Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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614 FXUS65 KBOU 030806 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 106 AM MST Tue Mar 3 2026 .KEY MESSAGES... - Mountain snow and low-elevation rain likely through Tuesday evening, with highest rainfall amounts north of I-76. - Potential for colder storm system with more widespread snow Thursday night through Friday, although uncertainty in amounts remains. && .DISCUSSION /Through Monday/... Issued at 1152 PM MST Mon Mar 2 2026 Current water vapor imagery shows an upper level shortwave trough over southwestern Wyoming/northeastern Utah. This weak system will trek into Colorado by Tuesday morning, with moisture advecting into the region. Scattered mountain snow showers will continue overnight tonight and throughout the day Tuesday. Given how warm we have been lately, snow levels will be around 8000-8500 ft overnight, before dipping down to 7000-7500 ft with the arrival of cooler air from the shortwave. The overall snowfall forecast for the mountains were not changed significantly from the previous forecast, with highest snow accumulations limited to elevations above 10,000 ft. The biggest change to the forecast is the precipitation amounts for the northern plains. Recent guidance now favors the 500-mb vorticity max right over the plains Tuesday, with good mid-level forcing throughout the day (mid-level lapse rates will be around 7-8 dg/km). The surface lee cyclone continues to trend farther south than previous runs, which will allow moisture to be pulled further south into the northern plains. Hi-res guidance now favors some areas receiving upwards of 0.50" of QPF by throughout Tuesday, with a few solutions indicating 1.00". Due to this, have increased amounts for areas north of I-76. Unfortunately, Denver area will not see the bulk of this precipitation, as guidance still favors ~0.10" of QPF. Expect rain showers across the foothills and plains throughout the day Tuesday before gradually ending northwest to southeast overnight. Upper level ridging will return to the state Wednesday and Thursday, with increased southwest flow aloft on Thursday ahead of an incoming trough. Temperatures will rebound to the 60s by Wednesday and possibly lower 70s by Thursday. ECMWF ensemble has consistently been warmer than the GEFS, with 36 out of 50 members showing max temperatures between 70-72 (compared to the GEFS, where all 30 members show max temperatures between 62-68 degrees). With these warm temperatures and dry conditions, elevated to critical fire weather conditions are possible on Thursday, particularly the Palmer Divide and eastern plains, where lee cyclogenesis could promote gusty winds. Guidance continues to be in good agreement of a shortwave trough breaking into two pieces of energies on Friday, with the weaker one ejecting into the northern Great Plains, and the other one trekking towards southern California and becoming a closed low. Cold air will advect into the region, with 700-mb temperatures dipping to -6 to -9 dg C. Moisture will begin to stream into the region by late Thursday night into the mountains, and Friday morning across the plains. At the surface, a lee cyclone will strengthen slightly and trek northwest, with a cold front pushing through the plains. Precipitation is possible across the forecast area, as GEFS and ECWMF ensembles have consistently shown measurable QPF with the latest few runs (and even snow!). However, how much moisture is still the question, as it will depend on the exact track of the ejecting trough. As of now, the ECMWF has a slightly southerly track than the GFS, which brings more moisture and colder air into the region. By the weekend, we will likely have weak flow aloft as Colorado looks to be in between the two systems. Dry conditions and warmer temperatures should prevail for the mountains and plains. && .AVIATION /06Z TAFS through 06Z Wednesday/... Issued at 1215 AM MST Tue Mar 3 2026 Light northwest winds will continue for the majority of the night. A shortwave trough, along with healthy moisture at the surface, will then create showers and potentially some thunderstorms after 15Z today. The initial wave of rain may come along a frontal boundary. If this is the case, rain around 16-18Z could be briefly intense with visibility down to 1/2SM and ceilings as low as 500 feet. In addition, winds could gust up to 30 knots out of the northwest at all terminals. Rain chances will continue through the day with visibility dropping to 3-4SM at times. Ceilings will generally stay between 700-1,500 feet. There is some uncertainty with regards to when the rain and low clouds will dissipate. Some models keep the low clouds and sprinkles through around 07-08Z. However, if there ends up being less rain than some of the high resolution models have, clouds and sprinkles may clear by 04-05Z. VFR and drainage winds are forecast through the rest of the night Tuesday night once the clouds clear. Otherwise, winds will be pretty consistent from the north through the day today. Winds will shift to a lighter northwest in the late evening. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...MAI AVIATION...Danielson