textproduct: Pendleton

KEY MESSAGES

- Much above normal temperatures through next week.

- Low, mainly Cascade shower and thunderstorm chances today through Sunday.

DISCUSSION

An area of high pressure will remain over the Pacific Northwest early today. However, it will begin to move eastward as an upper trough moves eastward towards the Washington and Oregon coasts.

This trough will then drop southward into Saturday and eventually close off an upper low. The low will continue to move south to a position off of California and strengthen into early Sunday. By later Sunday, the low will move onshore in central California, then move south and east over the southern Great Basin.

Behind this low, strong high pressure will build back in to the Pacific Northwest.

High temperatures will start out today in the 70s to lower 80s across the region. On average, this is about 10 to perhaps 15 degrees above normal. By Monday, highs will be mainly at or above 80 degrees, with the COlumbia Basin and Yakima Valley close to 90 degrees. These high temperatures on MOnday would be 15 to 20 degrees above normal. Similar temperatures are expected Tuesday and Wednesday. Highs should peak early next week, probably Tuesday or Wednesday.

There is some uncertainty in the guidance as to what happens after midweek, but temperatures should at least cool down a couple of degrees. In the Monday through Wednesday time frame, NBM probabilities of high temperatures >= 90 degrees reach about 60 percent across the Columbia Basin and Yakima Valleys. ECMWF EFI for high temperatures anomalies are generally 0.8 to 0.9 across the Columbia Basin and 0.7 to 0.8 across a broader swath of the region.

As far as shower and thunderstorm chances go, there is a chance of showers (30 percent) today in portions of the Oregon Cascades and a slight chance (20 percent) in the Washington Cascades, but thunder potential is confined to the Oregon Cascades and portions of central Oregon (<15 percent).

Saturday will see the best potential for rain and thunder, albeit still low chances with rain chances as high as 40 percent across portions of the Oregon Cascades and lower chances across some of the nearby highlands. Thunder potential will still be mainly confined to the Oregon Cascades and central Oregon with thunderstorm potential still 15 percent or less, though the areal coverage could be greater.

By Sunday coverage decreases again and mainly confined to portions of central Oregon and the Cascades, with less thunderstorm coverage as well.

With the low taking a further south track then it looked like a few days ago, it now looks like Monday onward will be dry.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

VFR conditions are expected through the TAF period with winds 10 kts or less. CIGS will begin to lower to around BKN100 toward the end of the period at DLS, RDM, BDN and YKM.

Preliminary Point Temps/PoPs

PDT 80 51 81 51 / 0 0 0 0 ALW 80 55 82 55 / 0 0 0 0 PSC 83 51 86 52 / 0 0 0 0 YKM 81 54 84 55 / 0 0 0 0 HRI 83 50 85 51 / 0 0 0 0 ELN 76 50 79 50 / 0 10 0 0 RDM 78 44 77 43 / 0 10 10 10 LGD 74 46 77 47 / 0 0 0 0 GCD 75 48 78 47 / 0 0 0 0 DLS 82 55 84 56 / 0 10 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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