textproduct: Pendleton

KEY MESSAGES

1. Dry conditions will persist through the week.

2. Slight Chances of dry thunderstorms Wednesday and Thursday.

3. Diurnally breezy winds and low RHs.

DISCUSSION

Satellite and radar continue to advertise mostly clear and dry conditions across the region thanks to the upper level ridge situated near the four corners. Areas of smoke and haze are still present with winds generally from the southwest, pushing smoke transport across Central Oregon through Northeast Oregon. Air Quality continues to be sub-par through noon on Friday as an Air Quality Advisory is issued (via the Oregon Department of Environmental Quality) for counties near Central Oregon and the Eastern Mountains.

Very low potential (up to 5% chance) for dry thunderstorms to develop from Central Oregon through the Eastern Mountains during peak day-time heating hours today and tomorrow. Guidance is in good agreement that a small pocket of low to mid level moisture will move over the previously mentioned areas through the next 24-hours with models struggling to forecast for the MUCAPE values for the lifting mechanism. GFS, NAM, and the ECMWF are all over the place with MUCAPE values with NAM being the most aggressive with 300-500 J/kg, GFS putting almost nothing developing, and the ECMWF somewhere in the middle. Regardless, chances remain very low and are not expected to be widespread if storms develop.

Through Friday: The upper level ridge will push slightly more to the west (>85% chance) with a trough just situated to the northeast. Diurnal wind breezes will continue, with breezier winds near the mountain gaps and parts of the Basin. Dry conditions persist with minimum relative humidity values dropping to the mid-teens to lower 20 percent range and with slightly enhanced diurnal breezes with the upcoming shortwave, elevated fire weather conditions will persist at least through this period.

Saturday: The approaching shortwave will bring tight pressure gradients to move-in to the region, allowing for breezy to locally windy conditions to develop. NBM advertises 50-70% chances of winds exceeding wind advisory (>45 mph gusts) Saturday across the Kittitas Valley, Simcoe Highlands, and parts of the Columbia Basin. Wind highlights have not been issued, but additional monitoring may be needed as the event gets closer. On the fire weather side, minimum relative humiditys recover slightly into the 20 to 30 percent range, but its put off by the stronger developing winds. A Fire Weather Watch has been issued for the Columbia Basin and the eastern part of Wallowa County following the anticipation of overlapping breezy winds and low relative humidity levels. Additional fire wx highlights are possible as more guidance comes through with increased confidence of an issuance.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

VFR conditions currently across all sites, which will stay the course through the period. Breezy winds currently across KDLS/KRDM/KBDN will slowly subside this evening from sustained winds of 10-15kts and gusts of 20-25kts. Light winds of 10kts or less tonight into Thursday morning, with diurnal winds picking up for KDLS/KRDM/KBDN in the afternoon.

Preliminary Point Temps/PoPs

PDT 56 88 55 91 / 0 0 0 0 ALW 62 90 61 93 / 0 0 0 0 PSC 60 92 59 95 / 0 0 0 0 YKM 58 91 59 94 / 0 0 0 0 HRI 60 91 59 94 / 0 0 0 0 ELN 55 86 56 91 / 0 0 0 0 RDM 48 88 49 93 / 0 0 0 0 LGD 57 92 56 97 / 0 0 0 0 GCD 55 94 56 98 / 0 0 0 0 DLS 60 86 59 92 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Fire Weather Watch from Saturday morning through Saturday evening for WAZ691. OR...Air Quality Alert until noon PDT Friday for ORZ041-049-050-502- 503-505-506-509>511. Fire Weather Watch from Saturday morning through Saturday evening for ORZ691-693.