Area Forecast Discussion

KEY MESSAGES

* Dry and seasonable conditions continue through tonight.

* Precipitation chances and cooler temperatures return tomorrow and continue through the weekend.

* Cool and dry conditions for early next week.

DISCUSSION

Southwest flow continues over the forecast area ahead of a Pacific trough. This is resulting in near normal temperatures and partly cloudy skies, a pattern that is expected to continue through tomorrow afternoon. As the trough continues to push onshore the resulting moisture is expected to combine with moisture from TS Vance, resulting in several days of soggy conditions, particularly in western Arizona. Showers and thunderstorms begin to the east early Friday morning, with additional development further west by early evening. Activity remains mainly limited to the eastern half of the forecast area until Saturday evening when a secondary wave off the California coast kicks its way onshore. Impacts are still somewhat variable as they depend strongly on the path of this wave. The current, more aggressive track has this wave moving quickly and the associated moisture resulting in precipitation across the forecast area, however a slower track would limit the western moisture availability and keep showers largely in Arizona. Mountain snow remains a possibility, however snow levels aren't expected to drop below the peaks until Sunday morning, by which point most of the precipitation will have concluded, limiting most of the potential accumulation. Activity dries out by Monday as the system moves east, leaving dry conditions and slightly below normal temperatures through late week.

AVIATION...For Harry Reid...For the 00Z Forecast Package

This evening, winds shift to the southwest and become light, with increasing clouds expected overnight. Late tonight through mid- morning Friday, isolated showers are expected to develop across the area, mainly remaining over the higher terrain. However, there is a window between 09Z-12Z when there is around 10-20% chance of thunderstorms to develop and move northward across the Valley. Gusty outflow winds and SCT-BKN ceilings around 8kft can be expected with any shower or thunderstorm activity. Winds remain light through the morning, gradually veering to the southwest and becoming gusty with gusts to around 18-20KT by early afternoon. Late afternoon into early evening, there is potential for another round of thunderstorms, but confidence in precise timing, location, and direct impacts remains low at this time. Gusts diminish late evening with light winds overnight.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 00Z Forecast Package...Clouds continue increasing across the region through the forecast period, with ceilings becoming SCT-BKN between 7-10kft by Friday morning. Isolated to scattered showers and thunderstorms are expected across northwestern Arizona and southern Nevada late tonight, with a better chance Friday late afternoon. Gusty outflow winds and brief reductions in ceilings can be expected in the vicinity of showers and storms. Confidence in direct impacts to area terminals remains low at this time, with Las Vegas Valley terminals having the highest probability of seeing showers/thunderstorms in the vicinity. Gusty up-valley winds continue into early evening at KBIH in the northern Owens Valley, diminishing thereafter with 5- 10KT winds areawide through tonight. Winds shift to the south and southwest by Friday afternoon, with gusts to around 20-25KT common through the end of the forecast period.

SPOTTER INFORMATION STATEMENT

Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.