National Weather Service Forecast Discussion |
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044 FXUS65 KBOU 041729 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1129 AM MDT Tue Aug 4 2026 .KEY MESSAGES... - Elevated to critical fire weather conditions likely across the high mountain valleys through the next few days. - Cooler today and Wednesday before temperatures gradually warm back to the triple digits by next weekend. && .DISCUSSION /Through Monday/... Issued at 215 AM MDT Tue Aug 4 2026 Current conditions show a dramatic difference from this time last night, with overnight temperatures a good 15 to 25 degrees cooler than this time last night. Today`s high temperatures are still expected to struggle to make it out of the 70s across our lower elevations. This cooler airmass didn`t have enough oomph to make much of a difference in our mountain valleys, where afternoon highs are expected to warm into the mid to upper 80s once again today. With increasing zonal flow aloft expected to bring some gusty winds (25-30 mph) into North and Middle Park this afternoon, where much drier air still resides, a Red Flag Warning is in effect from 1 PM to 7 PM for these locations as relative humidities are expected to drop into the low to mid teens. Precipitation chances will remain limited to the southern Front Range and Palmer Divide this afternoon, where a few showers and thunderstorms will be possible. Westerly flow aloft will keep smoke around, with patchy smoke expected across the forecast area for at least another day. Wednesday will bring one more day of below normal temperatures to our lower elevations, though it will mark the start of another warming trend, with zonal flow turning more to the northwest as upper-level ridging starts to rebuild across the west. Critical fire weather conditions are expected across our higher elevations, expanding slightly due to RH dropping into the single digits coinciding with gusty winds up to 30 mph. A Fire Weather Watch has been issued for our mountain valleys and elevations above 9,000`. Our stretch of record-breaking heat appears poised to continue as temperatures are expected to gradually warm each day through the weekend, with some locations on the plains reaching the triple- digits as early as Friday. Precipitation chances don`t return to the forecast until late this weekend/early next week, and confidence in any meaningful rainfall remains low. && .AVIATION /18Z TAFS through 18Z Wednesday/... Issued at 1125 AM MDT Tue Aug 4 2026 VFR conditions are expected to prevail through the TAF period, though varying amounts of smoke could lead to occasional slant- range visibility issues through at least Wednesday morning. Satellite shows nearly all of the morning stratus has burned off, with just a FEW035 left near BJC/EIK/LMO, while thicker stratus still exists over far northeastern Colorado. Winds are currently light and variable, but should become steadier out of the northeast this afternoon with speeds generally under 10kt. A weak cyclone is likely to develop overnight, with light and variable winds returning for most of the terminals. While there is continued uncertainty with winds for Wednesday, most guidance favors a transition to east/northeast winds close to 18z. && .FIRE WEATHER... Issued at 215 AM MDT Tue Aug 4 2026 A Red Flag Warning is in place from 1300 to 1900 today for North and Middle park due to gusty westerly winds to 30 mph and relative humidities in the low to mid teens. Elevated to critical fire weather conditions are expected to persist across the higher elevations for the next few days due to critical fuels and RH dropping into the single digits each afternoon. A Fire Weather Watch in effect for Wednesday for our mountain valleys and elevations above 9,000` where winds are expected to remain gusty for another day (gusts to 30 mph). Winds are expected to slacken a bit after Wednesday, but with critical fuels and RH expected to drop into the single digits each afternoon, elevated fire weather concerns will likely remain in place through the forecast period. By Friday, hot temperatures are expected to return to the upper 90s to triple digits across the plains that will start to reintroduce localized concerns for elevated to critical fire weather conditions each afternoon through the weekend, both for the plains and higher elevations. Precipitation chances will remain very limited through the rest of the week. && .BOU WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM MDT this evening for COZ211-213. Fire Weather Watch from Wednesday afternoon through Wednesday evening for COZ211>214-217-218. && $$ DISCUSSION...9 AVIATION...Hiris FIRE WEATHER...9