Air Resources Laboratory / Special Operations And Research Division (SORD)
Weather Advisories:
Nevada National Security Site Weather Forecast
Air Resources Laboratory/Special Operations and Research Division
0630 PST Mon Jul 20 2026
Official Sunset Monday 1901 PST
Official Sunrise Tuesday 441 PST
Forecaster: J Wood
.Forecast Summary...Its mostly cloudy and humid this morning with monsoon moisture in place. This will set the stage for thunderstorms to develop by early afternoon. They will favor the higher terrain with the main threats being brief heavy rain and locally strong winds. This activity will diminish this evening. Similar conditions will be observed tomorrow. Monsoon moisture along with the threat of thunderstorms will be on the decrease by mid-week. A trough of low pressure currently looks to develop over the Pacific Northwest this weekend. Dry southwest flow could develop over the region giving us a break from monsoon conditions.
---For The Nevada National Security Site---
.Today...Mostly cloudy with isolated afternoon thunderstorms. Light and variable winds this morning becoming southwest 10 to 20 mph this afternoon. Higher gusts near thunderstorms. High temperatures 81 to 88 on the mesas, 95 to 103 at the lower elevations, 98 at Mercury.
.Tonight...Partly cloudy with isolated evening showers and thunderstorms. Evening southwest winds 5 to 15 mph becoming light and variable overnight. Low temperatures 65 to 73 on the mesas, 70 to 75 on the dry lakes, 75 to 82 at the lower elevations, 82 at Mercury.
.Tuesday...Mostly cloudy with widely scattered afternoon thunderstorms. Light and variable winds in the morning becoming southwest 10 to 20 mph in the afternoon. Higher gusts near thunderstorms. High temperatures 80 to 87 on the mesas, 93 to 100 at the lower elevations, 96 at Mercury.
.Tuesday Night...Partly cloudy with isolated evening showers and thunderstorms. Evening southwest winds 5 to 15 mph becoming light and variable overnight. Low temperatures 65 to 73 on the mesas, 70 to 75 on the dry lakes, 75 to 82 at the lower elevations, 81 at Mercury.
.Wednesday...Partly cloudy with isolated afternoon thunderstorms. Light and variable winds in the morning becoming southwest 10 to 25 mph in the afternoon. Higher gusts near thunderstorms. High temperatures 82 to 89 on the mesas, 95 to 103 at the lower elevations, 99 at Mercury.
.Thursday...Partly cloudy. Southwest winds 10 to 25 mph. Low temperatures 63 to 70 on the mesas, 70 to 75 on the dry lakes, 72 to 79 at the lower elevations, 79 at Mercury. High temperatures 83 to 90 on the mesas, 98 to 105 at the lower elevations, 100 at Mercury.
.Friday...Partly cloudy. Southwest winds 10 to 25 mph. Low temperatures 63 to 70 on the mesas, 70 to 75 on the dry lakes, 72 to 79 at the lower elevations, 78 at Mercury. High temperatures 83 to 90 on the mesas, 99 to 107 at the lower elevations, 103 at Mercury.
.Saturday...Mostly sunny. Southwest winds 10 to 25 mph. Low temperatures 60 to 67 on the mesas, 65 to 70 on the dry lakes, 70 to 77 at the lower elevations, 76 at Mercury. High temperatures 83 to 90 on the mesas, 99 to 107 at the lower elevations, 102 at Mercury.
.Sunday...Mostly sunny. Southwest winds 10 to 25 mph. Low temperatures 60 to 67 on the mesas, 65 to 70 on the dry lakes, 70 to 77 at the lower elevations, 75 at Mercury. High temperatures 83 to 90 on the mesas, 98 to 105 at the lower elevations, 100 at Mercury.
-End Forecast---J Wood
Weather questions or reports should be directed to the Duty Forecaster at 5-1255.
Air Resources Laboratory/Special Operations and Research Division
0630 PST Mon Jul 20 2026
Official Sunset Monday 1901 PST
Official Sunrise Tuesday 441 PST
Forecaster: J Wood
NNSS Forecast Weather Threat Matrix
Mon 7/20
Tue 7/21
Wed 7/22
Thu 7/23
Fri 7/24
Sat 7/25
Sun 7/26
Thunderstorms.
Thunderstorms.
Thunderstorms.
Heat.
Heat.
Heat.
Heat.
Threat/Impacts Legend
None/Low
Minor
Moderate
Major
.Forecast Summary...Its mostly cloudy and humid this morning with monsoon moisture in place. This will set the stage for thunderstorms to develop by early afternoon. They will favor the higher terrain with the main threats being brief heavy rain and locally strong winds. This activity will diminish this evening. Similar conditions will be observed tomorrow. Monsoon moisture along with the threat of thunderstorms will be on the decrease by mid-week. A trough of low pressure currently looks to develop over the Pacific Northwest this weekend. Dry southwest flow could develop over the region giving us a break from monsoon conditions.
---For The Nevada National Security Site---
.Today...Mostly cloudy with isolated afternoon thunderstorms. Light and variable winds this morning becoming southwest 10 to 20 mph this afternoon. Higher gusts near thunderstorms. High temperatures 81 to 88 on the mesas, 95 to 103 at the lower elevations, 98 at Mercury.
.Tonight...Partly cloudy with isolated evening showers and thunderstorms. Evening southwest winds 5 to 15 mph becoming light and variable overnight. Low temperatures 65 to 73 on the mesas, 70 to 75 on the dry lakes, 75 to 82 at the lower elevations, 82 at Mercury.
.Tuesday...Mostly cloudy with widely scattered afternoon thunderstorms. Light and variable winds in the morning becoming southwest 10 to 20 mph in the afternoon. Higher gusts near thunderstorms. High temperatures 80 to 87 on the mesas, 93 to 100 at the lower elevations, 96 at Mercury.
.Tuesday Night...Partly cloudy with isolated evening showers and thunderstorms. Evening southwest winds 5 to 15 mph becoming light and variable overnight. Low temperatures 65 to 73 on the mesas, 70 to 75 on the dry lakes, 75 to 82 at the lower elevations, 81 at Mercury.
.Wednesday...Partly cloudy with isolated afternoon thunderstorms. Light and variable winds in the morning becoming southwest 10 to 25 mph in the afternoon. Higher gusts near thunderstorms. High temperatures 82 to 89 on the mesas, 95 to 103 at the lower elevations, 99 at Mercury.
.Thursday...Partly cloudy. Southwest winds 10 to 25 mph. Low temperatures 63 to 70 on the mesas, 70 to 75 on the dry lakes, 72 to 79 at the lower elevations, 79 at Mercury. High temperatures 83 to 90 on the mesas, 98 to 105 at the lower elevations, 100 at Mercury.
.Friday...Partly cloudy. Southwest winds 10 to 25 mph. Low temperatures 63 to 70 on the mesas, 70 to 75 on the dry lakes, 72 to 79 at the lower elevations, 78 at Mercury. High temperatures 83 to 90 on the mesas, 99 to 107 at the lower elevations, 103 at Mercury.
.Saturday...Mostly sunny. Southwest winds 10 to 25 mph. Low temperatures 60 to 67 on the mesas, 65 to 70 on the dry lakes, 70 to 77 at the lower elevations, 76 at Mercury. High temperatures 83 to 90 on the mesas, 99 to 107 at the lower elevations, 102 at Mercury.
.Sunday...Mostly sunny. Southwest winds 10 to 25 mph. Low temperatures 60 to 67 on the mesas, 65 to 70 on the dry lakes, 70 to 77 at the lower elevations, 75 at Mercury. High temperatures 83 to 90 on the mesas, 98 to 105 at the lower elevations, 100 at Mercury.
-End Forecast---J Wood
Weather questions or reports should be directed to the Duty Forecaster at 5-1255.