After a year where we were seemingly off by a month in terms of temperatures (March was more like April, June was more like July, September was more like October), October in the west felt much more like a November in terms of storms and precipitation! An early transition to a winter circulation pattern in the North Pacific held strong throughout the month with aggressive troughs that brought record-breaking precipitation to many locations. October precipitation amounts were 150 to over 400% of normal with dominant SW to NE storm track patterns from central California to the Northern Rockies and western Oregon into eastern Washington (Figure 1). However, areas of the west to the south and east of these storm tracks remained very dry. The troughs, cloud cover, and precipitation along these storm tracks also kept temperatures cooler than normal across northern California and into the PNW (1-5°F below normal), while much of the intermountain west was much warmer than normal (1-6°F above normal). Nationwide there were no other areas of blue outside of what you see in Figure 1, with the rest of the US substantially warmer than normal (bulk of the country was 4-6°F above normal). Precipitation amounts nationwide were mostly lower than normal with the exception of the southeast from the influence of hurricane Matthew (>400% of normal) and the Great Lakes region (100-200% of normal) (not shown). Overall the precipitation pattern and amounts in northern California and the PNW dominate the national map.
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