FNUS73 KLSX 201028 FWSLSX Spot Forecast for Grasshopper Hollow RX...USFS National Weather Service Saint Louis MO 528 AM CDT Fri Mar 20 2026 Forecast is based on ignition time of 0800 CDT on March 20. If conditions become unrepresentative, contact the National Weather Service. .DISCUSSION... Well above normal temperatures will continue today with RH values hitting their minimum in the low 20s this afternoon. Initially light southwesterly winds will become westerly and increase in speed to approximately 5-7 mph at 30 ft. There is only a 10% chance that winds will increase above 12 mph in the burn area, increasing confidence that elevated fire danger criteria will not be met. Mixing will reach above 1,000 ft between 11 AM and 12 PM today and continue to mix into the afternoon, reaching a maximum between 4,000-5,000 ft by 3-4 PM. Winds between 10-15 mph within the mixed layer this afternoon will promote smoke dispersion. A weak, dry cold front will move into the area this evening between 11 PM-1AM, and winds will become northerly behind it. Cooling temperatures with sunset will cause RH to increase and the mixed layer to collapse, trapping any lingering smoke at the surface. .REST OF TODAY... Sky/weather.........Sunny (5-15 percent). CWR.................0 percent. Chance of thunder...1 percent. Temperature.........54 at ignition...Max 86. RH..................77 percent at ignition...Min 21 percent. Eye level winds.....1-2 mph using an adjustment factor of Wind (20 ft)........Winds west at 2 mph at ignition...otherwise Light winds becoming west around 5 mph early in the afternoon, then becoming light late in the afternoon. Mixing height.......500 ft AGL at ignition...otherwise max 6900 ft AGL. Transport winds.....West 12 to 16 mph. Smoke dispersal.....Poor /820 m/s-m/ at ignition. Max...good /13340 m/s-m/. TIME (CDT) 8 AM 10 AM NOON 2 PM 4 PM 6 PM Sky (%).........9 4 1 2 12 17 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............54 66 77 83 86 82 RH..............77 58 42 27 21 25 20 ft wind......W 2 W 3 W 4 W 5 W 4 SW 3 20 ft wind gust.9 12 11 13 14 11 Eye level wind..W 1 W 1 W 2 W 2 W 2 SW 1 Eye lvl wnd gst.4 6 5 6 6 5 Mix hgt (kft)...0.5 0.9 2.4 5.1 6.9 1.1 Transport wind..W 12 W 13 W 12 W 12 W 14 W 10 Vrate kt-ft/1K..5 10 24 51 83 10 Ventrate Cat....POOR POOR POOR FAIR GOOD POOR .TONIGHT... Sky/weather.........Mostly clear (10-20 percent). CWR.................1 percent. Chance of thunder...4 percent. Temperature.........Min 53. RH..................Max 86 percent. Eye level winds.....Light winds. Wind (20 ft)........Light winds. Mixing height.......Min 500 ft AGL. Transport winds.....West 7 to 10 mph shifting to the northeast 6 to 9 mph overnight, then shifting to the east around 7 mph early in the morning. Smoke dispersal.....Poor (390 m/s-m). .SATURDAY... Sky/weather.........Sunny (0-10 percent). CWR.................1 percent. Chance of thunder...4 percent. Temperature.........Max 87. RH..................Min 27 percent. Eye level winds.....Light winds. Wind (20 ft)........Light winds. Mixing height.......Max 5700 ft AGL. Transport winds.....East 6 to 7 mph shifting to the northwest 3 to 8 mph early in the morning. Smoke dispersal.....Poor (300 m/s-m) early in the morning increasing to fair max (6320 m/s-m) in the afternoon. $$ Forecaster...Delia Requested by...Chad Randolph Type of request...PRESCRIBED .TAG 2606655.0/LSX .DELDT 03/20/26 .FormatterVersion 2.0.0