Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 191805

Area Forecast Discussion
National Weather Service Louisville KY
205 PM EDT Mon Mar 19 2018

...Updated Aviation Discussion...

.Forecast Update...
Issued at 1140 AM EDT Mon Mar 19 2018

Adjustments made to the precipitation chances through this evening.
Scattered showers will begin to work into the west-central Kentucky
by mid afternoon with the highest coverage expected late afternoon
through the evening hours.

As far as the severe chances go, still a marginal threat across
extreme southern Kentucky along the KY/TN border as the warm front
sets up. 12z data not coming in as robust with the instability, but
there should be enough to support some thunderstorms this evening.

Overall, the rest of the forecast looks good.


.Short Term...(Today through Tuesday)
Issued at 315 AM EDT Mon Mar 19 2018

...Strong Storms Possible Across Southern KY this

Early this morning a line of showers was slowly pushing ENE out of
TN into southern KY ahead of an approaching low pressure system.
Expect this line of showers to slowly fade as it moves NE into our
area through the morning hours.  Lowered POPs between 12-18Z today.

This afternoon a strong upper low and initial sfc low pressure will
approach our region bringing showers/storms to the area.  The latest
model guidance suggests a round of mainly elevated showers/storms
should develop just north of a warm front located across northern TN
and move northeast through central KY/southern IN this afternoon and
evening.  Strong wind profiles (60-70 kts of 0-6 km bulk shear) and
some CAPE (Up to 500-750 j/kg) should be sufficient for strong
storms across southern KY with the main threats being small hail and
gusty winds.  If the warm front lifts a little farther north than
anticipated, then better sfc based instability could make it into
southern KY and create an isld tornado threat.  At this time though,
it looks like that threat should stay in TN and points south.  Also,
with a break in precip this morning, there is the possibility that
more elevated instability could build over central KY if there are
breaks in the cloud deck.  This could result in better CAPE overall
and a better chance for strong storms up into central KY.  The
threat for strong to marginally severe storms should diminish late
this evening.  Total rainfall amounts across southern IN/central KY
will range from a half to 1 inch through tonight.

Expect light rain showers to continue Tuesday as the upper low and a
new sfc low pressure deepen over southern IN/central KY.

Temperatures today will range from the mid 50s to mid 60s for highs
dropping back into the 30s/lower 40s tonight.  Tuesday will be
noticeably cooler on the back side of this weather system with highs
mainly in the 40s.

.Long Term...(Tuesday night through Sunday)
Issued at 335 AM EDT Mon Mar 19 2018

...Accumulating Snow Possible Tuesday Night into Wednesday Morning...

Tuesday Night - Wednesday...

The last few runs of medium range models indicate the potential for
a light accumulating snow Tue night into Wed morning as the
aforementioned low pressure system wraps up and slowly wobbles
across our region.  A change over to snow will likely happen Tues
evening as colder air pushes in from the NNW.  Light to at times
moderate snow looks to fall late Tues night through Wed morning
resulting in up to a few inches of snow along and east of I-65. A
slushy accumulation of snow may cause some negative travel impacts
Wed morning.

Precipitation is expected to end as snow or a mix of rain/snow Wed
afternoon from west to east with any snow accumulations quickly
melting as temps rise well above freezing Wed afternoon.

Thursday - Sunday...

The rest of the long term forecast looks to remain active with
another major weather system crossing the central U.S. late this
week. This system could bring rain to our area as early as Thu
night/Fri morning and into the weekend.  It has the potential to
bring some t-storms on Sat.  Sunday we should see another brief
break in precipitation.

Temperatures will be abnormally cold Wed/Wed night with a hard
freeze possible Wed night into Thu morning as lows dip into the 20s.


.Aviation...(18Z TAF Issuance)
Issued at 200 PM EDT Mon Mar 19 2018

Today a surface low sits just west of Tennessee. This system will
move east with a cold front extending south from the low. Ahead of
the cold front is a warm front extending southeast from the same
low. In the area ahead of these fronts showers will continue through
the forecast period. All of southern Indiana and central Kentucky
will see rainfall, and areas in southern Kentucky near Tennessee
have a slight risk for severe weather. Showers with some thunder
will move into BWG soon. In a couple hours HNB and SDF will start to
see showers before LEX does later this evening. Ceilings are
expected to fall into MVFR. In areas of heavy rainfall expect
visibilities to fall.




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