Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 030622 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
122 AM EST Sat Dec 3 2022

.UPDATE...
Issued at 122 AM EST SAT DEC 3 2022

Winds have been gusting upwards of 40 mph just off to our
northwest, where a better line of convective showers and embedded
thunderstorms have been progressing to the east. As such, have
reinstated the Special Weather Statement for the wind gusts
across the northwest half of the forecast area, generally where
the stronger 925 mb wind field will reside the longest through the
rest of the overnight.

UPDATE Issued at 1133 PM EST FRI DEC 2 2022

Forecast is largely on track, with showers and a few thunderstorms
having made their way into the area.

UPDATE Issued at 956 PM EST FRI DEC 2 2022

A brief, quick drop in temps occurred in eastern valleys early
this evening. However, with thickening clouds and increasing low
level flow, this trend did not last. Have updated temperatures
through the night in light of latest obs and model forecasts, with
readings generally expected to be near steady or slowly rising.

Showers are on the increase, and a few thunderstorms have been
observed in central KY. Few changes were made to the inherited
precip forecast, which seemed to have things covered pretty well
with showers and possibly thunderstorms developing.

In terms of wind, the higher elevations have seen gusts topping
40 mph, but elsewhere, mixing has not been effective enough to
result in anything more than about 20-30 mph gusts to this point.
Unless the gusts become more prevalent, may allow the SPS to
expire shortly, or only address the higher elevations in a new
issuance.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 240 PM EST FRI DEC 2 2022

Present surface analysis has a warm front lifting northeast of the
region. This has ushered warmer temperatures into the region but due
to the widespread cloud cover, temperatures have been slow to warm
and will be somewhat limited to the low to mid-50s for highs. Along
the I-75 corridor will likely see the warmest temperatures because
of lack of extended cloud cover. Present radar has a few radar
returns across the southwestern area and a "line" of weak dBZ from
Pike to Eliott counties but with low to mid-level dry air in place;
these are mostly virga showers but a few sprinkles can`t be ruled
out.

Tonight, a shortwave trough will move through the mostly zonal flow.
Accompanying this trough is a surface low and associated cold front.
The surface low is progged to eject toward the Great Lakes while
dragging a cold front through the forecast area. Ahead of the front,
increased surface winds are likely due to the WAA behind the
departing warm front. Aloft, a potent jet streak is progged to move
through the trough but with the strong inversion at the surface,
those fast moving upper-level winds will remain largely aloft. A few
stronger gusts may mix down with any of the elevated convection
embedded with the cold front. Due to the strong winds staying aloft,
opting for an SPS instead of a wind advisory. However, above 2,500
feet, that won`t be the case as that would be above the inversion
and those winds will be more prominent. As the cold front gradually
approaches from the west, showers will increase in coverage from
west to east, mainly after 4Z. Showers and very isolated
thunderstorms continue through early Saturday afternoon before the
front exits. Showers end and high pressure builds into the region.
Cold air advection behind the front will bring overnight lows down
into the upper teens and lower-20s. High pressure continues through
the remainder of the period; thus remaining quiet.

.LONG TERM...(Sunday through Friday)
Issued at 240 PM EST FRI DEC 2 2022

Key Points:

* A quasi-stationary surface frontal zone will become established
  across the region from Tuesday until Friday, that will tend to
  keep our weather unsettled with passing disturbances.
* With the exception of the very start and the very end of the
  period, temperatures will average at or above normal.

Aloft, relative zonal flow will back from just north of west to the
southwest by mid-week next before veering to the west-northwest by
the end of the period across the Ohio Valley, which will be
sandwiched between a mean low (~489 dam low) over the Hudson Bay
region and high pressure (~591 dam) over the Gulf of Mexico.

At the surface, Canadian high pressure will be centered across the
Midwest and Ohio Valley regions at the start of the extended. This
high will shift eastward to the Atlantic seaboard by early next week
as another storm system approaches from the west. A cold front will
settle down across the region by Wednesday and with a lack of better
forcing aloft will stall. This stalled frontal boundary (lingering
baroclinic zone) then becomes the focus for multiple passing
disturbances until the very end of the period. By Dy7, Friday, a
better organized surface low pressure system will pass through the
Midwest, and with better upper level support, drive what remains of
any lingering surface features (boundaries, etc.) south-southeast
out of our area.

Core westerlies (of the polar jet) remain generally north of our
forecast area, thereby keeping any more winter-like air masses
bottled up to our north through the period. As a result,
temperatures will generally run well above normal.

Seasonably cool highs in the 40s on Sunday will warm to between 50
and 60 degrees for the bulk of the period, or until Friday when
colder air moves back into the area behind an exiting cold frontal
system. Near normal morning lows around 30 on Monday will also warm
into the 40s for the remainder of the period. Wednesday morning lows
may not drop below 50 for some locations...a normal high temperature
for this time of the year. Total QPF from Monday through Friday are
currently forecast to range from between one and two inches
generally north of the Mountain Parkway to between two and three
inches south of the Mountain Parkway. Peak totals of around 3 inches
are expected for areas near or along the Tennessee state line. With
this rainfall event being spread out over a period of 4-5 days, we
are currently not expecting any notable hydro issues given
relatively dry antecedent conditions (abnormally dry to moderate
drought conditions across the area) and only light to moderate
rainfall intensities expected from rainfall through the extended
period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 122 AM EST SAT DEC 3 2022

VFR conditions will generally hang on through the next few hours,
before ceilings lower to MVFR from northwest to southeast between
09 and 13z. The other exception to this will be any passing more
intense showers or thunderstorms, in which some brief MVFR/IFR
conditions will be possible. Showers are expected to fill in
across the area through 10z, as a strong cold front approaches
from the west. Showers will then gradually diminish from northwest
to southeast through the rest of the morning hours as the front
passes through the region. Clouds will also scatter out from
northwest to southeast during the afternoon, with a return to VFR
conditions. South to southwest winds of 10 to 15 kts, with gusts
of 20 to 30 kts at times, will continue through the overnight
hours. Winds will then shift to the northwest between 13 and 17z,
as the boundary transits the forecast area. Northwest winds will
continue to be gusty through the early afternoon, before
diminishing later in the day.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GEOGERIAN
SHORT TERM...VORST
LONG TERM...RAY/GEERTSON
AVIATION...GEOGERIAN


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