textproduct: Pendleton

KEY MESSAGES

- Elevated fire weather concerns continue through the weekend. Fire Weather Watches issued for the Columbia Basin through Central Oregon

- Hot today with moderate Heat Risk, but will be cooler through the weekend. Temperatures remain very warm in the upper 80s Saturday and Sunday.

- Moderate Heat Risk returns Monday (60-80% chance).

DISCUSSION

Now through Sunday: Satellite currently depicts clear skies with dry conditions through the area thats in response to a ridge situated over the region. EURO and GFS deterministic in the short-term agree that the ridge will push off to the east and a shortwave over British Columbia and Alberta will clip through the PacNW and bring temporary relief from the heat over the weekend (>85% chance). Highs will drop from the expected mid to upper 90s in the lower elevated areas on Friday to the low to mid 80s Saturday and Sunday, thus dropping the Heat Risk from a value of '2' to a '1' in most places. With the oncoming shortwave, breezy to locally winds will develop with the strongest winds expected to occur Saturday. Current NBM guidance advertised medium-to-high chances of the Kittitas Valley (60-80% chance) and gaps of the Cascade mountains near The Dalles (40-60% chance) reaching or exceeding 40 mph gusts. Current confidence is low-to-medium (20-40%) that these regions will exceed wind advisory criteria and will need additional monitoring tomorrow if highlights are necessary. Dry air is expected to linger with minimum relative humidities reaching the teens to low 20s percent range (possibly reaching the single digits in parts of Central Oregon and Southern Blue Mountains). With the on-set of breezy winds mentioned earlier, elevated fire weather concerns will be present with the addition of a Fire Weather Watch in-effect Saturday for WA690 (Kittitas/Yakima Valley), WA691 (Washington Columbia Basin), OR691 (Oregon Columbia Basin), and OR700 (Southern Central Mountains).

Monday through Wednesday: Guidance is still in good agreement that a secondary ridge will push on-shore early next-week, re- introducing subsidence into the region. This will bring another warm trend through at least mid next-week (60-80% chance) and bring a secondary peak in temperatures and Heat Risk events. Current NBM guidance jumps the chances of temperatures exceeding 90 degrees from around 0-20% Sunday to 30-50% Monday in most of the lower elevated areas. Chances of greater than 90 degree temperatures jumps to 90%+ throughout the lower elevations on Tuesday and Wednesday with moderate Heat Risks (value of '2') advertised with isolated areas of a major Heat Risk (value of '3') in The Dalles on Tuesday only. Chances of temperatures exceeding 100 degrees still doesn't look impressive with chances ranging from 0-20%. If the oncoming secondary ridge turns out to be stronger than forecast, it is possible to see isolated to scattered areas seeing 100+ degree high temperatures (with it being day 4 and 5, there is time to monitor for trends).

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

VFR conditions prevail with light and variable winds at less than 12 knots sustained in the Columbia Basin sites. Sites in Central Oregon (BDN/RDM) and The Dalles (DLS) will develop breezy winds with gusts up to 20-30 knots from the northwest by 22Z-0Z. Breezy winds will prevail for DLS through the rest of the period, but winds are expected to weaken in RDM and BDN by 03-04Z. Otherwise, no CIG or VIS issues expected.

Preliminary Point Temps/PoPs

PDT 91 59 84 51 / 0 0 0 0 ALW 93 64 86 57 / 0 0 0 0 PSC 95 61 91 55 / 0 0 0 0 YKM 94 59 90 54 / 0 0 0 0 HRI 94 63 86 54 / 0 0 0 0 ELN 90 57 82 52 / 0 0 0 0 RDM 91 51 83 41 / 0 0 0 0 LGD 91 55 83 47 / 0 0 0 0 GCD 94 54 86 45 / 0 0 0 0 DLS 95 63 81 56 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Fire Weather Watch from Saturday morning through Saturday evening for WAZ690-691. OR...Fire Weather Watch from Saturday morning through Saturday evening for ORZ691-700.