GENERAL OUTLOOK
A zonal flow across the Pacific Northwest allowed a series of cold fronts to bring reinforcing shots of cool air to the region. West of the Cascades and across northeast basins, below normal temperatures were accompanied by above normal precipitation. Across southeast basins, precipitation was generally below normal.
Pacific Northwest mean temperatures departed -2.2 degrees from normal relative to 1961-1990 normals (31 stations). Mean temperature departures ranges from -4.1 to 0.7 degrees.
There were only 2 new high temperature records in June and both were established in Pocatello - 92 was reported on the 1st and 91 was recorded on the 8th.
There were several new low temperature records established in June. They included: 32 at Missoula on the 3rd, 31 at Missoula and 34 at Eugene on the 4th, 29 at Pocatello and 32(tie) at Kalispell on the 5th, 41(tie) at Astoria on the 13th, 32 at Pocatello on the 14th, 35 at Great Falls on the 17th, and 33 at Eugene on the 25th.
There were 4 new daily precipitation records established in June. On the 3rd .96 and 1.49 inches of rain fell in Butte and Missoula respectively. On the 12th Missoula received .70 inches. On the 27th Seatac Airport reported .61 inches of rain.
June precipitation was 117 percent of normal (1961-1990) at COLUMBIA ABOVE COULEE, 65 percent of normal at THE SNAKE RIVER ABOVE ICE HARBOR, AND 99 percent at COLUMBIA ABOVE THE DALLES.
Seasonal, October through June precipitation was 70 percent of normal (1961-1990) at COLUMBIA ABOVE COULEE, 72 percent of normal at THE SNAKE RIVER ABOVE ICE HARBOR, AND 70 percent at COLUMBIA ABOVE THE DALLES.
Very little snowpack remains with only the upper Columbia in British Columbia and the upper Kootenai still responding to above normal temperatures. All other areas are receding slowly with low base flow conditions.
Streamflow during June was dismal with many drainages only 25 to 45 percent of normal flow. Some northern drainages where some snow still exists had runoff volumes close to 60 percent but these were few.
Streamflow forecasts dropped in most areas based upon lack of snowmelt responses and low current runoff conditions, which suggest that the summer base flows may well be lower than previously forecast. Most drainages are still expected to have flows above those experienced in 1977 but some new low flow records may also be established.
The July 1st forecast at Grand Coulee for the January - September runoff is 41.8 million acre feet (maf) - 57%, a decrease of 0.7 maf from the June final and would establish a new record low flow previously set in 1944 of 44.0 maf. The January - July forecast at Lower Granite Reservoir is 14.0 maf - 47 percent, a decrease of 0.8 maf but is still above the low flow of record of 12.9 maf. The January- July forecast at the Dalles is 54.7 maf-52 percent and represents a decline of 0.8 maf from the June 1 Final, yet remains above the record low flow of 53.4 maf set in 1977 .