Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 291706
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
106 PM EDT Wed Oct 29 2014

...Updated Aviation Discussion...

...Forecast Update...
Issued at 745 AM EDT Wed Oct 29 2014

The back edge of the clouds is about halfway through the region, but
in its wake are a thin layer of low clouds, as evident on satellite
fog product, area webcams, and automated observing stations. Have
add patchy dense fog to the forecast for the next couple of hours,
as the HRRR and NARRE both hint at these clouds sticking around.
Also issued a special weather statement highlighting the impact.

Issued at 620 AM EDT Wed Oct 29 2014

Updated the forecast to reduce precip chances over south central KY
as precip is making quick progress eastward out of the area early
this morning.  Also, added some patchy fog over portions of
southwest Indiana and west central KY where clearing has begun and
visibilities are dropping at some observation sites.

.SHORT TERM (Now through Thursday)...
Issued at 300 AM EDT Wed Oct 29 2014

Early this morning, a shortwave was riding NE along the cold front
just to our south and east.  This wave will provide another round of
light rain showers to south central KY and southern portions of the
Bluegrass during the pre-dawn hours.  These locations may see up to
an additional tenth of an inch of rainfall early this morning.

This last wave of rainfall should exit the Lake Cumberland region
around or just after sunrise with cooler, drier air pushing in
from the NW throughout the day.  Skies will become mostly sunny by
mid morning with high temps topping out in the upper 50s to lower
60s this afternoon.

Tonight sfc high pressure will enter the Ohio Valley with most
models progging it to become centered over our region around
sunrise.  This high will provide light winds, subsidence, and good
rad cooling conditions which will result in low temps in the mid to
upper 30s Thurs morning.  Temps in this range will make at least
patchy frost formation possible in sheltered/valley locations.
Tonight could be a Frost Advisory candidate especially for southern
Indiana and north central Kentucky.  Will need to re-evaluate winds,
dewpts, and temps this afternoon to determine if frost formation
would be widespread enough for a Frost Advisory Thurs morning.  Stay
tuned!

After a cold start Thurs morning, temps should warm into the mid 50s
to around 60 Thurs afternoon.  Clouds will be on the increase Thurs
afternoon as the next weather system approaches for Thurs night.

.LONG TERM (Thursday night through Tuesday)...
Issued at 420 AM EDT Wed Oct 29 2014

...Blast of Cold Air Coming This Weekend with Sub-Freezing
Temperatures Likely by Sunday...

OK, let`s cut to the chase.  Friday evening is what you`re really
interested in, since the streets will be full of little goblins and
you`ll either be accompanying them or opening your doors for them.
Either way, it`s not going to be pleasant. Light showers will be
occurring in most areas with temperatures falling through the 40s -
if not into the 30s - before the last doorbell is rung.  And some of
the precipitation falling from those showers will likely be in the
form of light snow if you stay out too late. When you add north
winds gusting from 15 to 25 mph, well, let`s just say that it`s
going to be cold.

The extended period will bring us a taste of the season to come as a
progressive upper level weather pattern keeps forecasters on their
toes.  We start out with a series of upper disturbances diving south
out of Canada, deepening a trof over the eastern U.S. and dragging
the colder air into the Ohio Valley.  Showers will first move into
the region overnight Thursday, then increase in coverage during the
day Friday along with the push of cold air coming in rapidly on
north winds as a tight surface gradient sets up between Low pressure
over the Appalachians and High pressure over the upper Mississippi
Valley.  This leads into the aforementioned blustery weather Friday
night.

Wind chills Friday night will fall into the 20s, but with the gusty
winds, actual air temperatures should not fall below freezing
Saturday morning.  The same won`t be true for Sunday morning though,
as the surface High moves in from the upper Mississippi Valley,
clearing out skies and dropping winds off to allow for peak
radiational cooling by Sunday morning.  Temperature by dawn on the
day we move the clocks back an hour should be in the upper 20s
across the entire area, effectively putting an end to the outdoor
growing season.

A gradual warmup will occur Sunday into Monday as the High drifts
slowly east and return southerly flow sets up.  This will set the
stage for the next chance for showers from Monday night into
Tuesday.  These will stay in the form of rain, rather than snow,
though, as daytime temperatures moderate back into the upper 60s
Monday and Tuesday - up considerably from Saturday`s max
temperatures in the 40s.

&&

.AVIATION (18Z TAF Update)...
Updated at 103 PM EDT Wed Oct 29 2014

VFR conditions are expected through the TAF period, although there
could be some light fog in prone locations towards Thursday
morning.  For the remainder of this afternoon, expect westerly winds
to turn more WNW and continue around 10 knots with gusts upwards of
15 knots at times.  Clouds (around FL035) from the northwest will
attempt to push into KSDF and KLEX this evening, but will likely
struggle to do so as they mix out late this afternoon.

Some guidance is trying to hint at more fog development overnight at
KLEX and KBWG.  However, drier air is quickly working in and even
guidance suggesting fog has morning dewpoint depression upwards of 3
degrees.  Therefore, will just hint at fog development with a 6SM
group at KLEX and KBWG, but leave any restrictions out for now.
Otherwise, Thursday will just feature some increasing high clouds,
but winds will remain light with VFR conditions continuing.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&

$$

Update.........RJS/AMS
Short Term.....AMS
Long Term......JBS
Aviation.......KJD





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