textproduct: Pendleton

KEY MESSAGES

- Mostly warm, dry conditions persist through the next few days.

- Elevated fire weather conditions for wind/low RH continue.

- Small chance (0-10%) of dry thunderstorm development across the Southern Blues and Eastern Mountains Wednesday and Thursday.

DISCUSSION

Current satellite shows a few cumulus clouds across the Cascades with mostly sunny conditions across most of the region. Smoke and haze originating from wildfires in Central Oregon through parts of the Southern Blues is clearly visible streaming from the SW to NE, bringing hazy conditions across the Colombia Basin. An Air Quality Advisory initiated via the Department of Environmental Quality is in effect through much of the Colombia Basin and Blue Mountains through noon tomorrow due to ongoing smoke transport.

Synoptically, southwest flow continues and will persist through the next couple of days as a trough just offshore of British Colombia paves way through the PacNW through Friday evening. Periods of embedded shortwaves within the trough will bring very low chances of dry thunderstorm development (0 to 10 percent chance) across portions of the Southern Blues and Eastern Mountains, potentially triggering new ignitions. Deterministics Wednesday and Thursday advertise a pocket of very slight moist air with 45-65% RH in the low to mid levels passing through the Southern Blues and Eastern Mountains, along with 150-300 J/kg of MUCAPE developing during peak heating according to the REFS. Precipitable water values stay at below 1.00 inch in the development region (80-90% chance), suggesting any thunderstorm that initiate will be mostly dry in nature with little to no potential for wetting rains to occur.

As the trough approaches the area early Saturday morning to afternoon, tight pressure gradients will develop and bring gusty to locally windy conditions across the region. Areas across the Kittitas/Yakima Valley's, Columbia Basin of Oregon, and the Cascade Gap region have the greatest chance of exceeding wind advisory criteria (>45 mph gusts) Saturday. Chances of exceedance reaches 50-80% across the mentioned areas, with wind highlights possible as we get closer to the event. This will also consequently enable to the potential of elevated to critical fire weather conditions developing Saturday. Joint probabilities of 25% or less humidity AND sustained winds of 20 mph or more are advertised at 15-35% chances by 5 PM Saturday. Will monitor for the trend going through tomorrow to see if fire weather highlights are warranted.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

VFR conditions to prevail through the period. Low confidence (15-25%) in smoke impacts at sites through the period. Winds will increase to 12-18kts with gusts to around 25kts at site DLS, with periodic gusts up to 20kts at sites RDM/BDN in the afternoon. Winds will otherwise be light through the period. Lawhorn/82

Preliminary Point Temps/PoPs

PDT 54 86 56 88 / 0 0 0 0 ALW 59 88 62 90 / 0 0 0 0 PSC 56 90 60 92 / 0 0 0 0 YKM 55 89 58 91 / 0 0 0 0 HRI 56 89 60 91 / 0 0 0 0 ELN 51 85 55 86 / 0 0 0 0 RDM 47 88 48 88 / 0 0 0 0 LGD 53 91 57 92 / 0 0 0 0 GCD 52 94 55 94 / 0 0 0 0 DLS 58 87 60 86 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...Air Quality Alert until noon PDT Wednesday for ORZ041-044-049- 050-502-503-505>511.