FXUS65 KGJT 200905 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 305 AM MDT Wed Aug 20 2025 .KEY MESSAGES... - Hot and dry conditions remain through the end of the week, with near-record high temperatures expected. - A few isolated showers or thunderstorms will be possible over the San Juans in the afternoon. - Confidence is high that moisture will return starting tomorrow, increasing chances of precipitation and bringing some cooler temperatures for the weekend. && .SHORT TERM /THROUGH THURSDAY/... Issued at 304 AM MDT Wed Aug 20 2025 High pressure remains overhead today, helping to keep skies mostly clear and temperatures hot. Highs this afternoon will run 10-15 degrees above normal, approaching record values yet again. Some very modest moisture continues to nudge northward, filling in mainly across the San Juans. This will fuel afternoon cloudiness and isolated to widely scattered showers or thunderstorms over the higher terrain of the southern and central Divide. The main concerns remain gusty outflow winds and lightning, however, with very low (<20%) chances of wetting rain today. The high is expected to wobble a bit tomorrow in response to a wave passing to our north, shifting the moisture plume to the east. We'll see PWAT values climb through the day tomorrow, approaching near- normal values for late August. Current guidance has PWATs climbing 100-120% of normal across the region tomorrow, which amounts to 0.75- 1.00 inches. This is a substantial improvement over the 0.20-0.30 inch PWAT values we've seen the last few days. As a result, we will see an increase in shower and storm coverage tomorrow afternoon, although it will still be confined to the higher terrain of the southern and central Divide mountains. Chances of wetting rain remain low (<20%) tomorrow, as surface levels will still be quite dry. Instead, gusty winds and lightning, along with perhaps some small hail, will be the main concerns. Temperatures will stay 10-15 degrees above normal. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 304 AM MDT Wed Aug 20 2025 The high pressure will be directly overhead at the start of the long term period. Ensembles continue to indicate moisture increasing thanks to flow around the high pressure. The deterministic EC and GFS both show PWATs increasing from north to south to about 150% of normal by Saturday, and by Sunday a second push of moisture increases this to 200%. This increased moisture looks to stay through the start of the work week. Shortwaves will rotate around the high pressure and work on this moisture, allowing more widespread showers and thunderstorms to fire. Coverage will slowly increase day by day, with the best coverage looking to be Sunday onwards. Cloud coverage will have a significant impact on whether strong convection forms in the afternoon or a more stratiform event occurs. If daytime heating is at a maximum, some storms will likely bring heavy showers to the region while continued cloudiness will bring a more soaking type of rain. These will probably be game day decisions to make on how each day will play out. Having said all that, the last several model runs have all shown this increase in moisture, showers, and storms so confidence is increasing that this monsoon push will come to fruition. Hot temperatures on Friday will start decreasing heading into the weekend, dropping to near normal values by Sunday, and possibly below normal by Monday due to clouds and precip. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1117 PM MDT Tue Aug 19 2025 Skies are mostly clear across the region, and will remain so through the next 24 hours. The exception will be along the southern and central Divide mountains, where clouds and showers will linger. There will be a slightly higher chance of showers or thunderstorms impacting KTEX and KDRO tomorrow afternoon, with lightning and gusty, erratic winds the main concerns. Otherwise, winds will be light and follow typical terrain driven patterns. A fire located north of KEGE is producing quite a bit of smoke that may lead to reduced visibility at the airport, and MVFR conditions. Otherwise, VFR conditions will prevail. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...BGB LONG TERM...TGJT AVIATION...TGJT