951 FXUS65 KBOU 100059 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 659 PM MDT Mon Jun 9 2025 .KEY MESSAGES... - Warming trend with above normal temperatures Tuesday through Friday. Even warmer weather possible this weekend. - Chance of afternoon showers and thunderstorms mainly over the higher terrain most days. Best chance of rain comes Wednesday and Thursday. && .DISCUSSION /Through Monday/... Issued at 136 PM MDT Mon Jun 9 2025 As expected, most of the afternoon convection has formed just to the south and west of our CWA. One storm did develop over southern Park county earlier but quickly drifted into Fremont county. Our CWA border essentially is on the border of the "moisture" and "no moisture" line that`s well defined in GOES mid-level water vapor (CH-09/6.95um) satellite imagery today. That`s led to most locations across the Denver metro seeing a rather pleasant June afternoon, with current temperatures in the mid/upper 70s along with sunny skies and light winds. Moisture will at least attempt to make a return into our forecast area as a ridge slowly tries to build across the southwestern CONUS. We should see at least a few more showers and perhaps a weak storm or two across the Front Range mountains, but with very weak steering flow (GFS mean storm motion is <5kt), it will be hard for anything to develop across the I-25 corridor during the afternoon or evening hours. Forecast soundings would suggest more wind than rain anyways. Mid/upper 80s are likely across the plains with a few low 90s possible east of the urban corridor. Moisture is expected to increase again on Wednesday, with a better chance of rain across the higher elevations of the Front Range. The overall synoptic pattern is still somewhat messy, with one shortwave tracking across southern Idaho into northern Wyoming while a weak cutoff low tracks across the TX/OK panhandle. As a result, a majority of the convection would again be initially driven by terrain effects. With more moisture to work with over the plains (surface Tds in the mid 40s) at least a few storms could survive the slow journey into the lower elevations, but overall coverage looks to be isolated to scattered. A gradual drying trend is expected to end the week and continue through this weekend, as a large ridge builds to our south. At least some isolated/widely scattered convection is possible again Thursday before drier southwesterly flow aloft scours out the remaining mid-level moisture by Friday or Saturday. Unsurprisingly, the developing ridge and drying conditions will likely lead to warmer temperatures by this weekend. There is fairly high confidence that this weekend will feature the warmest weather of this spring, with temperatures in the 90s across most of the plains. Both the GFS/ECMWF advertise mid-90s highs for the Denver metro by Sunday, with broad support from their respective ensemble systems (~75% of individual GEFS/ECME members >90F). Above normal temperatures look to generally continue into next week, with no obvious signal that the ridge will break down in the longer term period. && .AVIATION /00Z TAFS through 00Z Wednesday/... Issued at 657 PM MDT Mon Jun 9 2025 Weak normal drainage winds are expected overnight at DIA, commencing around 04Z this evening. Weak southeasterly winds are likely until then. There will be no ceiling issues. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hiris AVIATION.....rjk