JKL issues Area Forecast Discussion (AFD) at Aug 18, 4:32 AM EDT281
FXUS63 KJKL 180832
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
432 AM EDT Sun Aug 18 2024
.KEY MESSAGES...
- Below normal temperatures are expected Sunday through Wednesday
behind a cold front passage late Saturday night.
- Showers and thunderstorms will remain possible Sunday and
Monday, especially in the afternoon and early evening, with a
drying trend for Tuesday into Wednesday.
&&
.SHORT TERM...(Today through Monday)
Issued at 432 AM EDT SUN AUG 18 2024
Low pressure aloft will move rapidly out of the Southern Plains
north-northeast into the southern portions of Hudson Bay during
the short term. Associated trough will pass through the Ohio
Valley late Saturday and Saturday night. At the surface, a cold
front will slide east-southeast approaching the Ohio River by late
Saturday night before stalling out just to the northwest of our
forecast area. This will provide a good chance of showers to the
area late Saturday into Saturday night. QPF totals appear somewhat
meager, with generally around a quarter inch or less being
advertised by guidance. With some limited (elevated) instability
(250-500 J/kg) and effective shear of 30-40 kts, will plan to
maintain inherited slight chance of thunder.
Strong/steep low level lapse rates (steep potential temperature
gradient through the boundary layer), 0-3 km lapse rates
approaching 7C across our western zones, should tap into a strong
H925 30-35kt and H850 40-45kt LLJ for some gusty winds Saturday.
ECMWF EFI suggests a likelihood of some moderately high wind gusts
as compared to climatology, adding confidence to the forecast.
Bottom line is that confidence is growing for surface gusts
probably climbing to around 35 kts (35-40 mph) by early Saturday
afternoon, especially for our western most zones and our higher
terrain across our east.
.LONG TERM...(Monday night through Saturday)
Issued at 432 AM EDT SUN AUG 18 2024
This particular long term forecast package is defined by clearer
skies and cooler temperatures than what we have witnessed here in
Eastern Kentucky as of late. This drier and cooler air will advect
into the region via northwesterly/northerly flow throughout the
atmospheric column on the backside of the now-ejected upper level
low pressure system that caused this weekend's active weather. At
the surface, a high pressure system will drop into the Great Lakes
Region from Canada. Together, these features will work to instill
a modified continental polar airmass over the forecast area. This
notion is confirmed by modeled NOAA HYSPLIT back trajectories for
next week, which suggest that this airmass originated in
Northwestern Ontario/Saskatchewan. This particular piece of
forecast guidance also suggests that the air will be subsiding
(sinking) as it approaches the Ohio River Valley, which reaffirms
the notion that this airmass will be dry. As such, skies should be
mostly clear next week, although the potential for some Canadian
wildfire smoke to advect into the air aloft will need to be
monitored closely in the coming days.
In short, fall-like sensible weather should settle into Eastern
Kentucky on Monday night and stick around until Thursday, when the
surface high shifts east and southerly return flow begins to
slowly reintroduce warm, moist air into the column. Under clear
skies, expect well-defined ridge-valley temperature splits and
perhaps the formation of patchy valley fog on Monday, Tuesday, and
Wednesday evenings. In low-lying areas, overnight lows could drop
down into the upper 40s on Tuesday and Wednesday, whereas
ridgetops will see MinTs in the lower 50s. Afternoon highs will be
climatologically cooler than normal for this same time period,
with temperatures staying in the 70s across the entire area on
these dates. By Thursday, a warming trend will emerge, and
afternoon highs will incrementally increase into the 80s and then
perhaps the lower 90s in the Bluegrass by Saturday afternoon. Both
low temperatures and dewpoints will recover into the 60s in this
same time frame, and cloud coverage should subtly increase in
response to these warmer temperatures. Precipitation chances,
however, remain suppressed below 10 percent for the entirety of
this week's forecast. Thus, no hazardous weather is expected at
this point for the Monday night to Saturday timeframe.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 228 AM EDT SUN AUG 18 2024
Showers and thunderstorms continue to wane across the area.
Main forecast challenge will be residual moisture and the
development of low stratus and at times fog. MOS guidance is
generally optimistic, especially with VSBYS. However, LIFR to MVFR
CIGS can not be ruled out at times. Regional satellite does show
some patchy, transient low stratus going through cycles of
developing and dissipation across the area. In addition, ensemble
solutions show a fairly high probability (60-80%) of at least
LIFR CIGS at times through 13-14Z. Ensemble mean VSBYS also drop
to between 2-5 miles at times, especially across the north where
there is a bit more clearing and thus a better chance for the
development of patchy fog. Thus the potential for lower stratus,
and at times some light fog will exist through the remainder of
the overnight, or until the surface front clears the area.
Currently the surface boundary is positioned roughly from KFGX to
KFFT, to just south of KSDF. It will take from now until around
15Z for the surface front to move completely southeast of the
forecast area. Winds will be light, around 5 kts from the west,
but will veer out of the west-northwest through the day at 5-10
kts.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RAY
LONG TERM...MARCUS
AVIATION...RAY
Source:
JKL issues Area Forecast Discussion (AFD) at Aug 18, 4:32 AM EDT---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
