textproduct: Pendleton

KEY MESSAGES

- Light showers prevail through the afternoon in the Basin into the Yakima/Kittitas Valley.

- Mostly dry conditions continue Wednesday and later through the day.

- Active weather with breezy winds through the late part of the week and into next week.

DISCUSSION

Radar currently advertises light precip across the Columbia Basin into the Yakima/Kittitas Valley that will continue through the afternoon hours. Soundings from OTX taken at 12z show lower level dry air, which will allow little precip to accumulate out of this system. PoPs are tapered up to 15% through the general populated areas north of the Blue Mountains.

Area of low pressure is located right off the coast of California and is expected to move inland (>90% confidence) over southern Oregon and northern California over the next few hours. Rain chances continue to be low (<20% chance) through late Wednesday, but conditions remain mostly dry with ridging developing just north in British Columbia. Ridging will keep the weather dry and slightly warmer going through late Wednesday, but guidance is in great agreement that a shortwave from the Pacific will move inland by late Wednesday/early Thursday. Light precip and locally breezy winds develop with the passage, otherwise not expecting mush of any impacts from this system (50-70% chance).

Looking towards the weekend, EURO and GFS members are hinting of another weather system with a shortwave embedded pushing along the area with periods of high PoPs (50-70% chances) along the Cascades with lower chances (10-30% chances) across east of the Cascades and into the populated centers across the rest of the CWA. That shortwave will then push north and northeastward into Canada by early next week (50-70% confidence), with another system right behind located in the Pacific. Guidance gets shaky after Sunday/Monday with guidance struggling with the strength and timing of the second shortwave. GFS members favors a stronger/wetter system, while Euro members trend towards a weaker/drier system. At this point not seeing meaningful impacts currently, as IVT values are currently <250 kg/ms through Monday. Still plenty of time to monitor for this evolving forecast incase the set-up changes.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

A broken band of elevated showers across the Columbia River Gorge bringing -RA at DLS with roughly 9000 ft ceilings. Visibility was around 2SM at ALW and PDT in BR. Conditions will be slow to improve as cloud cover lingers this morning. Light winds at all terminals through the TAF period and at least some risk (10 to 30 percent confidence) for returning IFR/MVFR category BR/FG issues again after 6z for ALW and PDT.

Preliminary Point Temps/PoPs

PDT 31 53 37 56 / 0 0 40 30 ALW 35 52 41 54 / 0 0 40 50 PSC 31 54 36 59 / 0 0 30 10 YKM 32 55 37 58 / 0 0 50 0 HRI 29 54 36 59 / 0 0 50 20 ELN 27 52 31 53 / 10 0 60 0 RDM 22 57 30 53 / 0 0 40 0 LGD 31 57 36 54 / 0 0 20 50 GCD 31 58 36 54 / 0 0 20 10 DLS 35 57 42 60 / 0 0 80 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...None.