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 180614 AAA

National Weather Service Jackson KY
214 AM EDT Sun Aug 18 2019

Issued at 214 AM EDT SUN AUG 18 2019

The forecast remains on track, with mostly clear skies and some
patchy valley fog forming once again. Early morning lows look on 
target, and have only freshened up the hourly temperatures to get 
these more in line with the current trends in observations. 
Updates have been sent. 

UPDATE Issued at 952 PM EDT SAT AUG 17 2019

Isolated shower and storm activity in west-central Kentucky has 
subsided. Some residual clouds from this linger, as well as some 
high clouds over far eastern Kentucky. Some river valley fog 
development is possible towards dawn, but other than this, a fair 
weather night is expected. Current temperatures across eastern 
Kentucky are in the lower to mid 70s. The forecast low 
temperatures, lower to mid 60s in the valleys and upper 60s on 
ridgetops, still seems reasonable. Therefore, no significant 
changes were made overall other than to ingest the latest 
observations and blend them into the overnight hours. A new ZFP 
was not needed. Updates have been sent to the web and to NDFD.

UPDATE Issued at 538 PM EDT SAT AUG 17 2019

The forecast largely remains on track. Current temperatures are 
in the upper 80s to around 90 degrees. Some showers have persisted
in central Kentucky, with a few lighting strikes observed as 
well. Updated PoPs to account for some of this activity moving 
into Rockcastle County. However, these showers and storms have 
been on the downward trend over the last hour. Therefore, this 
activity is likely to continue to decrease. Other than this, 
ingested the latest observations and blended into the evening 
hours. Updates have been sent to NDFD and to the web.


.SHORT TERM...(This evening through Sunday night)
Issued at 305 PM EDT SAT AUG 17 2019

18z sfc analysis shows high pressure holding on over eastern
Kentucky keeping the convection away - at least for now. A decent
cu field developed this afternoon for the area but that did little
to slow the temperature rise most places with readings currently
peaking in the mid to upper 80s along with a few 90 degree
reports. Dewpoints, meanwhile, are in the mid 60s most places - a
far cry better than they where the last time it was this warm.
Winds have been rather light today - mainly out of the southwest. 

The models are again in pretty good agreement aloft through the 
short term portion of the forecast. They all depict moderately
fast flow over the area tilting more southwesterly in the near
term as ridging builds slightly to the southeast. By the end of 
the period the flow will be more northwest and divergent coming 
from just north of the core Southern Plains ridge. A couple of 
shortwaves will pass by to the north of Kentucky during this time
as well, but likely staying far enough away to affect eastern 
Kentucky much. Given the agreement, have favored the model blend 
as represented by the NBM for this time frame. 

Sensible weather will feature a very small chance of a 
thunderstorm in the northwest parts of the area into the first 
part of the evening, but below mention in the weather grids for
now. Then look for clearing skies and quiet conditions tonight
along with some river valley fog developing. Similar conditions
take hold Sunday and Sunday night with temps a notch higher in the
afternoon and slightly milder at night - still with a chance for
valley fog along with some ridge to valley temperature

Again used the NBM as the starting point for all the short term 
grids with some adjustments for terrain differences both nights 
and a tempering of the highs on Sunday from guidance owing to 
some cloud cover. For PoPs, kept them just below 15% into this 
evening - slightly above the guidance - otherwise dry. 

.LONG TERM...(Monday through Saturday)
Issued at 240 PM EDT SAT AUG 17 2019

The extended period looks to be fairly active, as a trough of low 
pressure aloft and a slow moving frontal boundary move across the 
region. The trough is forecast to move slowly across the Great Lakes 
and Ohio Valley regions through out the period, while the surface 
front is more likely to move slowly across our area from late 
Wednesday through the end of the upcoming work week. We will see 
lower chances of rain to begin the period, with the highest chances 
of rain on tap while the front lingers about the area from late 
Wednesday through Thursday. Thunderstorms will be possible each day, 
mainly during the afternoon and early evening hours.

Temperatures will run well above normal Monday, Tuesday, and 
Wednesday, with highs on those days forecast to reach the upper 80s 
or perhaps even 90 for some locations. After that, the weather 
should cool off quite a bit, as the front stalls over the area and 
cooler air filters in from the north. Widespread cloud cover and 
persistent precipitation from mid week onward will also have an 
impact on daily temperatures. Nightly lows will range from the upper 
60s to slightly over 70 the first few nights, and will cool into the 
lower 60s to end the week. Winds should be generally light and out 
of the south or southwest to start things off, before shifting to 
the west and then north toward the end of the week after the front 
drifts south of the area.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)

VFR conditions will prevail through the period besides some MVFR
or worse fog seen in the deeper river valleys once again through
13z. Once again, lower crossover temperatures should yield mainly
VFR conditions at the TAF sites. Some diurnally driven cumulus at
4-6k feet agl will be seen during the day, with south to southwest
surface winds averaging less than 5 kts through the period.