The warmest day of the week was able to produce record highs in the Tri-Cities and Walla Walla on March 19. Additionally, Hermiston tied their existing record for that date. Low elevation spots on the Hanford Site, around the Tri-Cities, and in the Hermiston area were able to tap 80°F (27°C) with widespread 70s (21-26°C) elsewhere in the Columbia Basin and Yakima Valley. Below is a list of new records listed by the National Weather Service in Pendleton:
RECORD HIGHS FOR MARCH 19
NWS PENDLETON CWA
| Location | 2024 High | Old Record |
| Tri-Cities | 80°F (27°C) | 1934: 77°F (25°C) |
| Walla Walla | 75°F (24°C) | 1960: 71°F (22°C) |
| Dallesport (The Dalles) | 77°F (25°C) | 1988: 73°F (23°C) |
| Ellensburg | 76°F (24°C) | 1947: 74°F (23°C) |
| Hermiston | 80°F (27°C) | 1934: 80°F (27°C) |
These records represent official climate stations in the NWS Pendleton county warning area. A few sensors were even warmer, though not by much. Some on the Hanford Site recorded 81°F (27°C) and one near Road 68 in Pasco hit 82°F (28°C). Those highs seem reasonable to me. A site near Echo claims a high of 84°F (29°C) but is warmer than nearby stations. It is owned by Union Pacific, whose stations are commonly too warm on sunny days. The official climate station for the Tri-Cities is located at the Tri-Cities Airport in Pasco.
The high of 80°F (27°C) at the Tri-Cities Airport is the earliest 80°F high on record with observations dating back to 1894. The old record was March 24 set in 1939. The updated dates for temperature thresholds in the Tri-Cities is as follows:
FIRST TEMP DATES
TRI-CITIES AIRPORT (PASCO)
| Threshold | 2024 | Average |
| 70°F (21°C) | Mar 17 | Mar 22 |
| 80°F (27°C) | Mar 19 | Apr 23 |
| 90°F (32°C) | —– | May 19 |
| 100°F (38°C) | —– | Jun 27 |
This comes as a strong upper level ridge centered along a line from Reno to Spokane to Banff dominates weather conditions in the Inland Northwest. Thankfully for snowpack and water supply, the ridge is beginning to break down. This will usher in gradually cooling temperatures. Marine influence is already spreading into Western Washington and Western Oregon ahead of a weak cold front forecast to move through Wednesday. Mostly sunny skies are forecast in and around the Columbia Basin through midday Thursday.
The area trends breezier today with wind gusts to 30 mph (50 km/h) in the Lower Yakima Valley and the exit region of the Columbia Gorge, including Hermiston, Sunnyside, and Toppenish. Gusts more in the 20-25 mph (30-40 km/h) range seem reasonable for the Tri-Cities. This is below the level the National Weather Service uses to issue wind advisories, but will be noticable. Wind will be strongest in well-exposed areas like fields and hilltops. Neighborhoods with mature trees will see lighter winds.
Wednesday will still bring highs around 70°F (21°C) but look to dip near to below 60°F (15°C) by Sunday in the Tri-Cities and Hermiston. Expect to be a few degrees cooler in places like Yakima, Walla Walla, and Moses Lake. Rain chances resume in the Columbia Basin into Friday evening and last through the weekend to bring between about a quarter and half inch (6 to 12 mm) of rain to lowland areas.
Declining snow levels will bring between about 6 and 12 inches (15-30 cm) of snow to higher elevations of the Cascades with some snow on the passes this weekend. Spokane may also get a little bit of snow, most likely not exceeding two inches (5 cm) and possibly not sticking at all.
The featured image is observed highs in and around the Columbia Basin on March 19 via the National Weather Service.
