Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 151517
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1117 AM EDT Wed Apr 15 2015
Issued at 1115 AM EDT Wed Apr 15 2015
Precip shield is diminishing in coverage as it tries to spread north
into Kentucky, with easterly low-level flow pulling quite a bit of
dry air into the region. However, cloud bases continue to gradually
lower. Isolated to scattered light showers will be possible across
more of central Kentucky by mid to late afternoon. Hi-res forecasts
have been updated, but the overall trends in the zones remain on
track. Better coverage tonight with low-end likely POPs, and a small
chance for embedded thunder as an upper-level wave moves through.
.SHORT TERM (Now through Thursday)...
Issued at 310 AM EDT Wed Apr 15 2015
In the near term, partly to mostly cloudy skies were noted across
the region this morning with temperatures generally in the lower to
middle 50s. We expect temperatures to drop to their minimums over
the next couple of hours with readings generally in the 50-55 degree
range. Some light rain showers will affect areas down around the
Lake Cumberland region with only trace to just a few hundredths of
an inch of precipitation.
Surface frontal boundary over middle Tennessee will continue to lift
northward today and pass through the commonwealth and the into
southern Indiana tonight. Under partly to mostly cloudy skies,
temperatures will likely warm into the upper 60s to around 70 in the
north with mainly lower 70s across the south. Scattered rain
showers with a rumble or two of thunder will mainly be confined to
south-central KY during the day. Rainfall amounts of less than a
quarter of an inch are expected.
Shower activity should become a bit more widespread and heavier
later tonight as the frontal boundary lifts northward and an upper
level disturbance passes through the region. Guidance suggests
likely PoPs and we`ll continue those in the upcoming forecasts. It
will be rather mild with lows in the upper 50s to the lower 60s.
Additional rain showers and isolated thunderstorms will be possible
during the day on Thursday. The best chances for precipitation on
Thursday will be across most areas early in the day and then become
more focused in the eastern sections during the afternoon hours.
With plentiful moisture around and some surface based instability,
some heavy rainfall will be possible with this activity. Total QPF
amounts through Thursday afternoon will generally range from one
half to one inch with locally higher amounts. This additional
rainfall, combined with already saturated grounds, may result in
additional hydrologic problems across portions of south-central KY.
Temperatures will remain mild with readings in the upper 60s to the
.LONG TERM (Thursday night through Tuesday)...
Issued at 307 AM EDT Wed Apr 15 2015
...Unsettled Weather Continuing Into Early Next Week...
The long term period will begin with an upper level closed low
centered over Colorado. Across the lower Ohio Valley weak ridging
will be in place. This will transition to southwesterly flow by the
weekend as the closed low becomes an open wave and shifts eastward.
Friday night will see some residual ongoing showers and possibly a
thunderstorm or two. Another weak wave will move through the upper
level flow on Friday. Despite a mid level warm layer, temperatures
look to warm enough on Friday to overcome the cap. Thus isolated to
scattered showers and thunderstorms will develop. These should
dissipate during the evening and Friday night could actually be dry.
Will hold on to slight chance pops as the models have had a hard
time maintaining continuity with any one solution. However, both the
0Z runs of the GFS and ECMWF show Friday night dry as of now.
For Saturday a weak low will develop over the Lower Mississippi River
Valley and move northeast into southern IL/IN by Sunday morning.
Overrunning showers look to spread into the area during the morning
hours. More widespread showers and a few thunderstorms will begin to
move into southern KY during the afternoon and evening hours with a
good chance for rain regionwide overnight as the low moves
northeast. For Saturday afternoon, coverage of precipitation looks
to be isolated to scattered at best across southern IN and north
Precipitation will continue on and off Sunday into Monday until a
cold front moves through Monday afternoon/evening. High pressure
will then build in bringing at least 24 hours of dry weather before
the next wave moves in.
All in all another one to perhaps two inches of rain can be expected
through the long term period. Though this should not cause
widespread problems, it may exacerbate or prolong any ongoing
flooding. Certainly any areas receiving repeated storms in a short
period may experience localized flood issues.
.AVIATION (12Z TAF Update)...
Updated at 630 AM EDT Wed Apr 15 2015
A frontal boundary located across middle TN will drift northward
across the region today. A band of light rain showers will
accompany the front as it lifts northward. This will mainly impact
the KBWG terminal this morning and may affect the KLEX terminal this
afternoon. MVFR cigs are likely at KBWG through the forecast period
with easterly surface winds. MVFR ceilings are likely to develop at
KLEX throughout the day and continuing into the evening/overnight
hours. Ceilings at KSDF look to remain VFR this morning, but an
eventual build down into the MVFR range looks likely after 15/17Z.
Rain showers will become more numerous later this afternoon and
evening at all the terminals as a mid-level wave approaches from the