672 FXUS65 KBOU 051145 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 545 AM MDT Thu Jun 5 2025 .KEY MESSAGES... - A few strong to severe thunderstorms over the eastern plains Thursday afternoon. - Another round of strong to severe storms possible Friday afternoon. - Slow warming trend into the weekend, with chances for showers and storms each day through the week. && .UPDATE... Issued at 346 AM MDT Thu Jun 5 2025 I`m pretty sure I`ve written the same forecast discussion for the past several nights. You are probably not shocked to learn that tonight`s AFD won`t be all that different. Stratus has become more widespread over the past couple of hours, though so far it has remained east of I-25. Guidance has been of little help so far with regards to the westward extent of the stratus deck, but given how much moisture has been around for the last week I would guess that there will at least be some stratus through the morning hours across most of the urban corridor before it once again scatters out. As noted in the previous discussion, yet another weak shortwave is expected to track across the region today, leading to more scattered afternoon showers and thunderstorms. We expect things to get going a little earlier than the past few days... generally towards the early/mid afternoon. There`s at least a marginal severe threat across most of the I-25 corridor and plains today, as the afternoon features modest MLCAPE along with deep layer shear magnitudes near 40-50kt. The HREF and several MPAS CAMs favor a corridor from roughly northern Weld county towards Fort Morgan/Akron where things are a little less capped, with weaker convection across most of the Denver metro. Still, we`ll likely continue our streak of measurable rainfall at DEN today given the anticipated coverage of afternoon and evening convection. More overnight stratus is expected overnight Thursday night. By Friday... yep you guessed it, another shortwave is expected to track across the region, leading to more showers/storms during the afternoon. Temperatures will again be below normal (upper 60s to mid 70s plains), with modest instability redeveloping. Can`t rule out a stronger storm or two but at this point the overall severe threat would be fairly marginal. && .DISCUSSION /Through Wednesday/... Issued at 241 PM MDT Wed Jun 4 2025 It has taken a while, but clouds have scattered out over most of the area, which should allow temperatures to reach the upper 60s to lower 70s. This combined with dew points in the mid to upper 40s will lead to MLCAPE up to 800 J/kg. Some of the storms that develop may be strong with small hail and heavy rain. We are seeing scattered to numerous showers and thunderstorms across the Four Corners region being produced by a shortwave trough lifting east- northeast out of the Desert Southwest. This trough will trigger scattered to numerous showers and thunderstorms late this afternoon (after 4pm) and this evening. Another weak shortwave trough is expected to bring a round of showers and thunderstorms Thursday. Timing will be earlier in the day with storms expected to develop a little after noon. At the surface, a trough drifts east across eastern Colorado Thursday. Best moisture and instability will be east of it with MLCAPE 900-1200 J/kg. Shear will be good as well, so a few of the storms that form in this environment could become severe. To the west of the trough across the Front Range, there will still be enough moisture and instability for scattered to numerous showers and thunderstorms. On Friday, we will see a shortwave trough push across the region. This will produce another round of scattered to numerous showers and thunderstorms. Mostly cloudy skies and an easterly wind will result in slightly cooler temperatures. This will lead to a little less instability with MLCAPE up to 700 J/kg, so most/all of the storms are expected to be sub-severe. Saturday will be the one dry (mostly) day. Subsidence behind Friday`s system will result in drier and warmer conditions. Most locations over northeast Colorado are expected to top 80 degrees. Can`t rule out a few high-based showers/storms over the higher terrain, but chances are less than 20 percent and any shower/storm will be weak and short lived. Temperatures take a step cooler Sunday behind a weak cold front that moves through Saturday evening. North/northeast winds behind the front will help to increase moisture across the area. This is expected to be enough moisture for scattered afternoon showers/storms. For Monday through Wednesday, a ridge will be weakening as it shifts east across the Central Rockies Monday and Tuesday. There`s expected to be enough moisture trapped under the ridge for late day showers and thunderstorms each day next week through at least Wednesday. Temperatures will warm up to near normal across northeast Colorado with highs in the upper 70s to lower 80s. && .AVIATION /12Z TAFS through 12Z Friday/... Issued at 539 AM MDT Thu Jun 5 2025 VFR conditions are expected to prevail through most of the day today, with MVFR/IFR conditions developing this evening into Friday morning. Stratus never quite managed to develop at the terminals overnight, and don`t expect that to change over the next few hours. Could still be some brief impacts closer to BJC where there`s one little patch of lower clouds and some BR, but don`t anticipate that lasting too much longer. Winds are already shifting to the west-northwest as a weak cyclone once again lifts out of the metro. A similar forecast to yesterday is anticipated for today, with weak northeast winds eventually developing by late morning or early afternoon. Scattered convection is expected to develop between 18-21z, with some impacts at the terminals likely between roughly 21-03z with one or more rounds of showers/storms. Ceilings should gradually lower this evening into the overnight hours. There`s a much better signal for widespread lower stratus overnight tonight, potentially lasting through mid-morning Friday. Some guidance is quite bullish getting in some IFR/LIFR cigs closer to 12z Friday. Will need to watch model trends for BR/FG potential as well. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hiris DISCUSSION...Meier AVIATION...Hiris