Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 201910

Area Forecast Discussion
National Weather Service Louisville KY
310 PM EDT Mon Mar 20 2017

.Short Term...(This evening through Tuesday night)
Issued at 259 PM EDT Mon Mar 20 2017

The precipitation from this morning has finally mostly moved out of
the region. Warm air advection through the day has contributed to
temps rising into the 70s across south and west central KY this
afternoon while much of the Bluegrass remains near 50. However,
winds have shifted to southerly across the whole area and become
gusty this afternoon. This will lead to a surge in temps through the
remainder of the afternoon for the cooler areas. Still think that
most will see highs at least in the 60s today, though it will come
later in the afternoon. Mid to upper 70s for highs are in reach for
southwest central KY.

As far as precipitation goes, a weak surface low will cross the
region this evening and a cold front will sag south overnight.
Showers and a few storms will accompany these features, mainly after
0Z tonight. The best chance for precipitation looks to be over the
Bluegrass, but even there it still looks to remain scattered in
nature. Soundings do show steep mid level lapse rates with a strong
inversion at the surface. There looks to be quite a bit of elevated
instability, on the order of 1000+ J/kg CAPE, so if storms do form,
some hail will be possible.

Precipitation should mainly end from the north overnight as the
front sinks southward. A few showers and storms could linger into
tomorrow morning across south central KY, but most areas look to be
dry. Another shortwave moving through the upper level flow will
approach and move through tomorrow afternoon into the evening. This
will bring a renewed chance for showers and storms, particularly
across south central KY, though the area of highest coverage does
look to be a bit further to the south than in previous model runs.
The storms across south central KY could become strong to marginally
severe in the afternoon and evening with hail and some gusty winds.
Precipitation looks to finally end tomorrow night.

Temperatures tonight will remain on the warm side ranging from the
upper 40s across southern IN to the mid to upper 50s across south
central KY. Highs tomorrow look to be in the 60s with lows back into
the 30s tomorrow night.


.Long Term...(Wednesday through Monday)
Issued at 308 AM EDT Mon Mar 20 2017

Mainly dry weather is expected from midweek through the end of the
work week. Surface high pressure will build in from the north on
Wednesday. Temperatures will be on the cooler side Wednesday with
highs in the mid 40s to mid 50s. Through the end of the week, upper
level ridging will build in. A warm front will move north across the
region on Thursday. The GFS/ECMWF then show a disturbance rounding
the top of the upper ridge on Thursday evening and possibly bringing
showers to the Bluegrass region. Will carry just low end pops with
this due to the uncertainty associated with it. Temperatures will
quickly rebound back into the 60s to lower 70s by Friday.

The weekend continues to look wet as a deep upper level low slowly
approaches and moves from the Midwest into the Great Lakes region.
Showers and storms look to move in from the west Saturday morning as
we sit solidly in the warm sector of the system. Precipitation will
overspread the area through Saturday into Saturday night. We could
still see scattered showers Sunday behind the front. These look to
move out Sunday night. The more spring-like temperatures will
continue this weekend with highs in the 60s to lower 70s.


.Aviation (18Z TAF Update)...
Issued at 143 PM EDT Mon Mar 20 2017

A dissipating MCS that moved by to our north and northeast earlier
this morning emitted low level outflow, about 2000 feet deep, that
turned winds at SDF/LEX to the northeast. This slab of easterly flow
has slowly been mixing out and winds have been gradually veering
through east to southeast, and should end up coming in from the
south or SSE for most of the afternoon at speeds around 10 knots at
those two airports. BWG will remain unaffected by the outflow and
keep its SSW winds and very warm temperatures.

A cool front roughly along a DTX-STL-AMA line will sink southward.
By this evening the front, possibly augmented by outflow from
thunderstorm activity to our north, will cross the Ohio River and
move into Kentucky. Scattered showers and isolated thunderstorms
will probably accompany the boundary, primarily affecting SDF/LEX.

As the surface boundary continues to advance southward, approaching
the Tennessee line by Tuesday morning, it will introduce post-
frontal low level moisture resulting in low ceilings. Ceiling
heights around a thousand feet can be expected, with dips into IFR
possible especially at LEX toward morning. MVFR BR can be expected
as well.

Those low ceilings will gradually mix out over the course of the
morning and any vsby restrictions will disappear as north breezes
come in to clean things out.




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