Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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972 FXUS65 KBOU 141612 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1012 AM MDT Fri Jun 14 2024 .KEY MESSAGES... - Numerous thunderstorms and a greater severe storm threat this afternoon - A return to hot and mainly dry weather this weekend into early next week. - Snowmelt producing minor impacts from high streams. Gradually diminishing flows next week. && .UPDATE... Issued at 1012 AM MDT Fri Jun 14 2024 Water vapor satellite imagery showing the strong short wave trough over the Four Corners with good lift ahead it across western Colorado. We are already seeing some lift across eastern Colorado as well with storms forming over far northeast Colorado. Clouds are also filling in along the Front Range. May end up being a struggle to reach the lower 80s across the Front Range due to the cloud cover. However, 10AM temperatures have climbed into the lower to mid 70s, so the lower 80s are not far away. Highest severe threat will be east of I-25 where more sun is expected and better moisture is residing. Storms are expected to form 11am-1pm over the mountains and foothills. This activity will increase in coverage and intensity as they progress eastward through the afternoon hours. MLCAPE of 1000-2000 J/kg over the eastern plains with 0-6km Bulk Shear of 35- 40 knots should yield some severe thunderstorms with large hail (2 inch diameter) and strong damaging winds. The strong/severe storms will be east of the Denver Metro area by late afternoon (after 5pm) and east of Colorado by mid evening. Current forecast on track. Only minor changes were made to the forecast. && .SHORT TERM /Through tonight/... Issued at 327 AM MDT Fri Jun 14 2024 GOES-18 mid level water vapor imagery displays deeper moisture arriving to Utah Colorado border this morning. This shortwave trough will be the main driver for scattered to numerous showers and storms across northeast Colorado. A few stations along the foothills and plains present dew points ranging from 45-58 this morning. With favorable thunderstorm conditions such as MLCAPE values between 1000- 1500 J/kg, and lapse rates near 7-8 C/km, there is a threat of storms becoming severe this afternoon. The highest probability area for severe storms sits east of I-25 corridor this afternoon. Storms could begin as early as 1 PM MDT. Model soundings indicate large DCAPE values between 700-1000 thus expect storms to produce wind gusts up to 65 mph. Additional hazards such as large hail and lightning could occur. Storm motion seems not significantly fast thus there is still a threat of localized flooding given precipitable water values are above normal near 1-1.5 inches. The only limiting factor for severe storms would be our inability to heat up this afternoon. Temperatures will remain cooler today. Expect low to mid 80s this afternoon for the urban corridor and plains; temperatures for the mountains and valleys hover between 60-75F. Severe storms should end across the plains a few hours before midnight. It is possible a few showers will linger as the short wave trough exits the eastern plains. && .LONG TERM /Saturday through Thursday/... Issued at 327 AM MDT Fri Jun 14 2024 The upper level trough will move eastward on Saturday with a drier airmass across the area. However, there will still be enough instability for isold to widely sct tstms in the aftn thru the early evening hours. Severe potential looks low but a few storms may produce gusty. Highs on Sat will rise back into the lower to mid 90`s over nern CO. For Sun into Mon, drier air in SW flow aloft will be over the area with a sfc lee trough over ern CO. Overall, it appears any tstm activity will be very isold. Highs both days will stay in the 90`s over the plains. Looking ahead to Tue, SW flow aloft will remain over the area. A cold front will move across the area but timing is still somewhat uncertain. At this point have gone with a blended solution and kept highs in the lower to mid 80s over nern CO. Tstm chances will depend on how much low level moisture moves in behind front and whether capping inversion can be broken. For Tue night into Wed, another surge of cooler air may affect the area. The GFS is stronger with this feature vs the ECMWF. The GFS has highs only in the 70`s across the plains while the ECMWF keeps readings in the lower to mid 80`s. As far as the upper levels, the flow aloft will remain SW. Once again, tstm chances will depend on how much low level moisture there is and the strength of the capping inversion. By Thu, SW flow aloft will continue. The ECMWF has temps rising back into the 90`s over the plains while the GFS has readings near seasonal levels. As for tstms, the GFS has low level moisture increasing across the plains with decent instability. This results in a good chc for aftn storms. On the other hand, the ECMWF is drier with less instability so it has far less activity. && .AVIATION /12Z TAFS through 12Z Saturday/... Issued at 520 AM MDT Fri Jun 14 2024 VFR conditions are possible until 20-21Z as scattered thunderstorms enter terminals this afternoon. Both KAPA and KDEN could decrease in visibility to MVFR due to heavy rainfall until 00Z. These storms could produce up to 30-40kts gusts. ALthough the main threat of heavy rainfall exits in the evening, lingering showers could occur through 03Z for all terminals. Winds will decrease in speed eventually shifting into drainage. && .HYDROLOGY... Issued at 327 AM MDT Fri Jun 14 2024 Precipitable Water (PW) values increase to between 1 and 1.5", with the highest amounts over the northeast plains. Storms will be more efficient rain producers leading to localized flooding issues. Cameron Peak would be most susceptible to a minor flood risk through this evening. Elevated flows continue in the mountain streams, with Flood Advisories remaining in effect for the streams above Granby and Grand Lake. Remain alert of the dangers of water that is running high and cold. Flows are expected to gradually decrease over the weekend and through next week as the peak snowmelt is passing by. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Meier SHORT TERM...AD LONG TERM...RPK AVIATION...AD HYDROLOGY...AD/RPK