Three Letters To Describe The Pacific Northwest Weather: H O T

Continued hot weather is in the forecast for the Pacific Northwest (PNW) through the rest of July as a strong upper-level ridge builds into the region. The Climate Prediction Center (CPC) has high probabilities of above average temperatures across the entire West Coast stretching into Alaska (see Fig. 1). High temperatures will be 6-18°F above average, which will rival the intensity and duration of the heat wave of mid-July. The warmest temperatures in Washington and Oregon will occur over the weekend as the upper-level ridge strengthens.

Fig. 1: CPC Temperature Anomaly Map For Days 6-10

So how hot will it get in the major cities of the PNW (see Fig. 2, 3, 4)?

Seattle: upper-80s to 90
Tacoma: low-90s
Olympia: low-90s
Portland: mid-90s
Eugene: mid to upper-90s
Medford: low-100s
Twin Falls: upper-90s
Boise: low-100s

The Coastal areas will escape the oppressive heat, due to the marine layer, which will keep highs in the upper-60s to low-70s.

Fig. 2: NAM Tuesday Forecast Highs

Fig. 3: NAM Wednesday Forecast Highs

Fig. 4: NAM Thursday Forecast Highs

Heat indices should remain close to the air temperature since humidity levels will remain low but the low humidity levels will increase the fire risk due to the ongoing abnormally dry conditions (see Fig. 5). Currently, there are a few fires burning in the PNW; this paired with a stagnant high-pressure, will allow a decrease in air quality in urban areas and valleys. People with breathing impairments should limit time outside.

Fig. 5: Current Drought Monitor

Overall, dry conditions can be expected in this region; however, a few isolated thunderstorms may develop during the afternoon hours across the higher-terrain. This convection will have minimal precipitation but contain gusty-winds due to evaporation and lightning. This could aid in sparking fires across northern California, southern Oregon, southern Idaho and northern Nevada.

Above average temperatures are in the forecast for the Southwest, too. A few records are possible in California. Coastal waters are well-above average in southern California making for a pleasant swimming environment (see Fig. 6).

Fig. 6: Current SST Anomalies

A break from the heat may begin next week as the upper-level ridge shifts eastward.