Effective March 3, 2026, NWS Las Vegas will split of several public forecast zones within our County Warning Area (CWA) into smaller, more localized zones. These zone alignment changes will enhance forecast precision by better accounting for geographically distinct weather patterns that impact these areas, while also strengthening messaging to the public and improving Impact-Based Decision Support Services (IDSS) for our partners that have responsibility for these areas.
Owens Valley: The current Owens Valley zone (CAZ520) will be divided into two segments: Owens Valley North (CAZ582) and Owens Valley South (CAZ581), with the boundary located just north of Owens Lake. This change recognizes climate variability between the north and south ends of the valley, with strong downslope wind events sometimes affecting one end more than the other. This change will also allow for enhanced communication of winter storm events and freeze products. In addition, because heavily traveled US-395 runs the length of the valley, splitting the zone will allow hazards to be more accurately messaged to local law enforcement road crews, and travelers along the route.
Colorado River Valley: The Colorado River Valley between Nevada and Arizona offers significant recreational opportunities thanks to Lake Mead and Lake Mohave. The proposed zone change would split the current zones (Lake Mead National Recreation Area (NVZ021) & Lake Mead National Recreation Area (AZZ036)) into four, creating separate zones for Lake Mohave. The new zones would be: Lake Mead NV Side (NVZ025), Lake Mead AZ Side (AZZ570), Lake Mohave NV Side (NVZ026), Lake Mohave AZ Side (AZZ571). These changes will better serve our recreation users on Lake Mohave, which can experience weather patterns that can differ significantly from Lake Mead. This will also benefit our National Park partners who rely on our daily forecasts for situational awareness and hazard preparedness. In addition, establishing distinct zones for each lake enables the issuance of lake-specific headlines, allowing for more precise communication of localized weather hazards than was possible when both lakes were grouped together in a single zone.
Southern Mohave County: Northwest Deserts (AZZ003) of Mohave County feature high desert terrain at elevations generally between 2,500 and 5,000 feet. The exception is the Hualapai Mountains in the central part of the zone, where elevations exceed 8,000 feet and support a mountain community, dense forest vegetation, and year-round recreational opportunities. The proposed zone change would create a new zone for the Hualapai Mountains (AZZ575), with a boundary defined roughly by the 4,500 foot contour, to better serve this high-elevation area. This new zone would be fully encircled by the existing Northwest Deserts zone (renumbered to AZZ576) This change was specifically requested by local emergency management and will improve messaging of both winter and summer weather conditions in the area.
The new configuration will enable WFO Las Vegas to deliver more geographically specific forecasts to both core partners and the public, ensuring that hazard products more accurately reflect local conditions. These changes will also strengthen our ability to communicate with emergency management, first responders, and the communities that rely on timely, accurate information from the NWS.
These zone changes require partners and users to take appropriate action to receive the new zone products using the Universal Geographic Code (UGC) zone code format listed in Table 1. Products affected by this change are listed in Table 2.
| Current Public Zone Name / Current UGC | New Public Zone Name / New UGC |
|---|---|
| Owens Valley (CAZ520) | Owens Valley North (CAZ582) |
| Owens Valley South (CAZ581) | |
| Lake Mead National Recreation Area (AZZ036) | Lake Mead - AZ Side (AZZ570) |
| Lake Mohave - AZ Side (AZZ571) | |
| Lake Mead National Recreation Area (NVZ021) | Lake Mead - NV Side (NVZ025) |
| Lake Mohave - NV Side (NVZ026) | |
| Northwest Deserts (AZZ003) | Northwest Deserts (AZZ576) |
| Hualapai Mountains (AZZ575) |
| Product Name | WMO Header | AWIPS ID |
|---|---|---|
| Avalanche Watch | WOUS45 KVEF | AVAVEF |
| Avalanche Warning | WOUS45 KVEF | AVWVEF |
| Special Avalanche Bulletin | WWUS85 KVEF | SABVEF |
| Winter Weather Message | WWUS45 KVEF | WSWVEF |
| Non-Precipitation Watch/Warning/Advisory | WWUS75 KVEF | NPWVEF |
| Flood Watch | WGUS65 KVEF | FFAVEF |
| Hydrologic Outlook | FGUS75 KVEF | ESFVEF |
| Zone Forecast | FPUS55 KVEF | ZFPVEF |
| Point Forecast Matrices | FOUS55 KVEF | PFMVEF |
| Tabular State Forecast | FPUS65 KVEF | SFTVEF |
| Area Forecast Discussion | FXUS65 KVEF | AFDVEF |
| Special Weather Statement | WWUS85 KVEF | SPSVEF |
| Public Information Statement | NOUS45 KVEF | PNSVEF |
If you have any questions or comments about this change, please contact:
Daniel Berc
Warning Coordination Meteorologist
National Weather Service - Las Vegas, NV
(702) 263-9744
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