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Area Forecast Discussion
National Weather Service Wilmington OH
724 AM EDT FRI JUL 29 2016

.SYNOPSIS...
A weak frontal boundary will remain across the area through much
of the weekend. This will lead to a chance of mainly afternoon
and evening thunderstorms each day. High pressure and a drier
airmass will build into the Ohio Valley Monday and Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Just a quick update to expand the dense fog advisory into the
Columbus area.

Areas of fog and stratus have been developing early this morning,
especially across southern and eastern portions of our area.
Given the abundance of low level moisture, expect this trend to
continue through at least daybreak. The big question has been whether
the fog or stratus will be more dominant and so far it appears
that the stratus is winning out. This has helped to keep any
dense fog fairly patchy so far this morning. As a result will
hold off on issuing an SPS for patchy dense fog at this point but
will continue to monitor vsbys and issue one if conditions worsen.

Otherwise, the combination of a lingering boundary, a weak
surface low, and some short wave energy aloft starting to push in
from the northwest, should lead to scattered thunderstorm
development later today as we destabilize. Wind fields are not
very impressive so think any severe threat should be relatively
low. PWs are also not quite as high as yesterday but they will
still be in excess of 1.5 inches through this afternoon. Thus,
with relatively slow moving storms, some locally heavy rainfall
will be possible with any storm.

Temperatures later this morning will be dependent on how much
stratus coverage we end up with and how fast it is able to burn
off. Eventually though, expect temperatures to push up into the
low to possibly mid 80s through this afternoon.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
While isolated to scattered shower and thunderstorm activity
should begin to taper off through the evening hours as we lose the
diurnal enhancement, a few showers may linger into the overnight
hours as some short wave energy will continue to push east across
the region. We will then destabilize again through the day on
Saturday and with the boundary still lingering across the area,
expect scattered showers and thunderstorms to redevelop once again
through the afternoon hours. Diurnally driven activity will then
taper off Saturday evening with lower end pops then possible on
into sunday as we begin to dry out and the better forcing shifts
off to our east. Highs both Saturday and Sunday will be in the low
to possibly mid 80s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
High pressure and dry conditions are expected for Monday into
Tuesday across the region.

Some model solutions are showing a complex of storms working down
into portions of the area Tuesday night into Wednesday morning.  The
best chance of precipitation with this appears to be across western
portions of the area.  There have been some run to run
inconsistencies and the GFS is maintaining a dry forecast during
this time, therefore limited any precipitation chances to the chance
category at this time.  The 12z ECMWF has come in drier for
Wednesday night into Thursday, which better corresponds with the
GFS.  Due to this went with a dry forecast to only a slight chance
of storms during this time.  

Better chances of precipitation look to hold off until after the end
of the long term period on Friday as a frontal boundary moves
through the region.  

High temperatures will generally be in the 80s with low temperatures
in the 60s to around 70.

&&

.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
Fog has formed across some of the terminals this morning due to
the light winds and dewpoint depressions near or at zero. Fog will
lift this morning giving way to VFR clouds as an upper level low
approaches from the west. PWATs remain elevated this afternoon
around 1.80" on the NAM and 1.70" on the GFS with k index values
in the mid 30s. The sun will then help to continue to destabilize
the atmosphere this afternoon leading to scattered showers and
thunderstorms. Given the unorganized nature of the convection have
left the mention as vicinity. Later this evening coverage will begin
to diminish as afternoon heating is lost. Some high res models
are holding on to coverage slightly longer than usual (compared
to normal diurnal based storms), but this makes sense given the
upper level low just to our west. Have adjusted TAFs to account
for this.

There is uncertainty on how much coverage there will be Saturday
as the GFS is trying to bring drier air into the area while the
NAM holds on the the moisture longer. For now have left the
mention of precip out of the CVG taf. Mostly light west winds will
continue through the TAF period as surface low pressure remains
north of the area.

OUTLOOK...Thunderstorms possible Saturday and Sunday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Dense Fog Advisory until 9 AM EDT this morning for OHZ054-055-
     063-064-071>073-080-082.
KY...None.
IN...None.

&&

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

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