textproduct: Pendleton

KEY MESSAGES

- Upper level high pressure building over the region through next week, with dry conditions prevailing and above normal temperatures

- Mostly light winds each day, but breezy Cascade gaps winds will develop Monday afternoon

- Increasing confidence in unsettled weather conditions returning at the end of the week

DISCUSSION

Visible satellite this afternoon shows clear skies across the forecast area as upper level ridging builds over the PacNW.

Upper level ridging continues to build into the PacNW from the northeast Pacific today, with ridging expected to remain overhead through the middle of next week(confidence 80-90%). Tomorrow into Monday the ridge axis will push east of the PacNW as an upper trough slides into northern BC, with zonal flow developing overhead and high pressure aloft to the south (confidence 80-85%). Tuesday through Thursday, ensemble guidance is in great agreement of upper level ridging building back over the PacNW then amplifying poleward. By Friday, two- thirds of the ensemble cluster members are in agreement of the upper ridge breaking down and an upper level trough approaching the PacNW. Meanwhile remaining members show the ridge breaking down but the upper trough remaining further north and zonal flow aloft developing over the region into Friday.

Through Monday, temperatures will be on a gradual increase, with peak afternoon temperatures in the upper 70s to mid 80s Monday (confidence 75-80%). Temperatures will drop a couple degrees into Tuesday, but expect high temperatures to remain in the upper 70s to low 80s. Conditions are expected to remain dry through Thursday with light, diurnally driven winds each day. The exception will be Monday, where breezy winds (15-20 mph with gusts to around 30 mph) will develop through the Cascade gaps as surface pressure gradients slightly strengthen in response to the upper trough passing to the north. On Friday, confidence is moderate (40-55%) in mountain showers developing across the Cascade crest/east slopes as well as the northern Blues, though confidence is low (20%) in forecast amounts at this time. The approaching upper trough will also result in breezy west winds through the Cascade Gaps and across the lower elevations, but confidence is also low (20-25%) in forecast wind speeds at this time. Lawhorn/82

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

High pressure maintains VFR conditions through the period with light and variable winds. Winds will mostly be less than 12 knots with diurnal driven speeds. No CIG or VIS issues expected.

Preliminary Point Temps/PoPs

PDT 47 80 51 83 / 0 0 0 0 ALW 53 80 58 83 / 0 0 0 0 PSC 49 81 50 84 / 0 0 0 0 YKM 51 82 52 84 / 0 0 0 0 HRI 49 81 51 84 / 0 0 0 0 ELN 49 78 51 79 / 0 0 0 0 RDM 42 88 48 86 / 0 0 0 0 LGD 49 88 53 86 / 0 0 0 0 GCD 49 91 55 88 / 0 0 0 0 DLS 56 85 57 86 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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