It is big, hard to get rid of, and persistent. Scary for those who love fresh snow.
Yes, it is the Godzilla Ridge. One so powerful that is may be hanging around for 1-2 weeks. Strong enough to give us sun in normally cloudy December.
A ridge is the term given to a high pressure area, and is usually applied when talking about upper level charts. Here are a series of 500 hPa (about 18,000 ft) upper level forecast charts from NOAA/NWS.
Monday at 4 PM...big ridge off our coast. Godzilla is here. And ridges bring descending air and warmer temperatures aloft.
Wednesday at 4 PM.....EVEN STRONGER and closer to the coast. A major trough on the East Coast, bringing colder weather there.
Friday at 4 PM...a small shift eastward and slightly weaker. Big cooling in the eastern U.S.
Sunday, December 13th...the ridge strengthens. Unbelievable
The latest weather.com forecast for Seattle, shows lots of sun this week and the probability of precipitation stays at 10% or less through Tuesday Dec 12th.
An interesting aspect of all this is that temperatures will warm substantially aloft, while cold air (and high pressure) moves into eastern Washington. As a result, a very strong pressure difference will develop near the Cascades crest (see map at 1 PM Wednesday, with lines of constant pressure--solid lines--and temperatures---colors), with localized strong easterly winds.
The wind gust prediction at this time (below), shows some gusty winds along the Cascade crest, with stronger winds north of Mt. Rainier downstream of the Stampede Gap. Strong easterly winds over the eastern Strait of Juan de Fuca.
With high pressure aloft and associated sinking air, the air above us will warm and dry. Take a look at the sounding of temperature (red) and dew point (blue) for 4 AM on Thursday. Temps and dew point are really separated, which means very dry air. And the freezing level is above 10,000 ft (700 hPa is roughly that height). Note the inversion (temp warming with height) near the surface. Air quality will decline.
