Area Forecast Discussion
Issued by NWS Jackson, KY
FXUS63 KJKL 211756
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1256 PM EST Sat Jan 21 2017
Issued at 1255 PM EST SAT JAN 21 2017
Mid/high level clouds have been rather thick today, and have
slowed the temperature rise. This is especially the case in
valleys which chilled very effectively before dawn, before the
clouds arrived. Thick that most valleys will eventually catch up,
but the hourly trends needed to be adjusted to account for it.
Some very light rain has been reported by the KLOZ ASOS, and have
left 20% pops in the forecast in the southeast part of the area
this afternoon. Radar is also showing returns near the northwest
edge of the forecast area. Have added a 20% pop there for this
afternoon, but it`s uncertain if precip can make it through the
drier air beneath where it`s originating.
UPDATE Issued at 940 AM EST SAT JAN 21 2017
The update only blends mid morning obs into the forecast grids,
with no substantive changes.
UPDATE Issued at 643 AM EST SAT JAN 21 2017
Forecast still on track early this morning. Middle and high level
cloud cover will continue to stream over the area today as a
weather system approaches from the southwest. Ingested the latest
obs into the hourly grids to establish new trends. No major update
to the forecast is required at this time.
.SHORT TERM...(Today through Sunday)
Issued at 302 AM EST SAT JAN 21 2017
The models are suggesting that most of eastern Kentucky should
experience dry weather today, due to progressively southeasterly
flow and the downslope warming and drying that will occur across
the area as a result. It appears that the best moisture associated
with an approaching weather system will remain just off to the
south of our area today. This, combined with the downslope
warming and therefore drying mentioned above, should be enough to
keep precipitation at bay for all but our southernmost and
easternmost counties today. After a brief lull, widespread
rainfall is expected to move in from the south and southwest this
evening through the end of the day on Sunday. An area of low
pressure is forecast to move out of the southern Mississippi
valley and across the Ohio and Tennessee valleys tonight and
tomorrow. As this system moves east, it is forecast to strengthen,
and therefore slow down, as it moves across our area. The slow
movement of this system, combined with a steady flow of warm moist
air off the Gulf of Mexico, will lead to widespread rain showers
across eastern Kentucky to finish out the weekend. We may even see
a few thunderstorms tonight and tomorrow due to the strength of
the passing low and the presence of weak elevated instability.
Rain could be locally heavy at times.
Temperatures will remain well above normal this weekend, with
highs expected to top out in the mid to upper 60s today, and the
lower 60s on Sunday. Overnight lows should be in the lower 50s.
Mostly cloudy to cloudy skies will be on tap as well. Winds should
generally be out of the south or southeast at around 5 mph during
.LONG TERM...(Sunday night through Friday)
Issued at 413 AM EST SAT JAN 21 2017
An amplified pattern looks to remain in place across the CONUS
through the extended portion of the forecast. Initially, it will
be more blocky, as two deep upper level lows start out affecting
the eastern and west third of the U.S. Eventually, by the end of
the work week, these two systems will merge across southeast
Canada, allowing for broader troughing east of the Rockies, and a
return of more winter-like air.
The aforementioned upper level low in the east will gradually
swing from the southern Appalachians to New England by Tuesday.
Anomalously low surface pressure will follow suit, bringing
widespread showers across eastern Kentucky Sunday night into
Monday, before gradually diminishing by late Monday night into
Tuesday. Locally heavy rainfall will be possible, and the 00z runs
have ramped up the QPF...with anywhere from 1 to nearly 3 inches
of rainfall. Given the overall wet conditions in the past few
weeks across our region, most of the rainfall will runoff, with
minor flooding of creeks, streams, and eventually some larger
rivers a possibility. As such, have issued a Hydrologic Outlook
highlighting this potential.
Colder air will be pulled in by Tuesday morning, possibly allowing
for a little snow for the highest elevations in far southeast
Kentucky; however, given the warm ground temperatures and low snow
ratios, impacts will be minimal. Another surface low pressure
system will then track from the southern Plains to the eastern
Great Lakes region by Thursday morning, bringing another chance
of precipitation to eastern Kentucky Wednesday into Thursday.
Detail differences between the ECMWF and GFS are more pronounced by
this time, so stuck fairly close to a blend of the solutions.
Wednesday highs in the 60s will be a thing of the past by Friday,
as highs return back to the 30s. Some snow chances will return
towards the end of the week; however, moisture will be in
question, so did not go as bold as some of the blended guidance
was producing, and allowed for mainly slight chances.
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1255 PM EST SAT JAN 21 2017
VFR conditions are expected to prevail until late tonight, with
mainly mid/high level ceilings. A bit of light rain will affect
far southeast KY this afternoon, and possibly near/north of I-64,
but it should not offer up much in the way of restrictions. The
next round of more significant weather will not arrive until late
tonight. Showers and lower ceilings are expected to spread into
the JKL forecast area from the southwest before dawn on Sunday.
The worst conditions should be in the far west and southwest, with
at least MVFR if not IFR occurring on Sunday morning. Further
east, drying downslope flow will work to erode the lowest clouds,
and the eastern tip of the state should remain VFR. However, there
still could be some showers even in the far east before the end
of the period. A few thunderstorms can`t be ruled out in the
southern part of the area by mid day on Sunday.