Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 250523

National Weather Service Jackson KY
123 AM EDT Tue Oct 25 2016

Issued at 123 AM EDT TUE OCT 25 2016

Just received a report of some dense fog already developing just
south of Manchester. With that in mind, will beef up the fog
forecast for the rest of the night going with patchy dense for
valley locations. Again, fog should remain limited to the river
valleys as drier air is slowly working into the area. Coldest
readings as of 1 am this morning is 38 degrees at the Paintsville
and Quicksand mesonet stations.

UPDATE Issued at 1157 PM EDT MON OCT 24 2016

With dewpoints still holding around 40 for most locations, looks
like fog will be favored over frost tonight, so have removed any
mention of frost from the forecast and stuck with patchy fog in
the river valleys. Also, tweaked the colder valleys down a few
degrees as we are already seeing some temperatures touching 40 on
the nose. Being we are already approaching cross over
temperatures, we may have to look at the possibility of some
localized dense fog near the river valleys. We`ll continue to
monitor satellite for any indications of some denser fog
developing. With weak dry air advection, any dense fog would be
confined to the more deeper sheltered valleys, where the dry air
may not make it into these locations as easily.

UPDATE Issued at 1054 PM EDT MON OCT 24 2016

Continuing to monitor falling temperatures this evening under this
clear and stable regime. Updated the near term forecast to
include the latest observations for temps and dew points to make
sure they are well on track with current conditions once more.
Rest of forecast continues to be in good shape. All changes have
been published and sent to NDFD/web. A new forecast package was
sent out to update to "rest of tonight wording", although content
really didn`t change from previous package.

UPDATE Issued at 747 PM EDT MON OCT 24 2016

Forecast seems to be in good shape at this time. Temperatures are
quickly dropping off with the loss of daytime heating this
evening. Loaded in the latest observations to make sure the near
term forecast for temps and dew points matched up well with the
ongoing conditions. Changes were not significant enough to
warrant any new forecast products. Near term grids have been
published and sent to NDFD/web.


.SHORT TERM...(This evening through Tuesday night)
Issued at 445 PM EDT MON OCT 24 2016

19z sfc analysis shows a dry and mostly cloud free cold front
settling through eastern parts of the state. This boundary is
switching winds more completely to the north at 10 to 15 kts.
Plenty of sunshine on either side of the front has led to near
normal temperatures in the mid to upper 60s north to the mild
lower 70s south while dewpoints were able to mix down into the
upper 30s and lower 40s this afternoon.

The models are in good agreement aloft through the short term as
they all depict a broad trough lifting northeast and out of the
area. This will allow heights to rise for Kentucky through
Wednesday morning while energy and the next developing trough over
the plains stay well north of the area. Accordingly, will favor
the blended model solution with a lean toward the higher
resolution HRRR and NAM12 versions along with the co-op MOS

Sensible weather will feature a clear and cool night, especially
after the post frontal winds die off. This will lead to a minor
ridge to valley temperature difference tonight and a more
significant one on Tuesday night as the sfc high shifts off to the
east. This will allow for some patchy frost to develop in isolated
spots of the deepest valleys both nights, though limited by the
dry air expected Tuesday night. As such, the vast majority of the
area of will stay frost free for another week. Additionally, both
nights could see some patchy fog along the rivers towards dawn.
Another pleasant and mostly sunny day can be expected for Tuesday
with highs similar to today - warmest southwest and 5 to 10
degrees cooler northeast.

Started with the CONSShort/ShortBlend for the bulk of the grids
with adjustments to the night-time temps revolving around terrain
differences, as well as knocking dewpoints down in the afternoon
and again Tuesday night. PoPs were again zeroed out through the
period - in line with all guidance.

.LONG TERM...(Wednesday through Monday)
Issued at 325 PM EDT MON OCT 24 2016

The extended period will feature a series of shortwaves embedded in
the northern stream moving through the Ohio Valley. The first
shortwave will make its way from the central plains across the Great
Lakes late Wednesday night/Thursday, dragging a cold frontal
boundary through Eastern Kentucky. This system will bring our next
chance for precipitation by dawn on Thursday. However, operational
models have continued to back off on the QPF potential with this
frontal passage so most locations will only see a tenth of an inch
or less.

The upper level pattern becomes a bit messy beyond Friday with
several additional impulses dropping through the Ohio Valley in west-
northwest flow. Differences exist between the GFS and ECMWF with how
far south and how strong these impulses become so have remained
close to the CR Superblend solution from Saturday forward. That
being said, there is the potential for a few showers Saturday
afternoon and evening and again late Sunday night. Ridging builds
back into the Tennessee Valley on Monday setting the stage for a few
more days of dry and mild weather.

Temperatures will remain near seasonable values through the period
with highs in the upper 60s and low 70s. Morning lows will vary a
bit more with potential cloud cover and passing showers. But most
mornings, lows should be near climatology, in the mid and upper


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

Mainly VFR conditions and light winds will be seen through Tuesday
night. Some patchy dense valley fog is expected overnight, but
should not impact the TAF sites.




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