textproduct: Pendleton

KEY MESSAGES

1. Dry and warm conditions will persist through the weekend

2. Breezy to windy through the gaps Saturday and again Monday

3. Pattern shift Monday will bring chances mountain showers becoming more widespread Tuesday onwards

DISCUSSION

Current satellite shows some fair weather cumulus clouds forming over some of the ridgelines throughout the region. Otherwise, mostly clear skies are being observed. With the lack of cloud cover, temperatures today ill warm up steadily with temperatures reaching into the upper 70s to low 80s for the vast majority of the region. Winds will be mostly diurnally driven and light.

No real change in the forecast through Saturday. Models remain in line with the upper level ridge remaining over the region through at least Saturday before being influenced by the next system. A slight shift from northwest to west winds will occur as the system begins to break down the ridge. Temperatures will continue to warm through the period with temperatures peaking Saturday. Raw NBM ensembles show temperatures to be in the upper 70s to low 80s starting tomorrow with 70-90% probabilities. By Saturday temperatures will be in the low to mid 80s with 70-90% probabilities. In office difference calculations from climate shows temperatures to be 5 to 10 degrees above seasonal normal today and tomorrow before reaching 10-15 degrees above normal by Saturday.

As mentioned above, the breakdown of the ridge from northwest flow to westerly flow will cause a slight increase in the winds, especially through the mountains gap areas. With the westerly or zonal flow, winds will be breezy with models showing sustained winds speeds nearing 20 mph with gusts near 30 mph with 70-90% of the NBM raw ensembles in agreement. The locations of the winds will primarily be through the mountain gaps of the Gorge and Kittitas Valley with 50-70% in agreement that the southern foothills of the Blues will see these winds as well. There will be a brief settling of the wind ahead of the next system that will be rolling through on Monday. Winds will then shift to the southwest as the upper level trough/low makes its way into the region. As the front moves inland, models and in house calculations show a tightening of the pressure gradients at the surface across the Cascades. This will bring increased winds back to the region leaning more towards windy conditions on Monday through the Gorge, Kittitas Valley and the southern Blue foothills. NBM raw ensembles are again in 60-80% agreement of sustained winds of 25-35 mph with gusts of 45-50 mph. Will be keeping an eye on the winds to watch for the need of a possible advisory for those areas.

Lastly, Monday onwards the upper level low will bring cooler temperatures and precipitation with Tuesday being the coolest day of the period. In house calculations show temperatures will drop to nearly 10-15 degrees below seasonal averages with the NBM ensembles showing temperatures in the upper 50s to low 60s with a few isolated Basin locations seeing near 70s with high confidence of 70-90%. Precipitation is expected to return to the Cascades Monday afternoon with 0.05 inches of rain possible over the 24 hours with 70-80% confidence. Models show the rain to become more widespread Tuesday with precipitation expected across a vast majority of the region. Tuesdays 24 hour rain total are near 0.05 inches in the mountains with 70-80% confidence on 0.01-0.03 for some of the lower elevations. On Tuesday as well, NBM models as well as ensembles show a 20% chance of isolated thunderstorms through central OR and the eastern mountains and into Wallowa County beginning after 11 AM. As the system steadily moves southeast, rain amounts will slightly decrease to 0.01-0.03 inches with 60-80% confidence and steadily decrease thereafter with mainly light showers expected through the remainder of the week.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

VFR conditions are expected through Saturday. Winds will generally be 10 kts or less. However, at DLS, PDT, RDM and BDN, winds will gust to around 20 kts Saturday afternoon, before decreasing to 10 kts or less Saturday evening.

FIRE WEATHER

Dry and warm conditions will persist through the weekend with a slight pattern shift to zonal flow Saturday and the southwest flow Monday as an upper level trough/low moves into the region. Daytime RHs will be at their lowest over weekend with the lowest RHs will be Sunday with widespread teens and low 20%. RHs tomorrow will be in the low to mid teens through central or and the Ochco-John Day highland with pockets along the southern Blues and in the Basin. Sunday is the highest day of concern, especially in the Kittitas Valley where RHs will be in the low to mid 20% and winds will be between 15-25 mph as well as the Basin with 15-20 mph winds. This puts this area of the region in elevated fire weather concerns where the overall fire environment suggests a moderate high risk for significant fires (5-19% probabilities).

Preliminary Point Temps/PoPs

PDT 49 83 50 82 / 0 0 0 0 ALW 53 84 55 82 / 0 0 0 0 PSC 52 89 54 87 / 0 0 0 0 YKM 53 88 52 85 / 0 0 0 0 HRI 52 86 54 85 / 0 0 0 0 ELN 50 78 49 76 / 0 0 0 0 RDM 44 83 43 84 / 0 0 0 0 LGD 45 82 47 83 / 0 0 0 0 GCD 43 84 45 86 / 0 0 0 0 DLS 56 82 54 83 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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