JKL issues Area Forecast Discussion (AFD) at Sep 9, 7:47 AM EDT034
FXUS63 KJKL 091147 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
747 AM EDT Tue Sep 9 2025
.KEY MESSAGES...
- Below normal temperatures and dry weather will persist through
tonight.
- Temperatures will warm to near normal by Wednesday or Thursday
and then persist into early next week with no measurable
rainfall expected.
&&
.UPDATE...
Issued at 740 AM EDT TUE SEP 9 2025
A few low clouds are present near the VA and TN borders otherwise,
mostly sunny skies prevail at this time. Valley fog is again
present, but has begun to lift or should begin to lift shortly and
should dissipate by in all areas by the 9 to 10 AM timeframe.
Temperatures are expected to moderate a couple of degrees warmer
for highs today compared to Monday.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 517 AM EDT TUE SEP 9 2025
Early this morning, rather broad upper troughing extended from
eastern portions of Canada across the Great LAkes to OH Valley to
Southeast between upper ridging centered over the Atlantic
northeast of Bermuda and another upper ridge extending from
northern Mexico and the Southwest Conus into the Southern Plains
and also across the Rockies to the Canadian Rockies. Further west,
another upper trough extends from BC south near the west coast of
the Conus. At the surface, a ridge of sfc high pressure extends
from the Northeast to the Southern Appalachians to GA while a weak
inverted trough feature ahead of the trough axis to the west
extends into eastern parts of the Commonwealth from the Gulf
coast and there are some lower clouds associated with it from the
southern counties int parts of middle and eastern TN. Recent
satellite imagery reveals valley fog is present especially south
of of I-64 in the rivers, forks, and main tributaries of the KY,
Cumberland, and Big Sandy basin. This fog may be dense in a few
spots at present. Temperatures ranged from the mid 40s in the
normally colder valley locations to the mid 50s on the ridges.
Today and tonight, a moisture starved shortwave trough is
expected to move into the Lower OH Valley as upper troughing
persists from near Hudson and James Bay into the Great Lakes to
eastern Conus between the ridging in the Atlantic centered east
and northeaster of Bermuda and upper level ridging that axis of
which shifts east to the Southern Plains to High Plains to parts
of the Central and Northern Plains. Guidance generally has the
axis of the sfc high pressure ridge extending from the Northeast
into the Southeast shifting a bit to the west and northwest into
eastern KY through today and tonight while the inverted trough
shifts west and northwest of eastern KY. Valley fog should lift
and dissipate within about 2 to 3 hours after sunrise or through
the 9 AM to 10 EDT timeframe this morning. With the inverted
trough across the area some low to mid level clouds will be
possible at times today. Otherwise, temperatures will moderate
about 3 or so degrees on average compared to Monday. Valley fog is
again favored tonight with another small to moderate ridge/valley
temperature split. Mid to upper 40s are anticipated for the
valleys for low with 50s elsewhere.
Wednesday, a shortwave trough should work across the Commonwealth
including eastern KY but will be moisture starved and should
produce little more than a few clouds at times. A more significant
but also moisture deprived shortwave should move to the Central
Great Lakes to mid MS Valley by late Wednesday. A ridge of sfc
high pressure should remain across the Appalachians and OH Valley
for Wednesday. Temperatures should moderate another couple of
degrees and near normals for this time of year for highs.
.LONG TERM...(Wednesday night through Monday)
Issued at 500 AM EDT TUE SEP 9 2025
The period is expected to begin with an upper level ridge centered
east and northeast of Bermuda with another upper level ridge
extending from Mexico across portions of the Southern Plains and
Southern Rockies into the Central and Northern Plains to Manitoba.
In between, an upper level trough is expected to extend south
across the Great Lakes to Lower OH valley to the Southeast from an
upper level low in Quebec while an upper level low and trough is
expected over the western Conus. Also at that point, an upper
level low and trough is expected to be located west and northwest
of Hudson bay while another trough is expected to extend from the
Gulf of AK vicinity into parts of the eastern Pacific. At the
surface, a ridge of sfc high pressure is expected to extend from
the Central and Southern Appalachians to the Lower OH Valley and
also into the Southeast as well as Southern Great Lakes.
Wednesday night to Thursday night, the consensus of guidance is
for the upper low initially centered over Quebec to move to the
Maritimes while the trailing trough at 500 mb crosses the eastern
Great Lakes as well and the Lower OH Valley and Appalachians and
moves into the Northeast to Mid Atlantic to Southeast. Meanwhile,
upper level ridging should build into the Great Lakes to mid MS
Valley regions behind this trough. Further west, an upper
trough/low meanders across the western Conus and an upper trough
moves to the Hudson to James Bay to northern Ontario areas. Even
further west, another upper trough is progged to approach the BC
coast to Pacific northwest Coast. Closer to home, the upper
trough will be very moisture starved as it works across eastern KY
with a ridge of sfc high pressure remaining in place across the
Appalachians. Guidance has limited moisture between 850 and 700 mb
with this system with moisture more scant than that between 700
mb and 500 mb with little or no QPF across eastern Ky as it
passes. Some non measurable sprinkles cannot be completely ruled
out from mid level clouds late Wed night into Thu as this system
passes eastern KY, but confidence in that was not high enough to
include at this juncture. Temperatures should moderate a couple
more degrees to near normal, particularly for high temperatures
on Thursday.
Friday to Saturday night, the upper level ridge is progged to
build into the OH Valley to Southern Appalachians to Lower MS
Valley region from the Southern Plains/Arklatex region. Further
north the upper low should work from the Hudson/James Bay to
northern Ontario area into Quebec to the northern to eastern Great
Lakes. Across the western Conus, the initial upper trough/low
should move to the Alberta/Northern Rockies to Central and
Northern Plains as the next shortwave nears the west coast of the
Conus. Gradual height rises at 500 mb should ensue for Friday
into Saturday across eastern KY. The 00Z ECMWF operational run is
more similar to the recent GFS operational runs with the upper
level pattern from eastern Canada to the Great lakes into the
eastern Conus compared to the 12Z/8th ECMWF operational run and
some previous ECMWF operational runs. This leads to less than
average confidence in the evolution of the upper pattern by late
Saturday and continuing Sunday and early next week. Near normal
temperatures are forecast to begin the weekend along with rain
free weather.
Sunday to Monday, even though the most recent operational ECMWF
run is generally more similar to recent GFS runs with the upper
pattern over the eastern Conus to end the weekend into early next
week compared to some of the previous ECMWF runs, confidence is
lower than average to end the period. These differences lead to
considerable differences in forecast cloud cover and temperatures
and perhaps low chances for convection. The NBM temperature
forecasts generally split the difference between solutions to end
the weekend and begin next week. However, if the recent GFS
runs were to verify with 500 mb heights near 590 dm for Monday
compared to around 585 dm 500 mb heights of the ECMWF,
temperatures for highs by Monday would be several degrees above
normal as compared to the current near normal forecast. Overall,
dry weather should continue.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 750 AM EDT TUE SEP 9 2025
VFR was reported at the TAF sites at issuance time with VFR for
the remaining AWOS sites. Satellite imagery and webcams reveal
valley fog in parts of the KY, Cumberland, and Big Sandy River
basins that is not affecting the TAF sites. These initial reductions
as low as LIFR and VLIFR should improve by the 13Z to 14Z
timeframe as the valley fog gradually lifts and dissipates.
Otherwise, once VFR conditions return to all areas the should
remain until around 04Z when fog may begin to develop in valleys
and expand in coverage and extent to end the period. At this
point, that fog is not expected to affect the TAF sites either.
Winds less than 10 kts are forecast through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...JP
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Sep 9, 7:47 AM EDT---------------
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