Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 290407
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1207 AM EDT Wed Oct 29 2014

...Forecast Update...
Issued at 1203 AM EDT Wed Oct 29 2014

Updated the forecast to adjust POPs back up to 20% through southern
Indiana and north central KY for the next few hours before slowly
tapering them south and east through the rest of central KY
overnight.  Isld showers have been slow to exit the area this
evening.  Forecast min temps in the 40s to around 50 still look on
track for this morning.

Issued at 825 PM EDT Tue Oct 28 2014

Quick update to the first period to show a fairly sharp gradient in
POPs in the general vicinity of the Western Kentucky and Bluegrass
Parkways. Cold front is cleanly south and east of the area, but an
impulse aloft has fueled showers that continue to stream ENE along
the backside of the boundary. Expect the precip to taper off from
west to east after midnight, but until then a gentle steady rain
with additional QPF on the order of a quarter inch.

.SHORT TERM (Now through Wednesday Night)...
Issued at 302 PM EDT Tues Oct 28 2014

The cold front is now located along a line from Cincinnati down
through Elizabethtown and Bowling Green. It will continue to push
east through our CWA by 4-5 PM in our NE and by 6 or 7 PM near Lake
Cumberland. A thin line of showers has developed right along the
front and will continue to push east. Other than the thin line of
showers and a few isolated showers ahead of the front, will see
relative lull in activity for a few hours this afternoon.

Expect to see another wave of precipitation develop along and behind
the front this evening as a surge in moisture ahead of a disturbance
in the SW flow aloft moves over the area. This precipitation is
expected to focus mainly across our SE CWA, with other locations
staying mostly dry. Best timing for this secondary round of
precipitation should be between 6 PM and 2 AM EDT. Will see a drop
off in low temperatures tonight, however the coldest air will lag
behind until Wednesday night. Look for lows generally in the 40s.

500mb trough axis will slide through tomorrow with high pressure
building in at the surface. Expect dry and mostly sunny skies,
although will be cooler behind the front. Look for highs around 60.

The center of the surface high arrives Wednesday night with brief
upper ridging in place. With slackening winds, mostly clear skies
and much drier air, temperatures look to fall into the mid and upper
30s. Some patchy and more widespread areas of frost will be a
possibility. Stay up to date of the latest forecasts for potential
future headlines.

.LONG TERM (Thursday through Tuesday)...
Issued at 330 PM EDT Tue Oct 28 2014

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

The medium range will start off with high pressure pushing off to
our east Thursday night with clouds increasing as a lead upper level
trough drops into the western Great Lakes.  This feature will likely
bring some drizzle and some light rain showers to the region
beginning late Thursday night.  Temperatures are likely to cool into
the lower-middle 40s.

A second and more potent upper trough will drop quickly southward
out of the Great Lakes during the day on Friday as a wave of low
pressure moves across southern KY/Northern TN.  These features will
bring plenty of clouds and light rain showers to the area during the
day.  As the low heads east Friday afternoon, temperatures will fall
as a large push of cold air drops southward out of the Great Lakes
into the Ohio Valley.  Early day high temperatures will warm into
the lower-middle 50s in the north with mid-upper 50s across the
south...with temperatures then dropping quickly through the
afternoon as gusty northerly winds pick up.

For Friday night, the upper trough will sharpen considerably and
close off as it drops through far eastern IN/SW OH/E KY.  This will
lead to a surface low developing to our east across the Virginias
and then moving off the US east coast.  Continued cold advection
aloft, as evidenced in time-height and model proximity soundings,
will lead to the atmospheric column cooling from the top down Friday
night.  Initially, light rain showers are expected Friday night, but
as the column cools down aloft, some light sleet and perhaps a
little light snow could mix in.  This is still rather questionable
as model time-height and soundings show deeper moisture departing as
the column cools.  For now, have added some slight chances of light
sleet and some light snow in for our eastern areas Friday night.
Surface temperatures will likely cool into the 30s Friday evening
and then bottom out in the lower-middle 30s in the east.  Thus, any
snow that falls will not accumulate.  Further west, within the drier
air, we`ll likely see a little more clearing which will allow
temperatures to fall into the lower 30s out in our western CWA with
the potential for some frost.

Saturday looks to be a cold/crisp day across the region.  Skies are
expected to clear from west to east.  Continued cold advection will
likely keep afternoon temperatures in the lower-middle 40s in the
east with mainly upper 40s out toward the I-65 corridor and points
west.  Clear skies and lighter winds will result in widespread
sub-freezing temperatures Saturday night and Sunday morning...with
areas of frost likely.  The multi-model consensus suggests lows in
the upper 20s to around 30 in most locations.

High pressure will quickly transverse eastward on Sunday resulting
in dry but with moderating temperatures.  Highs on Sunday will
likely warm to around 50 in the east with lower-middle 50s out in
the central and western sections.  Combination of upper ridging and
an increasing breezy southwesterly flow should result in more
moderation of temperatures on Monday with highs warming back into
the 60s.

Another strong upper level trough axis will approach the region
Monday night and into Tuesday bringing a very good shot of rain
showers and possible thunderstorms.  Temperatures will be milder
ahead of this feature with readings likely warming into the
lower-middle 60s.

&&

.AVIATION (00Z TAF Update)...
Updated at 700 PM EDT Tue Oct 28 2014

Cold front and what was a broken line of showers now pushing into
eastern Kentucky, and extending back into middle Tennessee. An upper
wave pushing into the Tennessee Valley is fueling another area of
more stratiform rain across the Pennyrile region, and this precip
will affect BWG and skirt LEX through this evening. Will maintain
MVFR ceilings there, with a TEMPO for MVFR visibilities in the
heavier rain. All this should remain south of SDF, which should hold
in with a mid-level ceiling and winds coming around to WNW.

Once the upper wave pushes east of the area, should go VFR if not
clear out fairly quickly. Light NW winds will keep it just mixy
enough that fog shouldn`t be a concern as we head toward morning.

Clear skies and W-NW winds holding just under 10 kt through the day
Wednesday.

&&

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

$$

Update.........RAS/AMS
Short Term.....BJS
Long Term......MJ
Aviation.......RAS





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