National Weather Service Raw Text Product

761 
FXUS63 KLMK 231046
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
646 AM EDT Tue Apr 23 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Southwest winds will gust 25-35 mph today, especially this 
    afternoon.

*   The gusty winds combined with filtered sunshine and temperatures 
    rising into the lower and middle 70s may lead to slightly 
    increased fire danger this afternoon in exposed areas where 
    fuels can lose moisture.

*   Light rain showers this evening and tonight, especially along 
    and north of I-64. 

*   Lows in the 30s Wednesday night from southern Indiana into the 
    northern Bluegrass region, and typical cold spots. 

*   Active weather Friday through the weekend, but plenty of 
    uncertainty in timing of any intervals of showers and 
    thunderstorms.

*   Weekend will feature temperatures in the 80s and breezy 
    southerly winds.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 303 AM EDT Tue Apr 23 2024

Southwest winds between low pressure over the Great Lakes and high 
pressure over Georgia and South Carolina, combined with sunshine 
filtered through high clouds, will bring us a warm and breezy spring 
day today. Winds gusting 25-35mph this afternoon will help to push 
temperatures into the lower and middle 70s.

The low to our north will advance along the St Lawrence River 
tonight and drag its trailing cold front through the Ohio Valley. 
The front will be weakening as it passes through and will have only 
a narrow band of moderately enhanced atmospheric moisture pooling 
along it, mostly in the mid and upper levels. Instability continues 
to look meager. So, a band of showers, mostly light, is expected to 
enter southern Indiana from the north by early evening and proceed 
southeastward across central Kentucky tonight, ending by the time 
the sun comes up tomorrow morning. General rainfall amounts over 
southern Indiana around a quarter to a third of an inch will 
diminish to less than a tenth of an inch in southern Kentucky. 

Despite the cold frontal passage, low temperatures by dawn will only 
fall to the upper 40s in southern Indiana and to the mid 50s in 
southern Kentucky, with colder air well behind the front over the 
upper Great Lakes closer to a dome of Canadian high pressure over 
Ontario.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 303 AM EDT Tue Apr 23 2024

===== Wednesday - Thursday =====

Dry weather is expected for our Wednesday and Thursday as sfc high 
pressure slides across the Great Lakes. Temperatures will be near 
normal for this time of year, with highs on both days on either side 
of 70F. For areas north of the Ohio River and in the Bluegrass 
region, temps could perhaps be a few degrees cooler where cloud 
cover may linger into the afternoon peak heating hours. Wednesday 
night and into Thursday morning should be a decent radiative cooling 
night, with clear skies and light winds. Temps will range from upper 
30s across the Bluegrass region to the mid 40s across south-central 
Kentucky. Some of our traditional cool spots may underachieve 
forecast lows, so maybe another opportunity for some isolated frost 
development in the Bluegrass.  


===== Friday - Weekend =====

While the mid-week will be quiet in the Ohio Valley, the upper flow 
transitions across the southwestern US as an upper low deepens and 
pivots towards the Plains. Deep southwesterly flow will take over by 
Thursday night, resulting in mild temps for Friday morning. Warming 
trend will continue for Friday and into the weekend, with temps 
warming to the low-mid 70s on Friday, and temps surging into the 80s 
for Saturday and Sunday. 


Precip Discussion... As for precip chances, we'll see PoPs make a 
return to the forecast by Friday morning. The aforementioned upper 
low will likely be located east of the Rockies by Friday morning, 
with a cold front stretching to the south into Texas, and a warm 
front extending out to the east and into the Tennessee Valley. This 
warm front boundary will push northward during Friday, bringing 
increased rain chances and isolated thunder to our area. Highest 
PoPs of Friday will be during the daytime hours. Model soundings are 
not too impressed with instability profiles, though the shear will 
likely increase later in the day as a broad LLJ expands into the 
lower Ohio Valley as the upper low spins towards the Great Lakes 
region. 

We'll remain in the warm sector of the low pressure system through 
the weekend, with some mid-level vorticity lobes swinging around the 
parent upper low to provide additional forcing. This will likely 
lead to additional on and off rain chances through the weekend. 
Still don't have much confidence on timing each little disturbance, 
so will keep a broad brush PoP going for majority of the weekend. If 
there's any area that has the best chance of being mostly dry this 
weekend, it'll be the Lake Cumberland region. 


Wind Discussion... A breezy period is expected for Friday and into 
the weekend as southerly sfc winds ramp up. To start things off, 
we'll likely see wind obs increase by the Friday afternoon hours as 
the LLJ expands eastward and the sfc pressure gradient tightens. Sfc 
winds will continue to ramp up for Saturday and Sunday as the 
pressure gradient remains in place, with each afternoon having high 
probabilities of wind gusts greater than 30 mph. For Saturday 
afternoon, roughly 80-90% of EPS members suggest wind gusts greater 
than 30 mph will be concentrated from Lexington and I-75 and 
pointing westward. For Sunday afternoon, between 70-85% of EPS 
members indicate wind gusts greater than 30 mph for the same areas. 
Probabilities for gusts greater than 40 mph fall below 40% at this 
time, but it's worth keeping an eye on in the coming days. 


==== Early Next Week =====

Another upper low system for early next week looks to follow a 
similar track as the late week system discussed above. This will 
likely bring shower and storms to the region for Monday. As of now, 
model soundings don't show much sfc-based instability, but will keep 
tabs on the trends throughout the coming days.

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 645 AM EDT Tue Apr 23 2024

Winds will pick up today in a tight gradient between low pressure 
crossing the Great Lakes and high pressure over Georgia and South 
Carolina. Winds coming in from the southwest will gust 20-30kt, 
especially this afternoon.

Tonight the low to our north will drag a cold front into the Ohio 
Valley. Light rain and lower ceilings will accompany the front, but 
flying conditions should prevail low-end VFR. The rain will only 
last a few hours before the front pushes through, and winds will be 
much lighter than what we will have seen during the day.

&&

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

&&

$$

SHORT TERM...13
LONG TERM...CJP
AVIATION...13