Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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461 FXUS65 KGJT 252012 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 212 PM MDT Wed Sep 25 2024 .KEY MESSAGES... - Dry and unseasonably warm conditions are expected for the remainder of the week. Near-record highs are expected from Thursday through the weekend. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 212 PM MDT Wed Sep 25 2024 The string of mainly clear and warm days with cool nights will continue with this high pressure ridge in control. No big changes to the forecast in this static pattern and expect temperatures to continue to warm a few degrees again tomorrow afternoon and likely pushing record territory in several locations. There may be just enough moisture and cooling aloft with a wave passing well to our north to pop a few afternoon cumulus on the mountain ridges but there will virtually be no chance of precipitation through Thursday night. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Issued at 212 PM MDT Wed Sep 25 2024 By Friday, the high pressure will have retrograded to the west over the Desert Southwest with the ridge extending north over the Intermountain West to southern Idaho and Wyoming. A longwave trough from the Central Pacific to the Great Lakes over the northern States and southern Canada is keeping a strong zonal flow with a 140 kt jet core over these areas that is capping the ridge from extending farther north and quickly whisking any shortwave disturbances off to the east before they can dig south into the region. A particularly strong disturbance tries to disrupt the zonal flow Sunday night into Monday, but only makes it south to Montana before speeding east out onto the Northern Plains. The only impact from this system will be a brief period of northwesterly flow aloft as the high retrogrades to the west, but then returns to the zonal pattern to the north as the high pressure swells back to the east over the Rockies. Hence, this pattern looks to continue through mid next week with little change. Subsidence under the ridge has warmed the mid layers of the atmosphere enough to cap any development of cumulus over the mountains in spite of the nominal moisture that remains in place over eastern Utah and Western Colorado. This sunny dry weather will dominate the extended forecast with record or near record high temperatures 10 to 15 degrees above normal across the region through Monday with the morning lows running about five degrees above normal. Note, record highs are in the forecast for the lower valleys while the high country is forecast to have only near record highs. The only exception to the clear skies is an upper-level disturbance rotating around the low over the Mississippi Valley toward the central and southern Colorado mountains Friday afternoon that could lead to some cumulus development and a very slight chance of a shower or thunderstorm forming along the Divide. Stay tuned over the next 12 hours on this one to see if the high resolution models pick up on this. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1118 AM MDT Wed Sep 25 2024 Light terrain driven winds and clear skies can be expected over the next 24 hours...hence solid VFR conditions dominate the forecast. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...15 LONG TERM...DB AVIATION...GJT