Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 281045
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
645 AM EDT Tue Mar 28 2017

...Updated Aviation Discussion...

.Short Term (Now through Wednesday)...
Issued at 200 AM EDT Tue Mar 28 2017

The upper level low/cold pool aloft is centered over the Ohio Valley
early this morning, and WV imagery shows the wave spinning east
along the Ohio River. Sufficient moisture in the lowest 5-7 kft and
the surface trough draped south across the forecast area have
supported the development of a thin line of light, scattered
showers. As of 145 AM, these showers were pushing into the eastern
CWA. No thunder is expected.

Expansive stratus region can be seen on IR satellite to the
northwest of the forecast area, across Illinois and Indiana. Some
partial clearing has been able to develop in the system`s dry slot
across portions of western KY and now central KY. Fog development
has been common off to the west and southwest in these areas of
clearing, but any window of clearing should be brief. Stratus will
gradually fill in to the south and east from Indiana this morning.
Surface winds are fairly light, but should stay up around 5 mph for
much of the morning. Patchy fog is definitely possible through 14z,
and could briefly become dense before low clouds work back in.

Low pressure will scoot off to the east this morning, and the
Bluegrass region may see some isolated light showers. Otherwise, the
bulk of the day will be dry, mostly cloudy, and cooler. Upper level
heights slowly rise through the day as ridging returns, but clouds
and northwest winds will keep highs in the mid 60s.

Upper ridging holds across the region tonight, with surface high
pressure centered near Hudson Bay. The weather across central KY and
southern IN will be quiet. Surface winds will turn northeasterly as
low pressure moves into the southern Plains. Lows tonight will fall
into the mid to upper 40s for most, with around 50 degrees near the
TN border. Dry weather continues Wednesday, with highs in the mid
60s to low 70s.

.Long Term (Wednesday Night through Monday)...
Issued at 315 AM EDT Tue Mar 28 2017

Wednesday evening looks dry, but rain chances start to increase once
again during the early morning hours of Thursday as a low pressure
system begins to eject eastward out of the Plains. Warm advection
showers and storms are possible Thursday morning as a warm front
lifts north of the area. Deep, southerly flow will pump moisture
into the Ohio Valley, with surface dewpoint rising well into the 50s
on Thursday. Showers and thunderstorms are most likely Thursday
afternoon through Thursday night.

Strong thunderstorms will be possible as well. This is another
fairly dynamic system with a potent mid-level wave. Forecast
soundings suggest sufficient instability and deep layer shear for
strong convection. The best chance for widespread rain looks to be
Thursday night into early Friday with the approach of the cold
front. Its arrival coincident with the diurnal heating min calls
into question the available energy.

Thursday will be warm with strong southerly flow pushing highs well
into the 70s for most. Thursday night will be quite mild with clouds
and rain in the area, with lows in the mid to upper 50s. There is a
good chance for rain Friday morning as the front pushes through. The
afternoon and evening will feature diminishing rain chances from
west to east. Lows Saturday morning will likely be in the 40s.

Saturday looks cooler, with highs in the low to mid 60s. Overall,
the weekend looks pretty quiet with dry weather expected. Upper
level ridging will be in place across the eastern CONUS, with a
surface high sliding over the Great Lakes. Temperatures will fall
into the low to mid 40s Saturday night before recovering into the
mid 60s to low 70s for Sunday. The next shot at precip will be on
Monday as another low pressure system swings through the region.
Temps are likely to stay mild, with highs in the 60s and 70s into
next week.

&&

.Aviation (12Z TAF Update)...
Issued at 644 AM EDT Tue Mar 28 2017

Low level moisture flowing around the back side of a surface low
moving from the Upper Ohio to the Potomac Valley this morning will
continue to bring low ceilings to the region. The lowest ceilings
should take place a few hours after dawn, on the upper end of IFR.
Those ceilings should lift into MVFR during the day today but skies
will remain BKN/OVC as low level moisture gets trapped under a sharp
inversion around 875mb.

We could see a few showers today, especially at LEX, as a weak
surface trof moves from north to south across the area. Any shower
activity will be light and isolated, though, so no need to include
in the TAFs at this time. This boundary will also shift winds from
northwest to north this afternoon.

High pressure nosing into the Great Lakes tonight will shift winds
further, to the northeast, as low ceilings persist.

&&

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

$$

Short Term........EBW
Long Term.........EBW
Aviation..........13


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