Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 200544

Area Forecast Discussion
National Weather Service Louisville KY
144 AM EDT Mon Mar 20 2017

...Updated Aviation Discussion...

.Short Term (Now through Monday Night)...
Issued at 250 PM EDT Sun Mar 19 2017

Satellite images this afternoon shows the clouds that developed over
portions of southern IN and north central KY beginning to erode.
These clouds should mostly dissipate over the next few hours.
However, more clouds will move in from the west tonight as a system
approaches the region.

For tonight, showers and storms will develop across northern IL and
IN. A few showers may move into southern IN before daybreak, but
most of the precipitation looks to stay to the north of the forecast
area. Monday looks to be mainly dry, though a few showers or storms
could affect southern IN and north central KY.

The better chance for showers and a few storms in the short term
period will come Monday night as a cold front sinks south across the
lower Ohio Valley. This front looks to stall near the KY/TN border
early Tuesday. Rain chances will be diminishing towards daybreak

As for temperatures, the coldest temps tonight will be across east
central KY closer to the departing high pressure and where clouds
will move in the latest. Lows there will drop into the lower to
mid 30s. The rest of the region will see lows in the upper 30s to
lower 40s. With the return to southerly flow tomorrow, highs will
reach into the lower 60s in the Bluegrass to the upper 60s to lower
70s along and west of I-65. Tomorrow night will be much warmer in
the mid 40s to mid 50s.

.Long Term (Tuesday through Sunday)...
Issued at 308 PM EDT Sun Mar 19 2017

The stalled frontal boundary near the southern KY border will remain
mainly stationary through Tuesday. A shortwave will approach during
the afternoon and move through during the evening and overnight
hours. This wave will spark another round of showers and storms
Tuesday that will continue into Tuesday night. Rain chances for
Tuesday look to be higher across the board than for Monday.
Soundings do show some decent CAPE developing across south central
KY near the boundary. A few stronger storms with hail and gusty
winds will be possible Tuesday afternoon and evening in this area.

The boundary will finally push well south of the region by Wednesday
morning. High pressure building in from the north will bring
clearing skies. A warm front will push back to the north across the
region on Tuesday. The models have trended drier with this front as
we will be under the influence of ridging, so the forecast was
trended dry as well. Friday we should be solidly in the warm sector
ahead of the next system. The dry streak will continue with highs
topping out in the upper 60s to lower 70s.

For next weekend, the 12Z model runs have come into better
agreement. A deep closed upper low will develop across the Plains
Thursday/Friday and move into the Missouri Valley by Saturday
morning. The GFS has trended towards the deeper solution, closer to
the Canadian and ECMWF. Thus, precipitation will be slower to move
in and slower to move out. Scattered to numerous showers and storms
are looking more likely through much of the weekend.


.Aviation (06Z TAF Update)...
Issued at 145 AM EDT Mon Mar 20 2017

Clear skies over the TAF sites at issuance time, but satellite
showing low clouds  moving in from the west. There has been
considerable erosion of the lower clouds south of the Ohio River
over the past few hours, so only went SCT040 at BWG to start, but
these should fill back in later this morning. Kept a quick change to
BKN040 at SDF and LEX per the previous TAF issuance, with timing of
09Z and 12Z respectively.

CIGS should remain at or above MVFR heights through the day before
lowering with VCSH at SDF and LEX after 21/00Z.




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