Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 060723

Area Forecast Discussion
National Weather Service Louisville KY
323 AM EDT TUE OCT 6 2015

.SHORT TERM (Now through Wednesday)...
Issued at 305 AM EDT Tue Oct 6 2015

Shortwave upper ridge is being flattened by a weak and moisture-
starved wave swinging through the region. Only sensible wx impact
has been cirrus, which is holding our overnight temps up in the 60s
in most locations.

Overall pattern through Wednesday is marked by ridging at the
surface and aloft, which will keep us warm and dry. Temps may be
limited by high-level clouds today, but given how we have
overachieved on most quiet days recently, will not cut more than a
degree or two off persistence. Radiational cooling will be limited
tonight by surface dewpoints solidly in the 50s, and a very light NE
breeze. Will not stray far from guidance mins.

.LONG TERM (Wednesday Night through Monday)...
Issued at 316 AM EDT Tue Oct 6 2015

Wednesday Night - Thursday Night...

Expansive surface high pressure will translate across much of the
eastern CONUS through mid week, with very low amplitude NW flow
aloft in control. This setup will lead to dry conditions with partly
to mostly clear skies until Thursday night. Chances for showers and
perhaps a rumble of thunder could arrive across southern IN and
north central KY by dawn on Friday, depending on eventual timing of
upper system and associated cold frontal boundary. However, there
remains some slight disagreement in timing with the 06/00z data.
Continued with a compromise between the faster GFS/GFS ensemble
mean/NAM and the slightly slower ECMWF.

A light southerly flow will return to the region on Thursday along
with a slight bump in thicknesses which should allow for a degree or
two warmer than Wednesday. This will put highs in the upper 70s East
to low 80s West. Expect lows 54-59 on Wednesday night, however
expect milder conditions Thursday night with an increase in cloud
cover, low level moisture and southerly flow ahead of the
approaching cold front.

Friday - Friday Night...

Despite the timing differences in models, Friday looks to hold the
greatest rain potential of the period. This will occur as deeper
moisture pools ahead of a a shortwave trough embedded in the NW flow
aloft and associated cold front. Will continue with pops high enough
to support Sct-Num coverage on Friday, with a small chance for some
thunderstorms. Deep layer shear would be marginally strong enough to
support a few organized storms if timing allows for a narrow axis of
instability. Overall, shear looks marginal and instability looks
meager at best so won`t make any changes to forecast from a thunder

Temps will be dependent on exact timing of fropa, so will look to
top out in the 70s. Lows Friday night will be cooler around 50.

Saturday - Monday...

Canadian surface high pressure and dry NW flow aloft will dominate
through the remainder of the weekend and into the first part of next
week, returning the forecast to dry. Overall cooler conditions will
prevail Saturday/Sunday in the 60s and lower 70s. Temps should be
back in the mid/upper 70s by Monday. Saturday night should be the
coolest of the period with lows 45-50. However, lows will be back in
the low 50s by Sunday night.


.AVIATION (06Z TAF Update)...
Issued at 1255 AM EDT Tue Oct 6 2015

High pressure at the surface and aloft will maintain a dry column,
keeping prevailing VFR conditions through the valid TAF period. Only
concern is fog potential at BWG. Very light NE wind is enough to be
a limiting factor, so will just include a TEMPO for MVFR
visibilities around daybreak.


.LMK Watches/Warnings/Advisories...


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