textproduct: Pendleton

KEY MESSAGES

- Warming temperatures through Tuesday.

- Isolated thunderstorm chances in central Oregon mountains today, low thunderstorm chances (20 percent or less in central Oregon Monday, shifting to eastern Oregon mountains on Tuesday.

- Elevated to critical fire weather conditions redeveloping from Tuesday onward.

DISCUSSION

Zonal flow across the area will become more southwesterly on by Monday. Several short waves moving through the flow will bring shower and thunderstorm chances mainly to the mountains of central and eastern Oregon.

Thunderstorm chances today will be very low (<15 percent) and confined to the mountains of central Oregon. The best (albeit low) chances look to be on Monday and over the mountains of central Oregon, with chances 20 percent or less. By Tuesday the threat moves more into eastern Oregon.

By later Tuesday, an upper trough and cold front will approach the region, and move through early Wednesday. Winds will increase ahead of the trough/front. By Thursday through Friday, we are back in a more zonal flow. By the weekend the flow turns southwest again as a large ridge begins to build in from the four corners area. Exactly how strongly this ridge build in will have a big impact on our temperatures and guidance has not been consistent on the handling of the ridge.

In the meantime, temperatures will warm through Tuesday, with Tuesday being the hottest day, in advance of the approaching trough/front. High temperatures on Tuesday will be into the 90s in most locations with highs in the Columbia Basin/Yakima Valley being close to 100 degrees if not exceeding 100 degrees. On Wednesday, the trough/cold front will move across the area and temperatures will decrease by about 5 to 10 degrees.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

VFR conditions are expected through the TAF period. At RDM and BDN, afternoon wind gusts to around 20 kts are expected. All other sites will be 10 kts or less through the period.

FIRE WEATHER

A trough and cold front will approach the area on Tuesday, with the cold front moving trough early Wednesday, Winds will increase in advance of the front. The flow will become more zonal behind the trough/frontal passage and winds are gusty winds are expected to continue. Zonal flow is expected again on Thursday, before a more southwesterly flow develops on Friday.

Breezy to windy conditions are expected on Tuesday into Wednesday, especially across the Cascade Gaps, Simcoe Highlands, Kittitas Valley an the Oregon Basin and Gorge. Wind gusts look to be 25 to 35 mph, and possibly as high as 40 mph. Probabilities of wind gusts of >=25 are greater than 90 percent. Probabilities of wind gusts >=39 mph are 50 to 80 percent in many of the above locations and 90 percent in the Kittitas Valley. Wind gusts look to be lower on Thursday before ramping up again on Friday. Wind gusts on Friday in these same areas. Wind gusts look to be 25 to 35 mph. Probabilities of wind gusts >=25 mph are greater than 90 percent. Probabilities of wind gusts >= 39 mph are lower though, only about 30 to 60 percent, on average.

These winds coupled with RH values, mainly in the teens will lead to elevated to critical fire weather conditions from Tuesday onward. RH values do look slightly higher on Wednesday, but the stronger winds could end up negating that. Thursday's lesser winds could end up helping there, but will have to see how the gusty winds and low RH values fit together as the week progresses.

Preliminary Point Temps/PoPs

PDT 87 55 90 59 / 0 0 0 0 ALW 88 59 91 63 / 0 0 0 0 PSC 90 56 94 60 / 0 0 0 0 YKM 91 58 95 61 / 0 0 0 0 HRI 90 56 93 61 / 0 0 0 0 ELN 87 55 92 59 / 0 0 0 0 RDM 88 54 89 53 / 0 0 10 0 LGD 88 55 89 57 / 0 0 0 0 GCD 92 55 90 55 / 0 0 20 20 DLS 92 60 96 63 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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