135
FNUS73 KLSX 301333
FWSLSX

Spot Forecast for Horton Farm Unit 3...Missouri Department of Conservation
National Weather Service Saint Louis MO
733 AM CST Tue Dec 30 2025

Forecast is based on ignition time of 0900 CST on December 30.
If conditions become unrepresentative, contact the
National Weather Service.

.DISCUSSION...
Light northwest wind will turn slowly to the west and then southwest
by the end of the day as a ridge of high pressure crosses the area.
There is a strong inversion this morning with mixing heights below
1000 feet.  It is unlikely that the mixing height will rise above 1600
feet until 1200 to 100 PM.  Light winds below the inversion will produce
poor ventilation rates.

.REST OF TODAY...

Sky/weather.........Sunny (15-25 percent) then becoming partly
                    sunny (55-65 percent).
CWR.................0 percent.
Chance of thunder...0 percent.
Temperature.........20 at ignition...Max 37.
RH..................67 percent at ignition...Min 34 percent.
Eye level winds.....Light northwest wind at ignition turning
                    to the west by around noon and then the southwest
                    by 400 to 500 PM.
Wind (20 ft)........Winds northwest at 7 mph at
                    ignition...otherwise West winds 6 to 7 mph
                    shifting to the southwest around 6 mph late in
                    the afternoon.
Mixing height.......900 ft AGL at ignition...otherwise max 2500 ft
                    AGL.
Transport winds.....West 10 to 16 mph.
Smoke dispersal.....Poor /2260 m/s-m/ at ignition. Max...marginal
                    /5590 m/s-m/.

TIME (CST)      9 AM   11 AM  1 PM   3 PM   5 PM   7 PM
Sky (%).........2      5      25     54     57     32
Weather cov.....
Weather type....NONE   NONE   NONE   NONE   NONE   NONE
Tstm cov........
CWR.............0      0      0      0      0      0
Chc of thdr (%).0      0      0      0      0      0
Temp............20     28     33     36     35     32
RH..............67     48     38     35     38     45
20 ft wind......NW 7   W 6    W 6    W 7    SW 6   SW 6
20 ft wind gust.13     11     11     13     11     12
Eye level wind..NW 3   W 3    W 3    W 3    SW 3   SW 3
Eye lvl wnd gst.6      5      5      6      5      6
Mix hgt (kft)...1.3    1.8    2.2    2.5    1.0    0.6
Transport wind..NW 13  NW 13  W 13   W 16   W 10   W 14
Vrate kt-ft/1K..14     20     25     36     9      7
Ventrate Cat....POOR   POOR   POOR   POOR   POOR   POOR

.TONIGHT...

Sky/weather.........Partly cloudy (25-35 percent) then becoming
                    mostly clear (5-15 percent).
CWR.................0 percent.
Chance of thunder...0 percent.
Temperature.........Min 27.
RH..................Max 81 percent.
Eye level winds.....Light southwest wind shifting to the west.
Wind (20 ft)........Southwest winds around 6 mph shifting to the
                    west 7 to 9 mph after 3 am.
Mixing height.......Min 600 ft AGL.
Transport winds.....West 13 to 18 mph.
Smoke dispersal.....Poor (1040 m/s-m).

.WEDNESDAY...

Sky/weather.........Mostly sunny (35-45 percent).
CWR.................0 percent.
Chance of thunder...0 percent.
Temperature.........Max 45.
RH..................Min 58 percent.
Eye level winds.....Light west wind.
Wind (20 ft)........West winds 5 to 7 mph.
Mixing height.......Max 2500 ft AGL.
Transport winds.....West 12 to 18 mph.
Smoke dispersal.....Poor (1040 m/s-m) early in the morning
                    increasing to fair max (6100 m/s-m) in the
                    afternoon.

$$
Forecaster...Carney
Requested by...Cassidy Morrison
Type of request...PRESCRIBED
.TAG 2528136.0/LSX
.DELDT 12/30/25
.FormatterVersion 2.0.0