JKL issues Area Forecast Discussion (AFD) at Nov 12, 4:43 AM EST993
FXUS63 KJKL 120943
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
443 AM EST Tue Nov 12 2024
.KEY MESSAGES...
- A cold front will increase chances for rain from Wednesday night
to Thursday evening.
- Temperatures will be be a few degrees below normal Tuesday
through Friday, with the exception of Wednesday.
&&
.UPDATE...
Issued at 1230 AM EST TUE NOV 12 2024
No significant changes to the forecast with just the inclusion of
the latest obs and trends for the T/Td/Sky grids for the update.
These minor adjustments have been sent to the NDFD and web servers
along with a freshening of the zones and SAFs.
UPDATE Issued at 1007 PM EST MON NOV 11 2024
Not many changes made to the grids as they've been largely on
track. Just a few touch-ups based on the latest surface
observations and updates to Sky grids based on latest satellite
imagery. Lastly, updated evening text and radio products based on
the changes. Grids have been saved and sent.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 413 PM EST MON NOV 11 2024
Late this afternoon at the axis of n upper level trough extended
from the Hudson Bay region to the Northeastern Conus to the
Carolinas. A shortwave trough/upper low moving through the upper
level trough was over the lower St Lawrence valley headed to the
Maritimes while another shortwave trough/upper low was working
into the eastern Great Lakes. An upper level ridge was centered
from Mexico into the western Gulf of Mexico with ridging north
through TX to the Dakotas while a trough was working into the
western Conus. At the surface, the front that crosses the region
last night into this morning was working across the Appalachians
with a ridge of high pressure having nosed into the Lower OH
Valley from the Southern Plains. Another sfc low was moving from
Ontario into Quebec with the associated cold front nearing the
Lower OH Valley from the mid MS Valley. A sfc ridge high pressure
was in place from Manitoba and western Ontario into the Dakotas
and upper MS Valley. Drier air has moved into eastern KY behind
the first cold front with current dewpoints generally ranging
through the 40s though afternoon mixed dewpoints in some cases
were in the upper 30s.
Tonight and Tuesday, the shortwave trough nearing the eastern
Great Lakes at present will rotate into the Northeast and then to
the Maritimes to western Atlantic with the axis of the mean upper
level trough also working well east of eastern KY. Meanwhile, the
upper level ridge to the west will work east across the Plains
and build into the MS Valley and then to the western Great Lakes
to the Lower OH Valley to the Gulf of Mexico. To the west, an
upper level trough will work deeper into the western Conus and
then to the Rockies. Tuesday night, the axis of the upper level
ridge will shift to a James Bay to eastern Great Lakes to
Southern Appalachians to eastern Gulf of Mexico line. At the
surface, the upstream cold front will drop to near the OH River
during the early to middle part of the evening and into eastern
KY late in the evening into the overnight hours. This boundary
should sag south of eastern KY by dawn as sfc high pressure
building east across Ontario and into the Great Lakes and into the
Lower to Middle OH Valley and eastern KY. This boundary will
become more diffuse on Tuesday as it sags further south as high
pressure at the surface and aloft dominates with rising heights
expected at 500 mb. High pressure at the surface and aloft will
continue to dominate on Tuesday night as well as both shift east.
Behind the boundary tonight, PW is progged to fall to the 0.2 to
0.3 inch range if not slightly lower, or climatologically below
the 10th percentile for this time of year, with only a modest
increase in PW to about 0.2 to 0.4 by late Tuesday night. 850 mb
temperature, especially in the north and east will be a couple of
degrees colder on average compared to today.
The cold front tonight may bring a bit of an increase in mixiness
as it passes so the timing and intensity of fog formation in
deeper valleys is uncertain. In addition, there will be a bit of
increase in moisture generally below 850 mb as the front passes so
a few to scattered low to mid level clouds cannot be ruled out.
Otherwise, any lingering clouds and valley fog should lift and
mix on Tuesday morning and give way to mostly sunny to sunny
skies. Under high pressure shifting eastward and a trend to
southerly gradient/flow for ridges, a moderate ridge/valley split
is expected for Tuesday night. Some deeper valley fog may again
form, especially south of the Mountain Parkway.
.LONG TERM...(Wednesday night through Monday)
Issued at 443 AM EST TUE NOV 12 2024
The extended will start off quite active, as a strong area of low
pressure is expected to move through the region. This system will
bring widespread rain showers to the Ohio and Tennessee Valley
regions Wednesday night and Thursday. The rain will gradually taper
off Thursday night, and should exit the area by early Friday morning.
The latest models have a large trough of low pressure spinning off
the eastern seaboard, with strong high pressure, at the surface and
aloft, sprawled across New England, the eastern Great Lakes, and
southward down the eastern CONUS into the eastern Gulf of Mexico.
West of the high our next weather maker will be taking shape and
moving out of the Great Plains and across the Mississippi Valley
into the Ohio and Tennessee Valleys to begin the period. Another
high pressure system will be in place along the Rocky Mountains and
western and southern Plains, with another well developed low
pressure system moving into the Pacific Northwest. This overall
pattern will shift to the east mid-week, bringing rain to eastern
Kentucky. After the first low pressure system moves off to our east
early Friday, the western ridge will move into the Great Lakes and
Ohio and Tennessee Valleys heading into the weekend. This system
will bring dry and warmer weather to our area. Cooler temperatures
will be on tap again in the wake of the first low pressure area. The
weekend ridge should begin to break down and move off to our east to
begin the new work, as another area of low pressure moves in from
the west. This system could bring scattered showers back to eastern
Kentucky Sunday night through Monday night. No weather hazards
expected in the extended at this time.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1245 AM EST TUE NOV 12 2024
VFR conditions will prevail across all TAF sites through the
aviation forecast period. Fog is likely to develop overnight but
will not filter into any of the TAF sites. Lastly, winds are
forecast to be light and variable with a slight in bump in
northeasterly winds Tuesday afternoon.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JP
LONG TERM...AR
AVIATION...VORST/GREIF
Source:
JKL issues Area Forecast Discussion (AFD) at Nov 12, 4:43 AM EST---------------
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