Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 171030
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
630 AM EDT Fri Apr 17 2015
...Updated Aviation Discussion...
.SHORT TERM (Now through Saturday)...
Issued at 303 AM EDT Fri Apr 17 2015
In the near term, partly to mostly cloudy skies were noted across
the region. The cloud cover and light winds has so far kept fog
from developing, however, expect some light fog to eventually
develop over the next few hours. For now, will keep patchy fog
wording going in the forecast for early this morning. Temperatures
were generally in the upper 50s to the lower 60s. Not expecting
much fluctuation in temperatures over the next several hours.
For today, mid-level ridging will continue to build over the area
with some drier air in the mid level attempting to move in from the
north and west. Partly to mostly cloudy skies will be see this
morning, but we should see sunny skies break out after the lunchtime
hour or so. As the sun breaks out, we`ll see temperatures warm into
the lower-middle 70s. The warmest areas will likely be out west of
Mid-level ridging will continue to increase tonight resulting in
mostly clear skies across the area with overnight lows cooling into
the lower-middle 50s. Dry and tranquil conditions will continue
into the day on Saturday. Some mid-high level cloudiness will
increase from SW to NE throughout the day. A sustained southerly
wind flow combined with sunny skies will result in afternoon highs
warming into the mid and upper 70s. Some spots may top 80 degrees
down across southern KY.
.LONG TERM (Saturday Night through Thursday)...
Issued at 255 AM EDT Fri Apr 17 2015
...Unsettled Weather Continuing Into Early Next Week...
Saturday Night - Monday...
Saturday night we will see a transition in the upper level pattern
as the closed low to the west begins to shift eastward and becomes an
open wave. This will shift the ridging over the lower Ohio Valley to
the east. At the surface a low pressure system will develop to the
southwest and track northwest of the forecast area through Sunday.
Precipitation will be on the increase Saturday night, especially
after midnight as the low approaches and a LLJ increases. With some
elevated instability, there will be a chance of thunderstorms with
these showers. Rainfall will be moderate to potentially heavy at
times with plenty of available moisture with this system.
There could be a break in precipitation on Sunday afternoon before
the cold front associated with a stronger low pressure system over
the Great Lakes region swings through. Showers and storms will
continue Monday morning before tapering off Monday afternoon.
Rainfall amounts of one to possibly two inches will be possible
through this time frame. This rain may lead to additional rises on
area streams as well as ponding of water in low lying areas.
Monday Night - Tuesday Night...
A broad upper level trough will build in early next week across the
eastern half of the CONUS. At the surface high pressure will be in
control. This will lead to dry and somewhat cooler weather Monday
night through Tuesday night with highs in the 60s and lows in the
Wednesday - Thursday...
Forecast confidence is low for Wednesday through Thursday. The
models are having a difficult time handling how the upper level
trough moves out. This leads to differences in the handling of waves
moving through this flow. Will keep low pops in from Wednesday
through Thursday with temperatures similar to Tuesday.
.AVIATION (12Z TAF Update)...
Updated at 630 AM EDT Fri Apr 17 2015
Plenty of low-level moisture left over from previous rains combined
with light wind flow has resulted in low clouds at all the terminals
this morning. The cloudiness has kept fog to a minimum and current
thinking is that low cloudiness will be the primary aviation concern
this morning. Ceilings look to run around 1200-1500 ft AGL through
the morning hours. Still think there could be a short period where
ceilings could dip under 1000 FT AGL...most likely between
17/12-14Z. We should start to see mixing take place by mid morning
which will allow ceilings to lift through the MVFR range and
generally expect a return to VFR after 17/16Z. Surface winds will
generally light/variable throughout the morning and then become
light out of the SW this afternoon.