Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 292250
Area Forecast Discussion
National Weather Service Louisville KY
650 PM EDT FRI JUL 29 2016
...Updated Aviation Discussion...
Issued at 612 PM EDT Fri Jul 29 2016
Did a quick update to increase pops across our NW CWA where moisture
convergence has increased along a boundary that is roughly along the
Ohio River. Meanwhile, a broken line segment with a bit of a cold
pool push is moving into our western CWA where some 40 mph gusts are
possible. Latest mesoanalysis shows a moderately unstable airmass
coincident with around 30 knots of effective bulk shear. Reasonable
to think that a brief severe storm is possible, but more concerned
about training storms along the boundary, as rainfall rates have
been periodically impressive. Overall, best storm coverage is an an
area that can handle a bit more precipitation, but will be
monitoring the potential for localized Flash Flooding and marginal
severe potential over the next several hours. Do expect storms to
diminish in coverage and intensity later this evening. At this
point, don`t expect a widespread Flash Flood threat so don`t
anticipate any headlines for now.
.SHORT TERM (Now through Saturday Night)...
Issued at 335 PM EDT Fri Jul 29 2016
Isolated/scattered convection is ongoing in central Kentucky, with
the greatest coverage and intensity along the Tennessee border.
Looking upstream, an upper impulse swinging through the Wabash
Valley has generated a broken line or T-storms that will head toward
southern Indiana and north central Kentucky by early evening.
Therefore we will see the focus shift from our southern zones to our
northwest zones in the next couple hours, but given recent rains,
and the humid air mass, any storms could produce localized flooding
through this evening. Also seeing just enough instability to combine
with the forcing aloft, so a few strong storms could produce gusty
winds, especially along and north of Interstate 64.
Look for POPs to diminish this evening given the loss of heating,
and mid-level drying behind the upper disturbance. However with this
much low-level moisture, cannot rule out a slight chance, so will
hang on to that POP through the overnight.
Rinse and repeat for Saturday as we remain under a broad upper trof,
and the air mass remains juicy. Expect convective coverage to be
slightly less given the slight decrease in deep moisture, as well as
the lack of dynamics to focus convection. Still look for scattered T-
storms, with the main threat still localized heavy rainfall and
flooding. Given the low convective temps in this air mass, expect
max temps to run near or just below climo, but with limited cooling
.LONG TERM (Sunday through Friday)...
Issued at 335 PM EDT FRI JUL 29 2016
Broad upper trofiness overhead on Sunday will start to shift
eastward on Monday, but will not fully give way to the upper ridge
centered over the Southern Plains. This will leave the NW flow door
open for episodic MCS activity through at least the middle of the
week. Therefore will maintain at least a 20-30 POP for much of the
week, and while it will continue to show a diurnal focus, confidence
in the timing of POPs is still on the low side. By Wed-Thu expect
enough influence from the ridging to push temps back into the lower
90s in quite a few places. Air mass will remain quite humid, keeping
mins solidly above normal throughout.
.AVIATION (00Z TAF Update)...
Issued at 650 PM EDT Fri Jul 29 2016
Scattered convection continues to develop/move along a surface
boundary and ahead of a broad upper disturbance. Current radar
trends put the TAF sites in favorable scenarios for no t-storms in
the very short term, although cannot rule out a stray storm until
shortly after sunset when instability is lost. Storms should pass
close enough to SDF/BWG to warrant VCTS until 1-3Zish, but otherwise
expect VFR to prevail for much of the evening.
Once convection dies off, focus will shift to potential for lower
ceilings and vis at BWG/LEX. Upper clouds from convective complex
will complicate potential for fog at BWG, but sill think MVFR vis is
possible toward dawn when upper clouds thin and light surface winds
prevail. Think LEX could see a combo of vis/cig problems through the
overnight as well. Would expect vis reductions first, then a
transition to lower stratus toward dawn.
Scattered convection is on the table again tomorrow, but with
confidence in timing/coverage low, will hold off on any mention for