JKL issues Area Forecast Discussion (AFD) at Nov 27, 4:56 PM EST647
FXUS63 KJKL 272156
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
456 PM EST Wed Nov 27 2024
.KEY MESSAGES...
- Rain is forecast to return this evening and linger into
Thanksgiving Day.
- Precipitation could briefly mix with or change to snow Thursday
night before ending with little or no accumulation anticipated.
- Another system is forecast to affect the area this weekend and
could bring light snow accumulation Saturday evening into Sunday.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 456 PM EST WED NOV 27 2024
Regional radar shows returns expanding from northwest-to-
southeast late this afternoon. Model soundings suggest that the
dry air in the low-levels (evident in the 12z RAOBs from ILN and
BNA) are gradually saturating. As of 2130z, no stations had
reported measurable rainfall; but the MRMS RALA returns would
suggest that the rain is probably reaching the surface at a few
locations northwest of the Hal Rogers Parkway/Kentucky 80
corridor. Temperatures are seasonably cool ranging from the upper
40s to mid 50s, except in the 40s above ~3,000 feet. The latest
surface analysis shows a near stationary frontal boundary
developing from near Boone, NC to roughly Whitesburg, KY to near
Irvine, KY then westward through Owensboro and beyond to an ~1003
mb surface low over the Red River Valley of the South. Looking
aloft, the low's parent system is a positively-tilted 500H
shortwave trough (extending from Quebec southwestward to the Texas
Panhandle) translating through broad troughing around an ~520dam
low over Quebec.
The 500H shortwave will trek over the Ohio Valley by 12z Thursday
and on into the Canadian Maritime Thursday night. Rain develops
this evening as this system sends the surface low racing
northeastward across eastern Kentucky after midnight tonight. A
cold front wrapping counterclockwise around the backside of the
low will sink through eastern Kentucky late tonight and depart
into the upper Tennessee Valley by dawn. There will be several
hours late tonight ahead of the cold front where weak elevated
instability (sufficient for isolated lightning) is expected to
work into the two tiers of counties adjacent to the Kentucky
border as well as southern portions of Perry and Letcher. Once
frontal boundary and associated steadier rains depart early
Thursday morning, northwesterly upslope flow and lingering low-
level moisture will likely keep fog and a chance for drizzle
around for several hours before lifting into a low stratus deck.
Cold air advection will send 850 mb temperatures dropping to ~-5C
by 0z Friday. A second vort lobe, passing through the mean trough
aloft, will approach the Ohio Valley Thursday night with a
resurgence of low-level cold air advection dropping 850mb
temperatures closer to -10C. Ahead of this disturbance, steepening
low-level lapse rates and cloud temperatures becoming cold enough
for ice will be supportive of a resurgence in precipitation,
mainly in the form of light upslope snow/snow showers (possibly
mixed with rain initially in valleys) on Thursday night. Warm
surface temperatures should preclude any notable impacts.
In sensible terms, rain will gradually increase in coverage this
evening and become widespread overnight. A rumble of thunder will be
possible roughly near and south of an imaginary line from Whitesburg
to Manchester to Somerset. As colder air begins to seep in from
the northwest, temperatures will settle back into the upper 30s
west of the Pottsville Escarpment and near/north of the I-64
corridor to the mid 40s in deeper valleys along the Virginia
border. Any lingering steady rain tapers quickly after sunrise on
Thursday, leaving behind low clouds, drizzle, and a raw
northwesterly breeze. The drizzle should dry up by early
afternoon, but overcast skies are likely to prevail through the
day. Storm total rainfall between 0.25 and 0.50 inch can be
expected at most locations. Thursday's temperatures will hold
nearly steady in the north and fall slightly in the southeast,
leading to widespread highs in the 40s. Light snow/snow showers,
initially mixed with a little rain in some valleys, are expected
to redevelop Thursday night as temperatures fall back into the mid
20s to lower 30s, except into the lower 20s at the highest
elevations near the Virginia/Kentucky border. For most places, a
few flakes in the air to perhaps a light dusting of accumulation
on elevated/grassy surfaces is about all that can be expected.
However, up to around 0.5 inch of accumulation cannot be ruled out
above 3,000 feet where the light snow should be more persistent
and the air temperatures colder.
.LONG TERM...(Friday through Wednesday)
Issued at 203 PM EST WED NOV 27 2024
The forecast period begins with our area on the backside of a
departing surface cold front. Behind the cold front, northwesterly
flow and CAA will be filtering into the area bringing cold and
blustery conditions for Black Friday. PVA around a closed upper-
level circulation, that's forecast to build into and park itself
over southern Canada, will bring isolated PoP chances for portions
of the CWA before tapering off late morning. Highs for Friday are
forecast to climb into upper-30s to low-40s but with breezy winds
in the afternoon, the apparent temperatures will be in the
upper-20s to lower-30s. While the upper levels of the atmosphere
are chaotic, surface high pressure will build into the region and
keep the forecast area dry through from Friday afternoon through
early Saturday afternoon.
A quick moving Alberta Clipper is forecast to dive southeast into
the forecast area later Saturday afternoon. With cold air in
place, PoP associated with this clipper will be mostly in the form
of snow. The quick-moving nature of a clipper will be on full
display with this system is it moves into the area late Saturday
afternoon and will be out of the CWA by Sunday afternoon. With
this clipper, a few individual ensemble members continue to
highlight the possibility of light accumulations. Any accumulation
should largely be confined to elevated objects and grassy
surfaces. Weak surface high pressure builds back into the area
for rest of Sunday into Monday with northwesterly flow advecting
the coldest air of the season into the region. Overnight lows for
Sunday into Monday are forecast to be in the mid to upper teens.
Model confidence going into early next week diminishes a little
as the ECMWF wants to bring another quick-moving clipper through
the forecast area late Monday into Tuesday whereas the GFS builds
surface high pressure over this same time frame. Models come back
into agreement again for another potential system for Tuesday
night into Wednesday. The path of this system from the southwest
could keep the forecast area in the coldest portion of the
precipitation shield and lead to another round of light snow
accumulations to end the forecast period.
In summary, the active forecast period will feature multiple
disturbances bringing some snow chances to the forecast area.
Also, the coldest temperatures of the season are forecast to build
into the region as day time highs struggle to climb out of the
30s. Lows will follow the same trend as overnight temperatures
are forecast to bottom out in the mid to upper teens with a few
lower-20s sneaking in at times.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 115 PM EST WED NOV 27 2024
VFR conditions are expected through at least 3z as clouds thicken
and lower. While spotty light rain, sprinkles and/or virga are
possible late this afternoon and evening, a steadier rain spreads
from northwest to southeast between 1 and 7z as a low pressure
system tracks into Kentucky. Further visibility and ceiling
reductions to MVFR/IFR are expected as the rain moistens the low-
levels and ceilings could approach airport minimums after 6z. The
rain should gradually taper from the northwest after sunrise
Thursday but poor flying conditions are likely to linger. Winds
will be southerly to variable at less than 10kts this afternoon
then becoming variable to northwesterly tonight and Thursday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...VORST
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at Nov 27, 4:56 PM EST---------------
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!
