Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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204 FXUS65 KBOU 252356 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 556 PM MDT Sat May 25 2024 .KEY MESSAGES... - Only isolated late day mountain showers and thunderstorms on Sunday with dry conditions over the rest of the forecast area. - Warm through the coming week. There will be limited late day thunderstorm activity on Tuesday with better coverage Wednesday through Friday. Strong to severe storms will be possible Wednesday and Thursday. && .SHORT TERM /Through Sunday/... Issued at 245 PM MDT Sat May 25 2024 Convection is continuing over the mountains and foothills, mainly north of I-70 at this time. There are also scattered showers and storms moving eastward across the northern half of Weld County. Upstream of our CWA, the storms are producing 60 mph gusts and some lightning. Models bring the weak upper trough axis across the CWA tonight, then fairly strong northwesterly flow aloft on Sunday. The QG fields show some upward vertical velocity this evening in front of the trough axis, then downward energy moves in after 06Z continuing through most of Sunday for the forecast area. Cross sections show a mountain wave set-up from 09Z to 18Z on Sunday, so will hit the winds pretty hard on the high mountains and foothills. The low level winds briefly go to drainage patterns later this evening after the convection, but then downsloping kicks in after the upper trough moves eastward. Fairly strong northwesterly winds are progged all day for the CWA on Sunday. Looking at moisture, precipitable water values and low level dew points drop off overnight with Sunday looking pretty dry for all areas. There is little to no CAPE progged on any of the models for Sunday afternoon as well. For pops, will keep them high over the alpine areas this evening, then decrease them overnight as the upper trough moves across and east. For the plains, "scattered" pops will suffice with evening, with nothing overnight. On Sunday, will go with 10-20%s over the high mountains in the afternoon, otherwise the rest of the CWA will be dry. Temperature- wise, Sunday`s highs look quite similar to this afternoon`s readings. && .LONG TERM /Sunday night through Saturday/... Issued at 150 PM MDT Sat May 25 2024 The weather on Memorial Day will be about as nice as it can be. Ridging aloft with subsident flow will lead to plenty of sunshine and slightly above normal high temperatures. Temperatures will reach the mid to upper 70s across the plain and in the 60s across the higher terrain. The axis of the ridge will be over Colorado on Tuesday. There will be a slight increase in low level moisture but only isolated showers are expected Tuesday afternoon and evening. Soundings indicate steep lapse rates and a dry boundary layer so strong winds will be possible from these showers. A broad trough will move across the western US Wednesday through the rest of the work week. There will be lee cyclogenesis across the high plains and strong southeasterly flow will develop in the low levels across the eastern plains. There will bring healthy moisture return from the Gulf of Mexico and moderate to strong instability will develop. It appears a dryline will setup between DIA and Akron and this may provide enough low level forcing to generate storms along it. Given the good instability and enough shear, storms that form along the dryline could be strong to severe with large hail and damaging wind gusts possible. Models do not agree with the trough placement on Thursday but this trough may provide strong forcing to our forecast area. The healthy moisture and instability will continue to be across the eastern plains. Depending on the trough location, there is potential or this day to be an active severe weather day with several strong to severe storms. On the other hand, the trough could end up being far away from our forecast area and with less forcing and shear, there could be minimal severe storms. Nonetheless, this period will need to be watched. A cold front appears it will move through our forecast area on Friday. This will lower high temperatures and may lead to more stable conditions. By next weekend, slight ridging will build back in over Colorado with limited coverage of showers and storms and warm temperatures. && .AVIATION /00Z TAFS through 00Z Sunday/... Issued at 555 PM MDT Sat May 25 2024 One round of scattered showers and a couple thunderstorms have moved off to the east. There is another batch in western Colorado, and these will attempt to move into the area again after 02Z. These, too, will likely produce some gusty and variable winds, but we`ll have a little lower gusts in the TEMPO group for these, closer to 25-30 knots. The most likely time period would last until about 04Z before we start to stabilize, but still a low threat after 04Z due to additional showers/virga moving off the mountains through at least 06Z. Eventually, winds will transition more southwesterly overnight with clearing skies. For Sunday, winds are expected to turn more west/northwest by 15Z-17Z with daytime heating and mixing, and then gust to around 25 knots off/on during the remainder of the day from the northwest. The airmass will be too dry and stable for any shower or storm threat Sunday. VFR conditions will prevail. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM....RJK LONG TERM.....Danielson AVIATION...Barjenbruch