Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 100716
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
316 AM EDT Mon Mar 10 2014
.SHORT TERM (Now through Tuesday)...
Issued at 250 AM EDT Mon Mar 10 2014
High-level clouds are trying to work in from the north, while a
batch of low-level clouds continues to move northeast across central
Tennessee early this morning. The low clouds may work into our south
in the pre-dawn hours, yet continue to move eastward and may even
dissipate some with early morning mixing at about 925 hPa. Will
continue to monitor those through the early morning hours and make
more adjustments as necessary. The high clouds will eventually make
it into our northern CWA later this morning and afternoon.
Otherwise, expect a warm start to the week! Sunshine, even filtered
through some high clouds, combined with breezy southwesterly winds
will help propel temperatures above normal for this time of year,
generally reaching the middle 60s. The bust potential here rests
with just how thick the cirrus clouds across our northern CWA will
be this afternoon. Winds will relax overnight, yet remain in the
5-10 mph range. Temperatures will only drop into the low and middle
40s. High clouds will continue to increase tonight into Tuesday.
Cloud bases will lower late in the day Tuesday as our next area of
low pressure approaches for Tuesday night. Temperatures in the 60s
to low 70s are expected Tuesday afternoon, with warm-air advection
ahead of the surface low.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 255 AM EDT Mon Mar 10 2014
A warm front will lie to our north Tuesday evening, as apparent by
the forecasted warm day mentioned above. One upper low, now over
northwest Mexico as per latest water vapor, will scoot by to our
south as another upper trough, now off the Pacific Northwest coast,
moves into the Central Plains. This latter system will force a
surface low to deepen along the front, bringing a surge of moisture
in here later Tuesday night.
Multiple models carry this surface low across the Commonwealth state
at some point late Tuesday night, with the 12Z ECMWF (and the newer
version coming in) and 00Z NAM having slower solutions. The
proximity to the deepening surface low will mean we will continue to
carry elevated thunderstorms, mainly in the 06-12Z time frame. The
pressure gradient will be tight on the back side of this low, so
20-30 knot gusts look likely during the day Wednesday.
High pressure building in quickly behind this front should bring an
end to the main precip quickly, by the end of the day Wednesday.
Temperatures likely will peak in the morning and then steadily
decline through the day. They may get cold enough for snow showers
in the afternoon, but given warm antecedent grounds, not expecting
significant accumulations at this time. Cannot rule out some light
snow showers over the east in the evening, as the main trough axis
kicks through, so will keep in slight chances there. The surface
high ridge axis will be across the region Thursday, then east of us
on Friday, allowing for another warmup, back to climo values.
The GFS continues to try and bring in some precip Saturday, with a
front that the 12Z Euro also has. GEM indicates some precip as well,
but still like the Euro`s solution with a stronger high over the
southeast U.S. that blocks return flow of moisture up here. Will
lean toward that solution and force precip chances into the slight
range, under guidance. The 12Z Euro brings a stronger system down
Saturday night/Sunday that if it verifies could bring some snows
back to the region. The new 00Z version backed off on this system
quite a bit, holding off its influence until just beyond this
period. Given the lower confidence, will keep in the slight chance
.AVIATION (06Z TAF Update)...
Updated at 120 AM EDT Mon Mar 10 2014
VFR conditions are expected at all TAF sites through the valid
forecast period. Winds will be the main forecast concern early this
morning through the afternoon hours, as the pressure gradient
tightens across the region. Surface winds tonight will remain out of
the south-southwest at 4-8 knots. There will be a brief period of
marginal LLWS at SDF and LEX from about 08-10Z. However, this is
also about the time surface winds are expected to slightly increase,
so will not include LLWS at this time. Southwest winds will be on
the increase through the day, with speeds in the 12-15 knot range
and gusts around 20 knots being possible after about 15Z. Speeds
then decrease for the overnight hours.