Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 010013
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
713 PM EST Sun Feb 28 2021

.Forecast Update...
Issued at 713 PM EST Sun Feb 28 2021

Widespread showers and embedded thunder will continue through the
evening ahead of an advancing cold front. Instability has waned and
should continue to decrease with weak low and mid level lapse rates.
Still, some stronger gusts have managed to make it to the surface in
the past hour in southwest Indiana and northwest Kentucky. Spoke
with SPC and decided to hang on to the Tornado Watch in the Bowling
Green area just a bit longer as the current convection moves
through, but the watch will probably be dropped in the next hour or
two.

&&

.Short Term...(This evening through Monday)
Issued at 320 PM EST Sun Feb 28 2021

It`s been an active weather day across the Ohio Valley as we have
seen training showers and thunderstorms drop significant rainfall
amounts in a short period of time, leading to flooding issues across
the Commonwealth. Kentucky Mesonet shows 24 hour rainfall amounts
are around 2-3 inches, with some locally higher amounts. Sfc
analysis places our CWA within the warm sector of the sfc low
(located over Green Bay), with the warm front situated to our north,
and the cold front trailing through IL and SE MO. Temps have surged
to the 60s and 70s, and even dewpoints in the low 60s.

The current environment remains supportive for heavy rain and
potentially strong storms for this afternoon. The core of the LLJ
is working off to our east this afternoon, where 850mb winds are
around 55kts. Over our CWA, still expect to see 35-45kt winds as the
tail end of the jet pushes east. At the sfc, historic PWATs for late
Feb are in the 1.5-1.6" range, and with model soundings showing a
tall and skinny CAPE profile and a deep warm cloud layer, efficient
rain-producing cells will continue this evening ahead of the
approaching cold front and within a deep SW flow conducive to
extreme moisture transport.

Glancing at KY Mesonet obs, current SW wind gusts are highest
(roughly 15-25 mph) from south central KY to the Bluegrass region.
This matches up well with where the greatest moisture transport and
nosing of highest PWATs are located. SPC Mesoanalysis reveals
MUCAPE of 500-1000 J/kg over our south-central KY counties, with
MUCAPE of 1500 J/kg just to the south in TN. Best chance to see any
potentially strong storms should be this afternoon, where the best
wind energy combined with instability will be. Still think the best
environment will be to our south, but can`t completely rule out a
rogue strong/severe storm. Best wind energy is in the lowest 1 km.
Effective Bulk Shear will be around 50 kts, along with SRH sfc-1km
near 150-300 m2/s2, there is a threat for brief spin ups. Given the
threat for our SW CWA, coordinated with SPC and neighboring WFOs to
include Warren/Allen/Logan/Simpson in Tornado Watch 13. CAPE should
mostly diminish by this evening, but should still see precip
continue tonight as the frontal boundary pushes through.

Cold front will pass through our southern IN counties around 00z,
and should be our entire CWA by 03-04z tonight, evident by NW flow
and CAA advection. PoPs will linger over our SE CWA through tomorrow
morning despite being post-frontal. We will dry out across the
entire region by noon or so tomorrow. Clouds hang around until
tomorrow afternoon, but temps are still expected to reach near 50F.

.Long Term...(Monday night through Sunday)
Issued at 245 PM EST Sun Feb 28 2021

The main weathermaker for the upcoming week is a progressive
southern stream wave that will make its way east from the Red River
Valley across the Tennessee Valley Tuesday night and into the
Carolinas on Wednesday. Model agreement isn`t great, but there
remains some potential for light precip across mainly southern
Kentucky. Temperatures are marginal for precip type, but keep in
mind the temp guidance seems more in line with a suppressed
solution, so will adjust to limit or perhaps eliminate snow
mentions, as it should be warm enough for mostly/entirely rain as
far north as we actually see precip. Low probability and low QPF
should yield little or no impact.

Once that disturbance departs the rest of the week looks quiet, with
fairly strong sfc high pressure to our N/NW for much of the time.
Plains ridging and east coast trofiness will maintain a NW to at
times zonal flow aloft, so temps should be near or slightly above
climo.  Slight cooling trend into the weekend as the deep upper low
backs up across the Maritimes into Quebec, and heights drop across
the Great Lakes and Ohio Valley.

&&

.Aviation...(00Z TAF Issuance)
Issued at 613 PM EST Sun Feb 28 2021

One last wave of widespread showers and embedded thunder, stretching
from northeast Texas to southwest Indiana at press time, will
translate across the TAF sites this evening and into the overnight
hours. Primarily MVFR visibilities and ceilings can be expected in
this activity. BWG stands the best shot at thunder this evening.

Low clouds will hang around into Monday morning before mostly clear
skies take over in the afternoon as high pressure builds in. Expect
northwest winds in the 10-15kt range behind tonight`s departing cold
front.


&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch until 7 AM EST /6 AM CST/ Monday for INZ083-084-
     089>092.

KY...Flood Watch until 7 AM EST /6 AM CST/ Monday for KYZ023>043-
     045>049-053>057-061>067-070>078-081-082.

&&

$$

Update...13
Short Term...CJP
Long Term...RAS
Aviation...13



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