Area Forecast Discussion Issued by NWS Jackson, KY
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FXUS63 KJKL 171649 AAB
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1249 PM EDT Sun Mar 17 2024
.KEY MESSAGES...
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- A deep trough passing aloft brings a threat of light snow
showers and flurries on Monday afternoon.
- Freezing conditions tonight and a hard freeze Monday night
could kill any cold sensitive vegetation that has emerged
prematurely due to early season warmth.
- Temperatures rebound back to near normal through mid-week, with
lower confidence in the next potential chance of precipitation
moving in towards the end of the work week.-- End Changed Discussion --
&&
.UPDATE...
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Issued at 1245 PM EDT SUN MAR 17 2024
Minor adjustments were made to hourly grids based on recent
observations. This led to no substantial changes at this time.
UPDATE Issued at 720 AM EDT SUN MAR 17 2024
Just a quick update to the forecast mainly to add in the current
obs and trends for the T/Td grids. These minor adjustments have
been sent to the NDFD and web servers.-- End Changed Discussion --
&&
.SHORT TERM...(Today through Monday)
Issued at 435 AM EDT SUN MAR 17 2024
08Z sfc analysis shows a broad area of low pressure northeast of
Kentucky and dragging a cold front through this part of the
state. This process is keeping a deck of clouds over much of the
area - especially south - along with southwest winds around 10 mph
just ahead of the boundary. In turn, this has limited the
radiational cooling most places and led to fairly uniform
temperatures in the upper 40s to lower 50s - though some low 40s
have been achieved in the most sheltered northeast valleys.
Meanwhile, dewpoints have fallen into the mid 30s to lower 40s
range - the resultant dewpoint depression and winds are keeping
most of the fog at bay this morning.
The models, and their individual ensemble suites, are still in
pretty good agreement aloft through the short term portion of the
forecast. They all depict fast zonal flow tilting more
southwesterly later today and more sharply tonight in response to
a deep trough extending through the southwest portion of the Ohio
Valley on the way to its digging through the Tennessee Valley by
Monday evening. This mid level flow will bring a stream of energy
down over Kentucky for Monday with accompanying height falls.
Given the still small model spread, have again favored the NBM as
the starting point for the forecast grids with mainly just some
terrain distinction added to the hourly temps and low temperatures
tonight and spotty PoP potential from the CAMs on Monday
afternoon.
Sensible weather will feature one last day of near normal
temperatures before colder air overwhelms the early warmth of
spring we have seen for the past week. Despite the weak CAA today,
enough sunshine will support readings climbing into the low to
mid 50s north and upper 50s to around 60 in the far southeast.
Although the clouds and continued sfc winds of 5 to 10 mph will
keep readings from dropping as far as they could, they still will
be below freezing most places - for the first time in quite a
while. Caution is urged for those who may have been lulled into
thoughts of an early spring and brought any plants outside or
where some early fruit tree blossoms have developed. Just know
that Monday night will be even colder. This is due to a further
surge of cold air into the area with another, mostly dry, cold
front keeping highs only in the 40s along with a potential for
some flurries and sprinkles during the afternoon - mainly for
eastern parts of the area.
The main adjustments to the NBM starting point were to again add
some terrain distinctions into low and hourly temperatures
tonight. PoPs were generally single digits from the NBM and kept
there through Monday evening.
.LONG TERM...(Monday night through Saturday)
Issued at 538 AM EDT SUN MAR 17 2024
A deep trough will start out just west of the Appalachians at the
beginning of the period, with a REX block hanging on across the
West. Through the middle of next week, the REX block breaks down,
with the southern stream closed low likely transitioning to an
open wave as it moves east over the southern Plains. The trough in
the East curls northeast with time, with cyclonic flow setup from
the Upper Midwest through the Ohio Valley, New England, and the
Mid-Atlantic. The southern stream short wave trough will continue
east through the end of the work week, with the operational GFS
still on the slower and more intense-side of the ensemble
envelope. The ECMWF remains quicker, more dampened, and further
southeast with the moisture. As such, there is still lower
confidence on precipitation chances from Thursday night through
Friday. Have maintained chance PoPs during this time frame, but
PoPs now only peak at around 40% for Friday, still trending down
overall from the past few days.
A cold air mass will be settled in across eastern Kentucky Monday
night, with high confidence of a hard freeze, as temperatures
settle into the low to mid 20s. Readings will rebound into the low
to mid 50s Tuesday, and then upper 50s to lower 60s for Wednesday.
A passing dry cold front will knock temperatures back down for
Thursday, with highs retreating to the low to mid 50s north, to
near 60 bordering Tennessee. Clouds will be on the increase during
the afternoon, with precipitation chances increasing from the
southwest Thursday night and Friday, before reducing to just slight
chances (20%) by Saturday. Temperatures will generally average
near normal through the rest of the period.
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.AVIATION...-- Changed Discussion --
(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1249 PM EDT SUN MAR 17 2024
Sfc high pressure centered in the Saskatchewan and Alberta border
vicinity is expected to move south and become centered over the
Central Plains/Central U.S. by the end of the period and also builds
into the OH Valley region and the Commonwealth. However, a shortwave
trough will rotate across Ontario and into Quebec as well as the
Central and Eastern Great Lakes and extended from the St Lawrence
Valley to the eastern Great Lakes to Lower OH Valley during the
next 24 hours. Although VFR is expected to prevail some mid and
low level clouds in addition to high clouds are expected to cross
the region at times. Cloud bases nearer to or below 5kft agl or
perhaps lower will be most prevalent from 15Z on as some high
based snow showers or flurries with no visibility restrictions
should begin to develop as peak heating approaches on Monday.
West to northwest winds at 10 to 15KT are expected to begin the
period with some gusts nearing 20KT, though these should slacken
toward 5KT from the west to northwest tonight. Winds should
increase late in the period toward 10KT and out of the northwest.-- End Changed Discussion --
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...GEOGERIAN
AVIATION...JP