Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 172323
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
723 PM EDT Sun Mar 17 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

* Turning unseasonably cool tonight through Monday night, with
  subfreezing temperatures possible both nights.

* Dry and breezy on Tuesday, resulting in some fire weather
  concerns.

* Near normal temperatures and precipitation chances return towards
  the second half of the week.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 257 PM EDT Sun Mar 17 2024

Our region will remain in strong W-E zonal flow aloft the remainder
of today and tonight as anomalously low H5 heights are noted over
eastern Canada and the Great Lakes. At the surface, we are post-
frontal with a strong Canadian airmass steadily advecting into our
area through tomorrow.

We`ll continue to see gusty W-WNW winds in the 20-30 mph range
through early evening as cold advection has taken hold and steeper
low level lapse rates is allowing for good mixing. Temps should stay
in the 50s, but the cool NW winds will likely make it feel colder,
especially into the early evening.

Look for a quiet night with temperatures falling under continued
cold advection. Looking for a pretty hard freeze in many spots as
temperatures fall into the 25 to 30 degree range for most. The
growing season hasn`t officially began yet (per collab with ag
partners), however some early blooming vegetation will likely be
affected. Will likely message the hard freeze these next two nights
in an SPS.

A shortwave rotating through the parent trough will approach
tomorrow, with increasing mid level clouds. 850-700 mb moisture is a
bit more impressive than it was yesterday at this time, however
would still only expect a few sprinkles/flurries at best given the
dry air below H85, and the relatively high cloud bases. Given the
increasing clouds and continued cold advection, expect highs to
struggle tomorrow, only reaching the low and mid 40s. It is possible
some spots don`t get out of the upper 30s in our NE CWA. These temps
are well below normal for this time of year. Look for gusty winds
again tomorrow, although maybe not as strong as today given the
increased cloud cover hurting mixing a bit.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 257 PM EDT Sun Mar 17 2024

Upper trough axis will push eastward and off the Mid-Atlantic coast
by Tuesday morning as 500m heights increase over the Ohio Valley. At
the surface, high pressure will continue to build in over the Lower
Mississippi Valley helping to back winds from the northwest to the
southwest by Tuesday morning. Although winds will remain high enough
to minimize radiative cooling under clear skies, 850T will be
between -6 to -9C with a very dry column allowing temperatures to
easily fall into the mid/upper 20s with a few protected valleys into
the low 20s. Although we have various trees and other vegetation
beginning to bloom, the growing season hasn`t officially started so
no frost/freeze headlines are planned.

Rex blocking pattern across the western CONUS from the start of the
week will start to breakdown for the middle of the week. Close upper
low over the Desert Southwest will get picked up by the Subtropical
Jet as the northern Polar stream sets up a northwest flow over the
Great Lakes and Ohio Valley. It will remain dry through at least
Thurs thanks to sfc high pressure building in over the region and
with increased heights, temperatures will return to seasonal norms
ranging from the low/mid 50s on Tues to upper 50s/low 60s on Wed
with morning lows in the mid/upper 30s. The one thing to watch for
Tuesday will be increased southwest winds as a sfc low work across
the upper Great Lakes tightening the pressure gradient over the Ohio
Valley. With plenty of dry air within the column, may need to watch
this period for elevated fire weather concerns.

As the aforementioned closed low opens up into a shortwave trough
Wednesday night it will work eastward across the southern US into
Lower Mississippi Valley and TN Valley for the end of the week. As
sfc high over the Ohio Valley departs to the east Thurs. a sfc low
is expected to develop along the Gulf Coast of the southern US and
move over FL by Fri. An inverted sfc trough will work across both
the TN/OH Valley increasing precipitation chances over the area late
Thurs night through the day Friday with PoPs ranging between 20-35
percent. Temperatures will be near normal with highs around 60
degrees and lows in the mid/upper 30s to low/mid 40s.

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 723 PM EDT Sun Mar 17 2024

VFR conditions are expected through the upcoming TAF period.  While
we`re in the post frontal airmass, a band of stratocu will move
through southern IN and northern KY this evening producing a deck of
clouds at KHNB/KSDF and eventually KLEX.  Winds are still gusty this
evening, but will likely diminish right after sunset.  Winds will
remain up overnight which will keep fog development low.  VFR
conditions are expected for Monday. Winds will pick up by mid-late
morning and remain gusty into the afternoon with a sct-bkn deck
redeveloping across the region.

&&

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

&&

$$

SHORT TERM...BJS
LONG TERM....BTN
AVIATION.....MJ


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