Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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363 FXUS65 KBOU 122346 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 546 PM MDT Wed Jun 12 2024 .KEY MESSAGES... - Much above normal temperatures will continue on Thursday. Isolated high based showers and storms with gusty outflow winds in the afternoon and evening hours. - Snowmelt producing minor impacts from high streams, mainly in Grand County. - Slightly cooler conditions will arrive Friday and Saturday with scattered showers and storms. Some of these storms could be strong to severe along the plains with heavy rain on Friday. && .SHORT TERM /Through Thursday/... Issued at 251 PM MDT Wed Jun 12 2024 Radars are indicating isolated showers and thunderstorms over the mountains at this time. Highs have reached the mid 90s over the plains for the warmest day of 2024 so far. Seems to be a bit more convection than most of the models indicated earlier. The storms are pretty high based and downdraft CAPE is pretty high. Outflow winds will be the main issue with the storms later this afternoon and evening. The latest high resolution models are showing limited convection over a good part of the CWA this evening. With that and reality in mind, will up pops into 10-30% range for much of the CWA. Models now are not showing much convection for Thursday afternoon, but we`ll see how that evolves as well. Temperature and thickness grids point to it being a tad warmer on Thursday than today for the western half of plains and high country. The eastern half of the plains could be a bit cooler behind a cold front that moves in Thursday morning. && .LONG TERM /Thursday night through Wednesday/... Issued at 227 PM MDT Wed Jun 12 2024 Upper level high pressure will remain over the Central and Southern Rockies Thursday night with mostly dry weather and mild temperatures across the forecast area. The exception may be across the northeastern plains east of the Front Range Urban Corridor where moisture convergence along a weak front could kick off a few evening showers and storms, some of which could be strong. Friday and Friday evening, an upper level shortwave will move across the state bringing cooler temperatures and increased precipitation chances to the CWA. With plenty of instability (1000 J/KG to 2500 J/KG) and shear (35+KTs), some of the storms could become strong to severe, especially across the eastern plains. In addition, heavy rainfall will be possible on the plains where PW`s are expected to range between 1.00"-1.50". Warmer and drier weather is expected to return across the area over the weekend as the upper level shortwave moves into the Central Plains States and upper level high pressure rebuilds over Colorado. On Saturday, there could be isolated to scattered (10%-30%) afternoon and evening showers and storms across the foothills and Palmer Divide as lingering moisture combines with daytime heating. Some of the stronger storms could produce brief heavy rain and small hail. By Sunday, hot weather is expected to make its return with max temperatures are expected to climb into the mid 90s across the plains. The hot and dry conditions combined with increasing winds may lead to elevated fire weather conditions across the portions of the high country and Palmer Divide on Sunday. On Monday, upper level high pressure will be centered over the Eastern U.S. with a moderate southwesterly flow aloft over Colorado. This pattern will result in continued hot and dry weather across the region. However, with better low level moisture further east across the plains, can`t rule out a few late afternoon and evening storms northeast of Denver, some of which could be strong. The hot and dry conditions combined with increasing winds may lead to elevated fire weather conditions across the portions of the high country and Palmer Divide on Sunday. These conditions are expected to spread eastward across portions of the plains on Monday. The hot and dry conditions combined with increasing winds may lead to elevated fire weather conditions across the portions of the mountains, foothills and Palmer Divide on Sunday. On Tuesday, an upper level shortwave moving across the Northern Rockies will push a cold front across Northeastern Colorado. Consequently, much cooler temperatures along with isolated to scattered (10% to 30%) late afternoon showers and storms are expected Tuesday and Wednesday. && .AVIATION /00Z TAFS through 00Z Thursday/... Issued at 546 PM MDT Wed Jun 12 2024 Gusty microburst winds affected the airports this afternoon. Upstream satellite observations are showing some stabilization, so appears winds should start to settle down at the Denver area TAF sites 00Z-02Z, with normal drainage winds resuming from the south/southwest. For Thursday, the main concern once again will be gusty outflow winds from isolated high based showers/storms. While the upper levels see some drying, the weak advection of low level moisture combined with strong diurnal heating and upslope behind a weak "cool" front, could be just enough for another round of high based convection and gusty outflow winds. Most likely this would occur after 21-22Z, but enough threat to have TEMPO VRB gusty winds to 35 kts in the forecast. && .HYDROLOGY... Issued at 227 PM MDT Wed Jun 12 2024 Elevated flows continue across the upper Colorado River basin in Grand County, with Flood Advisories in effect for streams above Granby and Grand Lake. Remain alert of the dangers of water that is running high and cold. Flows may increase over the next few days as hot temperatures are expected followed by showers and storms on Friday. Heavy rainfall will be possible on the plains where PW`s are expected to range between 1.00"-1.50". However, the storms are expected to be moving at around 25 KTS which should limit the flooding potential. Moisture levels across the high country will be lower; however, there could be localized areas of heavy rainfall which could cause flooding issues across the burn scars. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...RJK LONG TERM....JK AVIATION...Barjenbruch HYDROLOGY....JK