COZ205-221030-
COZ205-221030-
Colorado River Headwaters-
1220 PM MDT Fri Aug 21 2026

Fire Weather Planning Forecast for Wrn Colorado and Ern Utah
National Weather Service Grand Junction CO
1220 PM MDT Fri Aug 21 2026

.DISCUSSION...

Mountain showers and thunderstorms will occur this afternoon and 
last through the evening, with the greatest chances for wetting 
rain being over the San Juan Mountains. Gusty outflow winds and 
lightning are the primary concerns today, but periods of heavy 
rainfall are possible with stronger storms. Tomorrow increased 
atmospheric moisture will allow for more widespread coverage of 
convection and greater chances of wetting rain. Periods of heavy 
rainfall are more likely tomorrow, which means the flash flood and
debris flow risk over burn scars increases. High temperatures 
will drop by about 5 degrees between today and tomorrow. 

...GUSTY ERRATIC WINDS CAN BE EXPECTED NEAR ANY SHOWERS
OR THUNDERSTORMS...
...THE SMOKE DATA IS CALCULATED FROM AN AVERAGE AT 6000 FEET MSL...


.TONIGHT...
Sky/weather.........Partly cloudy (40-50%). Isolated showers and 
                    thunderstorms until 2400. 
Chc of lightning....10 percent. 
Min temperature.....54-64 F. 
Max humidity........49-59%. 
20-foot winds.......Downslope/downvalley winds 3 to 6 mph. 
                    Localized gusts up to 20 mph in the evening. 
CWR.................10 percent. 
15K Ft MSL Winds....North 5 to 10 mph shifting to the south after 
                    midnight. 
Mixing Height.......8000 ft AGL until 2000, then 500 ft AGL. 
Transport Winds.....Southeast 5 mph. 
Smoke dispersal.....Poor. 

.SATURDAY...
Sky/weather.........Partly cloudy (40-50%). Scattered showers and 
                    thunderstorms after 1200. 
Chc of lightning....50 percent. 
Max temperature.....79-89 F. 
Min humidity........20-30%. 
20-foot winds.......Downslope/downvalley 3 to 6 mph becoming 
                    upslope/upvalley 4 to 8 mph by 1100.
CWR.................50 percent. 
15K Ft MSL Winds....Southwest 5 to 10 mph. 
Mixing Height.......1500 ft AGL until 1000, then 6500 ft AGL. 
Transport Winds.....Southwest 5 mph. 
Smoke dispersal.....Poor until 0900. Fair after 1200. 

.SATURDAY NIGHT...
Sky/weather.........Mostly cloudy (60-70%) until 2400, then partly 
                    cloudy (30-40%). Scattered showers and 
                    thunderstorms until 2400, then isolated 
                    showers. 
Chc of lightning....40 percent. 
Min temperature.....51-61 F. 
Max humidity........65-80%. 
20-foot winds.......Upslope/upvalley 4 to 8 mph becoming 
                    downslope/downvalley 3 to 6 mph by sunset.
CWR.................30 percent. 
15K Ft MSL Winds....West 15 to 20 mph. 
Mixing Height.......2500 ft AGL until 2000, then 500 ft AGL. 
Transport Winds.....South 5 mph. 
Smoke dispersal.....Poor. 

.SUNDAY...
Sky/weather.........Partly cloudy (40-50%). Isolated showers until 
                    1200, then scattered showers and thunderstorms. 
Chc of lightning....30 percent. 
Max temperature.....76-86 F. 
Min humidity........22-32%. 
20-foot winds.......Downslope/downvalley 3 to 6 mph becoming 
                    upslope/upvalley 4 to 8 mph by 1100.
CWR.................20 percent. 
15K Ft MSL Winds....West 15 to 20 mph. 
Mixing Height.......2000 ft AGL until 1000, then 7500 ft AGL. 
Transport Winds.....Southwest 5 mph until 1200, then west 10 to 15 
                    mph. 
Smoke dispersal.....Poor until 1200, then very good until 1500, 
                    then good. 

.FORECAST FOR DAY 3 THROUGH 7...
.MONDAY...Partly cloudy. Scattered showers and thunderstorms.
Lows 49-59. Highs 75-85. Winds less than 15 mph. 
.TUESDAY...Partly cloudy. Scattered showers and thunderstorms.
Lows 48-58. Highs 75-85. Winds less than 15 mph. 
.WEDNESDAY...Partly cloudy. Scattered showers and thunderstorms.
Lows 47-57. Highs 75-85. Winds less than 15 mph. 
.THURSDAY...Partly cloudy. Isolated showers and thunderstorms.
Lows 47-57. Highs 75-85. 
.FRIDAY...Partly cloudy. Isolated showers and thunderstorms. Lows
48-58. Highs 76-86.