The warmest temperatures felt so far in 2012 are expected in Seattle, Wash., and Portland, Ore., over the Mother's Day weekend.
The mercury should reach 80 degrees in Seattle on Sunday while Portland makes a run at 90.
The key ingredient to the warm spell is offshore winds. The flow of air across the Pacific Northwest will be from warm interior areas towards to the cool ocean. This flow of air will keep the cool ocean air at bay.
The offshore wind will couple with warm air over most levels of the atmosphere. This is a classic set up to bring temperatures close to record levels across the Pacific Northwest.
Even areas right along the coast like Astoria, Ore., will be well into the 70s this weekend.
The warm temperatures will also be felt across much of Interior California as well.
Unlike Washington and Oregon, the wind will be onshore, so coastal areas like San Francisco and Los Angeles will be much cooler with some clouds and fog. For example, Fresno is expected to reach 92 Saturday while Los Angeles and San Francisco will not even reach 75.
The warm spell will not last long. A weak cold front will move into the Pacific Northwest Tuesday, turning winds onshore and bringing cooler temperatures.
This front could tough off thunderstorms with a threat for lightning strike and little to no rainfall in portions of California and Oregon. Such a setup could spark wildfires.
Meanwhile, the warm weather will be pushed east towards the Plains.
Pittsburgh will remain dry until after another mild spell unfolds Easter Sunday and Monday.
Detroit will remain dry until after another mild spell unfolds Easter Sunday through Monday.
Rain and thunderstorms spreading to the East on Tuesday will put the brakes on the warmup following Easter weekend.
Although spring may be in full swing, more than one-third of the Great Lakes remains covered in ice.
Cleveland will remain dry until after another mild spell unfolds Easter Sunday through Monday.
At least 13 are dead and three are still missing after an avalanche cascaded down a climbing route on Mount Everest early on Friday morning.
Nation City, SD (1881)
79-day snow blockade lifted -- first train arrived.
Watertown, OH (1901)
April 19-21, 45 inches of snow - state record.
El Paso, TX (1971)
4" of snow -- late season record.