RED ALERT: HIGH HEAT INDEX
The first heat wave of 2013 is about to sweep into the PNW. This one will have a rather unique attribute as compared to typical heat waves - it will be muggy.
Temps in OR jumped rapidly yesterday. The ridge will set up the warmest temperatures of the year, and even challenge record highs for many. The key difference this time will be elevated relative humidity. Surface humidity levels will combine with high temps to have us all feel uncomfortable outside. Usually we have cooler overnight conditions during our heat wave events - this time the dew points will remain high, so it will be uncomfortable even at night.
The weekend will present temps in the 90s in most west side locations. There may be a slight offshore air flow kick-in by Monday, for the hottest period of this cycle being Monday/Tuesday west of the Cascades. HUMIDITY will remain a factor. Sweat city. Don't be surprised if some sites in the Willamette Valley tip into triple digits Tuesday.
The long 4th of July holiday weekend will continue on the warm-to-hot side, although peak temps will subside from earlier in the week. It will remain dry (excluding thunderstorm action) for the first half of July. Temps are likely to jump back up in the July 10-14 period. Overall, Spotted Wing Drosophila programs must remain in place; high humidity will challenge plant disease management, esp where overhead irrigation is utilized.