961
FXUS63 KLMK 081226
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
826 AM EDT Sun Sep 8 2024

.KEY MESSAGES...

* Fair weather today and Monday with chilly mornings and pleasant
  afternoons with plenty of sunshine.

* Overnight lows tonight will dip into the 40s. Temperatures in the
  low to mid 40s could approach or break low temperature records at
  Lexington and Frankfort.

* Dry weather through at least Wednesday.

* A few spots will touch 90 degrees Tuesday and Wednesday.

* A tropical system may bring showers to the region Thursday night
  through Friday night. Confidence is low concerning rainfall
  amounts. No severe weather is expected.

* Overall, odds are tilted toward warmer and drier than normal
  conditions through the first few days of October. Drought
  increased in areal coverage over the past week and may spread and
  intensify further over the next few weeks.

&&

.UPDATE...
Issued at 825 AM EDT Sun Sep 8 2024

Cool start to the morning, but each climate site stayed just above
record low values. Cold spot for the morning was 38 at Brandenburg
Kentucky Mesonet station! Looks like a beautiful Sunday morning
across the region. Some light river fog over our region should be
quick to burn off. Forecast highs still look good for the low-mid
70s today.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 312 AM EDT Sun Sep 8 2024

A closed upper low is spinning northeast into southwestern Quebec
this morning, with upper level troughing extending south into the
Ohio Valley. This system will continue to pull away to the northeast
today, followed by mid and upper level ridging building in from the
northwest tonight. A very dry airmass is in place. Sfc high pressure
over MO/IL will drift lazily ESE over the Lower OH Valley later
today and tonight.

Expect clear skies and light northeasterly winds. We`ll see chilly
mornings this weekend along with pleasant afternoons. Temperatures
are in the upper 40s to mid 50s at the moment and will continue to
slowly fall through sunrise. Temps in the mid 40s to lower 50s
should be common by daybreak. Temperatures will warm into the low to
mid 70s this afternoon before tumbling back into the 40s early
Monday morning. Our coolest sheltered locations will likely dip into
the lower 40s, and there is a small chance (~10% chance) for a few
upper 30s in our coolest valleys in the Bluegrass Region.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 312 AM EDT Sun Sep 8 2024

The Great Lakes upper troughing from the weekend will lift into
eastern Canada allowing the western ridge to slide eastward and
slowly amplify over the course of the week (though interrupted by a
tropical system coming up out of the Gulf...more on that later). At
the surface, high pressure will drift from the Ohio Valley to the
East Coast, suppressing convection well to our south near the Gulf
of Mexico. As a result, we`ll have dry and much warmer conditions
through at least early Thursday. While high temperatures will still
only be around the lower 80s on Monday (just a couple degrees below
where they should be at this time of year), highs Tuesday will be in
the 85-90 degree range, and on Wednesday the mercury will rise into
the upper 80s and lower 90s (4 to 9 degrees above normal). Dew
points will be comfortable, hovering around the 40s Monday and
Tuesday...lo-mid 50s Wednesday.

Of significant interest this week will be a tropical system over the
western Gulf, which will be our only chance of rain as it approaches
the region toward the end of the work week. Models are actually in
decent agreement taking this area of low pressure currently over the
Bay of Campeche generally northward through the western Gulf of
Mexico and then landfalling in Louisiana. However, once the system
comes ashore, confidence decreases. At this time it appears that the
disturbance will move up the lower Mississippi Valley, weakening as
it does so. Sometimes tropical systems can bring our region large
amounts of rainfall. However, this system will already be relatively
weak as it runs into pre-established upper ridging, and PWATs are
expected to be only slightly above normal. Though the 00Z/08
operational ECMWF has come in quite wet, there`s plenty of variation
among the various inter-model QPF plumes. It`s worth noting that the
operational GFS is wetter than the model`s mean. Given these factors
plus the fact that we`re talking about a tropical system that`s only
recently begun to develop and is still several days away, confidence
is low regarding widespread significant rains. While it`s definitely
something worth watching, at this time it would be premature to get
hopes too high for heavy rainfall amounts. Stay tuned, though.

Drought?
Though winds will be light, the warm temperatures, low
daytime humidity levels, and copious amounts of sunshine early-mid
week will encourage strong evaporation rates. The potential for
tropical showers late this week notwithstanding, CPC outlooks are
calling for odds tilting toward warmer and drier conditions to
prevail overall through the first few days of October. Drought has
already intensified and increased in geographical coverage in the
Ohio Valley during the past week. Further drought development
appears to be a good possibility in the coming weeks if the outlooks
verify, particularly if this Friday`s rains underperform.

&&

.AVIATION /12Z TAFS THROUGH 18Z MONDAY/...
Issued at 637 AM EDT Sun Sep 8 2024

VFR weather expected. Sfc high pressure currently centered over
Illinois will drift ESE over the Lower OH Valley today into tonight.
Expect clear skies and light northeasterly winds through the period.
Dry air in place is expected to continue to limit the fog potential.

&&

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

&&

$$

UPDATE...RJS
SHORT TERM...EBW
LONG TERM...13
AVIATION...EBW