FXUS63 KLSX 100252

AFDLSX



Area Forecast Discussion...Updated Aviation

National Weather Service Saint Louis MO

952 PM CDT Fri May 9 2025



.KEY MESSAGES...



-Dry weather continues through Sunday before a return to an active 

pattern next week.



-Temperatures will continue warming through next week.





&&



.SHORT TERM...  (Through Late Saturday Night)

Issued at 127 PM CDT Fri May 9 2025



A surface high has moved into the mid-Mississippi Valley today and 

the center of this feature will slide over the forecast area 

tonight. A clear sky and calm winds from the high will allow for 

effective cooling and Saturday morning's lows will drop into the low 

to mid 40s across much of the area. More sheltered locations could 

see lows near or just below 40 degrees. 



A mid-level low will stall across the lower Mississippi Valley over 

the weekend, and combined with the persistent surface high, will 

result in dry conditions and a clear sky. So despite the chilly 

start, another day of abundant sunshine and mild warming aloft will 

allow temperatures to warm into the mid 70s across the area Saturday.



Delia



&&



.LONG TERM...  (Sunday through Next Friday)

Issued at 127 PM CDT Fri May 9 2025



The surface high's influence will continue through Sunday, keeping 

the weekend dry across the forecast area. For the St. Louis region 

this will feel like a special treat. The last dry weekend recorded 

at KSTL was April 11-12! By Monday this blocking pattern will begin 

to erode and the mid-level low will drift northeastward into the 

Ohio River Valley. As the low moves east of the forecast area it 

will bring an increase in shower and thunderstorm chances Monday and 

Tuesday, mainly during the afternoon, enhanced by diurnally driven 

instability.



While the best forcing and moisture for rain will be east of us 

across the Ohio River Valley, chances for rain do extend up into our 

forecast area, mainly across southeast Missouri and southern 

Illinois. Rain is projected to be light, with only a 50% chance of 

exceeding 0.1" across southeast Missouri and southern Illinois. By 

Tuesday evening the mid-level low will be sliding away from the mid-

Mississippi Valley, allowing a mid-level ridge to move into the 

region within the southern stream flow. This ridge will prompt a 

drier mid-week period and kick our warming trend into high gear with 

highs reaching into the 80s to near 90 for the second half of the 

work week. 



While the ridge will be in place across the area into the end of the 

work week, a northern stream trough will swing across the US-Canada 

border into the Great Lakes region by the end of the work week. The 

surface reflection will bring a cold front through the area at the 

end of the work week and the chance for showers and thunderstorms 

returns to the area.



Delia



&&



.AVIATION...  (For the 06z TAFs through 06z Saturday Night)

Issued at 952 PM CDT Fri May 9 2025



VFR flight conditions and light winds are expected to prevail

through the period.



Carney



&&



.LSX WATCHES/WARNINGS/ADVISORIES...

MO...None.

IL...None.

&&



$$



WFO LSX