textproduct: Pendleton

KEY MESSAGES

- Minor to Moderate HeatRisk through the weekend

- Breezy to windy through Wednesday

- Critical Fire Risk Today and Wednesday

UPDATE

Red Flag risk is hitting the 80% threshold for criteria in a couple of zones, OR700 and WA690 for Wednesday afternoon. Drier air will be the favoring factor to lean into Red Flag warnings despite the weakening winds behind the front on Wednesday. Dew points will be about 10 degrees lower across the Kittitas valley/WA690 allowing lower RH and increased risk for fire spread in the afternoon, as what is leftover from the initial strong gradient helps push sustained winds back to near 30 mph again in the afternoon. Combined wind and RH thresholds are lower across OR700 however still meeting the red flag criteria.

DISCUSSION

Current satellite should some clouds forming over the area due to the shortwave. This has assisted with keeping the overnight temperatures warm. Current ground observations so many locations through the Basin with temperatures in the low 70s at 330 am. Temperatures tomorrow will remain in the 90s through the Basin (70- 90%) with central, N. central and the foothills seeing high 80s (70- 90%) while the higher elevations outside of central OR will see the high 70s to low 80s (70-90%). Models show the ridge to remain in place over the long term period with a few weak shortwaves on Wednesday and Saturday bringing only a slight temperature difference to the region. Otherwise, dry and warm conditions will persist through the end of the week.

Models show the shortwave that is moving over the ridge will bring a tightening of the surface pressure gradients. In house calculations using the GFS, NAM and RAP all show a tightening of between 9-12 mb. This will bring increased winds across the region, especially through the gaps and along the foothills. Due to this, an Wind Advisory has been issued for today from 10 AM to 11 PM in the Simcoe Highlands of Klickitat County and through the Kittitas/Yakima Valleys for west winds between 25-35 mph with gusts to 55 mph (80-90%). The foothills will see sub-advisory winds yet still breezy with winds 15- 20 mph with gusts to near 35 mph (70-90%). Winds will begin to settle into a more diurnal pattern overnight Wednesday.

With the increased winds and prolonged dry conditions, fire weather conditions have become elevated across the Basin as well as the Kittitas Valley with isolated pockets elsewhere. With RHs dropping into the teens and the increased winds expected today, a Red Flag Warning has been issued for the Kittitas/Yakima Valley as well as the WA & OR Columbia Basin for winds and RHs. The RFW will be valid from 10 AM today (Tuesday) through 11 PM tonight.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

VFR conditions currently across all sites, which will stay the course through the period. Strong winds from the northwest have already arrived at terminals as sustained winds of 20-25kts and gusts of 30-40kts will be possible through the day and into the overnight period. Winds will begin to subside slowly into Wednesday morning as skies stay clear. 75

FIRE WEATHER

Red Flag risk is hitting the 80 % threshold for criteria in a couple of zones, OR700 and WA690 for Wednesday afternoon. Drier air will be the favoring factor to lean into Red Flag warnings despite the weakening winds behind the front on Wednesday. Dew points will be about 10 degrees lower across the Kittitas valley/WA690 allowing lower RH and increased risk for fire spread in the afternoon, as what is leftover from the initial strong gradient helps push sustained winds back to near 30 mph again in the afternoon. Combined wind and RH thresholds are lower across OR700 however still meeting the red flag criteria.

Preliminary Point Temps/PoPs

PDT 89 52 83 50 / 0 0 0 0 ALW 90 55 83 56 / 0 0 0 0 PSC 94 55 88 54 / 0 0 0 0 YKM 90 55 88 53 / 0 0 0 0 HRI 91 55 86 54 / 0 0 0 0 ELN 80 51 80 50 / 0 0 0 0 RDM 89 47 86 46 / 0 0 0 0 LGD 88 49 80 47 / 0 0 0 0 GCD 91 48 85 46 / 0 0 0 0 DLS 86 57 84 57 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Red Flag Warning until 11 PM PDT this evening for WAZ690-691. Red Flag Warning from 11 AM to 9 PM PDT Wednesday for WAZ690. Wind Advisory until 11 PM PDT this evening for WAZ024-026-521. OR...Red Flag Warning until 11 PM PDT this evening for ORZ691. Red Flag Warning from 11 AM to 9 PM PDT Wednesday for ORZ700.