631
FXUS63 KJKL 091929
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
329 PM EDT Thu May 9 2024

.KEY MESSAGES...

- Some showers and perhaps a storm or two are possible at times
  from this afternoon through early next week.

- A cold front passing tonight will usher in cooler temperatures
  from Friday through the weekend, with warming then returning.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 329 PM EDT THU MAY 9 2024

Large scale trough over the Great Lakes continues to have smaller
shortwaves travelling west to east across the Upper Ohio Valley. One
such feature is interacting with a diffuse low pressure center,
stretching roughly from SW OH to central VA, to generate some really
light rain showers embedded within a larger scale stratocumulus
field. So far not seeing much get taller on satellite imagery. The
window for measurable rain chances still is fairly narrow in space
and time. Still looking at far eastern KY and NE KY with the best
chance to measure.

That shortwave passes east, along with the surface low later this
evening. Another quick-moving disturbance will pass through OH
toward daybreak Friday. Expect some low clouds to swipe across our
area, especially along and just ahead of the cold front that will
pull our temperatures to below normal. Once again, cannot rule out
an isolated light rain shower to form  By Friday afternoon, a bigger
shortwave will force that cold front through the area. Still not
sold on any high rain chances for the region, but if it does fall,
not looking at high rainfall totals. Moisture may be tall  Peak
totals likely will stay under a quarter inch for most locations.

Friday night, brief shortwave ridging will filter in behind those
systems, allowing for one 12 hour period with very low pops.
Clearing skies and relatively light winds will allow temperatures to
fall into the 40s, likely with some valley fog by daybreak.

.LONG TERM...(Friday night through Wednesday)
Issued at 542 AM EDT THU MAY 9 2024

Our weather at the beginning of the long term period will be under
the influence of a longwave trough over the northeast CONUS and
shortwave troughs rotating around it. A cool air mass will persist
over our area in this regime. One shortwave trough will be
departing to our east on Friday night, and in its wake, transient
surface ridging will build in from the west. This results in skies
becoming mostly clear. Another shortwave trough moves southeast
over the Ohio Valley on Saturday, and with it we can look for a
potential for showers to return. The greatest probability will be
over the northeast portion of the area, closest to the shortwave.
Have included a slight chance of thunder over our northeast
counties based on NAM forecast soundings, but it looks very
marginal. This wave departs to the east by evening and precip and
most clouds dry up again.

At this point, the heart of the longwave trough also shifts east,
and ridging aloft approaches from the west on Sunday and passes
over on Monday. This brings dry weather and mostly clear skies
from Sunday night through at least Monday morning. At the surface,
high pressure passes eastward south of our area on Sunday and
departs eastward on Monday. Increased sunshine will allow for
temperatures to return to near normal on Sunday, with a further
climb on Monday as warm air advection becomes more pronounced.

Our next weather system will begin to affect the area already by
late Monday. A nearly stationary closed upper level low centered
over UT today will eventually open up and get absorbed back into
the flow. Timing of these features can be tricky, especially at
longer time ranges. At present, a model blend suggests it will
approach us from the west late Monday and arrive on Tuesday. It
is expected to support a weak surface low which will help to pull
moisture northward on the back side of the departing high. The
GFS is faster than the ECMWF with the system and shows some light
precip reaching our southwestern counties by Monday evening. Both
models have precip here on Tuesday. Based on this, have used only
a slight chance late Monday, increasing to likely by Tuesday
evening. It looks like there will be little change in air mass
behind the system, and models try to generate more convection with
heating on Wednesday. Have used a chance POP on Wednesday, with
the best upper level support departing to the east.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 117 PM EDT THU MAY 9 2024

High clouds clearing off to the east, but low clouds moving in from
the west to fill the gap. KSJS/KSYM may briefly dip below the
MVFR/VFR threshold with these clouds. Isolated to widely scattered
showers/storms may impact those sites. Winds will pick up from the
west at all sites with gusts of 15-20 kts. Should be a break in the
cloud cover/rain chances/wind gusts this evening before low clouds
develop again toward daybreak Friday.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...SHARP
LONG TERM...HAL
AVIATION...SHARP