653
FXUS63 KLSX 282314
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
614 PM CDT Tue May 28 2024

.KEY MESSAGES...

- Isolated showers and thunderstorms will move southeast across parts
  of northeast Missouri and west central and southeast Illinois
  through early this evening. Gusty winds are possible with the
  stronger storms.

- Dry weather is expected Wednesday and Thursday with near normal
  temperatures.

- The chance of showers and a thunderstorms will return Thursday
  night through next Tuesday with temperatures climbing above
  normal. The risk for strong to severe weather remains low.


&&

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 158 PM CDT Tue May 28 2024

Latest water vapor imagery is showing another shortwave trough
moving southeast across the Upper Midwest that the RAP brings the
southern end of it across the area later this afternoon and early
this evening. The weak ascent provided by this shortwave and weak
instability (RAP MUCAPES in the 500-1000 J/kg range) support keeping
isolated showers and thunderstorms across northeast Missouri and
west central and south central Illinois through early this evening.
Like yesterday, RAP soundings are showing some inverted V profiles,
so couldn`t rule out some gusty winds with some of the stronger
storms.  These storms will die out after sunset with the loss of
daytime heating, and then expect dry weather through tomorrow night
as the HREF is showing a upper ridge and a surface high moving in
from the Plains.

Temperatures will be slightly cooler over the next 24-36 hours as the
surface ridge moves through the area causing the winds to veer from
northwest to northeast.  this will cause weak cold air advection and
temperatures too fall slightly below normal.

Britt

&&

.LONG TERM...  (Thursday through Next Tuesday)
Issued at 158 PM CDT Tue May 28 2024

There is reasonable agreement in the global models with a upper
ridge moving through the area on Thursday and a shortwave trough
moving through the Midwest slightly slower on Saturday compared to
yesterday. Thereafter, we will be in quasi-zonal flow going into
early next week which the individual models have different timing
of subsequent shortwaves. At this point the LREF has the most
members (40-50%) showing precipitation chances on Friday night and
Saturday and again Monday into Tuesday with a break in between.
Severe weather chances during this period looks relative low as
the overall CAPE/shear parameter space in the model guidance is
not nearly as supportive of the level of severe weather that we
have seen in the past week and the CIPS/CSU guidance is not
particularly impressive.

Temperatures will start out just below normal on Thursday before
climbing above normal Sunday through Tuesday as 850mb temperatures
increase and low level flow turns more south-southwesterly.
Confidence in the warm up is increasing as the NBM IQR is only
4-6 degrees through next Tuesday.

Britt

&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 614 PM CDT Tue May 28 2024

Scattered showers and sub-severe thunderstorms will continue into
very early evening, weakening both with time and southern extent.
After these diminish, dry and VFR conditions will prevail through
the TAF period with surface winds veering to northerly by tomorrow
morning.

Jaja

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX