textproduct: Pendleton

KEY MESSAGES

1. Wind Advisories through 11 PM Friday night

2. Friday afternoon showers and thunderstorms over the eastern mountains

3. Dry and cool over the weekend warming up beginning Monday

DISCUSSION

Current satellite is showing some convection beginning in southern Grant County with a cell that is putting out a few strokes of lightning. Satellite and radar both show a solid line of showers that expands much of OR and WA moving into the Cascades with ground observations showing 0.01-0.03 inches of rain along the crests of the Cascades and portions of the eastern slopes. Also, ground observations are also showing winds beginning to pick up in the Kittitas Valley and across the Simcoe Highlands and the lower Columbia Basin.

Winds today are expected to reach advisory levels through the Kittitas Valley, Simcoe Highlands, foothills of the southern Blues and the Gorge of WA and OR. Highest confidence in seeing 25-35 mph sustained winds and 50 mph gusts is 80-90% through the Kittitas Valley. Moderate to high confidence in the remaining areas seeing winds of 20-30 mph sustained and 45-50 mph gusts. A wind advisory is in effect through 11 PM Friday night.

Mountain showers are already beginning to occur across the Cascades and are expected to occur over the eastern mountains this afternoon with 70-90% probabilities of 0.01-0.05 inches of rain for the next 24 hours. Not only will there be rain showers, models also show there to be increased chances of thunderstorms along the eastern mountains this afternoon with radar already picking up a cell in Grant County. As for the rest of the eastern mountains, there is a 15-30% probability of thunderstorms. CAMs models show there to be a deep layer of instability between 300-500 J/kg, lapse rates in the 8- 9 C/km and lifted indices of -3 to -5 and effective bulk shear around 25 kts. This is a prime environment for a few isolated thunderstorms to pop off over the eastern mountains later this afternoon.

After today, models show the upper level low to traverse across the region to the north while westerly flow aloft moves in. The westerly flow aloft will bring dry and cooler temperatures across the area through the weekend with many places seeing temperatures in the low to mid 60s Saturday with isolated 70s in the Basin (70-90% probabilities). Sunday will see slightly warmer temperatures in the mid to upper 60s with the foothills of the Blues, the Gorge and the Basin seeing low to mid 70s (70-90% probabilities). In house calculations show these temperatures to be between 5 to 10 degrees below seasonal average for this time of year.

Lastly, models show an upper level ridge pushing into the region bringing back dry and warming conditions. By Tuesday, in house comparisons show temperatures to be heading towards 5 to 10 degrees above normal again. NBM shows temperatures to be in the mid to upper 70s with isolated 80s in the Basin and the Gorge Monday increasing to low to mid widespread 80s Tuesday. By Tuesday night models show the upper level low to retrograde back towards the region bringing with it chances of precipitation and eastern mountain thunderstorms midweek onwards.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

VFR conditions will generally prevail through the period.

The main concern continues to be wind. Gusty winds will continue through early evening, and will gust in the 30 to 35 kt range at DLS and PDT and 20 to 30 kts elsewhere through the evening, then should become 10 kts or less. DLS, PDT and ALW is expected to gust in the 20 to 25 kt range again on Saturday afternoon.

Preliminary Point Temps/PoPs

PDT 41 67 42 71 / 10 0 0 0 ALW 47 68 47 72 / 10 10 0 0 PSC 45 73 43 77 / 10 0 0 0 YKM 43 72 42 77 / 0 0 0 0 HRI 43 70 43 74 / 0 0 0 0 ELN 39 65 40 72 / 0 0 0 0 RDM 31 62 30 67 / 0 0 0 0 LGD 41 64 37 68 / 10 10 0 0 GCD 36 65 34 70 / 30 0 0 0 DLS 45 69 45 76 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until 11 PM PDT this evening for WAZ024-026-521. OR...Wind Advisory until 11 PM PDT this evening for ORZ041-044-508.