Scientific Forecaster Discussion
fxus63 kjkl 120458
Area forecast discussion
National Weather Service Jackson Kentucky
1158 PM EST Mon Nov 11 2019
issued at 1158 PM EST Monday Nov 11 2019
Continuing to see rain change over to snow across eastern
Kentucky. Temperatures here at jkl are nearing the freezing mark,
with a few flakes starting to mix in with the rain. Near term
pop/weather forecast seems to be on track with these change overs.
However, did note that based on the latest hi-res model guidance,
and radar trends, the ongoing forecast did seem to diminish the
precip a bit prematurely overnight. Went ahead and slowed down the
exit of pops into the early morning hours based on these trends.
This still matched up well with the ongoing quantitative precipitation forecast forecast, and
consequently allowed US to match up better with our neighbors as
well. Also, tweaked the temperatures slightly in the near term a
couple times over the last few hours based on the latest
observations. Overall, ongoing forecasted lows still seem to be in
good shape. All updates have been published and sent to ndfd/web.
A refreshed version of the west-southwest was sent out, along with updates
to the zones to change to overnight wording and catch any minor
changes to timing of precip.
Update issued at 718 PM EST Monday Nov 11 2019
Went ahead and increased pops across the east a bit over the last
couple of hours based on the current radar trends. Rain will
continue to overspread eastern Kentucky quickly through the
evening as the cold front begins to shift into eastern Kentucky.
Much colder air is on the heels of the front. However, current
forecasted temperatures and change-over trends still seem on
track based on the latest observations, so only minor tweaks have
been made here. Will continue to monitor as we head throughout the
evening and update if needed. Winds are also starting to ramp up
along the frontal boundary, and should remain gusty through the
overnight even after it has moved through. All updates have been
published and sent to ndfd/web.
Short term...(this evening through Tuesday night)
issued at 453 PM EST Monday Nov 11 2019
The winter weather event headed into the area still looks pretty
much on track with the previous forecast. You would not know it
from the current conditions. Temperatures were generally in the
60s ahead of a cold front extending from southeast of Cincinnati
to just east of Bowling Green late this afternoon. Temperatures
abruptly drop to the 30s behind the front. Precipitation was
occurring near and behind the front, initially as rain, but it was
currently changing over to snow in southern Illinois and southern in.
Models are in good agreement for the front and its precip to
progress southeast through the jkl forecast area tonight, with the
rain changing to snow. After such a warm day, ground temperatures
will tend to initially melt snow that tries to accumulate.
However, the snow will probably persist long enough into the
freezing air to allow accumulations to eventually occur. This will
initially be on grass and elevated surfaces. Cold air rushing in
could eventually cause slippery roads in general. However, it will
be a matter of timing of Road surfaces getting down to 32 deg
compared to when precip ends. The west-southwest was left in place everywhere
due to the ongoing threat of slick conditions developing tonight.
Measurable precip should be gone long before the advisory is set
to expire at 11 am Tuesday. However, surrounding offices also
have an advisory extending into the day Tuesday, and some slick
spots may linger. Hence, the advisory is being left to run to
maintain consistency with neighbors. It may very well be able to
be cancelled early.
Shallow convection with saturation at levels with temperatures
colder than -10c will keep flurries going through much of the day
Tuesday, but as enough drying occurs they should taper off later
in the day. That will leave US with dry weather and very cold
temperatures on Tuesday night as the Arctic air mass settles over
the region with near record cold.
Long term...(wednesday through monday)
issued at 336 PM EST Monday Nov 11 2019
Operational models are in better agreement than usual. Pattern
continues to be amplified and quite progressive. Two main features
of interest. The first is a deepening trough that drops southeast
out of The Rockies/Great Plains and across the eastern Continental U.S.
Through the first half of the period. Additional short wave energy
appears to drop into the base of this trough as it approaches the
Ohio Valley, causing it to dig southward into the deep south and
forming a cutoff low before the end of the week. Evolution of
this system takes any significant weather well to our south as a
surface wave of low pressure develops over the southeast along
and/or just off the Atlantic Seaboard...southeast of Florida/GA/SC
coast. Thereafter, a broad long wave trough will sweep across the
conus, reaching the Ohio and Tennessee valleys at the very end of
Sensible weather features generally dry weather with below normal
temperatures through the period. Highs Wednesday of around 40 will
seem warm after experiencing teens for morning lows. Temperatures
moderate through the week, climbing back to normal levels by
Monday. Overnight lows will generally drop into the 20s each
morning. Weather appears dry overall. First system mentioned
earlier will propel a dry surface cold front through eastern
Kentucky Thursday, with little more to show for it other than some
additional clouds and a reinforcing shot of cooler air. At this
time any sensible weather remains well to our south and east.
Second system will bring a slight chance of some rain to the area
at the very end of the forecast window.
Aviation...(for the 18z tafs through 18z Tuesday afternoon)
issued at 151 PM EST Monday Nov 11 2019
A potent cold front is starting to make its way into eastern
Kentucky from the northwest. This is resulting in increasing winds which
will shift to the northwest as the front passes over, gusting upwards to
20 kts. These breezy conditions are expected to continue through
the remainder of the taf period as well. This frontal boundary is
also result in rain, which is now moving across eastern Kentucky,
and will increase in intensity and coverage over the next few
hours. Visible and ceilings are expected to quickly fall to IFR and
possibly even LIFR at times over the next couple of hours along
the boundary. As cold air quickly works in behind the frontal
passage, any lingering light rain will change over to light snow
before tapering off late tonight. Precip will linger longest in
the far southeast portion of the state (ksjs), but all sites should be
dry by dawn. However, MVFR ceilings may stay in place through much of
the day, with cold air bringing the potential for continued snow
flurries so long as the clouds stick around.
Winter Weather Advisory until 11 am EST Tuesday for kyz044-