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 overnight 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.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

VFR conditions persist through the forecast period. Winds are under 10 kts and variable across the TAF sites YKM/ALW/PSC with YKM/ALW seeing an increase to near 11 kts between 04-07Z respectively. DLS/PDT/RDM/BDN are all seeing winds between 10-15 kts with gusts between 20-26 kts. A brief decrease in winds for RDM/BDN between03-20Z before ramping right back up to breezy winds again. CIGs will remain 25kft through the period.

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.

Preliminary Point Temps/PoPs

PDT 59 84 51 84 / 0 0 0 0 ALW 64 86 56 85 / 0 0 0 0 PSC 62 90 55 88 / 0 0 0 0 YKM 58 89 54 88 / 0 0 0 0 HRI 62 86 54 87 / 0 0 0 0 ELN 57 81 51 84 / 0 0 0 0 RDM 51 83 41 83 / 0 0 0 0 LGD 55 83 47 81 / 0 0 0 0 GCD 54 85 44 84 / 0 10 0 0 DLS 62 81 56 89 / 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.