By Rod Hill on 2012-10-01
The 2011-2012 water year and September come to an end. Despite our recent dry stretch, the water year, thanks to another wet spring and especially June, finishes with a surplus. The water year ends with: 39.73" of precipitation.
Normal Water Year 36.03" / 2011 - 2012 surplus: +3.70"
Interesting to note that the adjusted 30-year water year average is drier than the 1980 - 2010 average which was 37.07".
September ends with .04" of rainfall, which is the 4th driest at PDX. Here is the dry list:
September 1993: Trace
September 1965: .01"
September 1991: .02"
_________________________________________________
The combo months of August & September were the driest in the record book which dates back to 1871! The two month rain total was .04 inches. Only three times in recorded history, have the two months produced less than .50" of total rainfall. There does not seem to be any correlation between our recent dry weather and up-coming winter precipitation.
Looking forward, very little if any rain is expected the first two weeks of October. The driest October at PDX was .19" of rainfall back in 1988, 2nd driest was .27" in 1987. Normal October rainfall is 3.00". Our rainy season is said to begin November 1st when 19 of 30 days typically see rainfall during the month.
8th Longest Dry Streak At PDX