Spot Forecast
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
189 FNUS75 KBOU 231203 FWSBOU Spot Forecast for Forsythe II - Unit 44...USFS National Weather Service Denver/Boulder CO 603 AM MDT Thu May 23 2024 If conditions become unrepresentative...contact the National Weather Service. .DISCUSSION...Observations across the Boulder county foothills suggest a pretty strong surface inversion has developed this morning, with the RAWS site at 8000 feet about 15 degrees cooler than surrounding sites a few hundred feet higher. Initial conditions in the first few hours are a blend of obs between 8000-8500ft. Today should be warmer and windier for the spot location as stronger westerly flow develops. Main uncertainty is with how low RH gets this afternoon. This morning`s recovery was slightly better than forecast at the RAWS but surrounding sites were significantly drier above the inversion. Given that RH has been consistently lower than guidance the past couple of days, the spot forecast here calls for RH to bottom out near or just below 20% which is drier than any model guidance. Winds are also expected to increase quickly this morning into the afternoon, with sustained winds around 10-20 mph, with gusts generally around 25-35 mph. Wouldn`t be surprised if there`s a few gusts closer to 40 mph in some of the more favorable terrain, but perhaps not at the RAWS itself. An approaching front this afternoon and evening will bring slightly increased moisture along with a chance for an isolated shower, but chances for measurable precipitation are quite low. Overnight humidity recovery is forecast to be close to 50% again. Friday should be slightly cooler with slightly improved RH, along with isolated showers/storms in the afternoon again. .TODAY... Sky/weather.........Mostly sunny (10-20 percent) until 1400, then partly cloudy (25-35 percent). CWR.................4 percent. Chance of pcpn......10 percent. LAL.................1. Max temperature.....Around 66. Min humidity........20 percent. Wind (20 ft)........Southwest winds 9 to 15 mph until 1300, then 15-20 mph. Gusts up to 35 mph in the afternoon. Gusty and erratic winds expected near thunderstorms after 1500. Mixing height.......Below 1000 FT AGL until 0700, then 2200 ft AGL until 0900, then 6700 ft AGL until 1200, then 10200 ft AGL until 1600, then 7400 ft AGL. Transport winds.....West 20 to 26 mph until 0900, then 31 to 37 mph. Smoke dispersal.....Poor until 0800, then fair until 0900, then very good until 1000, then excellent. Haines Index........5 or moderate potential for large plume dominated fire growth. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........8 6 5 8 11 15 23 24 28 28 32 34 Weather cov..... SCH SCH SCH Weather type.... RW RW RW Tstm cov........ SCH SCH SCH CWR.............0 0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).0 0 0 0 0 0 10 10 10 10 10 10 LAL.............1 1 1 1 1 1 1 1 1 2 2 2 Temp............39 42 48 54 56 60 62 63 64 64 61 59 RH..............39 36 32 27 23 21 20 20 21 22 26 28 20 FT wind dir..SW SW SW SW W W W W W W W W 20 FT wind spd..9 8 8 9 10 12 14 15 16 17 18 18 20 FT wind gust.15 13 13 15 16 18 22 24 27 29 33 32 Mix hgt (kft)...0.9 1.1 2.2 4.6 6.4 7.4 9.0 10 10 9.3 7.4 6.4 Transp wind dir.W W W W W W W W W W W W Transp wind spd.20 21 26 33 33 33 36 36 33 31 37 33 Haines index....5 5 5 5 5 5 5 5 5 5 5 5 Vrate kt-ft/1K..15 19 51 132 185 215 280 309 298 251 237 185 SmokeDispersion.P P F VG E E E E E E E E .TONIGHT... Sky/weather.........Mostly clear (20-30 percent). CWR.................4 percent. Chance of pcpn......10 percent. LAL.................1. Min temperature.....Around 33. Max humidity........53 percent. Wind (20 ft)........West winds 10 to 20 mph. Gusts up to 30 mph in the evening. Gusty and erratic winds expected near thunderstorms until 2400. Mixing height.......3800 ft AGL until 2000. Below 1000 FT AGL after 0100. Transport winds.....West 23 to 30 mph until 2400, then 16 to 21 mph. Smoke dispersal.....Very good until 1900, then good until 2000, then fair until 2100, then poor. Haines Index........3 or very low potential for large plume dominated fire growth. TIME (MDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky (%).........26 26 27 30 26 23 19 18 16 17 17 17 Weather cov.....SCH SCH SCH Weather type....RW RW RS Tstm cov........SCH SCH SCH CWR.............0 0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).10 10 10 10 10 10 0 0 0 0 0 0 LAL.............2 2 2 1 1 1 1 1 1 1 1 1 Temp............56 50 46 43 40 40 38 37 35 35 35 33 RH..............32 37 42 45 46 44 44 44 46 47 48 50 20 FT wind dir..W W W W W W W W W W W W 20 FT wind spd..16 17 17 17 16 12 10 10 12 12 10 10 20 FT wind gust.25 28 28 28 25 18 16 16 18 18 15 15 Mix hgt (kft)...4.6 3.8 1.8 1.0 1.1 1.0 1.0 0.9 0.7 0.7 0.7 0.7 Transp wind dir.W W W W W W W W W W W W Transp wind spd.30 30 28 28 28 23 20 18 16 16 16 16 Haines index....3 3 3 3 3 3 3 3 3 3 3 3 Vrate kt-ft/1K..121 99 44 24 26 20 17 14 10 10 10 10 SmokeDispersion.VG G F P P P P P P P P P .FRIDAY... Sky/weather.........Mostly sunny (15-25 percent) until 1100, then partly cloudy (35-45 percent) until 1600, then mostly cloudy (60-70 percent). Slight chance of rain showers and thunderstorms after 1200. CWR.................4 percent. Chance of pcpn......20 percent. LAL.................1 until 1200, then 2 until 1500, then 3. Max temperature.....Around 60. Min humidity........27 percent. Wind (20 ft)........West 5-10 mph until 0900, then southwest 7-12 mph with gusts to 20 mph. Gusty and erratic winds expected near thunderstorms after 1200. Mixing height.......Below 1000 FT AGL until 0800. 7200 ft AGL after 1100. Transport winds.....West 10 to 18 mph until 1400, then southwest 15 to 21 mph. Smoke dispersal.....Poor until 1000, then fair until 1100, then good until 1200, then very good until 1700, then good. Haines Index........4 or low potential for large plume dominated fire growth. TIME (MDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........21 14 18 15 23 30 38 41 45 48 58 69 Weather cov..... SCH SCH SCH SCH SCH SCH Weather type.... RW RW RW RW RW RW Tstm cov........ SCH SCH SCH SCH SCH SCH CWR.............0 0 0 0 0 0 0 0 0 0 0 0 Chc of pcpn (%).0 0 0 0 0 0 20 20 20 20 20 20 LAL.............1 1 1 1 1 1 2 2 2 3 3 3 Temp............33 36 40 46 50 52 53 55 57 58 58 57 RH..............53 50 42 36 32 29 29 29 27 27 28 32 20 FT wind dir..W W W SW SW S S S SW W SW S 20 FT wind spd..8 7 6 5 7 8 10 11 10 11 9 8 20 FT wind gust.16 15 12 12 16 18 20 20 20 20 18 17 Mix hgt (kft)...0.7 0.8 2.3 3.5 4.7 5.8 6.9 7.3 7.7 8.1 6.9 5.6 Transp wind dir.W W W W W W W W W W SW SW Transp wind spd.15 12 12 10 13 15 17 18 20 21 17 15 Haines index....4 4 4 4 4 4 4 4 4 4 4 4 Vrate kt-ft/1K..9 8 22 31 52 76 103 117 131 146 106 72 SmokeDispersion.P P P P F G VG VG VG VG VG G $$ Forecaster...Hiris Requested by...Luke Finn Type of request...PRESCRIBED .TAG 2414199.6/BOU .DELDT 05/23/24 .FormatterVersion 2.0.0 .EMAIL luke.finn@usda.gov