JKL issues Area Forecast Discussion (AFD) at Nov 4, 4:45 PM EST794
FXUS63 KJKL 042145
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
445 PM EST Mon Nov 4 2024
.KEY MESSAGES...
- Above normal temperatures are expected this week, with record
or near-record high temperatures forecast for Tuesday.
- The next chance for widespread measurable rainfall arrives
Tuesday night into Wednesday.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 445 PM EST MON NOV 4 2024
Sunshine has been filtered through the day by high cirrus and
cirrostratus clouds. Even so, thermometers across the area soared
well above normal and have peaked in the mid 70s to lower 80s across
the Coalfields this afternoon at elevations below 2,000 feet and
mainly into the 60s at elevations above 2,000 feet. The
delightful weather is due to lingering effects of high pressure
ridging extending from the Southern Appalachians to a stout
surface high centered just off the New England Coast. Winds have
been breezy as well, gusting from the south up to between 15 to
25 mph at most locations.The increasing breeziness is the result
of a tightening pressure gradient across the Commonwealth between
the aforementioned high pressure ridge and a eastward-trekking
cold front extending from the Northern Ontario southward to
Texas. Looking aloft, the 500H analysis shows a deep long-wave
trough axis behind the front over the High Plains.
Model guidance is in good agreement during the short-term and
depicts the parent longwave trough undergoing rapid de-amplification
as it translates eastward over the next 24 to 36 hours in
response to additional shortwave energy now dropping into the
Pacific Northwest and beginning to carve out a 500H trough further
west. As it loses its upper level support, the cold front will
slow and start to stall over the Lower Ohio Valley by the end of
the forecast period. Many of the latest model solutions suggest
an even slower arrival of PoPs with the cold front compared to
other solutions of recent days. In fact, the 04/12z HREF members
show precipitation only reaching near or just southeast of the
I-64 corridor by 12z Wednesday.
In sensible terms, look for breezes to slow this evening, permitting
the more sheltered valleys east of the Escarpment to mostly
decouple, though sporadic weak mixing cannot be ruled out through
the night. Passing mid and high clouds can be expected through most
of the night as well. Lows are forecast to range from the lower 50s
in sheltered hollows near the Virgina border up to the lower 60s
over the thermal belt ridges and in open terrain over and west of
the Escarpment. HREF and time heights suggest that the mid and
upper levels will dry out Tuesday morning allowing for mostly
sunny to sunny skies for most of the day. Temperatures are
expected to peak from the upper 70s to lower 80s -- likely tying
or breaking daily record highs at JKL and LOZ. In addition to the
warmth, GFS BUFKIT mixed-layer momentum transfer supports peak
wind gusts in the 20 to 30 mph range outside of the most sheltered
hollows. Clouds should finally begin to increase from the
northwest on Tuesday night and likely shower chances reach the
I-64 corridor toward sunrise on Wednesday. Tuesday night's
forecast lows remain very mild, ranging from the mid 50s in the
most sheltered southeastern valleys to the middle 60s over and
west of the Escarpment.
.LONG TERM...(Wednesday through Monday)
Issued at 422 PM EST MON NOV 4 2024
The dry pattern that has been in effect is finally taking a shift,
with an active extended period expected. By 12Z Wednesday, a strong
high pressure ridge will have been pushed out farther off the
southeast Atlantic Coast, as upper level troughing takes hold of the
majority of the Conus. This troughing will be focused around an
upper level low in the Desert Southwest, with strong SW flow
expected across much of the Central and Eastern U.S., including the
Ohio Valley. The strong low pressure system will remain across the
Desert Southwest as the northern and southern systems/streams begin
to come out of phase, leading to more zonal flow across the eastern
U.S. by Friday. In fact, as the low system finally starts to slowly
progress farther northeast into the first half of the weekend,
heights may even strengthen across The Ohio Valley and Deep South,
with surface ridging moving in. However, by Saturday night, both the
GFS and ECMWF are in agreement that the upper level low will be
moving into the Central Plains, which will increase southwest flow
across the Commonwealth. The low should then traverse just north of
the state through the day Sunday. Currently the GFS is displaced a
bit farther south, likely impacting the state, compared to the
northern track of the ECMWF.
As for sensible weather...to start the period, a cold front will be
analyzed passing through eastern Kentucky. This will mean increasing
precip chances through the day, along with strong SW advection and
temperatures reaching well into the 70s. This is actually cooler
than the previous day, given the increasing clouds and precip.
However, it is still warm enough to warrant thunderstorm chances,
especially with the added lift of the front. Without the upper
level system moving for a couple of days, the surface front will
actually become stalled across the state into the first part of
Thursday, before finally dissipating as the flow becomes more zonal
and the systems unphase. This will see continued pops into Thursday,
slowly dissipating through the day.
High pressure will finally take hold with the rising heights Friday.
Even with a more northerly flow at the surface, overall we will
still be in the southern stream pattern and will miss out on the
best CAA. Temperatures will remain in the 60s and low 70s for highs,
still well above seasonal normals. This high pressure will be quite
short lived, unfortunately, as it quickly exits to the northeast of
the state by Saturday afternoon. The upper level system that was
over the Southwest will be pushing northeast towards the central
Plains, bringing a strong surface system with it. Models are not in
good agreement about the extent of the precipitation with this
incoming system. The GFS brings precip in by Friday evening, while
the ECMWF doesn't have precip moving in until late Saturday. That
being said, given the uncertainty, just kept with the NBM solution.
This brings precip into the forecast starting Friday night, slowly
ramping up Saturday, and then becoming more widespread by Saturday
night and Sunday as the system passes north of the state. During
this time, with SW flow still in place, despite clouds and rain,
temperatures will remain in the upper 60s and low 70s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1240 PM EST MON NOV 4 2024
VFR conditions prevail through the period at the TAF sites and
any fog tonight will be restricted to the most sheltered of river
valleys. Southerly winds at 6 to 12KT with gusts to around 20KT
are expected through this afternoon before slowing to variable at
around 5KT overnight. Winds increase aloft overnight leading to
LLWS potential late, especially west of I-75 where shear was
mentioned in the SME TAF. A brief period of LLWS exceeding 30KT
in the lowest 2kft AGL is also possible at sites further east
near sunrise on Tuesday but was not included in this TAF issuance.
Any LLWS will give way to gusty southerly winds of 10 to 15KT
with gusts of 20 to 30KT once mixing resumes Tuesday morning.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...JMW
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at Nov 4, 4:45 PM EST---------------
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