JKL issues Area Forecast Discussion (AFD) at Nov 2, 12:05 PM EDT762
FXUS63 KJKL 021605 AAC
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1205 PM EDT Sat Nov 2 2024
.KEY MESSAGES...
- Above normal temperatures return today; record or near-record
temperatures are forecast for Tuesday.
- The next chance for widespread measurable rainfall arrives
Tuesday evening into Wednesday.
&&
.UPDATE...
Issued at 1205 AM EDT SAT NOV 2 2024
For the mid-day update, adjusted for most recent surface obs. Also
adjusted the diurnal rise over much of the southeast-eastern
portions of the area that has seen a persistent stratus deck in
place through the morning. Temperatures are expected to catch up
to afternoon forecast levels once stratus has totally dissipated.
Fog has at least lifted enough that surface visibilities are up
and fog can be removed. Afternoon high temperatures and minimum
relative humidities may be a bit tricky with the slow start
through the morning, but in general expected highs look to be in
the ball park of our original forecast. Updated zones and grids
have been issued.
UPDATE Issued at 955 AM EDT SAT NOV 2 2024
This time of year, fog can tend to linger a bit further into the
morning, especially with any type of cloud layer that retards
mixing from the early morning sun. Thus fog has been a bit more
stubborn to mix out across our southeastern valleys. Updated grids
to incorporate most recent surface obs and for the slower trend
of dissipation of early morning vally fog. Will update the
forecast package again as fog finally lifts and mixes out.
Stratus across our southeast should gradually erode and mix out as
well.
UPDATE Issued at 725 AM EDT SAT NOV 2 2024
Hourly grids were updated to account for recent observations of
low to mid 30s for deeper valley locations generally north of the
Hal Rogers Pkwy and KY80 corridor with upper 30s to upper 40s
elsewhere. Valley fog and some low stratus in the southeast
should lift and dissipate over the next 3 hours or so following
sunrise. Milder temperatures are in store, with temperatures
returning to a few degrees above normal on average.
&&
.SHORT TERM...(Today through Sunday)
Issued at 453 AM EDT SAT NOV 2 2024
Early this morning, an upper level ridge extended from, the Gulf
of Mexico to near Bermuda with a subtle ridge axis northwest
to MO to SD. An upper level trough was moving across portions of
the western Conus. At the sfc, a ridge of high pressure was
centered from Ontario to MI and extended into the OH and TN
Valleys and much of the Appalachians. Locally, mainly just high
clouds were passing overhead, with low and mid clouds well south
and southeast of the region nearer to the frontal zone that
crossed the area on Thu night and early Fri that is sagging deeper
into the southeastern Conus. Fog and perhaps some low stratus
development was most prevalent from near Whitley County and then
the counties bordering VA though valley fog was also occurring
further north to near the Mtn Pkwy corridor. Deeper more
sheltered valley locations have cooled into the mid to upper 30s
from Wayne, McCreary, and Whitley Counties northeast to Martin
County per KY Mesonet and home weather station networks while
locations in more open terrain and on coalfield ridges were in the
low to mid 40s. Valleys nearer to the VA border where drier air
had yet to advect in were in the upper 40s to around 50 degree
range.
Today and tonight, the axis of upper level ridging will work east
and northeast to the western and then Central Great Lakes to
Lower OH to Middle OH Valleys, TN Valley, and Southern
Appalachians. Meanwhile, the surface high will work east and
reach near Lake Ontario and the middle Atlantic States to the
Carolinas by late tonight. An inverted sfc trough may lift into
the region to the north of the sfc boundary that will stall today,
but should begin to lift north as a warm front downstream of sfc
low organizing in the Plains in response to the upper level trough
working across the western Conus. For Sunday, sfc low pressure
should continue to evolve in the Plains as the upper level trough
axis moves to a MT to AZ line and approaches the Four Corners
region. The warm front downstream of the low should continue
lifting north and northeast and into eastern KY.
Valley fog will continue to remain through dawn and then is
expected to gradually lift and dissipate within two to three hours
of sunrise or by the 10 AM to 11 AM EDT timeframe. Temperatures
should moderate a few degrees from highs observed on Friday to
near normal to as much as 5 degrees or so above normal. Afternoon
mixing should result in low to mid 30s mixed dewpoints in the
north and some low 40s near the TN border. With high pressure
dominating, deeper valley should again drop to the mid 30s to low
40s tonight though ridgetops and more open terrain locations
should only drop into the 40s. Valley fog will again be favored to
develop by midnight and linger into Sunday morning. An increase
in moisture near 850 mb is expected for Sunday as the warm front
lifts north. Despite an increase in clouds, warm air advection is
also expected and highs should reach about 10 or more degrees on
average above normal on Sunday with low to mid 70s anticipated
outside of the higher terrain above 2500 feet.
.LONG TERM...(Sunday night through Friday)
Issued at 554 AM EDT Sat Nov 2 2024
The beginning of the long term forecast period is marked by
persistent warm air advection amidst deep southerly to southwesterly
flow. Aloft, a staunch ridge will gradually shift northward towards
the Carolinas as a deep trough ejects from the Plains into the
Midwest. At the surface, Eastern Kentucky will be firmly in the warm
sector by Sunday night, with the earlier warm front near the Ohio
River and this weekend's high pressure system up in New England.
This synoptic set up will yield much warmer than normal temperatures
and much higher atmospheric moisture content than what is
climatologically expected here in early November.
On Sunday night, minimum temperatures will be in the low to mid 50s,
nearly 15 degrees warmer than the previous night. This is a direct
result of the aforementioned warm air advection, as is an increase
in cloud coverage. Prolonged cloud coverage in the overnight hours
will work to relegate the effects of radiative cooling and thus the
conventional ridge-valley temperature splits overnight. Thus, the
warming trend continues on both Monday and Monday night. Highs on
Monday will be in the mid 70s area wide, and overnight lows will be
in the mid to upper 50s. By Tuesday, the center of the upper level
ridge will be closer to the forecast area. This will increase
subsidence, decrease cloud coverage, and facilitate strong diurnal
mixing processes on Tuesday afternoon. Tuesday looks to be the
warmest day in the forecast period, with potentially record-breaking
highs near 80 degrees across much of the area under partly cloudy
skies. A tightening pressure gradient will foster gusty winds ahead
of an approaching cold front into Tuesday night.
This cold front will trigger widespread rain chances across Eastern
Kentucky on Tuesday night and through the day on Wednesday. PoPs
peak between 60-70% across the northwestern half of the area, where
upper level support will be greatest. Instability continues to look
very low at this time, and the nocturnal approach of the front will
further limit thunder chances. Instead, expect a decent measurable
rain across the Commonwealth from this system, especially given the
front is expected to stall near our area.
Given the strength and persistence of the upper level ridge over the
southeastern CONUS, once this system's parent upper level trough
ejects northeast, upper level flow over Kentucky becomes quasi-zonal
again. This will allow the cloud coverage and rain chances to linger
for a few more days, albeit with less dynamic support and thus at
lower magnitudes. The continuation of these chances will allow most
of the area to receive a wetting rain by the end of the long term
forecast period. The latest modeled LREF ensemble probabilities of
greater than a quarter of an inch of rain through the end of the
forecast period are >65% across the entire area. The best chances of
higher rainfall totals will be further west, further away from the
influence of the ridge and closer to the better upper level dynamic
support during the main event on Tuesday night/Wednesday. The storm
total QPF for this first period of rainfall has trended downward
across the eastern half of the CWA, but the persistence of rain
chances for a few more days is captured in this more recent LREF
data. With this being said, there remains some model disagreement
with the forecast for Friday and beyond, so confidence in exactly
how long these damper and cloudier conditions will stick around is
low. A drying trend may emerge by next weekend, but slight chance
PoPs remain in the grids on Friday in this particular forecast
package. Temperatures late next week will be cooler than they were
out ahead of the front, but will remain seasonably mild. Expect
highs in the lower 70s/upper 60s and lows in the 50s/upper 40s on
Thursday/Friday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 727 AM EDT SAT NOV 2 2024
Sfc and upper level high pressure will largely bring VFR and
light winds to the period over the next 24 hours as only some high
and perhaps mid level clouds may pass from time to time. The
exceptions will be valley fog through about 13Z to 14Z, where
reductions down to IFR and even some LIFR and VLIFR are
anticipated in deeper valleys, though TAF sites should not be
affected. Deeper valley fog should again develop by the 03Z to
06Z period, with MVFR to IFR and perhaps LIFR reductions possible
late in the period. TAF sites should not be affected once again.
Winds will average at no more than 5KT mainly between north and
east throughout the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM...MARCUS
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Nov 2, 12:05 PM EDT---------------
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