Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Jackson, KY (JKL)

FXUS63 KJKL 180756

National Weather Service Jackson KY
356 AM EDT Sun Aug 18 2019

.SHORT TERM...(Today through Monday)
Issued at 355 AM EDT SUN AUG 18 2019

Surface high pressure remains aligned across the Appalachians,
with a stationary frontal boundary positioned east across the
lower Great Lakes. Aloft, a seasonably deep upper level low is 
churning across south central Canada, while a ridge is centered
across southern Texas. Most of the Mississippi Valley remains in a
more progressive zonal flow, with embedded short wave energy
traversing the flow across the Plains and into the Midwest/Great
Lakes region. Current temperatures are a few degrees milder across
eastern Kentucky compared to last night at this time. Mostly
clear skies reign with patchy river valley fog showing up nicely
on the Nighttime Microphysics Satellite Channel. 

The models are in good agreement through the short term, with
the upper level ridge across southern Texas amplifying and 
drifting north with time. This will allow for building heights 
into the Tennessee/Ohio Valleys with the heat continuing across 
the region. Today will feature mostly sunny skies and temperatures
reaching into the lower 90s for most locations across eastern 
Kentucky. Some convection may nip the far southeast, but for the 
most part this should stay on the Virginia side of the mountains, 
so will continue to keep things dry. A short wave trough will move
across the area later tonight, spreading at least an increase in 
high clouds. Lows will be milder still, generally ranging from 65 
to 70 degrees.

The short wave trough will move off to east on Monday, with
temperatures returning to the lower 90s once again. A few storms 
will be possible along the southeast terrain, as well as the 
Bluegrass region, as the CAMs indicate; however, with higher 
pressure noted through the majority of the column, could see 
convection being capped as well. Will maintain continuity for now 
and stick with at least some slight chance PoPs in the 
aforementioned areas. 
.LONG TERM...(Monday night through Saturday)
Issued at 324 AM EDT SUN AUG 18 2019

The period will begin with upper level ridge nosing in from the
Plains on Tuesday. Given the higher than expected high
temperatures yesterday, possibly owing to the dry antecedent
conditions, opted not to lower the NBM as much from yesterdays
forecast. Particularly on Tuesday as 592 geopotential height line
will progress into the Tennessee and Lower Ohio Valley. Also,
lowered PoPs some on Tuesday afternoon given the higher heights
forecast. After this the models continue to show a cold front
progressing toward the Ohio and Tennessee Valley by Wednesday into
Thursday. The best chances of storms in the period will generally
follow suite. The one difference seen in the latest runs has been
the inconsistency from the previous runs and the fact the the
front continues to look more anemic overtime. The inconsistency
from run to run makes it difficult to be sure how far south this
front will make it. Given this couldnt argue with the NBM
keeping some PoPs toward the end of the week near the Virginia and
Tennessee border until better model to model and run to run
consistency is seen. Still think the Bluegrass will have the best
shot at the driest air toward the end of the week, as the
dewpoints could still mix out into the upper 50s to lower 60s
versus the mid to upper 60s toward the Tennessee Valley.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)

VFR conditions will prevail through the period besides some MVFR
or worse fog seen in the deeper river valleys once again through
13z. Once again, lower crossover temperatures should yield mainly
VFR conditions at the TAF sites. Some diurnally driven cumulus at
4-6k feet agl will be seen during the day, with south to southwest
surface winds averaging less than 5 kts through the period.