El Niño Advisory: Positive equatorial sea surface temperature (SST) anomalies continue across most of the Pacific Ocean. There is a greater than 90% chance that El Niño will continue through Northern Hemisphere fall 2015, and around an 85% chance it will last through the 2015-16 winter.
Above normal over almost all of California and Nevada and southern Oregon and Seattle north to the border. The rest of the western Oregon and Washington and northeast Nevada should be below normal.
Only California remains above normal for temperature with most of the other three states being slightly to moderately below normal.
Temperatures for much of the four state area return to near normal. Much of eastern Nevada and eastern Oregon should be cooler than normal.
Warmer than normal across the entire four state region with temperatures in the mountainous areas at close to 1 degree C (1.8 degree F) above normal.
Warmer than normal across the entire four state region with temperatures in the mountainous areas at close to up to 0.4 degree C (0.7 degree F) above normal.
Warmer than normal across the entire four state region with temperatures in the mountainous areas at close to up to 0.4 degree C (0.7 degree F) above normal and with small and isolated areas along the coast and in the Central Valley being slightly below normal.
The mountainous areas of central California to the north and most of northern Nevada should be slightly to moderately drier than normal while the southern third of California, southern Nevada and the Central Valley and coastal areas of California should be well above normal for the month. Note that normal for the month of July is less than 1 mm so any moderate and often-convective rainfall in this month could greatly exceed the long term normal for the month. Oregon and Washington will be well below normal for the month especially in the coastal ranges.
Much of California and the southern half of Nevada should be wetter than normal however long term normal precipitation for the month is very low for the Central Valley. Mountainous areas have slightly greater rainfall than the month of September so the positive anomaly is a welcome outlook. Much of the coastal ranges of Oregon and Washington remain considerably drier than normal with much of the rest of both states being near normal to only slightly drier than normal.
Much of California and the southern half of Nevada should be drier than normal however long term normal precipitation for the month is very low for the Central Valley. Coastal areas in northeast California and the far south of the State and isolated areas of southern Nevada could be slightly wetter than normal. Oregon and Washington remain drier than normal but only slightly while northwest Washington should be slightly above average.
Near normal throughout the region but slightly wetter than normal south of Bakersfield and across southern Nevada while much of the rest of the state is should be close to normal for this historical month for the onset of the wetter season. In Washington and Oregon near normal to slightly wetter than normal conditions should prevail.
Most of the two state area should be slightly drier than normal but only slightly and this is a rainy season month. The southern half of the two state area in contrast could be only slightly wetter than the long-term average although in the southern-most part of California this is a very dry month historically. Washington and Oregon should be slightly wetter than normal while areas of the east in both states could be slightly drier than normal.
The northern third of the two state area outlook is for slightly to moderately drier than normal conditions while the central parts of both states should be close to normal and just the southern third of California should be only slightly wetter than normal. In Washington and Oregon slightly drier than normal conditions are forecast with slightly wetter conditions in the mountains of central Oregon and in the Cascades to the east of Seattle.