Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 280737

Area Forecast Discussion
National Weather Service Louisville KY
337 AM EDT Mon May 28 2018

.Short Term...(Today and tonight)
Issued at 314 AM EDT Mon May 28 2018

Currently the radar is quiet across the region with precipitation
associated with Alberto well to the south of the forecast area.
However, cirrus from this system is streaming across the region.
With plenty of low level moisture and light to calm winds, some fog
development is possible this morning. However, the cirrus may help
to mitigate widespread denser fog formation.

The dry weather should persist through mid morning at least.
However, by mid day to early afternoon, one of the outer bands
associated with Alberto will begin to affect the region with showers
and storms developing. The best chance for storms will be along and
south of the Western KY and Bluegrass Parkways. Will limit coverage
for now to 30-40%. The biggest threat today will be heavy rainfall
and cloud to ground lightning. Southern IN should stay mostly dry
and therefore will see the warmest temps today with highs in the
upper 80s to around 90. Highs across central will range through the
80s and partially depend on coverage of precipitation.

Showers and storms should diminish around sunset with a dry period
through much of the evening and early overnight hours. However, many
models do show another round of showers and storms developing after
06Z tonight. Placement of these storms varies, so will broad brush
the region with a 20-30% chance of precipitation. Lows tonight will
again range from the mid 60s to around 70 in metro areas,


.Long Term...(Tuesday through Sunday)
Issued at 330 AM EDT Mon May 28 2018

...Unsettled Weather Period This Week With Heavy Rainfall...

Tuesday - Wednesday...

The remnants of Subtropical Storm Alberto will impact our area Tue-
Wed of this week.  Not much has changed with the forecast track of
Alberto up through western/west central KY Tues afternoon/Tues
night.  This track will bring a focused swath of rainfall through
areas along and west of I-65 Tues afternoon and overnight.  High
precipitable water values typical in subtropical systems will result
in heavy to at times torrential rainfall Tues/Tues night.  1-2.5
inches of rain is forecast west of I-65 with high rainfall rates
expected at times.  Given showers/storms preceding the subtropical
system and then the heavier bouts of rainfall expected as the system
moves through, feel a threat for flash flooding is increasing.  Thus
will go ahead and issue an ESF highlighting the flash flooding

The other concern with the remnants of Alberto will be the threat
for strong to severe storms as much of the forecast area will be on
the right side of the passing subtropical system.  While the overall
system will be in a declining state, plenty of low level wind shear
is expected to persist Tue/Tue evening potentially resulting in
weak/brief tornadoes. Potential for any tornadic activity would peak
during the afternoon/evening hours on Tues.

By Wednesday morning, the remnants of Alberto should be exiting our
region to the north.  As the system departs, we`ll likely see
convective bands persist through the day on Wed.

Wed night both the 0Z NAM and GFS indicate a potent quick moving mid
level shortwave will push into the region from the west bringing
another convective complex.  Strong storms may be possible with
gusty winds being the main threat.

Thursday - Sunday...

Long range models continue to indicate a very active pattern to end
the work week with many upper level impulses crossing the region
bringing more rounds of showers/storms Thu/Fri.  GFS/ECMWF still
differ on how to handle upper level features for the weekend. Either
results in at least a small chance for showers/storms Sat/Sun.  The
GFS solution looks a bit overdone with an upper low sinking back
into the Ohio Valley.  Forecast temps are more reflective of the
ECMWF solution for the weekend.


.Aviation...(06Z TAF Issuance)
Issued at 125 AM EDT Mon May 28 2018

The remainder of the night will be dry for all the terminals. Cirrus
associated with Alberto will continue to stream overhead. Some light
fog will be possible towards dawn, with the best chance for denser
fog at LEX. However, given the high clouds, confidence is not high
enough to go below MVFR conditions.

Showers and storms are expected to develop again this afternoon as
one of the outer bands associated with Alberto moves in. The best
chance for these showers and storms will be across KY. HNB looks to
miss out on most of the rain today, so will keep a dry forecast
there. Winds today will generally be out of the east to east-
southeast outside of any thunderstorm.




Short Term...EER
Long Term...AMS
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