textproduct: Pendleton

KEY MESSAGES

- Low pressure will approach the region on Friday and will move inland late Friday night or early Saturday, bring shower and thunderstorm chances, mainly to the mountains and gusty winds.

- Fire weather conditions look to become elevated, if not critical as we approach the weekend.

DISCUSSION

A ramp up of hotter temperatures is expected over the next couple of days associated with the strengthening of an upper ridge over the Interior NW which is anchored until Friday night when an east Pacific upper low moves onshore near the WA/OR coast. Temperatures are forecast to reach around 100 degrees over southeast Washington and the Grande Ronde Valley. Heat Risk is highest Friday afternoon in the the moderate to major risk category across sections of the Lower Columbia Basin/Foothills of the Northern Blue Mountains-of WA. Relief comes in the the evening as the Heat Risk falls to moderate/Minor overnight into Saturday morning across these forecast zones. HREF lightning remains largely to to the west of the Cascade crest Friday, in a zone of upslope and meaningful probabilities for thunder (10 to 20%) from NBM members spread over the crest of the Oregon and WA Cascades overnight Friday and into Saturday. The probabilities for Thunderstorms are most robust at around 20% chances across the WA eastern slopes and Blue Mountains of Oregon on Saturday afternoon where higher CAPEs are forecast upwards of 300j/kg. Breezy to windy gap winds will be developing Friday night and peaking on Saturday afternoon.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

VFR conditions with some localized reduced visibility where localized smoke layer is causing haze in observations. Wind continues to be light and variable for another 24 hours at all area terminals.

FIRE WEATHER

Elevated fire weather risk is primarily driven by the dry fuels and low relative humidity each day through Friday. By Friday Night an upper low will move into he PacNW, spreading across the region for the weekend which will increase the winds though the Gaps on Saturday...leading to elevated fire risk for windy conditions, but no widespread overlapping low rh and winds are expected (no red flag conditions). The NBM members suggest about a 5 to 10% chance for dry Thunderstorms across the Blue Mountains of Oregon on Saturday afternoon.

Preliminary Point Temps/PoPs

PDT 95 62 95 66 / 0 0 0 10 ALW 97 67 99 72 / 0 0 0 10 PSC 97 61 99 64 / 0 0 0 10 YKM 98 65 98 69 / 0 0 0 10 HRI 97 64 97 67 / 0 0 0 10 ELN 94 64 95 66 / 0 0 0 20 RDM 96 56 94 54 / 0 0 0 10 LGD 98 61 100 64 / 0 0 0 10 GCD 98 61 100 63 / 0 0 0 10 DLS 99 67 96 66 / 0 0 0 10

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...Air Quality Alert until 11 AM PDT this morning for ORZ050-502- 505-506-509>511.