textproduct: Pendleton

KEY MESSAGES

- High winds and low RH into the evening for Grande Ronde Valley with red flag conditions, with winds persisting through Saturday morning.

- Up to a tenth of an inch of rain for the Cascade Crests Saturday (50-70% confidence).

- Uncertainty going into next week with another weather system pushing through the area, bringing possible precipitation (10-20% confidence).

DISCUSSION

Current satellite and radar imagery show clear skies with scattered cirrus clouds over most of the regions, with clouds increasing towards the afternoon. The Grande Ronde region currently has surface observations of 15-20% RH with 20-35kt wind speeds with gusts of up to 40kt. With the NAM and NCEP showing a large pressure gradient of 4-7mb until Saturday morning, continuing windy conditions of 20kt and gusts up to 30kt overnight into Saturday morning. Maximum temperatures were higher than previously forecasted and are now around the mid to upper 70's. A red flag warning has been issued until the early evening for the Grande Ronde Valley.

Saturday shows the emergence of a shortwave trough that will bring precip of up to a tenth of an inch (50-70% confidence) for the Cascade Crests. Along with the shortwave, a 850mb jet streak will bring breezy winds along the Kittitas Valley and parts of the Columbia Basin. The NBM advertises medium confidence (30 -60%) of wind speeds > 20mph for Ellensburg and lower confidence (40%) for the Lower Columbia Basin.

Guidance is in good agreement that on Sunday an upper level trough descends into a low level pressure system that will be off the coast by Monday night. Monday night the clusters show uncertainty on the exact strength of how deep the low extends but is in agreement with the timing and position of the low as it travels southward. Tuesday into Wednesday shows split flow emerging over the region with uncertainty present with the strength and timing of the low, with models split between the low being just offshore (49%) or starting to enter southern California (51%).

Thursday into Friday shows general agreement for the low moving through California that advertises chances for wrap around precipitation to occur through the CWA with low confidence(10-20%). Going into Friday shows low confidence chances for precipitation isolated within the Cascades and The Wallowas(10-20% confidence) as the models are largely uncertain to the strength of the flow over the Pacific NW and the remaining signal from the low pressure system in the Southwest.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Conditions will be VFR across the terminals for the duration of the TAFs. Diurnally driven winds under 10 knots become more westerly to southwesterly with gusts up to 20 kts after about 15 to 17Z at DLS/PDT/RDM/ALW.

Preliminary Point Temps/PoPs

PDT 43 69 35 62 / 0 0 0 0 ALW 50 70 41 64 / 0 0 0 0 PSC 39 72 35 64 / 0 0 0 0 YKM 43 70 37 62 / 0 0 0 0 HRI 41 70 37 63 / 0 0 0 0 ELN 40 61 31 59 / 0 0 0 0 RDM 35 67 29 63 / 0 0 0 0 LGD 45 70 36 67 / 0 0 0 0 GCD 39 73 35 71 / 0 0 0 0 DLS 47 69 39 67 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...Red Flag Warning until 7 PM PDT this evening for ORZ694.