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Area forecast discussion 
National Weather Service Jackson Kentucky
757 am EDT Monday Aug 31 2015

issued at 757 am EDT Monday Aug 31 2015

Updated the forecast this morning to input patchy dense fog across
the area this morning. Cloud cover associated with the weak
circulation moving along the appalachian range has drifted off to
the northeast. Will keep the fog in the forecast through 14z this
morning. Adjusted the cloud cover for this as well. A new zone forecast product has
been sent out for this update.


Short term...(today through tuesday)
issued at 405 am EDT Monday Aug 31 2015

Current conditions across the area feature a weak circulation at
this hour tracking northerly along the peaks of the appalachian
range. This center along with cloud cover will slowly track north
and east as east Kentucky looks to clear out a bit towards dawn.
This has already allowed for some significant fog development as
already noticed with some observations to the west and into
central Kentucky.

Heading into the day...with the barely noticable boundary still
to the northwest and the weak upper low over the Appalachians
tracking northeast out of the area...a good deal of lift will be
absent today. This...while the region is still under a
significant middle level ridge and weak upper level flow. This in
mind...steering flow is quite lacking...the impact from what is
left of Erika seems to still be stuck over Florida and drifting
northeast possibly to be kicked northeast along with the rest of
the unsettled weather up the East Coast. Hi res models...especially
the operation NAM and GFS have had a tough time pin pointing this
features and where they will drift in this weak flow.

That said...and especially with the cap the model soundings are
indicating...have gone with only isolated precipitation today since the
higher terrain areas will probably see a storm or two pop up.
West of this location will difficult especially with the
boundary...or whats left of it...still to the west and northwest.
Needless to say...for this evening...the loss of heating for the
day will bring an end to shower and thunderstorms over east
Kentucky. In fact...overnight the middle level ridge strengthens over
the Great Lakes region as surface high pressure develops just east
of the lower MS valley and extends into the Tennessee Valley. This
development...if still on track will lead to clear skies tonight
and more impactful fog development as well as a dry forecast into
Tuesday. Hence...have gone for warmer temperatures for Tuesday and a dry
forecast for now. In this pattern...model performance has been a
bit more to be desired.

Long term...(tuesday night through sunday)
issued at 405 am EDT Monday Aug 31 2015

The models remain in good agreement with an amplifying upper level
pattern to control across the Continental U.S. Through the period. Troughing
will be the rule in the western third of the Continental U.S....while ridging
will dominate in the east. There are some differences with the
progression of the trough towards the weekend...with the GFS more
progressive...while the European model (ecmwf) remains more amplified and slower.
Will continue to use a blended approach.

Above normal temperatures are expected across eastern Kentucky
through the end of the week...with a few shots of isolated
convection at times...mainly during the diurnally favored periods.
Highs will average from the upper 80s to around 90...with lows in
the middle to upper 60s.


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 757 am EDT Monday Aug 31 2015

Fog across the area this morning is dense in some
areas...especially over the west where some locations have cleared
out towards dawn. Will keep fog at the taf sites through 14z. With
best lift and instability lifting off to the northeast...showers
and thunderstorms through the afternoon will be isolated across
eastern Kentucky. With high pressure building into the area
tonight...fog development will be a bit more extensive towards
dawn and have put in IFR and below conditions at the sites towards
the end of the taf period.


Jkl watches/warnings/advisories...


short term...shallenberger
long term...geogerian

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