Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 171751

Area Forecast Discussion
National Weather Service Louisville KY
1251 PM EST Wed Jan 17 2018

...Updated Aviation Discussion...

.Forecast Update...
Updated 1028 AM EST Wed Jan 17 2018

Light snow and flurries continue across the region. This activity
should diminish this afternoon as the upper trof axis passes off to
our east and low level moisture wanes. In the meantime, a dusting of
accumulation will be possible under the stronger patches of
snowfall. Flakes will linger longest in the Blue Grass.

Updated 856 AM EST Wed Jan 17 2018

Several reporting locations around the region have been reporting
reduced visibility in -SN and returns are showing up on radar. Have
also received reports of light snow sticking to the ground in a few
locations. Looking out the window here at the weather office, the
light snow that is falling is probably a little more than what most
folks would consider "flurries." So, have upped the chance of
measurable snow to a mentionable value around 20% for the rest of
the morning.


.Short Term...(This afternoon through Thursday evening)
Issued at 310 AM EST Wed Jan 17 2018

First off, have had a persistent band of radar returns along I-65
near Shepherdsville. Have issued a couple of special weather
statements for light to moderate snow along this band, as traffic
monitoring programs have been showing slow downs in that area.
Trends in radar and satellite products is for that band to weaken.

Otherwise, latest water vapor imagery showing broad upper trough
oriented along the Ohio River Valley this hour. At the surface, have
a 1044 mb high pressure centered over the Central Plains, with a
ridge axis over the region. The trough looks to close off into an
upper low over the Appalachians later today, whereas the surface
high will drop into the lower MS valley through Thursday.

Until southwest winds become more established Thursday, we will have
to deal with very cold temperatures. Cloud cover early this morning,
though it is bringing a few flurries is allowing us to stay just
warm enough, with most locations staying above zero. Sites south of
the cloud shield earlier made it to several degrees below zero. We
should stay under this shield for much of the day, though we may
break out by late afternoon. After that we should stay clear into
Thursday, helping out with our warmup.

.Long Term...(After midnight Thursday night through Tuesday)
Issued at 310 AM EST Wed Jan 17 2018

Ridging moves into the Midwest to close out the work week, promising
a continued warming. Will still have to go a little under guidance
for temperatures until we can melt off the snowpack. We may see some
light rain showers Saturday. The southerly flow will pick up further
on Sunday, as our next storm system approaches the region. At this
point, models are focused on the Monday time frame for the best
chances for rains along the associated cold front. We then return to
some near normal temperatures Tuesday.


.Aviation...(18Z TAF Issuance)
Issued at 1240 PM EST Wed Jan 17 2018

Fuel alternate remains in BWG, SDF, and LEX. The low level cloud
cover producing light snow has moved southeast of HNB. The clearing
will slowly continue to move southeast. SDF will clear this
afternoon. BWG and LEX will clear around sunset. VFR conditions will
prevail after the clearing. Winds are out of the west at 5-8 knots.
Winds will trend to a south wind through the forecast period.




Short Term...RJS
Long Term...RJS
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