Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 122332
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
732 PM EDT Wed Aug 12 2020

.Short Term...(This evening through Thursday)
Issued at 310 PM EDT Wed Aug 12 2020

Showers and storms continue to blossom across south-central KY this
afternoon, with rainfall totals of 1-2+ inches being observed within
the stronger storms. Showers and storms will continue to be possible
into this evening, with a moist and moderately unstable environment
in place along and south of the quasi-stationary frontal boundary
draped across the lower OH Valley. Current mesoanalysis displays
PWATs in the 1.6 to 2.0 inch range and CAPE values of 1500-2000 J/kg
west of I-65. Showers and storms are therefore expected to generally
remain along and west of I-65, with the better chances south of the
Western Kentucky Parkway. The main threats within stronger storms
are brief gusty winds, heavy rainfall, and frequent lightning.
Localized flooding issues may also arise as these efficient
rainers move slowly, with storm motions generally around 5-10 mph.

Convection is expected to diminish towards sunset this evening as
instability wanes. Will once again see the potential for some patchy
fog to develop overnight, especially in areas that receive rainfall
today, as we may see some breaks in the clouds. Low temperatures
tonight will remain in the upper 60s to lower 70s.

Tomorrow afternoon and evening, scattered showers and storms will be
possible across the area as the weak mid-level low/trough continues
to slowly move eastward across the western OH/TN Valleys. Similar to
today, expect to find plenty of moisture across the area, along with
moderate instability and weak shear. Main threats within any
stronger storms will be locally gusty winds and heavy rainfall. High
temperatures tomorrow will be in the mid to upper 80s.

.Long Term...(Thursday night through Wednesday)
Issued at 305 PM EDT Wed Aug 12 2020

Lingering surface boundary will continue to be draped across
Kentucky, closer to the KY/TN border for Friday into Saturday. A
weak disturbance aloft will move across the state and interact with
this boundary. We`ll continue to see a gradient of PoPs from north
to south across KY with the higher chances of rain along the KY/TN
state line and south of the parkways. Those that do see rain and
storms on Friday could see heavy localized rainfall which could
result in some flash flooding.

By Saturday and Sunday, the upper level wave will move off to the
east into VA/WV, shifting the higher PoPs to the east over the
Bluegrass for the afternoon. The rest along and west of I-65 will
see a scattered chance of showers and thunderstorms. Temperatures
will remain near or just slightly below seasonal normals with highs
in the mid/upper 80s. It will also remain humid Friday through the
weekend with dew points still around the upper 60s and low 70s.
Overnight lows will also remain warm in the mid to upper 60s with
urban areas only dropping into the low 70s.

Changes arrive for the start of next week as the upper air pattern
becomes amplified once again as a large ridge builds over the
western US and a deep trough across the eastern Great Lakes. At the
surface, we will see a cold front sweep through the region late
Sunday into Monday. Showers and storms are expected ahead of the
front Sunday afternoon and evening but quickly exiting to our east
by Monday morning.

Behind this front it turns much cooler and drier for the first half
of the week. Highs Monday will be the warmest in the mid 80s, but
temps are much cooler by Wednesday as they will range from the low
80s and some only in the upper 70s. Overnight lows will be fall-like
dropping into the low 60s and possibly into the 50s.

&&

.Aviation...(00Z TAF Issuance)
Issued at 725 PM EDT Wed Aug 12 2020

Earlier precip over south-central Kentucky is largely dissipated
now, leaving behind an expansive mid-level ceiling. This should
persist through the night, limiting any fog potential toward morning
in spite of nearly calm winds and a very moist boundary layer. If
any location were to see fog, it would most likely be BWG where
heavy rain fell this afternoon. However, not confident enough to
include it in the TAF at this time.

Thursday will be dominated by mid/high-level convective debris,
which will keep ceilings solidly VFR and limit some of the diurnal
cu formation. However, do expect storms to pop in the afternoon,
which we`ll cover with PROB30 groups for SDF, BWG, and HNB. Farther
east, we can`t rule out a storm in LEX, but probabilities are still
fairly low. Will advertise MVFR conditions with the PROB groups, but
know that brief VFR will be possible.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Short Term...JML
Long Term...BTN
Aviation...RAS



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