Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 161035
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
635 AM EDT Thu Apr 16 2015
...Updated Aviation Discussion...
Issued at 630 AM EDT Thu Apr 16 2015
Did a quick update to increase PoPs across south-central KY.
Mid-level wave lifting northeastward out of TN is forcing a line of
convection across western KY in the Pennyrile region. This activity
will push east-northeastward and affect areas along and south of the
WK parkway from E-town southward to the KY/TN border. Torrential
rainfall, gusty winds, intense cloud to ground lightning and small
hail will be possible with this activity as it moves eastward.
Elsewhere scattered convection is expected to increase in coverage
as well as the mid-level forcing pushes northeastward across the
area. Much of this activity will push east of I-65 by mid-morning.
.SHORT TERM (Now through Friday)...
Issued at 304 AM EDT Thu Apr 16 2015
Current early morning observations show partly to mostly cloudy
skies across the region this morning. Temperatures ranged from the
upper 50s in the north to the lower 60s in the south. Regional
radar indicated a few clusters of showers/thunderstorms across the
region. In the very near term, expect convection down across the
Nashville metro area to move northeastward and affect our southern
counties over the next few hours. Convection out in the
Hopkinsville to Owensboro corridor should continue to develop and
move north-northeastward, affecting our far NW counties over the
next few hours. Temperatures will generally remain in the upper 50s
to the lower 60s...with a slight rise in temps across the south as
the warm front continues to work northward.
As we head into the morning hours, latest high resolution models
suggest that convection out to the west (in the HOP-OWB corridor)
should continue to grow upscale. This seems reasonable as regional
radar already shows renewed convection developing out across NW TN.
The LMK WRF solutions suggest this activity will remain mostly
confined to regions west of I-65 through the morning hours. A
secondary mid-level disturbance down across AR will shift NE later
today providing yet more forcing for scattered shower/thunderstorm
activity. Forecast challenge is that coverage will be largely hard
to pin down. For now, plan on continuing high chance to likely PoPs
across the area. Rainfall amounts of 1/2 to 1 inch with locally
higher amounts will be possible with the convection...though many
areas will see lesser amounts than that. Temperatures will be hard
to pin down as well given the precipitation and expected cloud
cover. For now, have stuck close to the multi-model consensus which
suggest highs in the upper 60s to the lower 70s.
For tonight, some upper level ridging and drier air should work into
the region from the NW. This should result in drier conditions
across the region for tonight and into the day on Friday. Highest
chances for any lingering precipitation would be mainly across the
eastern sections for tonight/Friday. Lows tonight look to drop into
the upper 50s with highs on Friday warming up in the lower-middle
.LONG TERM (Friday Night through Wednesday)...
Issued at 252 AM EDT Thu Apr 16 2015
...Unsettled Weather Continuing Into Early Next Week...
A cutoff upper low will be centered over Colorado at the beginning
of the long term period with ridging over the lower Ohio Valley. The
cutoff low will slowly shift eastward and become an open wave
through the weekend while flow over the forecast area transitions to
Friday night still looks like it will remain dry with the ridging
overhead, aside from a lingering shower or two early in the evening.
For Saturday into Sunday a weak surface low will develop over the
mid Mississippi River Valley and move northeast across IL and
IN. Models continue to slow the arrival of precipitation on
Saturday. The latest runs have precipitation moving into
southwestern portions of the forecast area Saturday afternoon.
Across the north and east, including Louisville, it looks like
showers/storms could hold off until after midnight, though a stray
shower or storm before this time cannot be ruled out completely.
With much of the day dry, temperatures Saturday should warm into the
mid to upper 70s.
Better chances for rain will come late Saturday night into Sunday
morning as a warm front moves north across the region. Scattered
thunderstorms will be possible, though instability is not too high.
Any showers/storm that do develop could be fairly efficient rainfall
producers with precipitable water values in the 1.5 inch range.
Precipitation should taper off during the day Sunday with another
round of showers Sunday night to Monday as a cold front associated
with a stronger low pressure system over the Great Lakes region
moves through. One to two inches of additional rainfall still seems
to be reasonable through the long term, which could exacerbate
ongoing flooding issues.
High pressure should build in Tuesday and remain in control
Wednesday leading to a couple of days of dry weather. However, with
a large upper low across the eastern half of the CONUS, temperatures
will be a bit cooler with highs in the 60s and lows in the 40s.
.AVIATION (12Z TAF Update)...
Updated at 635 AM EDT Thu Apr 16 2015
Mid level wave over NW TN will push northeastward this morning and
bring a round of convection to much of the region. KBWG will be
most impacted by the convection this morning through about 16/14Z or
so. Expect prevailing MVFR cigs/vsbys at KBWG with some temporary
drops to IFR or lower as the line of convection pushes through.
Prevailing winds will be southeasterly, but chaotic gusts within the
thunderstorms may approach 20-25kts over the next hour or two.
Trailing stratiform rainfall should end in the KBWG region by 16/15Z.
Further north at KSDF and KLEX, low end VFR to high end MVFR cigs
are expected with showers and storms in the vicinity of the
terminals throughout the morning hours. Current thinking is that
best convective threat at KSDF will be through about 17Z and through
about 20Z over at KLEX. Southeast winds will prevail but the winds
are expected to shift to the south during the afternoon hours.