Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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101 FXUS65 KGJT 111108 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 508 AM MDT Tue Jun 11 2024 .KEY MESSAGES... - Drier conditions move in today causing a downturn in activity. A quick shower or storms remains possible along the Divide and San Juans. - Highs will jump nearly 15 degrees from seasonal June values Wednesday and Thursday afternoon. - Active weather returns late week as the next system arrives Friday, along with some temperature relief. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 245 AM MDT Tue Jun 11 2024 A marked downturn in convective activity is expected today as dry air, noted in lower specific humidities, moves into the region thanks to west through northwesterly flow. That being said, some pockets of higher instability will be found along the Divide and portions of the San Juans so a quick shower or storm can`t be ruled out there. Elsewhere, look for some cumulus clouds developing over the higher terrain this afternoon and warm afternoon temperatures. Moving on to Wednesday, a high pressure center will be situated over the Mexico/Arizona/New Mexico border while a closed low continues to spin off the southern California coast. As far as our weather is concerned, we`ll experience similar conditions to what we`ll see today. CAM guidance is suggesting some light convection over portions of the central and northern mountains while the NBM keeps the whole area just about dry. Wouldn`t be surprised to see some slight chance PoPs for Wednesday in this afternoon`s package but for now, no mention of any precip. Under the high pressure, we`ll see a return to hot temperatures with the possibility for some triple digits especially for eastern and southeastern Utah and getting close in the Grand Valley. It`s not summer yet, but it sure feels like it. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 245 AM MDT Tue Jun 11 2024 The ridge axis will build directly overhead across western Colorado late Wednesday and into Thursday. A weak system undercutting the ridge will bring passing clouds to the region Thursday afternoon with a non-zero chance for a high-based shower or two over the higher terrain. Even so, dry weather is expected with continued warmer temperatures. Highs will trend well above normal with triple digit heat expected for the lower desert valleys, though if there ends up being too much cloud cover readings could hover near the century mark. On Thursday, the closed low will continue spinning off the coast of southern California, remaining fairly stationary before beginning to push onshore Thursday night. This will deflect the ridge to the east with flow aloft shifting to the south- southwest across eastern Utah and western Colorado. By Friday morning the low will reach southern Arizona and then arrive in the Four Corners region about 12 hours later. It will lift northeast across the area as an open wave late Friday afternoon before sliding east of the Divide on Saturday. This system will bring increased chances for showers and thunderstorms as we experience moderate moisture advection and dynamic lift from the shortwave itself. Showers will spread from south to north on Friday, though we will likely see high- based activity as early as Thursday night. With increased broad scale ascent and daytime heating some stronger storms will develop Friday afternoon which could produce heavier rainfall. Outside of that, a brief wetting rain will be the more likely outcome for our lower elevations with gusty winds being the primary concern from any convection. The good news is that the uptick in clouds and showers as well as the passage of the trough will drop temperatures back to below normal area-wide on Friday. Showers taper off from west to east late Friday night as a transitory ridge moves in behind the trough. Saturday will be mostly dry as a result though diurnally-driven scattered storms can be expected along the Divide Saturday afternoon. Temperatures will climb back to above normal under the weak ridge with additional warming occurring later in the weekend. This will be due to the shift to southwest flow as a closed low drops into the Pacific Northwest, encompassing the western CONUS in broad troughing aloft. The low will continue to dive south on Monday, strengthening the southwest gradient across the forecast area. No precipitation chances on the horizon just yet so we`ll close out the long term period with hot, dry and breezy weather. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 506 AM MDT Tue Jun 11 2024 High pressure starts building in today but even so, a few showers and storms will be possible along the Divide and the San Juans. Do not anticipate any convection to affect any airfields. With that, VFR conditions will remain in place for the next 24 hours. Occasional afternoon gusts of 20 to 25 mph are possible. && .HYDROLOGY... Issued at 245 AM MDT Tue Jun 11 2024 High elevation snow continues to melt through these warm June temperatures. However, forecast stage and flow across major rivers and tributaries are showing a plateau or are trending downward through the remainder of the week. As a result, these trends have prompted the end of Flood Advisories across the Western Slope. That being said, water flow is still running fast and high thanks to ongoing snowmelt. Please continue to heed any closures and use caution near riverbanks. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...TGR LONG TERM...MMS AVIATION...TGJT HYDROLOGY...ERW