342
FXUS63 KLMK 192315
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
715 PM EDT Sun May 19 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Dry weather and above normal temperatures weather Monday and
    Tuesday.

*   Unsettled weather late in the week, with highest confidence in
    showers and storms late Wednesday through Thursday.

*   Severe storm potential remains uncertain, with somewhat higher
    confidence in the potential for localized flooding.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 255 PM EDT Sun May 19 2024

This afternoon, high pressure is located over the region, leading to
light winds and mostly sunny skies. A diurnal cu field has developed
atop a deep near-sfc boundary layer; these clouds will gradually
dissipate this evening as we lose daytime heating. Temperatures have
risen into the low-to-mid 80s at this hour, with another 1-2 degrees
of warming expected before temperatures start to cool this evening.

Tonight, once afternoon cu dissipates, clear skies are expected
through the overnight hours as high pressure remains in control. The
combination of clear skies and light winds should promote efficient
radiational cooling after sunset, with temperatures in rural areas
and valleys dropping more quickly than in the urban heat islands.
Agree with the previous forecast thinking that any fog which
develops Monday morning should be confined to river valleys and
sources of greater sfc moisture, as low-level mixing this afternoon
has helped to bring somewhat drier air down to the surface.
Temperatures Monday morning should be fairly similar to this
morning, with lows ranging from the upper 50s in rural areas and
river valleys to the low-to-mid 60s.

Tomorrow, the large-scale pattern across North America will feature
digging upper level troughing along the west coast, SW flow across
the central Plains and upper Midwest, with ridging extending SW to
NE from the southern Plains across the Ohio Valley and into the
northeastern US. While the center of sfc high pressure will be east
of the Appalachians tomorrow, the pressure gradient will remain weak
over the Ohio/TN valleys, with light S/SW winds setting up during
the late morning and afternoon hours. Ridging and associated warm
temperatures aloft should suppress convection tomorrow afternoon,
although FEW-SCT diurnal cu would be expected to develop in the
presence of marginal low-level moisture. The combination of
slightly higher heights aloft and very weak warm advection should
allow us to add 1-2 degrees over persistence, with highs expected to
top out in the mid-to-upper 80s Monday afternoon.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 255 PM EDT Sun May 19 2024

Monday Night through Tuesday Night...

Upper ridging over the eastern CONUS will support very warm temps
and suppress most if not all convection. Temp forecast is a bit
tricky given that vegetation is quite green and soil moisture is
plentiful. GFS output is showing its typical seasonal warm bias, but
other guidance still supports highs in the mid/upper 80s, close to
10 degrees above normal.

Wednesday through Sunday...

Overall pattern turns unsettled for the latter half of the week as
southeast CONUS ridging breaks down. POPs ramp up on Wednesday as a
cold front moves into the Ohio Valley. Model soundings show modest
instability developing Wednesday afternoon, so severe wx can`t be
ruled out completely. However, shear is weak as the stronger
westerlies remain to our north. As such, expect SVR potential to be
limited, but locally gusty winds and heavy rainfall are possible.

Additional waves of showers and storms are possible Thursday and
Friday, but timing is tricky. More confident in Thursday as the
front will be dropping slowly through Kentucky. Look for a break at
some point as the front drops southward into the Tennessee Valley,
but POPs increase again sometime Friday as the boundary waves back
northward as a warm front. Shear remains weak, so our typical pulse
threats of localized gusty winds and heavy rain will be the main
hazards.

POPs remain in the chance range through the weekend as additional
disturbances move through, but would not expect a washout by any
means. Intervals of showers and storms, with substantial dry periods
in between, will be the flavor of the weekend. Temps through the
week will be near normal by day, just either side of 80, and solidly
above climo at night given the humid and at times cloudy environment.

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 714 PM EDT Sun May 19 2024

VFR conditions likely at all terminals throughout this TAF period.
SCT diurnal cumulus has mostly dissipated, and clear skies are
expected overnight. Winds will be very light or calm. Fog is less
likely Monday morning after the near-sfc layer was able to dry out
some this afternoon.

SSW winds will gradually increase to 4-7 kts after 15z Monday.
Expect FEW-SCT fair weather cu with some SCT thin cirrus overhead at
times as well.

&&

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

&&

$$

SHORT TERM...CSG
LONG TERM...RAS
AVIATION...EBW