Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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115 FXUS65 KBOU 221725 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1125 AM MDT Sun Sep 22 2024 .KEY MESSAGES... - Storm system exiting the area, with rain diminishing on the plains and only a few light snow showers remaining in the high country. - Well below normal temperatures for today. Patchy frost possible on the plains tonight. - Warmer and drier this upcoming week with no significant precipitation chances. && .UPDATE... Issued at 946 AM MDT Sun Sep 22 2024 Satellite shows the upper level low shearing out as it head eastward across the northeast plains this morning. There was a well defined deformation zone across northeast Colorado, with an enhanced band of precipitation stretching from roughly Boulder county eastward toward Fort Morgan and Holyoke. This rotated a bit farther north early this morning, but will be collapsing into early afternoon and weakening as the upper low continues to shear out and push east. We`ve cancelled the Winter Weather Advisory in the mountains (most locations only saw about 1-3 inches), and there are no lingering travel impacts per latest camera observations. We should see some breaks in the clouds develop from northwest to southeast across the area later in the afternoon. Temperatures will be far below normal for this first day Autumn, but enough breaks/thinning of the clouds to help it warm into the upper 50s to lower 60s across most of the plains. && .SHORT TERM /Through Tonight/... Issued at 346 AM MDT Sun Sep 22 2024 Upslope flow continues over northeastern Colorado this morning producing stratiform rainfall for lower elevations. Weather stations suggest a few areas along the plains and Palmer Divide received 0.10- 0.40 inches overnight. Scattered showers will continue for these areas until early afternoon as the upper level trough pushes northeast. Light snow continues across mountain webcams this morning. Snow showers should begin to decrease in intensity this morning leading to an additional 1-2 inches for areas above 10 thousand feet. As upper level forcing exits the region by this afternoon, cross sections indicate low to mid level clouds clearing over the forecast areas through this evening. Tonight, drier air enters. && .LONG TERM /Monday through Saturday/... Issued at 346 AM MDT Sun Sep 22 2024 Some patchy fog and/or frost may linger into the first half of the morning, but otherwise Monday should be a quiet day as drier northwesterly flow develops. Mostly sunny skies should prevail through the day with temperatures back above normal (mid/upper 70s). Though we`ve talked about the potential for a shortwave/cold front passing through late Monday into Tuesday, guidance has started to back away from this, keeping the better moisture/cooler temperatures off to the east of our CWA. Can`t completely rule out a couple of showers overnight but have reduced PoPs quite a bit compared to a few cycles ago. Guidance is also in much better agreement in the longer term, developing a large ridge axis over the region Tuesday into Wednesday. There`s a pretty good signal for temperatures to reach the mid/upper 80s, especially on Thursday. The ridge should slowly break down towards next weekend, but above normal temperatures will likely persist through at least Saturday. && .AVIATION /18Z TAFS through 18Z Monday/... Issued at 1125 AM MDT Sun Sep 22 2024 Rain has ended, but one last band of rain extends north of the airports, still trying to back in from the northeast. We think that band mostly dissipates through ~19-20Z so just VCSH to start, then dry. Ceilings will be improving through the afternoon. Light southeast flow has taken care of the MVFR ceilings for the most part, at least for KDEN and KAPA. We expect a break of the 4000-5000 ft AGL ceilings around 22Z, give or take an hour or two. Then VFR conditions will prevail with mostly clear skies overnight through Monday. Patchy fog threat tonight will stay north of the Denver TAF sites with light drainage winds almost certain (95%) to prevail. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Barjenbruch SHORT TERM...AD LONG TERM...Hiris AVIATION...Barjenbruch