NWS Area Weather Forecast Discussion
Louisville, KY

FXUS63 KLMK 250512

Area Forecast Discussion
National Weather Service Louisville KY
112 AM EDT Fri Sep 25 2020

...Updated Aviation Discussion...

.Forecast Update...
Issued at 835 PM EDT Thu Sep 24 2020

Forecast remains on track this evening. Only seeing some isolated to
scattered light echoes showing up on radar, some of which may not
even be reaching the ground. Most activity through the overnight
hours should remain south of the Ohio River.


.Short Term...(This evening through Friday)
Issued at 310 PM EDT Thu Sep 24 2020

Surface analysis this afternoon shows the remnants of Beta are
centered over the MS/AL border, with the bulk of the rainfall
associated with Beta occurring from northern AL up through eastern
TN. Over our area, current radar imagery shows just some scattered
light showers making their way across south-central KY.
Additionally, satellite imagery shows an expansive area of clouds
continuing to push in from the southwest, resulting in a noticeable
temperature gradient between our southern KY areas (lower 60s) and
our northern KY/southern IN areas (lower to mid 70s).

As we move into tonight, the remnants of Beta will continue to push
northeast into southeastern TN, resulting in the better moisture
then being confined to south- and east-central KY. Expect to find
best precipitation chances in these areas overnight as well as CAMs
suggest some scattered bands of precipitation may move up into the
area tonight and into tomorrow morning. Any precipitation is
expected to remain light however, with little in the way of QPF.
Overnight lows are forecast to be similar to this morning, with
temperatures generally remaining in the mid 50s to around 60.

A secondary shortwave trough is then progged to drop southeast into
the lower OH Valley Friday and help push the remnants of Beta
eastward into the Mid-Atlantic region. As this occurs, precipitation
chances are expected to gradually exit off to the east tomorrow
afternoon, and skies will begin to clear as drier air moves into the
region. High temperatures for tomorrow are forecast to be in the
lower 70s to near 80, with the cooler temperatures expected over
southeast portions of our forecast area as light rainfall and cloud
cover will linger here the longest.

.Long Term...(Friday night through Thursday)
Issued at 310 PM EDT Thu Sep 24 2020

Shortwave ridging builds across the area Friday night and Saturday.
With plenty of dry air in the mid and upper levels, this period is
expected to stay dry. Southwesterly low level flow and the ridging
aloft will support mild weather with lows in the upper 50s to lower
60s and highs around 80. There is a notable fog/low stratus signal
in the guidance for Saturday morning, so have added patchy to areas
of fog to the forecast. Low level moisture is present along with
very light winds in the lowest 5 kft AGL. At least patchy dense fog
looks possible Saturday morning.

An upper low will weaken/open as it moves northeast toward the area
on Sunday from the Lower MS Valley. This feature does not bring a
lot of moisture with it. Meanwhile, a large upper trough will dig
south over the northern Plains and Upper Midwest. The upper trough
digs southeast over the region Sunday night and Monday and persist
over the eastern CONUS throughout next week. Low chance PoPs arrive
late Sunday night/early Monday as moisture depth begins to increase
with mid-level PVA. The actual cold front sweeps through Monday-
Tuesday with the deepest moisture along/behind the boundary. Rain
showers will likely be accompanied by gusty winds, especially post-
frontal with colder air flooding the region. Fairly significant
timing differences remain between the operational GFS and ECMWF. The
weather is likely to dry out by midweek behind the front, but
exactly when that occurs is still somewhat uncertain.

Look for chilly weather mid to late next week with the first frost
of the season not out of the question. Thursday morning lows in the
40s are looking likely, but sheltered valleys/low spots could end up
dipping into the mid/upper 30s. Confidence is not high at this
point, but definitely something to watch.


.Aviation...(06Z TAF Issuance)
Issued at 110 AM EDT Fri Sep 25 2020

Expect lower clouds to build in at BWG over the next few hours.
Seeing a few showers down there now but also forming along the
SDF/LEX corridor. Have these very light rain showers in the forecast
for LEX/BWG through 12Z, but the main concern will be potential for
lower cigs. Went with LIFR at BWG and fuel-alternate MVFR at LEX
through daybreak. Cigs should slowly rise through the morning and
early afternoon as remnants of Beta continue pulling away to the
east of us. Next up will be fog potential again Saturday morning,
and hinted at that with the SDF TAF.




Short Term...JML
Long Term...EBW

Forecast Discussion from:
Script developed by: El Dorado Weather
Adapted by FrankfortWeather.us