textproduct: Pendleton

KEY MESSAGES

- Heat Risk threat builds-up Monday through Wednesday as a ridge pushes in the area.

- Elevated fire weather conditions continue through the week with dry air lingering and locally breezy winds developing.

- Wetter pattern possible by the end of the week, bringing relief from the heat.

DISCUSSION

Today: Satellite and radar both indicate dry conditions prevailing through the region as a weak shortwave pushes out of the region and a ridge begins to move in. As the shortwave pushes off, pressure gradients will not be as tight compared to yesterday and thus winds will not be as breezy today as they were yesterday. High temps across the lower elevation will be slightly cooler compared to yesterday with temperatures reaching the mid to upper 80s, with isolated areas reaching the low 90s (50-70% chance). Clear conditions will persist with an abundance of dry air in the mid-level, keeping things dry.

Monday through Wednesday: Guidance is in great agreement that the ridge situated just off-shore will continue to push into the area with the ridge axis over the area sometime late Monday night to Tuesday morning, persisting through Wednesday morning. A warming trend as a result will last through the mid-week with the hottest days looking to be Tuesday and Wednesday. High temperatures have slightly downtrended again over the last 24-hours, with NBM advertising high temperatures from 94-98 in the Columbia Basin, 92-97 in the Foothills, and 89-93 in Central Oregon. NBM v5.0 has all but eliminated the possibility of triple digits on Tuesday with isolated pockets in the Columbia Basin reaching 0-5%, with Wednesday looking slightly higher at 0-10%. For reference, some areas in the region were advertising values up-to 20% for triple digits to occur. Regardless, widespread moderate Heat Risk will develop Tuesday and Wednesday (70-90% chance). The Dalles has a moderate to high confidence (60-80% chance) of major Heat Risk (value of '3') on Tuesday, thus a Heat Advisory has been issued.

Thursday: Critical fire weather conditions are possible with relative humidities in the 9-14% range and developing breezy winds with an oncoming trough occur. Pressure gradients will tighten as a trough moves in the area, but will not benefit from the more moist air until widespread breezy winds occur (40-60% chance). Given this, Thursday will need to be monitored for potential critical fire weather conditions for all declared zones.

Friday through the weekend: Guidance is hinting of slightly unsettled weather to move back in the picture by the weekend, increasing chances of rain in the mountain ranges (confidence: 40-60% chance). A relief from the heat and dry air from the oncoming moisture transportation will be possible with the weather system.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

VFR conditions prevail with light and variable winds through the rest of the TAF period. No CIG or VIS issues expected.

Preliminary Point Temps/PoPs

PDT 84 52 88 53 / 0 0 0 0 ALW 85 58 89 58 / 0 0 0 0 PSC 89 56 92 57 / 0 0 0 0 YKM 88 57 90 60 / 0 0 0 0 HRI 87 55 91 56 / 0 0 0 0 ELN 84 54 87 57 / 0 0 0 0 RDM 83 45 88 52 / 0 0 0 0 LGD 81 48 85 50 / 0 0 0 0 GCD 84 45 89 49 / 0 0 0 0 DLS 88 59 93 64 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Heat Advisory from 11 AM Monday to 11 PM PDT Tuesday for WAZ024. OR...Heat Advisory from 11 AM Monday to 11 PM PDT Tuesday for ORZ041.