Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 171048

Area Forecast Discussion
National Weather Service Louisville KY
648 AM EDT Tue Apr 17 2018

...Updated Aviation Discussion...

.Short Term...(Today through Wednesday)
Issued at 310 AM EDT Tue Apr 17 2018

Closed upper level low continues to pull away from the Ohio Valley
this morning.  Lagging low-level cloud cover continues to slowly
pull eastward.  The back edge of the clearing line is approaching
the Louisville metro area now and based on current tracking should
clear our far eastern CWA after sunrise.  These low clouds will keep
a lid on temperatures across the eastern portions of the CWA with
readings likely staying in the 31-33 degree range through the
remainder of the overnight hours.  In areas west of the I-65
corridor where clearing has taken place, overnight lows in the mid-
upper 20s are very likely.  Some patchy areas of frost are likely
west of I-65, mainly in areas that are more wind protected.  For
now, will keep ongoing headlines in place, though our eastern areas
are likely to escape a hard freeze given the current cloud cover in

For today, we should see a decent warm up in temperatures as
southwesterly wind flow gets going. Highs will range from the upper
50s over SE IN and the Bluegrass region of Kentucky, with upper 50s
to the lower 60s across the I-65 corridor and off into southwest KY.

Tonight will not be as cold as we`ll have some mid-high level
cloudiness rolling through the region.  Lows look to range from the
lower 40s over SE IN and in the Bluegrass region to the mid-upper
40s across our southwest sections.

For Wednesday, we`ll start off the day partly cloudy, but will
likely see some increasing cloudiness by afternoon as a cold front
works in from the west.  Latest guidance continues to suggest a
slight chance of showers in the afternoon.  Temperatures will warm
into the upper 60s to the lower 70s across southern IN and northern
KY.  Mainly lower 70s are expected across southern KY.

.Long Term...(Wednesday night through Monday)
Issued at 329 AM EDT Tue Apr 17 2018

Fast moving cold front will push through the region at the beginning
of the forecast period (Wednesday night).  This will bring scattered
showers to the region followed by a period of cooler temperatures.
Lows Wednesday night will drop back into the upper 30s.  Highs
Thursday will likely range from 50-55 in most areas.  Depending on
how fast we clear out of clouds on Thursday, we could see another
frost/freeze event across our eastern areas as lows there drop into
the 30-32 degree range.  Temps do look to recover Friday afternoon
with highs in the upper 50s to near 60.  Lows Friday night look to
cool back into the 34-39 degree range.

Heading into the weekend, a strong upper level storm system is
forecast to slowly eject out of the western US and into the Plains.
The model solutions over the past few days have trended slower and
continue to be a bit more southerly with their storm track.  This
would result in drier conditions for Saturday and now into Sunday.
Though we really can`t rule out an isolated shower chance across
southwestern sections Sunday afternoon.  The 17/00Z Euro solution
has continued to trend more southerly with this run and would
actually keep our region dry through the remainder of the period.
Current blend guidance does keep some very low chances of precip in
the forecast for Sunday and Monday across the region.  This is
likely due to the GFS influence in the blend.  If current trends
continue in the Euro, we can probably start backing off precip
chances in subsequent forecasts.

Highs Sunday look to warm into the lower 60s in most areas, through
a few mid 60 degree readings are likely across southern KY.  Lows
Sunday night look to dip back into the 40s.  Highs on Monday should
be slightly warmer than Sunday with readings in the middle 60s.


.Aviation...(12Z TAF Issuance)
Issued at 647 AM EDT Tue Apr 17 2018

VFR conditions are expected through this TAF cycle. LEX may have to
contend with an BKN-OVC deck of stratocu around 4-5 K feet for
another 1-2 hours, before clearing.

Otherwise, expect a steady W wind today with a few gusts in the 20-
25 mph range possible. Later this evening, a warm front will develop
near the HNB/SDF/LEX sites as a surface low moves out of the central
Plains and into the mid Mississippi River Valley. Could see some
increasing VFR ceilings (~4-5K feet), and will have to watch for a
LLWS component. Although the magnitude is not overly strong (30-40
knots), the directional shear is quite impressive given the frontal
boundary in the region. The shear combined with a strong inversion
near the surface warrants LLWS mention.


IN...Freeze Warning until 10 AM EDT /9 AM CDT/ this morning for

KY...Freeze Warning until 10 AM EDT /9 AM CDT/ this morning for



Short Term...MJ
Long Term....MJ
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