Dalton Gardens Elementary School, ID Hourly Weather Updates

Key Messages

• Continued thunderstorm chances focused over mountain areas through the weekend.
• Temperatures warm back into the mid 80s to mid 90s by Sunday.
• Drier air returns early to mid next week.

Discussion

... Today through Sunday: The trough that brought afternoon and evening thunderstorms to the mountain areas yesterday has begun retrograding westward and off the PNW coast. This will result in southwesterly flow, which will aid in keeping PWATs 100-150 percent above normal (0.9-1.2"). We will remain in this pattern regime through the weekend and into early next week as the low stays in place off the coast. Incoming weak shortwaves paired with daytime heating and the added moisture will create chances for thunderstorms each afternoon and evening. Tonight, there is a 20-40 percent chance of thunderstorms focused along the Cascades and the ID Panhandle, and current radar does show thunderstorms moving towards the Cascades. Main impacts with these thunderstorms will be gusty outflow winds, localized heavy rainfall, and possible fire starts due to lightning. These impacts will remain similar through the weekend. While fire concerns are elevated due to lightning and gusty winds, the added moisture will limit any major fire weather concerns. Chances for thunderstorms will be similar on Saturday, but will be further confined to the Cascades and far SE Washington/Central ID. Thunderstorm chances will be further limited on Saturday as the low moves further off the coast.

Monday through Friday: Monday through Tuesday, the trough begins to move back towards the forecast area. This will bring more widespread chances of precipitation, though largest chances still remain confined to the ID Panhandle. Thunderstorm chances continue through Tuesday, then taper off as a warmer and drier air mass moves in. Currently, cluster analysis and long-term models remain in disagreement over whether we will continue seeing a cooler and wetter pattern or transition to a warmer and drier pattern. Roughly half of the clusters show much of the PNW in a drier and warmer pattern to end next week, while the other half shows us continuing to see lower heights. This will depend on whether the low off the west coast strengthens or dissipates. Overall: expect unsettled weather conditions to continue with chances of afternoon and evening thunderstorms in mountain areas through early next week. Temperatures will remain very close to or just below normal. /AS

Aviation

... 00Z TAFs: VFR and localized MVFR conditions are forecast, with the MVFR conditions largely from smoke impacts. The main potential for smoke will be near the Cascades and deeper basin, such as KEAT and KMWH. An upper trough will linger over the area tonight into Saturday, bringing isolated to scattered showers and thunderstorms. Chance will be found near the Cascades and northern mountains this evening, possible near KEAT. Saturday a broader threat of showers will be found but these will be more isolated in nature. Some may pass any TAF sites.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in smoke and haze continuing to impact local terminals, but low confidence in extent of reduced vis/cigs. Low confidence in showers or thunderstorms at KEAT Friday evening and at all TAF sites Saturday. This is the most impactful alternate scenario, and would require amendments should any cells move through.

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Confidence descriptors:

Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,

please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard

Watches / Warnings / Advisories

/WARNINGS/ADVISORIES... WA...Air Quality Alert until noon PDT Tuesday for Central Chelan County-Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-Waterville Plateau-Wenatchee Area-Western Chelan County-Western Okanogan County. ID...Air Quality Alert until noon PDT Tuesday for Lewis and Southern Nez Perce Counties-Lewiston Area.