Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 141050

Area Forecast Discussion
National Weather Service Louisville KY
650 AM EDT Fri Oct 14 2016

...Updated Aviation Discussion...

.SHORT TERM (Now through Saturday)...
Issued at 250 AM EDT Fri Oct 14 2016 major fog areas at any site or seen on any of the special
enhanced satellite products. Low level clouds across the bottom two
tiers of KY counties...with streams of cirrus pushing in from the
west acrs the srn 1/3 of counties. Still expecting a gradual
diminishing of the stratocumulus and stratus field by early morning.
Temps are falling nicely in the clear skies.  Brandenburg and
Cynthiana are a nippy 39 at 230 am.

A weak srn stream shortwave over TX/AR will move across the srn 1/2
of the CWA and bring very low POP chances starting this afternoon
across the far srn tier.  There is a very small amount of
instability today to support slight chance of thunder across the
south. Slight chance for SHRA tonight and Sat morning east of I 65
and south of I 64, and slgt chc of TSRA across the Bluegrass Sat
afternoon. Forcing is quite weak so have decreased POPS just a tad.
There is a little bit more instability too near the I 75 corridor
Sat afternoon which jives with SPC Day 2 general TSRA.

Clouds will be increasing this afternoon and therefore going below
guidance starting off so cool with high pressure centered over Lake
Erie.  Have dropped highs 2-3 degrees with mid and high clouds
moving in by late morning.

Saturday clouds will clear out in the west allowing highs to climb
into the low 80s while clouds will taper down temps across the
Bluegrass with highs in the 75 to 79 range.

.LONG TERM (Saturday Night through Thursday)...
Issued at 250 AM EDT Fri Oct 14 2016

...Big warm up Sun-Tue...
...Major Cool Down Wed-Fri...

Well...the medium and long term is basically the tale of two weather
regimes with the pattern starting off quasi zonal with a developing
large scale ridge over the Lone Star State.  This ridge is not as
herculean as model runs 24 hours ago, but 589m is still 1-2 SD above
normal for mid October.  This ridge is shunted to the east with the
northern stream carving a trough out over the Dakotas. LLVL winds
will become SSW and temps will rise. H8 temps will increase 3-6 C.
This will translate to surface temps rising to at least mid 80s but
upper 80s, especially Tuesday is very plausible.

Then...a high anomalous northern stream jet carves out a broad long
wave trof from Lake Gitche Gumee (Superior) and plows it along the
MS River. It will lead to major falling upper heights as far south
as Dixie Alley. Late next week, we will be in the upper 50s to mid
60s for highs depending how this evolves.

Sat Night and Sunday Night...

Surface high pressure over the Carolinas builds westward and bring
above normal temps (15 degrees above normal on Sunday).

Monday - Tuesday...

SSW flow will bring a very warm air into the Ohio Valley and coupled
with very dry vegetation and parched brown areas, temps will at
least hit mid 80s, but would not be surprised to see near 90 on
Tuesday. That would be 20 degrees above normal and be close to
record highs.

For your information...

Mon Oct 17 Record High Info

SDF    87     1965 (and previous years)
BWG    90     1917
LEX    87     1938
FFT    88     1938

Record high temps for Oct 18th

SDF    86     1910 (and previous years)
BWG    88     1963 (and previous years)
LEX    87     1938
FFT    88     1938

Wednesday - Friday...

A very strong upper trough dives SE into the Midwest and then Deep
South. The associated sfc cold front should bring some convection to
the area some time Tue night-Wed.  Then according to how the upper
level trough progresses, we may see more light rain chances (higher
POPs into the weekend).  A cool down will certainly accompany the
upper trough as well with highs falling back into the 60s by
Thu/Fri. Lots of cloud cover and could be a significant rain event
for the East Coast and could be a bad scenario for the waterlogged


.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Fri Oct 14 2016

So far we have avoided fog issues as dry air is winning the battle
at SDF and LEX, while a VFR strato-cu deck has worked back into BWG
to keep vis from tanking there. However, must continue to watch BWG
closely through mid-morning as the edge of the cloud deck remains
very close, and locations that remain clear for any length of time
have socked in. Will carry a TEMPO for borderline MVFR/IFR
visibility in BWG, while SDF/LEX remain unrestricted.

Southern stream impulse currently working its way across the
Mississippi will try to send a precip shield into south-central
Kentucky today, but hi-res models show that precip eroding as it
approaches and/or remaining over Tennessee. Better low-level jetting
develops after sunset, so will add VCSH to BWG from roughly 02Z
onward. Still a marginal setup and confidence is moderate at best,
so will keep prevailing VFR through the night.

Even less confidence in any potential northward expansion. At this
time will include VCSH in the planning period at SDF, and while LEX
seems to have a better chance for precip than SDF, it`s beyond the
scope of this TAF issuance. Will continue VFR, with light E-NE winds
veering SE toward daybreak Sat.




Short Term........JDG
Long Term.........JDG
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