Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 300514
Area Forecast Discussion
National Weather Service Louisville KY
1214 AM EST MON NOV 30 2015
...Updated Aviation Discussion...
Issued at 945 PM EST Sun Nov 29 2015
Precip shield expanded north into the I-64 corridor over the last
few hrs, but we are starting to see a lull west of I-65 and north of
the Western Kentucky Parkway. Deeper moisture is being shunted
toward the south and east, where we are actually seeing pockets of
Expect the trend to continue with precip tapering from the north and
west as the plume continues to be suppressed. However, water vapor
shows an upper wave working its way into SE Missouri, triggering a
smattering of light precip ahead of it. While POPs will continue to
trend lower through the night, we can`t rule it out completely until
that disturbance shears out and/or pushes to our east. Also with the
trapped low-level moisture beneath the shallow frontal boundary,
drizzle remains a possibility, but will not include it outside of
measurable POPs given that there isn`t currently drizzle in any obs.
That being said, all these trends are handled well in the going
forecast, so no updates planned.
.SHORT TERM (Now through Sunday)...
Issued at 325 PM EST Sun Nov 29 2015
A deep moisture plume continues to stream from the southern Plains
up through our southern CWA and off the mid Atlantic Coast as it
rides over top of a weak SE CONUS ridge. The plume remains oriented
nearly parallel to the surface front, which has now cleared our
region. A secondary surge in moisture is arriving over the region,
and will help to produce steady rain through the evening and much of
the overnight across central and southern KY. Expect mainly dry
across southern IN, deeper into the drier air. The rain will likely
continue off and on through Monday across our south. Will see an
increase in showers everywhere Monday afternoon as a warm front
lifts north. Many spots south of I-64 can expect a half an inch to
an inch through Monday evening, with the highest totals expected
near the Lake Cumberland region and the lower totals more across
central KY. Lows will mostly be in the 40s, with some lower 50s
hanging on near Lake Cumberland. Highs on Monday should recover to
the low and mid 50s in many spots as the warm sector becomes
Warm front will be north of our area by Monday evening with potent
closed upper low moving into the upper Midwest by Tuesday morning.
Main forcing ahead of the associated PV anomaly should be to the NW
of our CWA, however lift and moisture should be present to warrant
mention of pops everywhere. Most rainfall should continue to be
across the SE where subtropical moisture plume lingers in
coincidence with mid level frontogenesis. An additional .25" to .75"
is expected Monday night with the highest totals SE and lowest
totals NW. Small diurnal trend for Monday night as we remain under
a rainy and advective setup.
.LONG TERM (Sunday night through Friday)...
Issued at 325 PM EST Sun Nov 29 2015
Tuesday - Tuesday Night...
The potent closed upper low will rotate into the western Great Lakes
Tuesday/Tuesday Night. Meanwhile, a surface cold front will slide
through our region along with a mid level dry slot. This will
gradually shut the rain off from West to East, with areas west of I-
65 dry be early Tuesday evening. Only a few showers are expected to
be lingering along the I-75 corridor by dawn on Wednesday. Highs in
the 50s on Tuesday will quickly fall in the afternoon and evening as
the cooler/drier air works in behind the front. Lows Tuesday night
are expected to fall into the mid 30s NW to the low 40s SE.
Overall rainfall totals Sunday night through Tuesday night should
range between 1 and 2.5 inches along and east of a BWG to LEX line,
where a few locally higher amounts are possible near Lake
Cumberland. Heavy rain at times, combined with already saturated
grounds could lead to some local flooding concerns Monday evening
into Tuesday. Our far SE CWA continues to be in a slight risk for
excessive rainfall during this time.
Wednesday - Wednesday Night...
Trough axis associated with the potent upper system finally rotates
through the Ohio River Valley by Wednesday evening, returning us to
a cooler/drier pattern. Will have to watch for a few lingering
showers far east on Wednesday morning, and perhaps enough low level
moisture across southern IN to squeeze out some light precipitation
just ahead of the trough axis. Otherwise, expect a return of our
long lost friend, the sun. Despite increased sunshine, temps will be
cooler with only 40s to around 50 for highs on Wednesday. Wednesday
night lows drop to around freezing.
Thursday Night - Sunday...
Upper air pattern gets complex to end the week, which results in
lower overall confidence during this period. still pretty confident
in overall dry conditions, however potential disturbances in the
flow will bring chances for increased cloud cover and tricky temp
forecasts. Most of the disturbances depicted by the models look to
be moisture starved so will not mention any precip chances.
After another day of highs mostly in the 40s and lows in the lower
30s on Thursday/Thursday night, temps become fairly normal (for this
time of year) through the weekend. That brings mostly low 50s for
highs and lows in the low to mid 30s.
.AVIATION (06Z TAF Update)...
Updated at 1215 AM EST Mon Nov 30 2015
Well...A very challenging sets of midnight TAFs with a plethora of
low clouds and drizzle. Main pcpn shield pushing out of the LEX
TAF(in through 07z) and overnight should be MVFR to IFR CIGS and
perhaps some patchy drizzle near BWG which is closer to the front.
Trapped low-level moisture will keep the IFR stratus in solidly, and
the drizzle may not actually shut off especially at BWG.
During the afternoon a surface low will develop over NW Missouri and
lift a warm front northward out of Tennessee. Expect rain to move
back into BWG with winds veering south as the warm sector punches
in. Still plenty of moisture, so will keep the ceiling IFR, but it
wouldn`t take much to bring it up to low-end MVFR by the end of the
TAF period. LEX will remain socked in IFR through the period, but
the warm sector influence could spread rain and improving ceilings
into SDF during the planning period.
Placed rain in all 3 sites Monday evening through the overnight