textproduct: Pendleton

KEY MESSAGES

- Light showers continue through this afternoon with isolated storms possibly developing today.

- Breezy winds developing in the Simcoe Highlands and Kittitas Valley today, with winds peaking Friday.

- Cooling trend through Saturday, warming early next week.

DISCUSSION

Radar currently shows light showers across the area that will continue through the rest of the afternoon hours. Parts of the Southern Blue Mountains are seeing clearer conditions than earlier this morning, allowing for daytime heating to build into the area. This allows CAPE values to develop in the 250-500 J/kg range with 30-35 knots of 0-6km shear, bringing slight (10-20 percent) chances of an isolated thunderstorm this afternoon. Not expecting any of these storms to be severe, but heavy rain and pea size hail may impact areas where the strongest storms are present.

An oncoming shortwave with an embedded cold front will push through the area Thursday/Friday, allowing pressure gradients to tighten and bring breezy to windy conditions across the Simcoe Highlands, Kittitas Valley, and the Columbia Basin. Higher winds are expected across the Simcoe Highlands and Kittitas Valley (70-90% chance) though wind values appear to be sub-advisory level with more common values of wind gusts staying at 25 to 35 mph (50-70% chance). NBM does advertise 50-70% chances of exceeding wind advisory Friday, but confidence is not great enough to warrant a wind advisory yet. The oncoming trough will bring moderate rain and snow showers across the Cascades Friday and Saturday, but will leave most of the area east of it dry due to rain shadowing. Dew points and relative humidity will remain dry and, with combination of the expected breezy conditions Friday, bring elevated fire weather concerns through parts of the Columbia Basin (see 'FIRE WEATHER' below). Temperatures will cool down to the mid 60s to low 70s in lower elevation areas as a result of the systems passage. By Sunday, highs will hover in the mid to high 70s and be stable through at least through mid-next week (40-60% chance).

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

VFR conditions continue to prevail through the TAF period. Slight chance of showers in ALW/PSC, but nothing impactful to bring MVFR or lower values. Winds will be breezier overall by the afternoon to late afternoon hours, gusting up to 15 to 25 knots.

FIRE WEATHER

Elevated fire weather concerns expected this Friday across parts of FWZ WA691 (Columbia Basin of Washington). Concerns arise with the combination of breezy to windy and low relative humidity conditions developing. Minimum relative humidities will dry out in the 20-25% range Thursday and Friday. Breezy wind gusts will develop Friday in combination with the low relative humidity values, resulting in the potential for elevated fire weather potential.

Preliminary Point Temps/PoPs

PDT 78 47 75 47 / 20 10 0 0 ALW 79 53 76 52 / 20 10 0 0 PSC 83 52 80 49 / 20 10 0 0 YKM 80 48 80 47 / 40 0 0 0 HRI 81 50 78 50 / 20 0 0 0 ELN 73 45 72 44 / 50 0 0 0 RDM 74 37 76 40 / 10 0 0 0 LGD 76 44 74 43 / 40 20 0 0 GCD 78 42 77 42 / 40 10 0 0 DLS 78 53 77 52 / 20 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until midnight PDT tonight for WAZ026-521. OR...None.