National Weather Service Forecast Discussion |
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492 FXUS65 KBOU 181132 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 532 AM MDT Sun Oct 18 2026 .KEY MESSAGES... - Warm and dry conditions continuing into the upcoming week. - A few mountain rain and snow showers early in the week. - A more organized system by late week or next weekend, with an increasing chance of precipitation across the high country. && .DISCUSSION /Through Saturday/... Issued at 1055 PM MDT Sat Oct 17 2026 The forecast hasn`t changed much in the last day. We continue to sit underneath a broad ridge, while a weak cutoff low spins over far southern California. Water vapor satellite shows plenty of dry air over the forecast area, and unsurprisingly there hasn`t been much (if any) cloud cover over the last 24 hours. Sunday will be another very quiet day for the region, with temperatures a few degrees cooler than Saturday. A gradual increase in mid/high cloud cover is expected during the day as that weak cutoff low begins drifting to the northeast and upper level moisture slowly starts working into the state. That upper low should shear out into an open wave as it continues to drift towards the area on Monday. There should be more cloud cover during the day, and mid-level temperatures will be a couple degrees cooler, leading to forecast highs in the upper 60s to low 70s Monday afternoon. A few light rain or snow showers will be possible across the higher elevations but little to no accumulation is anticipated. A stronger closed 500mb low is expected to approach the California coast mid-week, with strengthening south-southwesterly flow aloft. Moisture will slowly increase from mid to late week as that low works eastward into the intermountain west. Chances for rain and snow showers over the higher elevations return to the forecast by Wednesday night, with more coverage expected by Thursday or Friday. Generally light precipitation amounts are expected across our forecast area, with more significant rain/snow accumulation over southwestern Colorado. As we approach next weekend, guidance generally tries to push cooler air into the plains. Ensemble guidance is split 50/50 on whether the I-25 corridor manages any precipitation, but at the very least this should get high temperatures back closer to normal values for mid/late October (low 60s). && .AVIATION /12Z TAFS through 12Z Monday/... Issued at 524 AM MDT Sun Oct 18 2026 VFR conditions expected through the TAF period. Drainage winds will relax this morning with winds becoming light and variable. A very weak front will move across the Denver metro around midday bringing northeast winds. These northeast winds could gust up to 17 knots and be sustained between 9-11 knots during the afternoon. Models do not indicate drainage winds will develop tonight. Instead, winds at all terminals may be light and variable or may keep a northwesterly component throughout the night. Light winds will become southeasterly during the late morning on Monday. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hiris AVIATION...Danielson