


Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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073 FXUS65 KGJT 300349 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 949 PM MDT Sun Jun 29 2025 .KEY MESSAGES... - Afternoon convection will bring some gusty outflow winds to the area, mainly over the higher terrain. - Deeper moisture moves in midweek bringing increasing chances for widespread showers and storms. - Unseasonably warm conditions remain in place through mid week. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 156 PM MDT Sun Jun 29 2025 As expected, increased moisture and daytime heating have allowed convection to fire over the higher terrain this afternoon. The 18Z Grand Junction sounding reported PWATs of 0.5 inches which is about a 25% increase from what it was yesterday. Surface based CAPE is only around 500 J/kg though midlevel lapse rates of 9 to 10C/km indicate enough instability, along with the moisture, for this convection. Of note, DCAPE is over 1600 J/kg and given the dry low levels, this holds so the biggest concern from any convection will be gusty outflow winds. Speaking of, upstream in central Utah, a few areas have reported 50 mph gusts so wouldn`t be surprised to see some of those higher gusts materialize in our CWA. Radar is also showing plenty of outflow boundaries across the area further highlighting those dry lower levels and gusty winds. For Monday, the deepest moisture drops to the San Juans which is where CAMs are showing the best chance (50 to 60%) for convection. Dewpoints will increase by about 10F so some light precip may actually hit the ground though gusty outflow winds will remain a concern. High temps through the period will continue to run 5 to 8 degrees above normal for late June/early July. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 156 PM MDT Sun Jun 29 2025 On Tuesday, there will be two main features driving our weather here. A closed low pressure over the coast of SoCal, and a high pressure over the Southern Plains. These two system will result in southerly flow, which will advect deep moisture into the area. Therefore expect scattered afternoon convection over the higher terrain perhaps propagating over some of the valleys through evening. PWAT values around 100-150 percent of normal do support a chance for localized heavy rain. Strong gusty winds are also possible with these showers. On Wednesday the low pressure begins to weaken into an open wave as it moves inland, but moisture advection continues. Expect another round of afternoon convection, but the coverage should increase compared to Tuesday. The models have been fairly consistent with bringing that trough through the region on Thursday. This wave should provide some lift, which happens to coincide with the peak moisture advection. PWAT values could reach 150-250 percent of normal. This increases the chance for heavy rain and overall storm coverage. Timing of the wave and morning cloud or existing showers will dictate storm intensity that afternoon. The potential for heavy rain and flash flooding could be maximized Thursday afternoon through the evening if conditions line up correctly. The models have been consistent with showing a dry air intrusion behind the departing wave on Friday. Although there are model differences regarding how much moisture will be left if any to support afternoon convection. They tend to overdue the drying in these situations, so hesitant to say dry everywhere. As of now it appears showers and storms still look possible somewhere in the forecast area Friday afternoon and evening. Best chances will be in the mountains as always. The exact location, coverage and strength of storms is unknown at this time. Details for the weekend are murky right now, with some models showing a lot of dry air and others showing enough moisture for showers. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 943 PM MDT Sun Jun 29 2025 Leftover cloud cover on terrain is dissipating and VFR conditions will continue through the overnight hours and into Monday morning. Showers and thunderstorms will develop on the terrain immediately west of the Divide Monday afternoon as well as across the San Juans and portions of the Uintas. Gusty outflow winds will remain the primary challenge to aviators around these storms. A few TEMPO ceilings and visibility restrictions are possible too. Kept PROB30 TSRA in KEGE, KASE, KTEX, and VCSH around KDRO during afternoon hours. Shower activity will subside near sunset and VFR conditions are expected to close out this TAF period. Afternoon winds will be less gusty Monday(aside from thunderstorm outflows) with a few afternoon puffs up to 20 mph around the region. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...TGR LONG TERM...KJS AVIATION...TGJT