textproduct: Pendleton

KEY MESSAGES

1. Hot, dry and windy conditions today through Kittitas Valley and Lower Columbia Basin of Oregon * RED FLAG WARNING THROUGH 10 PM TODAY*

2. Dry and warm conditions will continue through Tuesday

3. Pattern shift midweek will bring monsoonal moisture back to the region with chances of thunderstorms

DISCUSSION

Current satellite shows some cumulus clouds over the Wallowa Valley currently with no other clouds across the region. Hazy skies will persist through the day from the surrounding fires and an Air Advisory in effect for southeastern OR and Wallowa Valley through Monday.

An upper level shortwave disturbance is passing over the region just to the north of the area tightening the gradients across the Cascades. Breezy to windy conditions expected through the Cascades Gaps, and along the Lower Columbia Basin of Oregon. Winds coupled with very low relative humidities, a Red Flag Warning has been issued through 10PM for Kittitas Valley and the low Columbia Basin of Oregon due to low humidities and winds of 20-25 mph gusting to 30 mph with high confidence (80-90%). Once the shortwave passes, southwest flow will return ushering dry and warm conditions.

By Wednesday, models are in decent agreement and show a slight pattern shift with the upper level ridge shifting towards the Four Corners and advecting some monsoonal moisture up into the region. Clusters show the main difference to be mainly with the amplitude of the ridge. NBM raw ensembles show Wednesday to have 40% chance of thunderstorms through Deschutes and Grant counties after 2 PM. Looking at soundings show CAPE values over 350 J/kg, lapse rates 8.5- 9 C/km, effective bulk shear of 20-25 kts and LIs of -4 and PWATs of 0.05-1.0 inches. NBM QPF shows these storms to be more on the drier side with less than 10% chance of a wetting rain. Will continue to monitor as the event draws closer.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

VFR conditions are currently expected across all sites. However, due to nearby wildfires, virtually any site could have MVFR conditions for a period of time.

DLS, PDT, RDM and BDN will have gusty winds through this evening with DLS gusting to around 25 kts and PDT, RDM and BDN gusting to around 20 kts. These locations will decrease to 10 kts or less afterwards and the other sites will be 10 kts or less through the period.

FIRE WEATHER

A Red Flag Warning has been issues for Kittitas Valley and the Lower Columbia Basin of Oregon for low relative humidities and breezy winds through 10 PM tonight. Relative humidities in Kittitas are expected to reach as low 15% with winds of 20-25 mph and gusts to 30 mph while the Lower Columbia Basin of Oregon will see relative humidities as low as 17% and winds 10-20 gusting to 30 mph. With the fires already on the ground, this can lead to elevated fire spread and any new fires will spread quickly. The next timeframe of concern is Wednesday when there is a 40% chance of thunderstorms moving into the region.

Preliminary Point Temps/PoPs

PDT 55 91 60 92 / 0 0 0 0 ALW 61 93 64 95 / 0 0 0 0 PSC 57 93 61 95 / 0 0 0 0 YKM 57 94 63 95 / 0 0 0 0 HRI 59 94 62 94 / 0 0 0 0 ELN 54 91 59 93 / 0 0 0 0 RDM 49 93 60 91 / 0 0 0 0 LGD 54 94 59 94 / 0 0 0 0 GCD 54 96 60 94 / 0 0 0 0 DLS 59 96 65 96 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Red Flag Warning until 10 PM PDT this evening for WAZ690. OR...Red Flag Warning until 10 PM PDT this evening for ORZ691. Air Quality Alert until noon PDT Monday for ORZ050-502-503-505- 506-508.