FNUS73 KFSD 211120 FWSFSD Spot Forecast for Lake Fire...USWFS-Yankton Agency National Weather Service Sioux Falls SD 620 AM CDT Tue Apr 21 2026 If conditions become unrepresentative, contact the National Weather Service. ...FIRE WEATHER WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING... .DISCUSSION... Issued at 620 AM CDT Tue Apr 21 2026 Heading into southcentral SD, another warm day is expected as highs peak in the mid 80s for the day. As mixing increases just after daybreak, smoke dispersal will gradually improve. Light and variable winds this morning will gradually become more northeasterly into the early afternoon with sustained winds in the 5-10 mph range although an occasional gust up to 15 mph can't completely ruled out. Otherwise, drier conditions are expected from late morning through the early evening with relative humidity values between 15-20 percent expected as early as 2 pm. Lastly, low to locally moderate fire danger will persist through this evening. Looking ahead, strong southerly winds (35-45 mph) will return by Wednesday along with critical relative humidity values (15%-20%). This combined with unseasonably warm temperatures will lead to dangerous fire concerns from late morning through early evening. .TODAY... Max temperature.....Around 84. Min humidity........17 percent. TIME (CDT) 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky cover.......MCR MCR MCR CLR CLR CLR MCR MCR MCR PC MCR Sky (%).........7 13 8 5 3 4 10 14 17 26 18 Weather cov..... Weather type.... Tstm cov........ Chc of pcpn (%).0 0 0 0 0 0 0 0 0 0 0 Chc of thdr (%).0 0 0 0 0 0 0 0 0 0 0 Temp............51 50 56 65 70 75 78 82 83 83 84 Dewpoint........30 31 33 36 36 37 37 37 35 35 35 RH..............45 48 42 34 29 25 23 20 18 18 17 20 FT wind dir..WNW NW NNW NNW N N NNE NE NE ENE E 20 FT wind spd..6 6 7 7 8 8 9 9 10 9 9 20 FT wind gust.9 9 12 12 13 13 14 14 14 14 14 Mix hgt (kft)...0.4 0.4 0.5 1.1 1.4 2.5 3.6 4.6 5.4 5.8 5.9 Transp wind dir.NW NW NNW N N N NNE NNE NNE NE ENE Transp wind spd.9 9 9 9 9 10 10 10 10 9 9 Smoke Dispersal.PR PR PR PR PR FR GD GD GD GD GD .TONIGHT... Min temperature.....Around 56. Max humidity........69 percent. TIME (CDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky cover.......MCR PC MCR MCR MCR MCR MCR MCR MCR MCR MCR MCR Sky (%).........21 26 25 18 12 12 10 11 8 8 9 11 Weather cov..... Weather type.... Tstm cov........ Chc of pcpn (%).0 0 0 0 0 0 0 0 0 0 0 0 Chc of thdr (%).0 0 0 0 0 0 0 0 0 0 0 0 Temp............83 83 78 73 70 67 64 62 61 60 59 58 Dewpoint........34 35 37 36 36 36 36 36 38 39 41 43 RH..............17 18 23 26 29 32 35 38 42 46 51 57 20 FT wind dir..E ESE ESE ESE ESE SE SE SSE SSE SSE SSE SSE 20 FT wind spd..10 10 10 12 13 13 13 13 13 13 13 12 20 FT wind gust.14 15 15 16 17 17 17 18 18 18 18 17 Mix hgt (kft)...5.5 2.6 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Transp wind dir.ESE ESE ESE ESE ESE SE SSE SSE SSE SSE SSE S Transp wind spd.9 10 12 13 14 16 16 16 16 16 15 16 Smoke Dispersal.GD FR PR PR PR PR PR PR PR PR PR PR .WEDNESDAY... Max temperature.....Around 89. Min humidity........19 percent. TIME (CDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM2PM 3PM 4PM 5PM Sky cover.......MCR MCR MCR MCR MCR PC MCR MCR MCR MCR MCR PC Sky (%).........15 12 19 23 22 26 20 18 21 21 22 37 Weather cov..... Weather type.... Tstm cov........ Chc of pcpn (%).0 0 0 0 0 0 0 0 0 0 0 0 Chc of thdr (%).0 0 0 0 0 0 0 10 10 10 10 10 Temp............57 56 60 64 72 78 83 86 89 89 89 88 Dewpoint........44 46 46 48 48 51 50 47 45 43 42 42 RH..............62 69 60 56 43 39 32 26 22 20 19 20 20 FT wind dir..SSE S S S S S S S S S S S 20 FT wind spd..12 13 15 16 18 21 23 25 28 30 31 31 20 FT wind gust.16 17 21 22 25 29 31 33 37 40 41 40 Mix hgt (kft)...0.5 0.5 0.6 1.1 1.5 2.1 3.2 4.2 5.2 6.1 7.0 6.0 Transp wind dir.S S S S S S S S S S S S Transp wind spd.16 16 20 22 22 23 25 29 33 38 40 40 Smoke Dispersal.PR PR PR FR FR GD EX EX EX EX EX EX $$ Forecaster...IG Requested by...Duwayne Traversie Type of request...WILDFIRE .TAG 2610682.3/FSD .DELDT 04/21/26 .FormatterVersion 2.0.0 .EMAIL duwayne.traversie@bia.gov