GENERAL OUTLOOK
With few exceptions, an unseasonably low jet stream brought minor disturbances from the Gulf of Alaska region to the northern tier of the Pacific making for a cooler, wetter than normal June. The predominant Pacific zonal weather pattern was briefly interrupted mid June by a period of strong high pressure ridging for the entire region, and then again late in the month when a vigorous low pressure from the Gulf brought significant rain to the western and northeastern portions of the basin. Seasonal river flow peaks occurred mid June for the Kootenai and Upper Columbia basins.
Pacific northwest mean temperatures departed -2.6 degrees from normal relative to 1961-1990 normals (31 stations). Mean temperature departures ranged from -6.8 to 0.5 degrees.
Daily record minimum temperatures were broken at Pocatello (31 deg on the 9th, 34 deg on the 10th), Kalispell (26 deg on the 7th, 29 deg on the 10th), Great Falls ( 31 deg on the 10th, 36 deg on the 26th), Missoula (30 deg on the 30th), Eugene ( 37 deg on the 6th, 34 deg on the 9th, 36 deg on the 10th), tied at Portland (44 deg on the 7th).
A daily record maximum temperature was broken at Astoria (77 deg on the 11th).
No daily rainfall records occurred during June.
For June, precipitation was 107 percent of normal (1961-1990) at Columbia above Coulee; 99 percent of normal at the Snake River above Ice Harbor; and 95 percent at Columbia above The Dalles.
This product will only be available on the NWRFC web page beginning June 1999.
Please direct any questions to the NWRFC at 503-326-7401.