


Area Forecast Discussion
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
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180 FXUS65 KGJT 141145 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 545 AM MDT Mon Jul 14 2025 .KEY MESSAGES... - Above-normal temperatures remain status quo through the seven- day forecast. - Outflow winds and dry lightning remain a threat today as thunderstorm coverage increases across the western Colorado terrain. - Coverage of afternoon showers and storms will continue through the week, increasing chances for wetting rains and less wildfire smoke. && .SHORT TERM /THROUGH TUESDAY/... Issued at 425 AM MDT Mon Jul 14 2025 A decaying outflow boundary and some orographics tapped into some moisture and kept cloud cover along the Continental Divide and on the San Juans overnight. Rainfall was not noted anywhere, despite a few radar returns in the 550 corridor, likely just cloud cover. Satellite water vapor imagery is painting a plume of moisture across much of the West Slope. Lower levels look pretty anemic, aside from the San Juans and the Divide. This should be the target of opportunity for shower and storm initiation today. A passing shortwave across the northern half of the CWA could lend a hand in some orographic enhancement too. Ensemble forecasts show around half an inch of PWAT across much of the region today. This should be enough to see another afternoon of terrain based showers and thunderstorms. Aforementioned water vapor locations look pretty spot on for shower development. Coverage on the San Juans will look the best. While northward, coverage shifts to the east hugging the Divide. Dry boundary layer conditions still whittle confidence away on wetting rain. This will keep gusty outflow winds in the picture, much like we saw last evening across the Grand Valley when 40 mph winds worked westward out of some showers on the Grand Mesa. Wind will continue to move wildfire smoke around. Erratic outflows could push smoke into areas previously out of the downstream path. Our hot and dry air mass will keep temperatures consistent with yesterday, with area temperatures in excess of 5 degrees above average. This trend continues for Tuesday, as we hold on to warm conditions across the southern half of the U.S. Mostly zonal flow on Tuesday will send additional shortwaves across the region, likely shifting winds around, as well as providing additional orographic shower enhancement. Ensemble PWATS jump about 20 percent in value Tuesday, so expect to see additional terrain based storms and showers. Some cloud cover could take a bite out of a few afternoon highs too, but don`t bet on it. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 357 PM MDT Sun Jul 13 2025 High pressure will continue to support hot and dry conditions, with increased PoPs in the afternoon. The coverage of showers and thunderstorms vary each day as weak moisture advection elevates PWAT anomalies in different parts of our CWA. Unsurprisingly, the greatest chances for precipitation tend to be over the high terrain. On Tuesday PWATs are near or below normal, which may allow for convection over the high terrain, including dry thunderstorms. On Wednesday shower and thunderstorm coverage looks to increase as some moisture makes its way into our region, particularly north of I-70. However, at this point in time ensembles begin to differ on timing, placement, and magnitude of moisture advection. The ECMWF Ens favors stronger moisture advection later this week than the GFS Ens, which puts maximum PWAT anomalies at above 150% of normal and around 130% of normal, respectively. So, there is a chance for a push of monsoon moisture later this week, but differences in the guidance lowers confidence on this. High temperatures remain 5 to 10 degrees above normal for the first few days of the long term, but should begin decreasing towards normal as a trough from the Pacific Northwest propagates eastward. Despite dry weather, Red Flag conditions are expected to only be localized at times as winds generally stay below critical fire weather thresholds, with the exception of local areas. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 541 AM MDT Mon Jul 14 2025 VFR conditions begin the TAF period this morning with some scattered upper level clouds hanging along the Divide and in the San Juans. Winds will remain light this morning and afternoon with a few terrain influenced gusts this afternoon. Showers and thunderstorms develop on the terrain, favoring the San Juans and adjacent to the Divide north of there. Erratic and gusty outflow winds and lightning will pose the main threat to aviators this afternoon. Ceilings will likely not reach breakpoint conditions thanks to high based showers. Some cloud cover will stick around the mountains tonight, but thin out after midnight and terminals should finish up this TAF period under VFR conditions again. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...LTB LONG TERM...GF AVIATION...TGJT