textproduct: Pendleton

KEY MESSAGES

- Upper level high pressure over the region will continue to bring dry conditions and above normal temperatures through Thursday

- Locally breezy winds through the Cascade Gaps Monday afternoon

- Growing potential for mountain showers Friday into next weekend

DISCUSSION

A broad flat upper ridge was positioned across the western US with a tighter upper level height gradient and zonal flow from northern WA into the western Canada. This is a warm pattern for the Interior NW and Today is the warmest day of this upcoming period as surface winds are largely westerly and downsloping into the Columbia Basin, although still light across most of the the area. Low end breezy conditions forecast across the Kittitas Valley and the Eastern Columbia River Gorge near The Dalles and North Central Oregon This afternoon are the exceptions, as the NBM mean shows about 22-23 mph winds in the latter half of the afternoon. Light, mainly terrain/diurnally driven winds continue through about Thursday Night before the next pattern change may have minor impacts on the area. Tuesday and Wednesday will not be as warm across the lower elevations as the wind trajectories are lightener and more northerly/easterly across the Columbia Basin and Foothills of the Blues. Some of the warmest areas these days will be in the John Day Basin and Central Oregon Mountains where the NBM is hanging on to mid 80s and even around 90 degrees in the John Day Basin. Sometime Friday into Saturday a pattern change may cool temperatures across the region with low chances for precipitation (15% across the Mountain zones, higher to near 50% across the WA Cascade crest). However, there is significant differences in the ensembles for this period from about Friday Oct 9 through Sunday Oct 11 where the first and second cluster groups show a slight troughing influence whereas the other clusters offer continued ridging (i.e. cooler, wetter vs dry and warmer).

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Westerly components to the surface winds will tend to dominate Today as winds at most locations remain below 12 knots. A couple of exceptions are ALW and PSC where a more southerly wind component at ALW and more light and variable (less confidence in direction) are anticipated Today. Lastly DLS may see typical higher gap winds with sustained winds up to 20 mph for the afternoon into the evening hours. VFR this TAF set is a high confidence forecast (95%).

Preliminary Point Temps/PoPs

PDT 82 47 80 47 / 0 0 0 0 ALW 83 54 80 53 / 0 0 0 0 PSC 83 48 80 45 / 0 0 0 0 YKM 83 50 80 49 / 0 0 0 0 HRI 84 49 81 46 / 0 0 0 0 ELN 78 47 77 46 / 0 0 0 0 RDM 86 43 84 41 / 0 0 0 0 LGD 86 47 83 46 / 0 0 0 0 GCD 88 48 86 49 / 0 0 0 0 DLS 86 51 84 52 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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