Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 132326
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
725 PM EDT THU JUN 13 2013
...Updated Aviation Discussion...
.SHORT TERM (Tonight through Friday night)...
Issued at 300 PM EDT Thu Jun 13 2013
Positively tilted upper trough axis has pushed into eastern Kentucky
as of 18Z, driving the surface cold front and associated convection
east into the Appalachians and south into Tennessee. Surface high
pressure over northwestern Ontario will build south into the Great
Lakes and Ohio Valley, and will dominate our weather through Friday
The modest cu buildups and gusty NW winds that we are seeing this
afternoon with the disturbance aloft will diminish around sunset.
Dewpoints will drop into the mid/upper 50s as the Canadian air mass
takes over tonight. A relatively dry column will keep skies mostly
clear, except for a few diurnally driven Cu during the heat of the
day on Friday. Expect temps through the period to run a few degrees
cooler than average for mid June. Model agreement is quite close
tonight and Friday, but we favored the cooler GFS MOS for Friday
night given the favorable radiational cooling conditions.
.LONG TERM (Saturday - Thursday)...
Issued at 245 PM EDT Thu Jun 13 2013
Ridging aloft and surface high pressure to the southeast will be in
place at the beginning of the long term. This will keep things dry
across the area on Saturday. With southerly winds and partly cloudy
skies temperatures will rise into the mid 80s areawide.
By Saturday night the upper level ridge will begin to flatten out as
the first of a couple of weak waves approaches the area. Showers and
thunderstorms may move into southern Indiana and possibly north
central Kentucky along the Ohio River Saturday night. Thereafter,
there will be chances for precipitation off and on through Tuesday.
The best chance for showers and thunderstorms still looks to be late
Sunday night through Monday ahead of a weak front moving through
Monday night. With PWAT values rising to 1.75+ inches on Monday, we
could see some heavy rain from the storms that do develop.
High pressure will build in once again Wednesday through Thursday
bringing dry weather back to the area. Temperatures through this time
period will generally be around the mid 80s. Sunday will be the
warmest with some upper 80s to around 90 across south central
Kentucky. Low temperatures will range from the mid 60s to lower 70s.
.AVIATION (00Z TAF Update)...
Issued at 703 PM EDT Thu Jun 13 2013
VFR conditions should prevail through the entirety of this TAF
period at all three terminals. While the brisk northwesterly winds
will subdue themselves after sunset this evening, a tight pressure
gradient over the Ohio Valley throughout the night will keep winds
from going completely calm. A few lower level clouds could stick
around through much of the night, allowing for possible brief drops
to MVFR if said clouds drop low enough. Fog does not appear to be a
concern for the pre-dawn hours at the terminals given the greater
than calm winds and a few clouds potentially sticking around,
hindering the process. An additional hindrance in fog formation is
the lack of rain (greater than a trace) that fell at SDF and BWG.
By tomorrow, high pressure settling in over the Great Lakes will
allow for winds to remain under 10 knots but will make a
northeasterly shift. Fair weather CU clouds will make an appearance
in the afternoon but should pose no impact to aviation interests.