&

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

&&

$$
SYNOPSIS...Haines
NEAR TERM...Novak
SHORT TERM...Haines
LONG TERM...JGL
AVIATION...Coniglio



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