textproduct: Pendleton

KEY MESSAGES

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

- Temperatures begin to slowly increase today, with peak temperatures expected early next week (temperatures 5 to 15 degrees above normal)

- Light, diurnally driven winds will prevail each day

DISCUSSION

Nighttime satellite imagery tonight shows decks of cirrus moving east across the northern two-thirds of the forecast area, while mid level stratus over the Yakima/Kittitas valleys peaks through breaks in the cirrus.

Through the middle of next week, ensemble and deterministic model guidance stay in great agreement of the PacNW remaining under the influence of upper level ridging or zonal flow aloft. Through Friday night, the upper level ridge will remain quite flat over the PacNW due to separate shortwave passages through southern BC Thursday and Friday (confidence 75-90%). Meanwhile, the upper level ridge will amplify over the eastern Pacific during this period, then slide inland over the weekend (confidence 70-85%). 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 65-70%). By Tuesday through Wednesday, ensemble guidance is in great agreement of upper level ridging building back over the PacNW then amplifying poleward. Through Monday, temperatures will be on a gradual increase, with peak afternoon temperatures in the upper 70s to mid 80s Monday (confidence 65-75%). 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 into middle of next week 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. Lawhorn/82

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

VFR conditions to prevail through the period. CIGS around 6kft AGL or higher will dissipate around 18Z at sites YKM/PSC. Winds will be light and diurnally/terrain driven through the period.

Preliminary Point Temps/PoPs

PDT 74 46 78 48 / 0 0 0 0 ALW 75 52 78 53 / 0 0 0 0 PSC 77 46 81 47 / 0 0 0 0 YKM 74 49 80 49 / 0 0 0 0 HRI 76 46 80 49 / 0 0 0 0 ELN 69 45 75 45 / 0 0 0 0 RDM 77 41 80 41 / 0 0 0 0 LGD 76 48 81 47 / 0 0 0 0 GCD 81 47 82 47 / 0 0 0 0 DLS 80 53 83 52 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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