Air Resources Laboratory / Special Operations And Research Division (SORD)
Weather Advisories:
NNSS Fire Weather Forecast
Air Resources Laboratory/Special Operations and Research Division
Valid: Friday Aug 21 2026 to Monday Aug 24 2026
Issued At: 0800 PST Fri Aug 21 2026
Forecaster: J Wood
.Forecast Summary...Early morning thunderstorms around the site resulted in lightning overnight. The slight chance for thunderstorms is lessened until this afternoon when the risk for isolated storm development picks back up, particularly over the mesas in Areas 12, 19, and 20 and surrounding high terrain features. This will continue through the evening and into tomorrow with the greatest impacts located offsite. Winds will pick up on Sunday after an area of lower pressure enters the Pacific Northwest, but broad ridging keeps Nevada hot and dry early next week.
Friday: Aug 21 2026
Weather: Partly Sunny with a slight chance of thunderstorms.
Wind: Southerly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 82 to 90 on the mesas, 100 to 108 at the lower elevations, 101 at Mercury.
Relative Humidity:
_% to _% in the morning and 20% to 30% in the afternoon.
30% to 40% in the morning and 15% to 25% in the afternoon.
Mixing Height: 12,500 feet AGL.
Chance of Wetting Rains: 10%
Chance of Thunder: 15%
Dry Lightning Probability: 5%
Saturday: Aug 22 2026
Weather: Mostly Sunny with a slight chance of thunderstorms.
Wind: Southwesterly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 82 to 90 on the mesas, 100 to 108 at the lower elevations, 100 at Mercury.
Relative Humidity:
30% to 40% in the morning and 20% to 30% in the afternoon.
25% to 35% in the morning and 10% to 20% in the afternoon.
Mixing Height: 11,500 feet AGL.
Chance of Wetting Rains: 5%
Chance of Thunder: 15%
Dry Lightning Probability: 5%
Sunday: Aug 23 2026
Weather: Mostly Sunny.
Wind: Southwesterly winds 10 to 20 mph gusting to 35 mph.
High Temperatures: 81 to 89 on the mesas, 99 to 107 at the lower elevations, 100 at Mercury.
Relative Humidity:
30% to 40% in the morning and 15% to 25% in the afternoon.
20% to 30% in the morning and 10% to 20% in the afternoon.
Mixing Height: 12,000 feet AGL.
Chance of Wetting Rains: 0%
Chance of Thunder: 5%
Dry Lightning Probability: 0%
Monday: Aug 24 2026
Weather: Mostly Sunny.
Wind: Southwesterly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 79 to 87 on the mesas, 98 to 106 at the lower elevations, 98 at Mercury.
Relative Humidity:
25% to 35% in the morning and 15% to 25% in the afternoon.
20% to 30% in the morning and 10% to 20% in the afternoon.
Mixing Height: 11,500 feet AGL.
Chance of Wetting Rains: 0%
Chance of Thunder: 0%
Dry Lightning Probability: 0%
Weather questions or reports should be directed to the Duty Forecaster at 5-1255.
Air Resources Laboratory/Special Operations and Research Division
Valid: Friday Aug 21 2026 to Monday Aug 24 2026
Issued At: 0800 PST Fri Aug 21 2026
Forecaster: J Wood
.Forecast Summary...Early morning thunderstorms around the site resulted in lightning overnight. The slight chance for thunderstorms is lessened until this afternoon when the risk for isolated storm development picks back up, particularly over the mesas in Areas 12, 19, and 20 and surrounding high terrain features. This will continue through the evening and into tomorrow with the greatest impacts located offsite. Winds will pick up on Sunday after an area of lower pressure enters the Pacific Northwest, but broad ridging keeps Nevada hot and dry early next week.
Friday: Aug 21 2026
Weather: Partly Sunny with a slight chance of thunderstorms.
Wind: Southerly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 82 to 90 on the mesas, 100 to 108 at the lower elevations, 101 at Mercury.
Relative Humidity:
_% to _% in the morning and 20% to 30% in the afternoon.
30% to 40% in the morning and 15% to 25% in the afternoon.
Mixing Height: 12,500 feet AGL.
Chance of Wetting Rains: 10%
Chance of Thunder: 15%
Dry Lightning Probability: 5%
Saturday: Aug 22 2026
Weather: Mostly Sunny with a slight chance of thunderstorms.
Wind: Southwesterly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 82 to 90 on the mesas, 100 to 108 at the lower elevations, 100 at Mercury.
Relative Humidity:
30% to 40% in the morning and 20% to 30% in the afternoon.
25% to 35% in the morning and 10% to 20% in the afternoon.
Mixing Height: 11,500 feet AGL.
Chance of Wetting Rains: 5%
Chance of Thunder: 15%
Dry Lightning Probability: 5%
Sunday: Aug 23 2026
Weather: Mostly Sunny.
Wind: Southwesterly winds 10 to 20 mph gusting to 35 mph.
High Temperatures: 81 to 89 on the mesas, 99 to 107 at the lower elevations, 100 at Mercury.
Relative Humidity:
30% to 40% in the morning and 15% to 25% in the afternoon.
20% to 30% in the morning and 10% to 20% in the afternoon.
Mixing Height: 12,000 feet AGL.
Chance of Wetting Rains: 0%
Chance of Thunder: 5%
Dry Lightning Probability: 0%
Monday: Aug 24 2026
Weather: Mostly Sunny.
Wind: Southwesterly winds 10 to 20 mph gusting to 30 mph.
High Temperatures: 79 to 87 on the mesas, 98 to 106 at the lower elevations, 98 at Mercury.
Relative Humidity:
25% to 35% in the morning and 15% to 25% in the afternoon.
20% to 30% in the morning and 10% to 20% in the afternoon.
Mixing Height: 11,500 feet AGL.
Chance of Wetting Rains: 0%
Chance of Thunder: 0%
Dry Lightning Probability: 0%
Weather questions or reports should be directed to the Duty Forecaster at 5-1255.