Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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450 FXUS65 KBOU 080301 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 901 PM MDT Sun Jul 7 2024 .KEY MESSAGES... - Strong to severe thunderstorms are expected today across much of the plains, particularly east and southeast of Denver. - Drier starting Monday with a prolonged warming trend kicking off. - Starting Thursday through next weekend, prolong well above normal temperatures are likely. && .UPDATE... Issued at 901 PM MDT Sun Jul 7 2024 Severe threat has ended, and convection is winding down as we continue to stabilize. There are a few weak showers over the mountains and still streaming in from the northwest, but overall the drying and clearing trend is beginning. Lingering convection should be all but done before midnight, with clearing skies overnight. Enjoy the cool, crisp night before the heat arrives later this week. && .SHORT TERM /Through Monday/... Issued at 233 PM MDT Sun Jul 7 2024 Satellite imagery exemplifying today`s setup, with shallow strati-cu streaming westward and slowly but steadily advecting in better low-level moisture under an upslope flow regime. Meanwhile, thunderstorms have developed across northern Larimer and Weld Counties and is gradually pushing southeastward, with some secondary focal points for initiation beginning to show up across the foothills and north of Pikes Peak. Not much has changed with respect to the forecast over the past few hours. As convection continues marching into the plains, it will begin to encounter a more favorable environment for strengthening with moderate MLCAPE of 500-1,000 J/Kg and, more notably, impressive deep-layer shear which could exceed 50 kts per SPC`s latest mesoanalysis forecasts, roughly coinciding with the Slight Risk area. Still anticipate comparatively lesser coverage for locations roughly along and west of I-25, where instability will be a little more marginal and dewpoints may struggle to crack 50 degrees. The greater threat for severe weather will be concentrated along an axis from Morgan County southward into Elbert and Lincoln Counties. Since early this morning, guidance has come into quite good agreement when it comes to the progression of today`s convection. As far as timing is concerned, expect the main window for severe weather threats and large hail to be through mid evening, although it`s possible we could see some convection linger across the southernmost portion of our forecast area through late evening. Looking ahead into Monday, the trough will have moved due east of Colorado with subsident northwest flow filling in aloft. We`ll be quite a bit more stable and any afternoon showers or storms should be isolated, generally confined to our southern mountains and Park County where we`ll see light southerly winds near the surface and thus enhanced orographics. Otherwise, expect a much drier day, kicking off a prolonged warming trend. There`s high confidence in Monday being the coolest day of this upcoming week. Highs will be near normal, mostly in the low to mid 80`s in the plains, and 70`s for most mountain communities. && .LONG TERM /Monday night through Sunday/... Issued at 233 PM MDT Sun Jul 7 2024 Not many changes to the overall long term forecast period. As the shortwave trough exits, lingering mid level moisture could lead to weak diurnal convection for areas above eight thousand feet each afternoon Tuesday and Wednesday. Storms will likely remain sub- severe due to a lack of shear and instability. This should also keep the flood threat low for the burn areas. Starting Thursday, an upper level ridge finally arrives over Colorado. Cross sections indicate dry air throughout the 500-700mb layer. With the lack of moisture, only isolated chances (10-20%) of thunderstorms exists for Park, Summit, and Clear Creek counties. With strong ensemble agreement, widespread upper 90s to low 100s are likely starting Thursday through next weekend. NBM handles max temperatures well across the region. This heat may lead to tied/break max temperature records especially east of I-25. && .AVIATION /00Z TAFS through 00Z Monday/... Issued at 552 PM MDT Sun Jul 7 2024 Main thunderstorm threat has shifted to the south and east of the Denver area TAF sites, but still a low (10-20%) threat of thunder with still a little instability in northwest flow. A passing shower til about 02Z or 03Z would be more likely, however, given most instability has been worked over. Northerly winds will prevail early, then becoming variable toward 02Z-03Z before skies clear and normal light drainage winds settle in through 05Z. On Monday, the airmass will be more stable with only SCT clouds developing at 8000 ft AGL or higher. Normal diurnal wind patterns should prevail at speeds 10 kts or less. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Barjenbruch SHORT TERM...Rodriguez LONG TERM...AD AVIATION...Barjenbruch