textproduct: Pendleton

KEY MESSAGES

- Return of showers and isolated thunderstorms to the eastern mountains Today

- Breezy to gusty winds developing across the area Tonight into Friday morning, with strongest winds through the Cascade gaps

- Moderate-high confidence (65-80%) in freezing morning temperatures across lower elevation area Saturday

DISCUSSION

An upper trough and a cold front will move across the region later Today and Tonight, with limited weather impacts from winds, rains and convection. A limited convective threat today as CAPEs over the eastern mountains broadly 100-200 J/kg and higher elevated 400 J/kg pose an isolated lightning risk. Initially, the REFs is trending toward an initial warm advection induced swath of showers supported by the REFS mean lighting fields of 0.02-0.05 flashes/ sq KM/5 mins. This feature is focused across the John Day Basin at 8 am, and advecting across Pendleton/Walla Walla toward the Tri-Cities between about 9 and 11 am. The time window for best rain accumulations is between about 3 and 12z Friday (8 pm This evening - 5 am Tomorrow) when 3 hour probability matched means show areas in excess of a quarter inch every 3 hours across the Foothills Blues Mountains eastward into Wallowa county. The HREF 24 hr PMMs are at about 0.75 to 1 inch QPF across these areas and at least widespread wetting rain over the entirely of the eastern mountains.

A wind advisory remains in effect across the Kittitas and Eastern Columbia river Gorge zones for increasing wind This Evening through much of the overnight as the post frontal pressure isallobaric pressure rises cause channeling effects leading to NBMs probabilities for gusts in excess of 40 mph averaging 50 to 80 percent, particularly around The Dalles and Ellensburg.

Lastly, cold temperatures will return on the backside of this exiting weather system Friday night into Saturday morning, bringing potential for growing season ending sub freezing temperatures across the lower elevations of the Kittitas/Yakima valley, Blue Mt foothills and the Columbia Basin.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Scattered showers will spread northward across the Blue Mountains and into the Columbia Basin This Morning. Conditions are still expected to remain VFR with cloud bases generally above about 5k ft AGL and visibility better than 6 SM. Thunderstorms are possible as well however confidence is not high enough to include in any terminals as the better probabilities above about 10% are across the higher terrain of the eastern mys. A cold front will impact t the winds later in he afternoon and Tonight turning winds west with gusts to 20 kts and higher in the gaps areas like DLS, YKM.

Preliminary Point Temps/PoPs

PDT 58 36 58 28 / 80 50 0 0 ALW 59 41 58 34 / 80 70 0 0 PSC 62 37 66 29 / 60 20 0 0 YKM 67 39 66 31 / 0 0 0 0 HRI 59 38 63 29 / 70 30 0 0 ELN 66 34 59 26 / 0 0 0 0 RDM 60 24 54 19 / 70 10 0 0 LGD 66 37 53 25 / 70 90 10 0 GCD 65 36 54 26 / 80 80 10 0 DLS 69 43 64 34 / 10 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory from 7 PM this evening to 11 AM PDT Friday for WAZ024-026. OR...Wind Advisory from 7 PM this evening to 11 AM PDT Friday for ORZ041.