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Area forecast discussion...updated 
National Weather Service Jackson Kentucky
140 am EDT Friday Jul 31 2015

issued at 125 am EDT Friday Jul 31 2015

Did a quick update to touch up the sky...temp...and dewpoint
grids through the rest of the night based on the latest observation and
trends. These have been sent to the ndfd and web servers.

Update issued at 1054 PM EDT Thursday Jul 30 2015

The forecast remains on track tonight...with some valleys dipping
into the 50s. Mainly adjusted the hourly temperatures to account
for a quicker drop off within the more sheltered valleys through
the overnight.

Update issued at 809 PM EDT Thursday Jul 30 2015

Mainly freshened up the hourly temperatures and dew points
according to the latest trends in observations. Daytime cumulus is
drying up...with just a touch of high and thin cirrus moving in
from the west. The forecast is on track. Updates have been sent.


Short term...(this evening through Friday night)
issued at 312 PM EDT Thursday Jul 30 2015

West northwest flow aloft is in place across the region between a
middle level ridge centered over the Southern Plains and closed low
and associated trough centered over the Hudson Bay region and
extending into the Great Lakes and northeastern states. At the
surface...a cold front that crossed the area late last night and early
this morning...continues to depart to the east of the region. A
ridge of surface high pressure continues to build east into the Ohio
Valley region...and is ushering drier air on northwest flow. Dew points
are as low as the upper 50s in northern Kentucky...with low to middle 50s
over parts of Indiana.

Through Friday night...the pattern is expected to be amplified.
The middle level ridge will retrograde to the west and become
centered near The Four Corners region with ridging north building
north across the western Continental U.S.. meanwhile...the closed low will
meander to far northern Ontario through the end of the period with
the area in northwest flow aloft between the ridge and trough...although
the axis of the trough should remain generally east of the area. A
few weak shortwaves passing by in the flow should bring nothing
more than a few clouds from time time. A surface low pressure system
associated with one of these shortwaves should track across
Ontario and into Quebec late in the period...with the trailing
moisture starved cold front possibly dropping south of the Great
Lakes late Friday night.

With the ridge building in tonight...colder overnight lows...up to
10 degrees or more colder than this morning are expected.
Dew points moving into the north suggest a few lows in the upper
50s for valleys along and north of the mountain Parkway. Coop MOS
guidance also supports those numbers. The light winds and clear
skies should also favor some valley fog developing along a few of
the larger creeks and near area rivers and lakes.

Friday should feature highs near normal for late July under the
influence of high pressure...with much more comfortable dew points
and humidities compared to recent days. The ridge should
continue to dominate late in the period...on Friday night...with
overnight lows in most locations a degree or two warmer to
tonight. The exception to this will be the far south and southeast
valleys...where the drier air will be a tad slower to move
in...and lows Friday night may be a degree or two colder compared to

Long term...(saturday through thursday)
issued at 246 PM EDT Thursday Jul 30 2015

Forecast models indicate that a trough will remain in place over
the eastern U.S. Throughout the period. High pressure will remain
in place at the surface over our area through Monday keeping our
forecast dry and seasonably warm. A weak front will drop into the
Ohio Valley on Monday. Models are quite different in how they
handle this front from Tuesday through the rest of next week and
this lowers forecaster confidence. While the GFS indicates a quick
frontal passage Tuesday into Tuesday night...followed by dry
weather Wednesday and Thursday...the Gem and European model (ecmwf) indicate a
stalled front to our north or overhead with a better chance of
showers and thunderstorms. A model blend gives slight chance to
chance probability of precipitation Tuesday through Thursday and that seems prudent given
the model differences. Temperatures should remain near seasonal norms
next week with the ridge aloft centered well to our west.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 140 am EDT Friday Jul 31 2015

High pressure will continue to build across eastern Kentucky
overnight. Along with light winds and a few clouds at 5k feet...
some MVFR fog will be possible at the sme...sjs...and sym taf
sites between 08 and 13z...although expect that any IFR or worse
fog will be limited to the deeper river valleys...thanks to
larger dewpoint depressions in place tonight compared with last
night. VFR conditions will return everywhere after 13z...with
light northwest winds and mostly clear skies on tap through the
rest of the taf period.


Jkl watches/warnings/advisories...


long term...Abe

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