744 FXUS65 KBOU 232054 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 254 PM MDT Fri Apr 23 2021 .SHORT TERM...(This evening through Saturday) Issued at 243 PM MDT Fri Apr 23 2021 Scattered convection is now covering the alpine areas of the CWA. The showers are mostly of the light variety. There are limited lightning strikes around, certainly more than there were yesterday afternoon. There is no convection over the plains at this time. There is a back edge to the convection associated with the upper trough near the western Colorado border. Models have the upper trough east of the CWA this evening with northwesterly flow aloft expected. On Saturday, the upper level flow will become weaker and zonal as flat upper ridging moves in. Downward synoptic scale energy is in place tonight into Saturday morning, with weak upward energy progged for Saturday afternoon. For moisture, it dries out this evening and overnight. On Saturday, there is an increase in mid and upper level moisture. Nothing down low. For pops will go with 10-40%s early this evening, then they will be done around 04Z. On Saturday afternoon, there is a tiny bit of CAPE progged over the mountains and foothills only. There is very little low level moisture, so no pops. For temperatures on Saturday, readings look to be 3-6 C warmer than today's highs. .LONG TERM...(Saturday night through Friday) Issued at 243 PM MDT Fri Apr 23 2021 A few showers will be possible overnight Saturday as a weak/subtle shortwave lifts northeastward across the northern portion of the state. There's a brief period of moisture and synoptic scale lift that could spark a few light rain and snow showers, mainly to the west of the Continental Divide. Otherwise Saturday night will be quiet across the urban corridor and the eastern plains. Sunday will be warmer and drier than Sunday. Temperatures should easily reach the mid 70s, and may make a run at 80 degrees. The GFS is on the conservative side of guidance, with 700mb temperatures about 1-3C cooler than the Euro. Have leaned towards the warmer solutions with highs in the mid to upper 70s over the I-25 corridor and close to 80 further east. The only limiting factor could be cloud cover aloft, but even with some cloud cover it still looks warm. Southwest flow will also strengthen ahead of a deep trough centered over the Pacific coast. The combination of dry conditions and gusty winds warrants a Fire Weather Watch for our far southeast portion of the CWA... though more zones may be added as we get closer. Monday looks to be the driest and windiest day of the week. The flow aloft continues to increase ahead of the trough with very little moisture to work with. We did consider issuing a Fire Weather Watch across much of the plains but have held off for now. Either way, fire danger looks to be high both Sunday and Monday. Cooler and wetter weather arrives by Tuesday as the trough swings across the state. Forecast guidance continues to vary on the strength and depth of the system, but a fairly widespread precipitation event still appears likely across the mountains, foothills, and at least portions of the plains. The system departs by late Wednesday or Thursday and ridging returns, bringing warmer and drier conditions back to the forecast area. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 243 PM MDT Fri Apr 23 2021 Models show the winds going to normal drainage are DIA by late evening. If there are any showers at the airport, they should be done by 03Z. There should not be any thunderstorms, nor should there be any ceiling issues overnight or on Saturday. && .FIRE WEATHER... Issued at 243 PM MDT Fri Apr 23 2021 There is increasing confidence in critical fire danger conditions across portions of the eastern plains Sunday and Monday. Elevated fire danger is possible Saturday as humidities decrease and winds increase a bit across the plains. This will also help dry out fuels across portions of the plains, where precipitation over the last 7 days has generally been less than a quarter inch. By Sunday, the flow aloft strengthens ahead of an approaching trough axis. Humidities will fall to 10-15 percent across most of the plains with gusts up to 35 mph. It is possible that critical fire conditions continue Monday as strong winds and very dry conditions continue. Current forecast guidance suggests that Monday may be both drier and windier than Sunday, though this may change if the timing of our next storm system speeds up. As the trough axis passes through Colorado, it should alleviate fire danger concerns, with much cooler temperatures and widespread precipitation likely for most of the forecast area. Cool and wet conditions will continue Wednesday before a slow warming and drying trend through the end of next week. && .BOU WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Sunday afternoon through Sunday evening for COZ246-247. && $$ SHORT TERM...RJK LONG TERM...Hiris AVIATION...RJK FIRE WEATHER...Hiris