167
FXUS63 KLSX 141956
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
256 PM CDT Fri Jun 14 2024

.KEY MESSAGES...

- Temperatures are expected to remain above normal through next
  week with high temperatures mainly in the 90s. Sunday and
  Monday will be the warmest days with peak heat index values in
  the upper 90s to 105 degree range.

- There is a low chance (20 percent) of showers and thunderstorms
  over central Missouri late tonight and tomorrow. There are
  multiple chances (20-30 percent) for scattered showers and
  thunderstorms across the area next week.

&&

.SHORT TERM...  (Through Late Saturday Night)
Issued at 254 PM CDT Fri Jun 14 2024

Latest surface analysis is showing that a surface front extending
across far southern Illinois into southern Missouri into southern
Kansas.  The RAP is showing the front moving back to the north
across parts of Kansas and southwest Missouri late tonight in
response to a upper trough moving into the Plains.  Scattered
showers and thunderstorms will develop late tonight when the low
level jet interacts with the front.  This activity will eventually
move into the western CWA tomorrow morning and diminish as the low
level jet veers and the instability weakens as it moves to the east.
Saturday night looks dry as the aforementioned upper trough shears
out and stays to our north.

Lows tonight will drop down into 60s under a clear sky with light
winds with a dewpoints in the 50s. Highs tomorrow will be similar
to today with winds turning out of the east under a partly cloudy
sky. Winds will turn out of the south on Saturday night keeping
lows in the 60s.

Britt

&&

.LONG TERM...  (Sunday through Next Friday)
Issued at 254 PM CDT Fri Jun 14 2024

There is reasonable agreement between the global models and the LREF
that the upper ridge will move east of the area by Sunday and then
expand into a large area of high pressure that will cover the
eastern CONUS by the middle of next week. The surface high will
move from the Great Lakes to off the northeast coast by early next
week. This will allow a warm front to move northeast through the
area Saturday night into early Sunday. Thereafter, the low level
flow will stay mainly from the south the rest of the period as the
front will stay to the north where the westerlies will be shunted
north by the upper high. The LREF members are showing some low
chance (20-30%) for showers and thunderstorms at times next week
as weak systems will move across Missouri and Illinois at the same
time a deep flow of moisture will move up from the Gulf of
Mexico.

High temperatures will be mainly in the 90s next week as 850mb LREF
temperatures are forecast to staying around 20C.  The warmest days
are still forecast to be Sunday and Monday with highs in the mid-
upper 90s and dewpoints in the middle 60s to around 70. This will
result in some locations reaching heat index readings of 100-105
degrees during the afternoon hours.  After Monday, confidence in
reaching heat index levels is not as high as temperature and
dewpoints are not forecast to match up to reach critical levels. The
NBM IQR is wider Tuesday through next Friday (6-8 degrees) than it
is on Saturday through Monday (3-4 degrees) at St. Louis.

Britt

&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1237 PM CDT Fri Jun 14 2024

Dry and VFR conditions are expected through the period. Northerly
surface winds will veer out of the east by Saturday morning.

Britt

&&

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

$$

WFO LSX