Scientific Forecaster Discussion
fxus63 klmk 182315
Area forecast discussion
National Weather Service Louisville Kentucky
715 PM EDT Wed Sep 18 2019
..updated aviation discussion...
Short term...(this evening through thursday)
updated at 335 PM EDT Wed Sep 18 2019
The afternoon update for the short term is largely a persistence
forecast, with a couple of minor differences to note. The cu field
has blossomed nicely over the Bluegrass region this afternoon, with
areas further south and west remaining mainly sunny. Temperatures
are running in the 85-90 degree range.
Upper level ridging will continue to hold firm over the region. The
850 mb ridge axis will slowly slide eastward, allowing more of a
southerly component to the low level winds on Thursday. This should
help boost temperatures slightly, although low level thickness do
not change much (a small increase in the western cwa).
There continues to be a signal for scattered-broken stratus developing
Thursday morning, especially east of I-65. These clouds will tend to
slide north of the area and scatter out more during the afternoon.
Temperatures in the Bluegrass region should be a bit slower to rise
between 12-18z. Have afternoon highs in the mid/upper 80s east of I-
65 and upper 80s/low 90s near and west of I-65. Morning lows will
range from the upper 50s to mid 60s.
Long term...(thursday night through wednesday)
updated at 259 PM EDT Wed Sep 18 2019
Upper level ridging will remain in place through much of the
weekend, keeping the region hot and dry. Upper 80s to even some low
90s will be possible Fri-sun. The ridge will begin to break down as
a trough swings in from the west, dragging with it a weak surface
cold front. The front will generate some showers and thunderstorms
ahead of it Sunday into Monday, though the heaviest rains will
likely stay to our north and west where the better forcing/moisture
The forecast going beyond Monday becomes a bit uncertain as models
diverge on how the upper level fields evolve. In general, they show
a strong trough digging into the western Continental U.S. And eventually
transitioning into an upper level low, but vary on how far east the
low wobbles. There has been a westward trend with the placement of
the upper level low in the latest 12z guidance, with it not
affecting our region through the 7 day forecast. As a result, we're
not likely to see any beneficial rains through the midweek timeframe.
Aviation...(00z taf issuance)
updated at 715 PM EDT Wed Sep 18 2019
VFR conditions are expected through the taf period. Light winds are
expected overnight out of the east and southeast. Latest data shows
a scattered to broken deck of status developing around 19/06-7z
through daybreak in the 4-6 kft above ground level layer. We expect this deck to
mix out by mid-late morning with VFR conditions continuing through
the afternoon and evening hours.