Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Jackson, KY (JKL)

FXUS63 KJKL 212057

National Weather Service Jackson KY
457 PM EDT Sat Sep 21 2019

.SHORT TERM...(This evening through Sunday night)
Issued at 300 PM EDT SAT SEP 21 2019

The weather during the bulk of the short term period will be
dominated by a large area of high pressure. This ridge will be
situated over the region through late Sunday night before it
finally begins to break down as a trough of low pressure
approaches from the west. Cloud cover will be sparse through late
Sunday, before finally increasing in coverage late Sunday night
ahead of the trough. The latest model data is suggesting that
precip onset with the system will be several slower than before,
and the forecast precipitation probabilities were adjusted
accordingly. We should not see the first drops of rain in the area
until around dawn on Monday morning based on current data and
thinking. Temperatures will continue to run well above normal the
next two nights and during the day on Sunday. We could see highs
in the upper 80s across eastern Kentucky yet again on Sunday. Lows
the next two nights should be mainly in the low to mid 60s. 

.LONG TERM...(Monday through Saturday)
Issued at 440 PM EDT SAT SEP 21 2019

The period is expected to begin with a ridge centered along the 
Gulf Coast, a ridge extending from the Central Rockies into the
Northern Plains, a trough moving through the Great Lakes to mid MS
Valley region, and a trough moving through the western Conus. At
the surface, an area of low pressure is expected to be tracking 
through the St Lawrence Valley to begin the period with a cold
front trailing southwest to the OH Valley and then into the
Southern Plains. The shortwave trough will cross the area on
Monday to Monday with shortwave ridging building in quickly on
Monday night as the axis of the trough moves further east. Surface
high pressure will build across the area at that point. This will
usher in a drier and colder airmass.

Tuesday to Wednesday, the ridge axis will move east across the 
area with the sfc high also shifting east. The next trough that will
have digged into the Northern Plains will rotate east into the 
Great Lakes at midweek. This trough axis will move east on
Wednesday night into Thursday with the southern end of the trough
moving through the OH Valley. The axis of this trough will move
east Thursday into Thursday night with the pattern amplifying to
end the period with strong ridging building over the southeast
Conus and into the OH Valley and Appalachians and a trough 
entering the western Conus. 

The system on Monday will be a bit moisture lacking and move
across the area quickly. The GFS and ECMWF guidance have minimal
qpf across the area with the 12Z NAM completely dry. Scattered
shower and perhaps a thunderstorm should accompany the front and
precede the shortwave late Sunday night into the day on Monday.
Chances for thunder, that area very limited due to limited
instability, will peak from midday on Monday to Monday afternoon.
The threat for shower should end quickly on Monday evening as the
ridging and sfc high build in. 

As the shortwave trough passes by generally north of the area Wed
to Thu, another shearing front with even less moisture will
approach the area. Some of the GFS guidance generates
precipitationacross the area, but the preferred ECMWF has the 
front becoming diffuse more quickly nearer to the OH River by Thu 

Overall, other than the precipitation chances mainly on Monday,
chances for any additional precipitation area meager. Temperatures
will be closer to normal as the front moves through and behind 
the front on Tuesday, but they will still be above normal.
Temperatures well into the 80s should follow for Wed to Thu and
the strong ridge will lead to many areas threatening the 90 
degree mark by Sat and temperatures could approach or possibly 
exceed record highs. Saturday at this point looks to be the 
warmest day with 500 mb heights likely exceeding 591 mb. If the 
currently forecast highs do in fact occur on Saturday, it would be
the latest 90 plus degree readings on record for JKL and 4th 
latest for LOZ. 


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)

VFR conditions to prevail at all five TAF sites through the end of
the forecast period. A few low level clouds will form and persist
across the area this afternoon and this evening before dissipating
overnight. Localized valley fog will likely form again late
tonight into early Sunday morning, but this should not affect any
of the TAF sites.