Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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131 FXUS65 KBOU 262040 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 240 PM MDT Thu Sep 26 2024 .KEY MESSAGES... - Warm and dry for the foreseeable future with very limited chances of precipitation. - Record highs possible Sunday and Monday. - Front to bring slightly cooler conditions Monday night into Tuesday. - Periods of elevated to critical fire weather conditions possible next week. && .SHORT TERM /Through Friday/... Issued at 238 PM MDT Thu Sep 26 2024 Current observations show a new record high temperature has been set for Denver this afternoon. The previous record of 90F (set in 2010), will be replaced with today`s 91F as another day of above normal temperatures continues for northern Colorado. After today`s record breaking temperatures and some scattered cloud coverage expected to return to the forecast area overnight, low temperatures will be a few degrees warmer than last night. Overnight lows will range from 8-18F above normal across the CWA. A weak cold front is expected to slide south across the forecast area just before sunrise Friday morning. Northerly winds are expected to increase from north to south beginning around 2-3AM. The HREF Grand Ensemble shows probabilities ranging from 20-50% of wind gusts greater than 35 mph, mainly for the northeastern corner of the state from Weld County east, and southern Lincoln County. Probabilities diminish quickly for anything greater than 40mph. Gusty conditions should diminish by around 9AM. Warm and dry conditions are expected behind the front with high temperatures dropping slightly from today`s as northerly flow aloft returns and today`s slightly flattened 500 mb ridge rebuilds over the southwest. CAMs indicate potential for an isolated high-based shower over the high country tomorrow afternoon. Left enough PoPs in the grids to account for this. If anything were to form, it would likely be a passing virga shower, with forecast soundings indicating enough DCAPE values to support potential for an associated gusty outflow. && .LONG TERM /Friday night through Thursday/... Issued at 238 PM MDT Thu Sep 26 2024 This weekend`s weather will be dominated by upper-level ridging and, after Friday`s brief reprieve, daytime temperatures will rebound into the upper 80`s to locally even low 90`s for the lower elevations, peaking on Sunday. A few locations could approach daily records Sunday if hotter solutions verify. Clouds will be hard to come by, with ample sun and relatively light winds both days. A few northerly gusts could exceed 20 mph Sunday afternoon in the eastern plains, but speeds will not be sufficient to carry more than an elevated fire weather threat. A dry cold front will descend into northern Colorado on Monday, generally between late morning and late afternoon, associated with a broad upper-level trough well to our north. Monday`s high temperature forecast for many plains/urban corridor locations carries very high uncertainty at this time, given continued differences in the progged timing of the front. The latest guidance has, for the most part, delayed its arrival, with our northern tier of counties best positioned for an early enough onset to result in much cooler highs (e.g. in the 70`s). For the Denver area, there`s potential for the front to hold off just enough past peak heating to allow highs to climb back into the 90`s and thus again approach or exceed daily records. Regardless, expect some fluctuation in the temperature forecast for Monday until guidance comes into better agreement on frontal progression. The other consideration will be the increase of northerly winds in the afternoon, which could lead to more widespread fire weather concerns across the plains as humidity values in the teens linger. With limited if any moisture behind the front, temperatures will cool efficiently overnight, and some of the high mountain valleys look to fall below the freezing mark. Tuesday will see cooler temperatures following the front with highs down into the 70`s for the bulk of our plains and urban corridor, with ample sunshine making for a pleasant Fall day. We`ll return to mostly zonal flow aloft Tuesday onward, with ensemble guidance suggesting an increased influence from rebuilding high pressure and the return of a subsident pattern. As such, expect anomalously warm and dry conditions to prevail with highs into the 80`s returning by Wednesday. There could be pockets of near-critical or critical fire weather conditions across some of the higher elevations and foothills during this period, where the westerly afternoon breeze will be strongest. && .AVIATION /18Z TAFS through 18Z Friday/... Issued at 1159 AM MDT Thu Sep 26 2024 VFR conditions expected through the TAF period. Light and VRB winds this morning are expected to transition to an ENE/E component through the afternoon. A weak cold front is expected to slide south across the TAF sites early Friday morning that will shift winds to the N before sunrise, and enhance the northerly winds for a few hours in the morning. Northerly gusts to 20kts will be possible. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Bonner LONG TERM...Rodriguez AVIATION...Bonner