Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 191036
Area Forecast Discussion
National Weather Service Louisville KY
636 AM EDT THU MAY 19 2016
...Updated Aviation Discussion...
.SHORT TERM (Now through Friday Night)...
Issued at 250 AM EDT Thu May 19 2016
Well...currently with weak upper ridging and a surface high building
across the northern Show Me State. The mid deck cloud cover across
the area when the mid shift showed up for work has dissipated and
now the focus is on the low clouds and fog.
WebCams and regional obs combined with satellite imagery reveal
areas of fog increasing in coverage mainly east of I 75. There is
some patchy fog west of there, most notably at the BWG airfield.
The AVN Grids visibility model blend are pegging an area from BWG to
the Nrn Bluegrass for areas of IFR Clouds and lower vsbys. We will
be watching and make a late decision on SPS or possibly an advisory.
Have coordinated with JKL and will have another call before morning
forecast is issued.
Mid Morning - Thu Evening
High Pressure will bring the best day of the workweek with plenty of
sunshine and temperatures around 70, just a tad below climo. Great
day to get outside. With E-NE winds today, this cool wind will
shave 1-2 degrees off guidance for high temps.
Thu Night...Early Friday...
The upper low over the Land of Enchantment will push east thru the
Lone Star State, bringing substantial rain to Texas. Southerly flow
will deepen as the night progresses, feeding more Gulf moisture
northward into the Ohio Valley. Initially, most of this moisture is
mid-level, so it will take some time to saturate. Therefore, will
continue to slow the advance of the precip shield, just working
chance POPs into the southern half of Kentucky by daybreak on
The models, especially the GFS are much different than the NAM, with
the precip shield overspread the region, with categorical POPs over
the CWA by Friday afternoon. The GFS is a bit more suppressed with
the precip shield much farther south and east.
Looks like another soaking or rain (soundings do not support
thunder). Looks like 1-2 inches mainly south of the Wrn KY and
Bluegrass Parkways. Ground is fairly saturated from recent rain, so
localized flooding is quite likely, at least on a short-fuse basis.
For now will hold off on any type of Flood Watch but the day shift
will take another look at it today. FFG is way too high based on
amount of rain area has fallen across the area over the past week
and area webcams confirm lots of standing water and squishy land.
Likely POP Friday night east of I-65, with high chance farther west.
.LONG TERM (Saturday through Wednesday)...
Issued at 255 AM EDT Thu May 19 2016
Well...bit unsettled on Saturday, nice stretch of warmer weather Sun-
Tue and then next system will be over the area Tue Night-Thu.
First system will be east of the area by morning and then secondary
potent trough digging sharply across the OH Valley. Soundings
support steep mid level lapse rates. Looks like with some surface
heating and cooler air aloft, scattered afternoon and evening shra,
mainly east of I 65. Highs Saturday will begin a warming trend with
lower 70s west, and mid-upper 60s east where there are more clouds
and scattered showers.
Sunday through Tue...
Trough has moved out of the picture and heights are on the rise with
SW ridging. This will bring daytime sunshine and warming mercury
readings. Expect afternoon highs in the lower and mid 70s, possibly
a few upper 70s Sunday, upper 70s and lower 80s Monday. Lows should
be in the 50s.
Tuesday appears to be a transition day with mainly dry conditions
but at least a chance of a few storms late Tuesday in the far west.
Tuesday evening thru Thursday...
The ridge axis aloft will move east and break down somewhat
resulting in a west to southwest flow and/or flat ridge over the OH
Valley. This will result in a warm and increasingly unstable air
mass from the OH Valley westward across the central U.S. Within this
pattern, scattered or better coverage storms possibly MCSs are
expected each day and/or night over the central U.S. into the lower
Then scattered convection is expected Wednesday through Thursday.
However, this is predicated on where mesoscale or convective
boundaries set up, the effect of any MCSs, and where local
destabilization is greatest.
Afternoon highs each day will be warm and mainly in the lower and
mid 80s, along with more humidity. Dewpoints will be in low to mid
.AVIATION (12Z TAF Update)...
Issued at 635 AM EDT Thu May 19 2016
Fog not quite as low as it had been at KBWG, but more webcams from
that area are showing the fog, so upgraded it from BCFG to tempo
IFR/LIFR. This still should improved over the next hour or two. LEX
still is on the edge of getting worse visibilities, so have kept in
a couple hours of MVFR possible. Rest of the day should be VFR with
light northeast winds. Clouds will build down this evening as our
next system approaches, but rains should hold off until the end of
SDF`s 30-hour period.