Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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611 FXUS65 KBOU 010056 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 656 PM MDT Sun Jun 30 2024 .KEY MESSAGES... - Warmer today, with scattered afternoon storms. A few could be strong to severe. - Scattered showers and thunderstorms expected Monday. - Downward trend in showers and storms beyond Wednesday. && .SHORT TERM /Through Monday/... Issued at 315 PM MDT Sun Jun 30 2024 Radar shows showers and thunderstorms continuing to develop over the higher terrain this afternoon. A few cells are starting to develop over the Palmer Divide as well. We are just a degree or two off from reaching the convective temperature in the Denver metro according to an ACARS sounding; however, instability is marginal(< 600 J/kg MLCAPE). MLCAPE values (SPC mesoanalysis) show higher values 500- 1000 J/kg over the plains. Dewpoints haven`t lowered too much from mixing this afternoon which has kept surface moisture intact. This will support the showers/storms as they move east off the higher terrain. For the remainder of the afternoon and evening, expect a few rounds of scattered showers and thunderstorms. With regard to strong/severe potential, it is a marginal environment, but sufficient to support a few strong to severe storms and localized heavy rainfall and gusts. There`s a boundary set up along the Denver Cyclone through Elbert/Arapahoe counties which will warrant watching for storm initiation or weak spin ups. Tonight, a few high-res models show potential for another batch of shower/storms to move through late tonight. Given the lacking agreement, this will be a low chance. Showers push back across the high country around sunrise Monday. Monday, an upper level jet positions to the north of the region bringing weak ascent and better shear. However, instability is fairly marginal (< 600 J/kg CAPE). This will support scattered showers and storms with a couple stronger storms possible. With the plume of above normal moisture nudging into the high country, there is a minor threat flooding impacts on the burn areas. Enhanced flow should keep them moving; however, training storms could cause localized impacts from brief heavy rainfall. High temperatures will likely be in the mid 80s to low 90s for the lower elevations. && .LONG TERM /Monday night through Sunday/... Issued at 238 PM MDT Sun Jun 30 2024 Monday night, upper level high pressure will be over the Southern Plains States with an upper level trough over the Central and Northern Rockies. This pattern should push the plume of subtropical moisture to the south and east of the forecast area resulting in mostly dry conditions east of the mountains. The exception may be across far Southern Lincoln County where brief heavy rain may be possible due to lingering high PWAT`s. Precipitation chances may be higher across the high country due to a westerly orographic flow and lift from a passing shortwave. Some of these showers and storms could spread onto the adjacent plains, mainly north of Denver. However, with the lack of moisture and downsloping flow, only light rain and gusty winds are expected. Colorado will be under the influence of a quasi-zonal flow aloft Tuesday and Wednesday which will allow drier air to move into the region from the west. Therefore, mostly dry conditions are expected with possibly a few high based showers and storms with light rain and gusty winds. On Wednesday, models are showing a return of low level moisture on the plains with an upper level disturbance moving across Colorado from the west. As a result, can`t rule out one or two strong to severe storms across the plains east of Denver during the afternoon. On July 4th, a very dry airmass will move into Colorado from the west in response to a potent shortwave moving across the Northern Plains States. Consequently, dry weather and clear skies are expected through the day. Temperatures shouldn`t be too hot with readings only climbing into the mid and upper 80s across Northeastern Colorado. The warm temperatures combined with low relative humidity and gusty northwesterly winds may lead to fire weather concerns across the the mountains, foothills and adjacent plains during the afternoon and early evening. Cooler temperatures (upper 70s to low 80s on the plains) along with a slightly better chance (10% to 25%) for precipitation are expected on Friday behind the passage of a cold front. For next weekend, near normal temperatures along with mostly dry conditions are expected to continue as a dry westerly flow aloft remains over the region. && .AVIATION /00Z TAFS through 00Z Tuesday/... Issued at 655 PM MDT Sun Jun 30 2024 The weak rain showers look to be over for a couple hours at DIA. Models and upstream satellite pictures point to more showers after 03Z. Will leave the thunder out for now. A decent boundary pushed northward across DIA earlier. Will leave the southerly winds going the rest of the evening and overnight. Speeds should get pretty light by 05Z. There will be no ceiling issues. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Mensch LONG TERM....JK AVIATION.....RJK