-- Discussion containing changed information from previous version are highlighted. --
383
FXUS63 KJKL 140520
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
120 AM EDT Fri Jun 14 2024

.KEY MESSAGES...

- A weak cold front brings a low chance (10-30%) for a shower or
  thunderstorm on Friday into Friday evening.

- Hot and uncomfortable weather builds through this weekend, with
  highs in low to mid 90s and heat indices peaking out around 100
  degrees in some locations each afternoon from Sunday through
  Wednesday.

- Disorganized afternoon showers and thunderstorms will be
  possible from Monday onward.

&&

.UPDATE...
Issued at 1142 PM EDT THU JUN 13 2024

Touched up the forecast a little bit to account for current trends
across the area. Also, increase overnight temperatures a degree
or two to account for the increasing cloud cover moving southeast.
The increasing clouds overnight could limit the amount of
radiational cooling across the area thus warmer temperatures.
Lastly, updated text and radio products to reflect the changes.
Grids have been saved and sent.

UPDATE Issued at 721 PM EDT THU JUN 13 2024

Forecast remains on track. Blended latest observations into grids
to fine tune the temperature and dew point diurnal curves.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 440 PM EDT THU JUN 13 2024

Another classic mid-June day has unfolded across eastern Kentucky
today with thermometer readings ranging from the mid 80s in the
Coalfield valleys to the upper 60s atop Big Black Mountain 20z.
Dew points are moderate, generally lower to middle 60s at most
locations. Also, the cumulus field from earlier in the afternoon
is quickly fading as diurnal heating wanes. The latest 500H
analysis shows northwest mid-level flow from the Canadian Prairies
into the Ohio Valley with an embedded shortwave trough moving
over the Upper Great Lakes. At the surface, high pressure ridging
extends across the Southeast US from a high over the Western
Atlantic. Meanwhile, a cold front trails from low pressure over
western Quebec to near/over Sault Ste Marie and then south near
Chicago and then west southwest into Nebraska.

The models are in good agreement through the short-term, showing the
high pressure departing to our east tonight as the upper level
shortwave troughing scoots toward the Northeast US and drags the
cold front into the Lower Ohio Valley. Convection developing
ahead of this boundary over southeast Iowa/northern
Missouri/northern Illinois is expected trek east southeast
overnight and largely dissipate due to lack of instability as it
moves up the Ohio Valley early Friday morning. There is a small
chance (up to 20%) that locations north of I-64 could see a brief
sprinkle or shower with the remnants of this convection during the
morning hours, though a period of thicker cloud cover is more
likely. Otherwise, expect an extensive cumulus field to develop
again on during the day on Friday, with a few of the updrafts
evolving into showers or thunderstorms (10 to 30% chance) by
afternoon ahead of a subtle mid-level disturbance. Later Friday
night, the actual cold front sags into and through eastern
Kentucky; but with the upper level forcing largely remaining well
north of the forecast area, expect only small shower chances
(10-20%) to linger into the nighttime hours. Temperatures will run
above normal through the period with forecast highs in the mid to
upper 80s on Friday and lows in the mid 50s, coldest northern
valleys, to the mid 60s, warmest southern ridges, on both tonight
and Friday night. Valley fog is expected in the typically prone
locations tonight. Anticipate minimal fog coverage on Friday
night, especially at locations that remain dry, since weak dry air
advection will be ongoing.

.LONG TERM...(Saturday through Thursday)
Issued at 358 PM EDT THU JUN 13 2024

Models are in general agreement for our area during the weekend.
Surface high pressure will be passing east southeast over the Great
Lakes at the start of the period, with its influence extending
southwestward over KY to supply us with a relatively dry air mass by
summertime standards on Saturday. Aloft, a trough over the
northeast CONUS will be departing eastward while ridging over the
lower-mid Mississippi Valley develops eastward. As the surface high
departs, our low level flow will turn toward the south southwest to
carry in warmer and more humid air to finish the weekend. As upper
level ridging builds in, rising geopotential heights and warming
aloft will also allow for additional warming/air mass modification
of the lower levels. Forecast soundings don`t look favorable for
precip through Sunday, lacking enough instability to overcome
warming temps aloft.

The GFS and ECMWF are now in agreement for the high center at the
heart of the upper level ridge to gradually shift from the vicinity
of the southern Appalachians on Monday to the lower Great Lakes and
upper Ohio Valley by Thursday. However, they still differ in its
strength, with the ECMWF being stronger. That being the case, the
ECMWF is better at suppressing deep convection, with most days being
dry. The GFS allows for convection to bubble up through the warm air
aloft with scattered thunderstorms each day. This also impacts
temperatures, with the extra clouds and precip in the GFS preventing
readings from being as hot as in the ECMWF. A model blend yields
mostly slight chance POPs each day, mainly during the afternoon and
early evening hours. A compromise of forecast soundings suggests
temperatures slightly below NBM levels, but still plenty hot.

&&

.AVIATION...
-- Changed Discussion --
(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 120 AM EDT FRI JUN 14 2024

VFR conditions are expected to prevail through the TAF period as
high pressure will largely exist across the region. However, a
passing disturbance could bring a shower or thunderstorm through
the Friday evening. Confidence in precipitation chances and
coverage are very low; therefore, opted to keep out of the TAF
but isolated showers and storms will be possible through
00Z/Saturday. Light and variable winds will persist through the
TAF period but gusty outflows could exist where thunderstorm
activity is present.
-- End Changed Discussion --

&&

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

$$

UPDATE...VORST
SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...VORST