Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 271041

Area Forecast Discussion
National Weather Service Louisville KY
641 AM EDT Tue Jun 27 2017

...Updated Aviation Discussion...

.Forecast Update...
Issued at 620 AM EDT Tue Jun 27 2017

Last few showers currently exiting the Bluegrass region as
advertised, and clearing is well underway. Forecast is well on track
aside from a few tweaks to sky cover, but this update will also
include a ZFP update to clean up early morning wording.


.Short Term (Now through Wednesday)...
Issued at 310 AM EDT Tue Jun 27 2017

Fairly sharp upper trof swinging through the Great Lakes overnight,
trailing a weakening boundary into the Ohio Valley. Low levels have
been dry, so we have been dependent on dynamics to generate any
measurable precip, which has been limited to a smattering of showers
and a couple of thunderstorms in the I-64 corridor. A healthier band
of rain over southern Missouri is getting pushed SE into the
Tennessee Valley, and appears to be a non-factor for central
Kentucky. Hi-res models suggest the precip over southern Indiana and
north-central Kentucky should exit around sunrise.

Surface high pressure and NW flow aloft will settle in for the
balance of today and tonight, with comfortable temps and humidity
more typical of mid-May. Have gone just a couple degrees above
guidance, staying more in line with persistence as recent runs have
been a little too cool.

By Wednesday the surface high should retreat into the Carolinas, and
temps should recover to near normal under increasing heights and
light southerly low-level flow. On the bright side, we will enjoy
one more day of respite from the summer humidity as the southerly
flow is too weak yet to open up the Gulf.

.Long Term (Wednesday Night through Monday)...
Issued at 305 AM EDT Tue Jun 27 2017

Transitional period through Thursday night as zonal upper flow
prevails and the Gulf opens up in S-SW low-level flow. Typical
summertime humidity will return in this pattern with dewpoints
recovering well into the 60s on Thursday. Will carry slight chance
POPs by Thursday afternoon in south-central Kentucky in the warm
advection pattern, and in southern Indiana with a slowly approaching
front, though there is less confidence in that boundary getting
close enough.

Pattern starts to amplify on Friday with an upper trof digging into
the Plains, and will ramp up precip chances given the continued
moisture advection and better forcing. Will carry likely POP Friday
night as a surface boundary swings through, but as is typical this
time of year, it will get hung up not too far to our south.

Precip chances will persist through the weekend and into early next
week as a series of disturbances will cause the stalled front to
wave back and forth into the Ohio Valley. Temps through the period
will be near or slightly below climo by day, and just above at night
as clouds and moisture will limit diurnal ranges.


.Aviation...(12Z TAF Issuance)
Issued at 640 AM EDT Tue June 27 2017

The last of the isolated light showers have pushed east of LEX,
so the full TAF period is expected to be dry and VFR. Dry air
streaming in from the northwest has scattered out the overnight
clouds. Surface high pressure building through the Ohio Valley
today will bring mainly sunny skies and light winds.

After light, northerly winds today, the wind will again go light and
variable tonight and eventually southerly on Wednesday.




Short Term.....RAS
Long Term......RAS
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