Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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433 FXUS65 KBOU 101547 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 947 AM MDT Mon Jun 10 2024 .KEY MESSAGES... - Scattered thunderstorms this afternoon. A few strong to severe storms along with a risk of heavy rain, localized flooding with some storms. - Snowmelt producing minor impacts from high streams, mainly in Grand County. - Hot and mainly dry weather towards the middle to end of next week. There is potential for a day or two to need a Heat Advisory, most likely Thursday. - Cooler conditions will arrive Friday and Saturday with scattered showers and storms. Some of these storms could be strong to severe with heavy rain. && .UPDATE... Issued at 947 AM MDT Mon Jun 10 2024 Still on track for another round of afternoon/evening thunderstorms. Airmass not quite as unstable as yesterday, but with MLCAPE up to 1500 J/kg, a few strong/severe storms will be possible. Best lift from an upper level trough moving across the Northern and Central Rockies will be north of Colorado, but enough lift will move across the area to trigger storms. Expect better storm coverage to be across northern Colorado, thus increased PoPs a little more for this area. && .SHORT TERM /Through tonight/... Issued at 412 AM MDT Mon Jun 10 2024 The region remains under an upper level ridge today. Flow aloft is still on the weaker side out of the WNW, but perhaps not as weak as yesterday. A mid-level shortwave trough moves through the flow later this afternoon. The stronger synoptic support is further north of Colorado; however, it should provide sufficient ascent out ahead of it aligning with peak heating. Current Mid-Level Water Vapor satellite imagery depicts rich moisture transporting from the south, wrapping around the upper ridge over CO this morning. This correlates well with ensemble guidance keeping above normal moisture in the area today around 140-175% of normal. Precipitable water values rise to around 0.4-0.6" for the higher elevations and 0.8-1.1" across the plains/urban corridor. MLCAPE values range from 600-1500 J/kg. High level clouds will be around for the day, but shouldn`t limit instability as much as lower clouds would. With weaker upper level winds, 0-6km shear will be on the weaker side with some slightly better values closer to the northeast corner(20-30kts). Overall, this environment should support scattered thunderstorms with a couple strong to severe storms. Thunderstorms develop over the high terrain by early afternoon moving east onto the adjacent plains. The suite of high-res CAMs generally show a broken line/wave of storms pushing off of the higher terrain then filling in more as it moves across the east plains where the richer moisture and instability are. Hail 1-1.5" and strong gusts are possible with any severe storms. Storm motions should be a bit higher today, but can`t rule out a few strong storms capable of producing heavy rain for a period of time. This could still result in minor impacts in prone areas if a storm stays over an area long enough. Storms move east across the plains through the late afternoon-early evening hours. For temperatures today, highs rise into the 80s for the plains/urban corridor, 70s for the foothills, and 50s/60s for the mountains. && .LONG TERM /Tuesday through Sunday/... Issued at 412 AM MDT Mon Jun 10 2024 Little change to the extended forecast this morning. It does look like the drying aloft from the northwest on Tuesday is coming along towards the faster end of what we`d been thinking, and we`ve backed off a bit more on PoPs for Tuesday afternoon and evening. There should still be enough moisture and instability for a few storms, mainly over the Front Range. Temperatures rebound sharply for Wednesday and Thursday as an upper ridge pokes northward across the Rockies. There will probably be some late day cloud development drifting from the mountains onto the plains, but that`s about it. Thursday probably has the warmest air aloft, but there is a puff of northerly winds from the tail end of a shortwave that`s focused up on the Canadian border. There may also be a bit of cloud cover and attempted showers along the northern border in the afternoon. We`ll also be hot enough to generate some high based weak convection away from that forcing near the end of the day. All of that may take a couple of degrees off of the highs if there`s enough of it. There continues to be some vacillation about the details for Friday and Saturday, chiefly how strong the push of cooler air into the plains will be. There`s also been a trend towards a bit more mid level moisture drifting up from the south. The variations don`t really change the story though, of decent thunderstorm coverage and highs dropping back into the 80s for Friday. The upper trough coming out of the southwest will provide some lift in a favorable atmosphere, but timing varies on this from Friday night into Saturday. After that passes, we should have warming and drying again for less activity, but still some moisture east of the mountains. && .AVIATION /12Z TAFS through 12Z Tuesday/... Issued at 551 AM MDT Mon Jun 10 2024 Low stratus has developed across the parts of the Colorado plains early this morning with a portion being funneled southward toward BJC. This could bring lower clouds close to BJC or in view of the DEN field for a few hours this morning. BJC may also have brief periods of BR through 13/14z. Light and variable winds this morning transition light E/SE in the afternoon. Scattered thunderstorms are possible after 21z, with the threat continuing through around 01z. Gusty outflow winds up to 35 kts are possible with any passing/nearby storms as well as wind dir/speed changes from outflow boundaries from other storms. && .HYDROLOGY... Issued at 412 AM MDT Mon Jun 10 2024 Remaining runoff from last night`s rain in Douglas county is reaching the downstream reservoirs this morning and remaining lowland flooding should be ending within the next few hours. Elevated flows continue across the upper Colorado River basin and additional rainfall could lead to further increase in the flows. Remain cognizant of the dangers of these cold flows, and be aware of any Flood Advisories and Warnings. Winds aloft remain on the weaker side today, leading to slower storm motions, but a bit faster than Sunday. There is a minor threat for burn area flash flooding on Cameron Peak today. Periods of heavy rain are possible in storms today which may lead to localized flood impacts if a storm stays over a prone area long enough. Warmer and drier weather will follow, with the next threat of heavy rain on Friday and Saturday. Snowmelt may peak on the hottest days at the end of this week. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Meier SHORT TERM...Mensch LONG TERM...Gimmestad AVIATION...Mensch HYDROLOGY...Gimmestad/Mensch