textproduct: Pendleton

KEY MESSAGES

- Critical Fire Weather Saturday

- Heat risk increasing early next week

DISCUSSION

A compact upper low over southern British Columbia will swing southeast Today and Tonight continuing to carve out an upper trough across the Inland Northwest through the end of the weekend. This will leave the PDT CWA under northwest flow aloft/continued subsident and increasingly breezy boundary layer winds in the higher elevation zones. Some lower elevation zones will not see as much wind however heat will ramp up peaking on Tuesday and Wednesday where highs in the Lower Columbia Basin will reach the 90s broadly and the upper 90s in the Tri-Cities with overngiht lows remaining warm in the 60s. This extended period of hot temperatures continues into the middle part of the week before models (NBM members) indicate the first significant respite in highs mean reverting back into the 80s for the lower elevations on Friday. HeatRisk for the Eastern Columbia River Gorge pushes into the level 3 category Monday night and Tuesday. An Extreme Heat Watch has been hoisted for this period, which looks like at least heat advisories will be needed in more warnings and subsequent shift will evaluate the need farther out extending into Wednesday.

FIRE WEATHER

Late afternoon Saturday into early Saturday evening will present some critical fire weather risks across OR700 and OR/WA691 and WA690, due to low relative humidity and breezy to windy conditions. The primary timeframe will be between 3 and 8 pm where red flag warnings have been hoisted. Much lower winds are forecast for Sunday limiting the need for any additional Fire Weather Watches in the short term. Wind component of the red flag criteria upticks again Wednesday into Thursday where additional headlines for fire risk might be needed as the overall hot and dry pattern continues driving down relative humidity daily.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

VFR conditions persist through the forecast period. Winds are under 10 kts and variable across the TAF sites currently but are expected to increase at after 05Z to 9-10 kts then another increase after 15Z. PDT will see 15g22 after 15Z, RDM/BDN will see 12-15g20-25kts after 22Z and DLS with 15g25 kts after 00Z. Elsewhere will remain under 12 kts. CIGs will be SCT/BKN.

Preliminary Point Temps/PoPs

PDT 91 59 84 51 / 0 0 0 0 ALW 93 64 86 56 / 0 0 0 0 PSC 95 62 90 55 / 0 0 0 0 YKM 94 58 89 54 / 0 0 0 0 HRI 94 62 86 54 / 0 0 0 0 ELN 90 57 81 51 / 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 85 44 / 0 0 10 0 DLS 95 62 81 56 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Red Flag Warning from 3 PM to 8 PM PDT Saturday for WAZ691. Extreme Heat Watch from Monday morning through Tuesday evening for WAZ024. Red Flag Warning from 4 PM to 8 PM PDT Saturday for WAZ690. OR...Red Flag Warning from 3 PM to 8 PM PDT Saturday for ORZ691-700. Extreme Heat Watch from Monday morning through Tuesday evening for ORZ041.