Scientific Forecaster Discussion
fxus63 kjkl 201445
Area forecast discussion
National Weather Service Jackson Kentucky
945 am EST Mon Nov 20 2017
issued at 945 am EST Monday Nov 20 2017
Weather is quiet this morning. River Valley freezing fog and
is burning off quickly based on regional satellite imagery. Temps
will continue to rise above freezing over the next hour.
Afternoon highs look good, rising into the upper 40s to lower 50s.
No major update to the grids but will freshen up the zones and
other text products.
Update issued at 645 am EST Monday Nov 20 2017
With reports of dense fog in some of the river valleys and
temperatures well below freezing it looks like freezing fog is
affecting southeast parts of the state. This is supported by the
obs out of sme and the Harlan Airport as well as the latest GOES
satellite images from the combined fog channel. Have updated the
zones and severe weather potential statement for this threat and also issued a brief Special Weather Statement. With
this update did also adjust the T and TD grids for the obs and
trends. These have been sent to the ndfd and web servers.
Short term...(today through tuesday)
issued at 305 am EST Monday Nov 20 2017
07z sfc analysis shows cold high pressure moving into Kentucky.
This has cleared the sky for all but the far east where some low
stratus still holds on. With the clear skies and light winds
temperatures are radiating down with readings generally in the
mid to upper 20s. Dewpoints, meanwhile are running in the low to
mid 20s with many valley locations seeing small dewpoint
depressions that could result in some patchy fog. On the GOES
satellite fog channel there are indications of fog are showing up
in the deeper valleys so far this night. Have added some fog into
the wx grids for this through dawn.
The models are in good agreement aloft through the short term
portion of the forecast. Northwest flow starts off the first part
of the day as The Heights start to rebound over Kentucky in the
wake the departing deep trough from this past weekend. The flow
pattern will flatten out later today with some weak energy moving
over the state in the more zonal flow. A sharpening trough then
develops to the northwest on Tuesday and spread into the Ohio
Valley with a fairly strong batch of energy pressing into the area
later Tuesday - however, dry conditions at lower levels will give
this feature little moisture to work with. Given the model
agreement will favor the blended solution with a lean toward the
higher resolution nam12.
Sensible weather will feature a chilly and frosty start to the
morning followed by strong warming with plenty of sunshine today
as temperatures reach near 50 degrees by late afternoon. For
tonight, continued mostly clear skies and light sfc winds will
result in good radiational cooling and a decent ridge to valley
split opening up. Temperatures will continue their warming trend
on Tuesday as the winds adjust to the southwest and pick up a bit.
Along with at least partly sunny skies, temperatures will push 60
degrees by mid afternoon. Expect more in the way of clouds around
on Tuesday compared to today as a dry cold front approaches from
the northwest along with moisture seeping up toward the area from
the south and southeast.
Started with the consshort and shortblend for all the grids
through the short term portion of the forecast. Did make some
significant changes to low temperatures tonight for a moderate to
large ridge to valley temperature split. As for pops, kept them
low through the period - in line with the blends and MOS.
Long term...(tuesday night through sunday)
issued at 230 am EST Monday Nov 20 2017
Forecast looks to remain quiet through the Thanksgiving Holiday
weekend with no real chances at any precipitation. A moisture
starved cold front will be dropping southward Tuesday night and
will help to bring a shot of cooler weather for the middle of the
upcoming week. This cooler weather will last into Thanksgiving
day. A surface ridge will build in by Thanksgiving, allowing for a
sunny day for Thanksgiving. Southwest flow ahead of another
moisture starved front will develop into Friday, allowing for a
modest warmup heading into the end of the week. This front will
then pass late Friday night, with another cool down expected
Saturday into Sunday. Models continue to trend towards a drier
system for Friday night/Saturday, so have removed any rain
Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 700 am EST Monday Nov 20 2017
VFR conditions will dominate through the period. High pressure
building in from the lower-mid Mississippi Valley will keep any
cloud cover confined to a few cirrus through the period with
winds southerly at generally 5 knots or less. With the dense
freezing fog and low cigs at sme have included that as the
prevailing group before clearing out around 13z.