Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 241655
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1255 PM EDT Tue Mar 24 2015

...Updated Aviation Discussion...

...Forecast Update...
Issued at 1030 AM EDT Tue Mar 24 2015

Front has gone quasi-stationary near the KY/TN border, with the
strongest temp contrast noted across south-central KY where readings
range from the upper 40s to the mid/upper 50s over a fairly short
distance. Precip associated with mid-level warm advection continues
to push across central and southern Illinois, and while there has
been some lightning around STL most of this precip is fairly light
and spotty.

Have made some minor tweaks to hourly POPs but still sticking with
the general theme of a 20-30% chance north of the KY Parkways this
afternoon. Even with the slower rise in temps across most of central
Kentucky, still expect a sharp temp gradient this afternoon.
South-central KY could still get very close to 70, while southern
Indiana might not get out of the 40s if rain and/or clouds are too
persistent. Hi-res products updated but no real changes to zone
forecasts.

.SHORT TERM (Now through Wednesday)...
Issued at 312 AM EDT Tue Mar 24 2015

Early morning satellite imagery reveals mostly clear conditions over
southern KY this morning with partly to mostly cloudy skies over
southern Indiana and northern Kentucky.  A stalled out frontal
boundary lies across the region this morning.  North of the
boundary, temperatures are in the upper 30s while areas south of the
front are still in the lower to middle 40s.  For the remainder of
the overnight hours, not much change in the ambient conditions are
expected.  Overnight low temperatures will occur toward sunrise with
lower to mid 30s in the north with upper 30s to the lower 40s in the
south.

Later this morning, mid-level wave over the Plains will continue to
work northeastward into the Midwest and NW Ohio Valley.  A gradual
moistening of the atmosphere will occur and shower activity will
increase generally to our west and northwest.  Some of these showers
may impact our southern Indiana and portions of our northern KY
counties late this morning through the afternoon hours.  Rainfall
amounts would be very light.  A more complicated forecast is
afternoon temperatures.  With the frontal boundary draped out across
the region, a gradient of temperatures are expected once again.
Highs will range from the lower to middle 50s in the north with
upper 60s to the lower 70s across southern Kentucky.

The aforementioned frontal boundary will lift northward tonight.
This will allow milder air to filter in from the south to the
north.  With the front moving north of the region, much of tonight
will be dry with partly to mostly cloudy conditions.  Overnight lows
will only cool into the lower-middle 50s.

The frontal boundary is likely to shift a bit more south toward dawn
Wednesday which may bring some light rain showers to the region.
Overall coverage looks to be scattered at best.  The boundary will
lift northward again during the afternoon and rain chances will
decrease a bit as we get back into the warm sector.  Temperatures
are still tricky here.  Much of the guidance suggests temperatures
topping out in the very low 70s.  However, if we were to break out
of the clouds, a run at the mid-upper 70s would be likely.

.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Mon Mar 23 2015

The long term will begin with active weather, followed by a quieter
but much cooler end to the week. We will then see warming
temperatures with a chance for precipitation for the beginning of
next week.

For Wednesday night an upper level trough will approach
from the Plains. An associated surface low will track northeast
along the Ohio River overnight Wednesday into Thursday. The low will
drag a cold front through on Thursday. Showers along and ahead of
this front will move into the region late Thursday evening and
continue to move through overnight and into the morning hours. A
40-50 knot low level jet will develop overnight and some strong
storms with this system will not be out of the question. However,
instability will be limited given the timing of the system. Thus,
severe potential will be limited, but some storms could have gusty
winds with them or possibly small hail. Rain will move off to the
east Thursday with just a few showers lingering into Thursday
evening across the east. As the upper level trough deepens across
the eastern CONUS Friday another weak wave will drop through it
bringing a chance for some light, cold showers Friday.

Temperatures will fall quickly in the wake of the front on Thursday.
Highs may very well be at the beginning of the day with temps
falling or holding steady into the afternoon. Friday and Saturday
will be much colder than normal for this time of year with highs in
the 40s and lows dropping into the mid to upper 20s. High pressure
will keep the weather dry Saturday and Saturday night.

Another wave and cold front will move through Sunday into Monday.
The timing of this system is still somewhat in question. It could
bring a chance for more showers sometime through this time frame.
Temperatures will be Sunday into Monday with highs Monday back in
the upper 50s to around 60.

&&

.AVIATION (12Z TAF Update)...
Issued at 1250 PM EDT Tue Mar 24 2015

Quasi-stationary front is currently draped just south of BWG, but
VFR conditions prevail across central Kentucky. Spotty precip over
southern Illinois and Indiana, but conditions remain VFR as the
lower ceilings remain well north.

Expect a lowering of ceilings in SDF and LEX this afternoon as the
precip shield edges closer. Could see a lower deck but ceilings
should remain VFR. Any precip will be intermittent and VCSH should
cover it. BWG will remain dry and even a mid-level ceiling looks
like a worst case scenario there.

Front will lift northward overnight, with winds coming around to
southerly by daybreak. Small chances for precip as we get toward
sunrise but probabilities remain too low to mention.

Low-level jetting really cranks up out of the SW once the warm front
is through, but enough of that will mix down that we should see
surface winds pushing 15 kt, and would very likely stay out of any
LLWS mention. Jetting weakens and mixes out, so wind speeds should
stabilize at 10-12 kt for the remainder of the morning. MVFR
ceilings are quite possible but should stay above fuel-alternate.

&&

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

$$

Update.........RAS
Short Term.....MJ
Long Term......EER
Aviation.......RAS





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