JKL issues Area Forecast Discussion (AFD) at Dec 13, 2:55 AM EST149
FXUS63 KJKL 130755
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
255 AM EST Fri Dec 13 2024
.KEY MESSAGES...
- Temperatures warm to above normal this weekend into early next
week.
- Periods of rain are forecast to impact the area at times from
late Saturday evening into Tuesday.
&&
.SHORT TERM...(Today through Saturday)
Issued at 252 AM EST FRI DEC 13 2024
The eastern extent of a west-east oriented stationary front resides
across eastern Kentucky this morning, roughly bisecting the forecast
area. This boundary separates upper teens to mid-20s temperatures to
the north of the front from upper-20s to mid-30s temperatures to the
south of the front. This gradient is helping to fuel a westerly jet
stream aloft across the Ohio Valley within an overall area of
confluence aloft upstream of a large trough over the Northeast
U.S.
The stationary front will weaken and dissipate over eastern Kentucky
today as upper ridging approaches the region today and then moves
across eastern Kentucky tonight. A mid-latitude cyclone ejecting
from the Central and Southern Rockies will then move east-
northeast to the Upper Mississippi River Valley by the end of the
period early Saturday evening, with a stacked low over northern
Missouri and/or southern Iowa.
The stationary front today will serve as a focal point for high-
level clouds moving quickly east across the forecast area today.
With weak warm advection and the high-level clouds, expect highs
today in the lower 40s north to lower 50s south of the front.
Clouds gradually clear overnight with upper ridging moving overhead,
a good recipe for radiational cooling in the valleys below
increasing east to southeast surface flow just above the surface.
Went rather aggressive with lowering temperatures in the valleys
with lower 20s in the coldest valley locations, with temperatures
in the lower 30s on ridgetops.
Warm advection increases through the day Saturday, with PoPs
beginning to increase from the west right before the period ends.
Rain for the vast majority if not all of the forecast area likely
holds off until at least mid-evening. Increasing southeast
compressional warming just above the surface will help highs warm
into the 50s, with fairly good coverage of at least thin mid- and
high- level cloud cover over the area most of the day. Highest
temperatures will likely be just northwest of the higher terrain
such as Pine Mountain, where the effects of weak downslope warming
will be most prevalent.
.LONG TERM...(Saturday through Thursday)
Issued at 447 PM EST Thu Dec 12 2024
The long term forecast continues to look quite active as a series of
systems work to produce persistent cloud coverage, widespread rain
chances, and above normal temperatures throughout much of the
upcoming week. Aloft, guidance continues to resolve a progressive
pattern in which Eastern Kentucky will quickly oscillate between the
influence of upper level ridging and troughing features. At the
surface, this will be first be represented by a high pressure system
off to the Northeast on Saturday. By Sunday, a wave cyclone emerges
in the Ozarks, with its associated warm and cold fronts draping the
Ohio and Mississippi River Valleys, respectively. This first system
looks to fizzle out early on Monday morning, with its trailing cold
front becoming diffuse, as its upper level support opens up and
deamplifies. Shortwave upper level ridging may briefly build into
the area on Monday morning, but a second, faster-moving system will
be right on its heels headed into Tuesday. This second system looks
to have more potent upper level support in the form of a negatively
tilted trough. While our area will be firmly situated in the warm
sector, instability looks quite low in the available forecast
guidance. As a result, all precipitation with these first two
systems is expected to fall as plain rain.
Saturday's sensible weather forecast will start out as dry, but as
warm air and moisture stream into the column via veering winds
throughout the column, cloud coverage will increase. Expect
afternoon highs to warm into the mid 50s, with precipitation chances
increasing after sunset travel concerns late next week and next
weekend are encouraged to as the better upper level dynamic
ingredients for rain align. Thick, stratiform cloud coverage will
limit the effects of radiational cooling and warming on Saturday
night and throughout Sunday. Expect a muted diurnal temperature
curve, with lows on Sunday morning well above freezing near 40
degrees and highs in the lower 50s. The lack of clear frontal
passage on Sunday night and lingering cloud coverage will give
Monday's highs a head start; it will warm from the mid 40s in the
morning to near 60 that afternoon ahead of this second system. On
Monday night into Tuesday morning, the cold front associated with
this second system will push through the area. PoPs peak once again
after sunset on Monday night, and some clearing is possible in its
wake on Tuesday night. However, model spread begins to significantly
increase beyond this point in time.
Mild and wet weather remain in the forecast on Wednesday, but the
timing of the individual features responsible for said conditions is
quite uncertain at this moment in time. Of note, the 12z runs of
both the deterministic GFS and European models reintroduce moisture
to the area overnight as yet another warm front lifts across the
region. The 00z model runs and many other ensemble members resolved
neither this amount of moisture nor this fast of moisture return
behind Tuesday's cold frontal passage. This trend will need to be
monitored as more data comes in, as it would yield in warming temps
across the area at night, which the NBM guidance does not currently
depict. Thus, confidence in the forecast for Wednesday and beyond is
low. A broad signal for a return to colder weather exists late next
week, but it is far too early to provide any details regarding
precipitation type for next weekend. Interests with pre-holiday
travel concerns late next week and next weekend are encouraged to
pay close attention to the forecast as the time approaches, as
changes can and will happen at this temporal range.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1208 AM EST FRI DEC 13 2024
VFR conditions will prevail through the TAF period. High clouds
and occasionally some mid level clouds are expected throughout the
period. Winds be light and variable.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CMC
LONG TERM...MARCUS
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Dec 13, 2:55 AM EST---------------
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