Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 150625 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
225 AM EDT Fri Mar 15 2024

.KEY MESSAGES...

- Above normal temperatures continue through Saturday just not as
  warm as it has been.

- A cold front brings showers and thunderstorms to the area
  through this afternoon and early evening in the southeast.
  Rainfall will generally be a quarter to half of an inch.

- A deeper passing system aloft brings a threat of some rain/snow
  showers on Monday.

- Hard freeze conditions Monday night could kill any cold
  sensitive vegetation that has emerged prematurely due to early
  season warmth.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 511 PM EDT THU MAR 14 2024

Late this afternoon, the axis of an upper level ridge extended
from the Caribbean north near the eastern seaboard while another
upper level ridge extended across portions of the Pacific into
the northwest Conus. In between an upper level trough extended
southwest from the Hudson Bay region into the southwest Conus with
southwest flow aloft from the Southern Plains into the Lower OH
Valley. A closed low was located across the desert southwest with
the upper trough while a more progressive shortwave trough
extended from Ontario to the Northern Plains while additional
weaker shortwaves were moving in the southwest flow toward the OH
Valley region. At the surface, a wavy frontal zone extended from
the New England coast across the mid Atlantic states into the
southern Great Lakes to mid MS Valley vicinity to the Southern
Plains to southwest Conus in advance of the upper level trough
axis. Earlier convection generally passed north of eastern KY
although some isolated showers or storms were moving across the
region at this time, generally near or north of the Mountain
Parkway as a weak shortwave moves through the OH Valley region.
MLCAPE is currently analyzed in the 500 to 1000 J/kg range across
the western half or third of the CWA while instability further
east is minimal due to dewpoints only in the 40s to around 50.
Effective shear is sufficient for some organization to convection.

This evening and tonight, shortwaves in southwest flow should
continue to progress across the Lower OH Valley region while the
axis of the upper level trough shifts gradually southeast to an
Ontario to northern Great Lakes to SD line late tonight. This
trough axis should progress southeast across the Great Lakes and
pass across parts of the OH Valley and into the Northeast.
Another more potent shortwave will drop southeast across central
portions of Canada and is expected to reach western Ontario to
the upper MS Valley by the end of the period. In advance of the
shortwave working toward the Great Lakes and OH Valley, the wavy
frontal zone should gradually move south and east toward the
Commonwealth tonight and cross KY from Friday into Friday evening.
the frontal zone and a series of shortwaves will lead to
convection at times, though chances peak later tonight through
Friday when the combination of moisture and lift peaks. PW reaches
the 1 to 1.25 inch range late tonight through Friday afternoon
while forcing associated with the front and the passing shortwave
peaks during that time. QPF with this system has generally
trended down into the quarter to half of an inch range, though as
is the nature of convection some locally higher amounts should
occur where any stronger thunderstorms pass.

Above normal temperatures will persist ahead of the front through
Friday and even behind it on Friday night as only a modest cool
down is expected. The hourly temperatures and min T for deeper
eastern valleys is a bit tricky tonight, but cloud cover should be
insufficient for another ridge/valley temperature split tonight
with the deeper valleys dropping toward the 50 degree mark and
stayed close to the previous forecast with details for that.
Coalfield valleys may not drop below the 60 degree mark in some
instances. Temperatures for most areas should reach well into the
60s for highs on Friday in the warm sector. Lows on Friday night
should as much above normal as tonight, but still above normal
nevertheless in the low to mid 40s.

.LONG TERM...(Saturday through Thursday)
Issued at 615 PM EDT THU MAR 14 2024

An amplified long wave pattern will be in place through the
majority of the period. Beefier short wave energy will be inbound
from the western Great Lakes this weekend, with a northern stream
trough becoming entrenched over the East by early next week. This
will bring back more winter-like conditions across eastern
Kentucky at least temporarily. Meanwhile, as the eastern trough
exits off to the east and northeast, a stagnant closed low over
the southwestern CONUS will finally push east and transition to an
open wave, reaching the southern Plains by Thursday. Warm air
advection out ahead of this system, will result in moderating
temperatures by mid-week, with a small chance of rain returning
towards the end of the period.

It will be mostly dry this weekend, with a passing cold front late
Saturday night into Sunday morning bringing mainly an increase in
clouds. Temperatures will start out above normal with highs in
the 60s and lows in the 40s. Readings will then dip into the 30s
Sunday night, and likely only rebound into the low to mid 40s for
Monday, with the passage of a deeper short wave trough axis.
Colder temperatures aloft associated with the short wave passage
will support some snow showers mixing in with rain showers during
the day on Monday, especially to our northeast. Precipitation
will come to an end by early Monday evening, with clouds likely
clearing and winds calming enough to allow for most locations to
get down into the low to mid 20s, with a few spots possibly seeing
some upper teens by early Tuesday morning.

Warm air advection then kicks in out ahead of another approaching
system Tuesday night into Wednesday. Model agreement is not great
at this time, but both the GFS and ECMWF are maintaining a decent
pressure gradient over the area Tuesday night, which would
mitigate another strong drop off in the valleys. Still, dew points
will be particularly dry going into the night, so can not rule
out at least the more sheltered sites returning to the upper 20s,
while most other locations stay in the 30s. Another dry cold front
passes through Wednesday. Any cold air advection following this
will be short-lived at best, as the aforementioned southern
stream system quickly allows for another surge of warm air
advection out ahead of it. Highs will moderate back to near
normal in the mid to upper 50s on Wednesday, with lower 60s likely
by Thursday, with a small threat of rain later in the day.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 200 AM EDT FRI MAR 15 2024

In general, VFR conditions are expected through much of the
overnight, with brief reductions to MVFR and momentary IFR as
showers and thunderstorms move through into the day Friday. CIGs
will becomes increasingly more prevalent in the MVFR category
later in the morning, though, with the potential for IFR, or low-
MVFR, conditions along with showers beginning around or shortly
after 18Z/Fri. Continued low CIGs follow into the evening for most
locations. Winds, outside of storms, will be from the south to
southwest at 10 kts or so. With storms, they could exceed 35 kts.
The winds then become westerly and northwesterly prevailing by
midday Friday as the cold front passes across the area - but with
speeds generally remaining below 10 kts sustained.

&&

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

$$

SHORT TERM...JP
LONG TERM...GEOGERIAN
AVIATION...CMC/GREIF


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