Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 161735
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
135 PM EDT Sat Mar 16 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

* Fog has developed over the region bringing low visibilities,
  especially in river valley areas. Fog will dissipate with sunrise.

* Drier and less active weather for the weekend.

* Unseasonably cold for the start of the week with freezing
  temperatures expected Monday and Tuesday morning.

* Above normal temperatures and precipitation chances return for the
  end of the week.

&&

.UPDATE...
Issued at 1028 AM EDT Sat Mar 16 2024

Visibile satellite imagery still shows some lingering areas of dense
valley fog across central KY but area webcams are showing fog
quickly mixing out this morning.  Went ahead and let the Dense Fog
Advisory expire as scheduled. With clear skies and some afternoon
mixing, the going forecast continues to be on track so no changes to
the grids other than the Dense Fog Advisory expiring.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 335 AM EDT Sat Mar 16 2024

Light winds, clear skies, and recent rainfall has allowed for fog to
develop over the region. Dense fog, with visibilities as low as a
half mile, has developed in our eastern river valley areas. These
conditions are expected to continue through the overnight hours. A
Dense Fog Advisory has been issued for central Kentucky through the
Bluegrass region. If conditions worsen in other areas, this Advisory
may be expanded. With sunrise, fog conditions will begin to erode.

Weak surface ridging will keep light southwesterly winds and mostly
clear skies over the region. Expecting to see high temperatures this
afternoon in the low-mid 60s. This atmospheric set-up suggests dry
air mix down in the afternoon, which will bring RH into the low 30s
and gusty winds on the order of 15-20 mph.

A low pressure system moving east over the northern Great Lakes will
bring a cold front through the Ohio Valley tonight into Sunday
morning. Ahead of the cold front, an enhanced upper-level jet and a
small band of vorticity will move over the Ohio Valley in the late
afternoon and early evening. This could lead to some isolated
showers over central Kentucky and southern Indiana. However, these
showers are limited by the dry low-levels, which may lead to very
light drizzle/sprinkles or virga. In the overnight hours, jet
dynamics places small PoPs and very light rain/sprinkles over our
far northeastern counties and most southern tier of counties as the
front moves through. Otherwise, the cold front will bring a cooler
temperatures and breezy overnight winds on the order of 10-15 mph.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 335 AM EDT Sat Mar 16 2024

Pattern will be amplifying Sunday with a developing Rex block over
the western CONUS and a digging trof in the eastern CONUS. At the
sfc a dry cold front will move through Sunday morning, with strong
cold advection setting up as an upper vort lobe diving down the
western flank of a 519 dam closed low over Quebec brings a shot of
polar air into the Ohio Valley. Forecast highs in the 50s on Sunday
are on the low end of guidance but may end up too generous in this
pattern.

Another disturbance in the NW flow aloft drops in Monday, with the
core of the cold air Monday night. Not confident enough to include
POPs at this time, but could be just enough moisture to squeeze out
a few flurries over the Bluegrass region in the late afternoon/early
evening. Will keep an eye on this in subsequent forecast cycles.
What we are confident in is subfreezing temps both Monday morning
and Tuesday morning, with the potential for a hard freeze that could
impact early blooming vegetation. No headlines at this time as the
growing season has yet to really get underway based on coordination
with our ag partners. Daytime temps on Monday will struggle into the
lower/mid 40s, roughly 15 degrees below normal. Dry conditions will
continue through midweek, with temps recovering to near normal for
mid-March by Wednesday.

Late in the week the continued warming trend will push temps above
climo, but with increasing precip chances. Upper low starts to kick
out of the Four Corners Wednesday, and we could start to draw Gulf
moisture northward into the Ohio Valley as early as Thursday. Will
limit POPs to the 20-30% range, but increase from there on Friday.
The rain chances will continue into Saturday, not to reflect a multi-
day washout so much as low confidence in the timing.

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 133 PM EDT Sat Mar 16 2024

Fog has mixed out and skies are mostly clear this afternoon thanks
to a sfc ridge building in over the Ohio Valley today. Flight
categories will remain VFR through the forecast period. The main
impacts through the period will be some gusty southwesterly winds
that could gust 15-20 kts. A cold front across the Upper Midwest
will work southward and into the Ohio Valley later tonight. As the
boundary works through it will be relatively moisture starved
outside some mid clouds that will push through. The boundary will
also swing winds around to more west-northwest. Clouds will clear
out and remain quiet through the day tomorrow.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

UPDATE...BTN
SHORT TERM...SRM
LONG TERM...RAS
AVIATION...BTN/SRM


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