Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 172303

Area Forecast Discussion
National Weather Service Louisville KY
703 PM EDT Thu Oct 17 2019

...Updated for 00Z TAF Discussion...

.Short Term...(This evening through Friday)
Updated at 250 PM EDT Thu Oct 17 2019

Clear and calm conditions being seen across the region currently,
with some scattered cumulus clouds popping up. This quiet weather
will continue through tomorrow as an area of surface high pressure
slowly drifts eastward over us tonight. Expect low temperatures
tonight to drop into the mid to upper 30s, and combined with clear
skies and light winds, some areas of frost will be possible in the
morning, mainly across portions of south-central Indiana and into
central Kentucky. Will go ahead and issue a Frost Advisory for these
areas. Tomorrow, an upper level ridge will build in across the area,
with temps warming gradually into the mid to upper 60s. Winds will
be light out of the east/southeast.


.Long Term...(Friday night through Thursday)
Updated at 315 PM EDT Thu Oct 17 2019

Friday Night - Sunday Night...

As we enter the weekend, the upper pattern will feature a
progressive upper ridge axis across the Great Lakes into New
England, a shortwave trough across the central Plains, and a
tropical system across the Gulf Coast states. Other than the
retreating upper ridge axis, we look to mostly stay between these
features, which should keep us mostly dry. The tropical system looks
to slide well to our SE off the Carolina Coast by Sunday morning,
and it`s associated moisture should mostly miss us. There is a
weakening surface boundary that will try to slide into the area
later Saturday night, and could draw on just enough moisture to
produce a few showers. Will continue to carry low chance pops for
this time to account.

Sunday will be dry with only a small chance of a shower across our
far west CWA by sunrise Monday. During this time, deeper SW flow
will begin over the area as the upper pattern amplifies. We`ll see
increasing clouds and increasing southerly winds in response.

After chilly overnight lows in the low to mid 40s on Friday night,
we`ll see milder lows in the 50s on Saturday and Sunday nights.
Highs will trend toward slightly above normal for this time of year
as Saturday highs in the low 70s give way to Sunday highs in the low
and mid 70s.

Monday - Tuesday...

A mature mid latitude cyclone will move from the upper Midwest into
the Lake Superior region to start the new work week. Amplified
central CONUS troughing will result in deep SW flow over the Ohio
Valley as a 40-45 knot low level jet responds beneath intense mid
and upper level impulses. The deep moisture transport and increasing
forcing associated with these features will result in widespread
rainfall, and likely some scattered thunderstorms. Given the high
shear that will be in place later Monday into Monday evening, can`t
rule out a potential severe threat with this system, however
instability appears to be pretty meager ahead of the cold front at
this point. Regardless of whether there will be a severe threat,
gusty winds are likely on the table as gradient winds look to be
quite strong ahead of the cold front. Wind Advisory levels may be on
the table.

Overall, looks like a good bet for widespread beneficial rains,
likely around or over 1 inch through Monday night. The cold front
passes through with a quick clearing line from W to east early
Tuesday morning. Expect gusty W winds behind the front with
potential for more near Wind Advisory criteria gusts through Tuesday
afternoon. A look at soundings should a deep mixed layer as steep
lower level lapse rates allow for mixing up into at least a 35 knots
layer of winds.

Tuesday Night - Thursday...

We`ll be dry through mid week with temperatures slowly trying to
moderate toward the end of the work week.


.Aviation...(00Z TAF Issuance)
Issued at 700 PM EDT Thu Oct 17 2019

VFR conditions at all sites this entire forecast period.  North-to-
south oriented surface high pressure ridge lying just east of the
Mississippi River at 22Z will drift east into the Appalachians by

VRB04kt p6SM SKC would be sufficient for all terminals, but put in a
little directional wind detail for tomorrow afternoon to account for
return flow on the back side of the ridge.


IN...Frost Advisory from 2 AM EDT /1 AM CDT/ to 9 AM EDT /8 AM CDT/
     Friday for INZ076>079-083-084-089>092.

KY...Frost Advisory from 2 AM EDT /1 AM CDT/ to 9 AM EDT /8 AM CDT/
     Friday for KYZ024-025-027>043-045>049-053>057-062>067-



Short Term...JML
Long Term...BJS
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