JKL issues Area Forecast Discussion (AFD) at Mar 16, 8:30 PM EDT
736
FXUS63 KJKL 170030 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
830 PM EDT Sun Mar 16 2025
.KEY MESSAGES...
- After below normal temperatures for Monday, highs around 15
degrees above normal return for Tuesday and Wednesday.
- A mid-week storm system will bring a renewed chance of showers
and thunderstorms along with a sharp temperature drop.
&&
.UPDATE...
Issued at 830 PM EDT SUN MAR 16 2025
00Z sfc analysis shows deep low pressure exiting the area to the
east with chilly high pressure building in from the west on
northwest winds of 10 to 15 mph with occasional gusts up to 25
mph. Most of the showers from this system are clearing out of the
area, but a threat for more light showers will remain through the
night - transitioning to insignificant snow showers as they end
into Monday morning. Currently temperatures vary from the low 40s
northwest to the mid 50s in the far east. Meanwhile, dewpoints
range from the mid 30s west to the mid 40s east. Have updated the
forecast mainly to adjust the PoPs into the night per the current
radar and CAMs guidance. Did also add in the latest obs and
trends for the T/Td/Sky grids. These minor adjustments have been
sent to the NDFD and web servers along with a refreshing of the
zones, HWO, and SAFs.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 345 PM EDT SUN MAR 16 2025
A cluster of showers with isolated embedded thunder continues to
progress east northeast this afternoon, most widespread north of the
Hal Rogers Parkway/KY-80 corridor. This convection is along/ahead of
a secondary cold front. Over southeastern Kentucky, temperatures warmed
to around 70 in the valleys out ahead of the activity and dry air
was able to mix down quite impressively from aloft, causing dew
points to fall off into the 30s and 40s. This drying almost
certainly cut into the modeled instability and has kept
convection rather weak. Even so, we have received reports of
small hail and have observed gusty winds with the stronger cells.
The latest analysis shows the aforementioned front extending
from an ~988 mb surface low north of Georgian Bay southward
across Lake Erie, the mid-Ohio Valley, the Eastern Kentucky
Coalfields and Southern Appalachians. Behind that front, a sharp
500H trough axis extends from Lake Michigan southward down the
Mississippi Valley. To the west, an amplifying 500H ridge is found
over the Western CONUS with its axis aligned from Arizona
northward the Montana. The ridge is supporting an ~1019 surface
high centered over the Red River Valley of the South.
Any more substantial convection will exit northeast through late
afternoon as surface winds veer westerly and then northwesterly
behind the cold front. After another lull in precipitation, an
uptick in light rain shower/sprinkle activity can be expected
from mid-to-late evening onward as moist low-level flow becomes
more favorably aligned for upslope lifting in tandem with steep
lapse rates up to capping inversion at ~800 mb. Temperatures also
become marginally cold enough at the cloud top level for some ice
crystal growth after midnight. This should allow for flakes to
mix with the scattered showers/sprinkles, first over the higher
elevations 3,000+ feet near the Virginia border before snow levels
gradually sink to most valley floors by sunrise Monday. With warm
ground and overall light nature of the activity, no accumulation
is expected below 2,000 feet, and likely only a dusting to a few
tenths in most spots above that level. The precipitation will come
to an end Monday morning as a potent 500H vort lobe transits
eastward just behind the trough axis. In its wake, rapid height
rises commence aloft and surface ridging builds in from the
southwest as the high pressure center passes along the Gulf Coast.
Rapid low-level drying will also ensue as winds turn more
westerly, leading to rapid increase in sunshine late Monday
morning and early Monday afternoon. This will set the stage for
efficient radiative cooling on Monday night with moderate ridge-
valley temperature split formation anticipated overnight.
In sensible terms, look for scattered showers and isolated
thunderstorms late this afternoon (most widespread north of the Hal
Rogers Parkway/Kentucky 80 corridor) lifting northeastward late this
afternoon/early evening and diminishing. Winds will be blustery
out of the southwest to west with gusts to between 25 and 35 mph
through sunset. A low stratus deck builds in after those showers
depart with renewed light showers/sprinkles developing after
sunset as temperatures drop through the 50s and into the 40s.
Flakes could mix in at many locations after midnight as
temperatures dip into the 30s, but with no accumulation expected
outside of the highest elevations. Winds gradually subside
overnight. Any leftover flurries or sprinkles depart Monday
morning with skies forecast to clear across most of the area
between 10 AM and 2 PM EDT. Temperatures will remain notably
cooler on Monday with highs only in the lower 50s for most. Clear
skies persist Monday night with lows ranging from the upper 20s
in the colder sheltered valleys to the upper 30s on thermal belt
slopes/ridges.
.LONG TERM...(Tuesday through Sunday)
Issued at 340 PM EDT SUN MAR 16 2025
The extended period will be impacted by two different systems, with
some drying in between. In fact, the start of the period, Tuesday
morning, will be the first of the dry sections of the forecast -
lasting through the day Wednesday. During this time, upper level
ridging will be amplifying, as an upper level low begins to
strengthen downstream across the southern/central conus. By
Wednesday, this amplified ridge will continue to transition eastward
as the upper level low strengthens and nears the Mississippi River
Valley by the afternoon. This will allow a strong pull of WAA and
moisture into the region as the flow becomes SWrly throughout the
day. Given the strong pressure gradients both aloft and down towards
the surface, and good mixing ahead of this system, it will also be
likely that stronger winds will be allowed to mix down to the
surface, creating a breezy day Wednesday. Highs on Tuesday will top
out in the upper 60s to the low 70s, while Wednesday will warm
several more degrees into the low to mid 70s.
Meanwhile, at the surface, a strong low pressure system will develop
in accordance with the upper level low, quickly shifting northeast.
By Wednesday evening it will move from the Upper Mississippi Valley
toward the Upper Great Lakes. This will bring a fairly potent cold
front sweeping through the state Wednesday night. Models do also
show some wrap-around moisture that will linger with this system
through the day Thursday even after the front exits in the morning.
To show how drastic this frontal passage is, post frontal highs on
Thursday will only reach the upper 40s to around 50, some 20+
degrees cooler than the day before. In fact, as high pressure begins
to move back in Thursday night, with continuing NW flow, it's not
impossible that most locations will drop to just below freezing.
Thankfully it appears as though most of the moisture will be out of
the state by this point, but even for moisture that lingers in the
high terrain during the evening, it's possible that the rain could
change over to a rain/snow mix or all snow before finally ending.
The next dry period will arrive for Friday, as surface high pressure
passes across the state from west to east. The influx of sunshine
will help to boost temperatures a bit, with highs in the mid and
upper 50s. This warming trend will continue into the weekend, but at
a cost of the dry weather. Another upper level and surface low
pressure system will take form across the Southern Plains during the
day Friday, moving east towards the Ohio Valley for the weekend.
While the influx of SWrly flow will help boost the temps, it will
also advect moisture into the region, helping to spawn another round
of precipitation for during the day Saturday as the low passes
across the state. Models are in surprisingly good agreement about
this system, which is helping confidence in the forecast. As of now,
even with the WAA, temperatures are only expected to top out in the
upper 50s and low 60s on Saturday, which may hamper instability and
thunder potential - so just kept with rain showers for now. But this
may change as we get closer to onset.
The period will end with the system exiting by Saturday evening, and
another bout of high pressure moving in for Sunday. Ultimately, this
Saturday system won't result in any large airmass changes like the
mid-week system did, so despite it's exit, temperatures on Sunday
will remain steady-state, if not warming slightly with the sunshine.
Highs are currently forecast for the mid and upper 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 810 PM EDT SUN MAR 16 2025
On the backside of the departing system, drier air is inbound with
scant light pcpn left behind through the night. However, widespread
MVFR ceilings have developed and will persist for most areas
through at least 06Z along with the slim chance of rain/snow
showers but mainly sprinkles/flurries. Gradual improvement to VFR
is expected after sunrise on Monday. Winds will be from the
northwest initially at 10 to 15 kts with gusts to around 20 kts
diminishing through the night and staying northwest at around 5
kts on Monday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEERTSON
LONG TERM...JMW
AVIATION...GEERTSON/GREIF
Source: JKL issues Area Forecast Discussion (AFD) at Mar 16, 8:30 PM EDT (https://mesonet.agron.iastate.edu/p.php?pid=202503170030-KJKL-FXUS63-AFDJKL-AAA)
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