textproduct: Pendleton

KEY MESSAGES

- Moderate Heat Risk This Afternoon

- Isolated Thunderstorms possible Tonight and Wednesday

- High Winds on Wednesday

DISCUSSION

The warming ridge we are experiencing Today that will bring hot temperatures in the 80s and 90s will be replaced by a cooling eastern Pacific trough on Wednesday. A belt of moisture transport will bring widespread rain showers to the region, with NBM means showing one o to two tenths of an inch across the eastern mountains, and slightly less than that across the lower elevations like the Columbia Basin.

HREF 4 hour probability of thunder suggest the potential for tapping into instability across the northern Blues and Oregon cascades by late this evening, but isolated at best with 10 to 20% chances for lightning. That activity remains an overnight phenomenon ending before sunrise, but regenerating in the afternoon Wednesday especially across the mountains areas as overall instability will be weaker but showers more scattered to numerous (again lightning still isolated at 10%).

Onshore pressure gradients will be the primary driver for winds developing late Tonight and impacting through the day on Wednesday as the Portland to Spokane pressure gradient increases to about 10 mb or higher. This will produce strong sustained winds above 25 to 30 mph through the Gorge and foothills of the Blues as well as the Cascade Gaps where gusts will commonly be pushing 50 mph on Wednesday; as early as in the morning hours.

Wind advisories have been hoisted across the eastern Columbia Gorge beginning late This Evening, expanding across central Oregon, Lower Columbia Basin and the foothills of the northern Blue Mountains in Washington, Yakima and Kittitas Valleys by sunrise Wednesday. High Wind Warning for higher gust around 60 mph covers the Simcoe Highlands and foot hills of the Blue Mountains of Oregon Wednesday.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Terminals will see only cirrus Today with winds becoming more of a minor impact late in the TAF period. A pressure gradient will increase bringing gusty winds to the river gorge and DLS by this evening (after 03z) up to 25 or 30 knots for the overnight. Stronger winds will spread the other terminal locations on Wednesday.

Preliminary Point Temps/PoPs

PDT 85 52 66 44 / 0 0 60 20 ALW 88 56 66 48 / 0 0 70 30 PSC 91 56 71 47 / 0 0 60 0 YKM 87 55 70 44 / 0 20 70 0 HRI 88 54 68 46 / 0 0 60 10 ELN 83 48 63 40 / 0 20 80 0 RDM 90 42 62 33 / 0 40 70 0 LGD 91 51 64 40 / 0 0 80 30 GCD 94 48 66 37 / 0 10 60 20 DLS 88 53 67 48 / 0 40 60 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 8 PM this evening to 11 PM PDT Wednesday for WAZ024. Wind Advisory from 5 AM to 11 PM PDT Wednesday for WAZ026>029. High Wind Warning from 5 AM to 11 PM PDT Wednesday for WAZ521. OR...Wind Advisory from 8 PM this evening to 11 PM PDT Wednesday for ORZ041. Wind Advisory from 5 AM to 11 PM PDT Wednesday for ORZ044-510. High Wind Warning from 5 AM to 11 PM PDT Wednesday for ORZ507- 508.