Omega Block and the Upcoming Alaska warmspell.

 As like most avid weather hobbyists, I often spend my time studying the plethora of weather maps now available online.  With the upcoming warm spell forecasted for the majority of the state I found myself interested in the upper air patterns that is going to create it.  

The first and foremost player in this game is an unusually deep low-pressure system churning over the Bering Sea. While this area of the globe frequently experiences stormy weather and is the home of the semi-permanent Aleutian low it is unusual to see a storm this deep in the heart of summer.  Computer models have this storm dropping down to 977mb in depth.  Quite surprising for this time of year.  This deep of a storm would be more common in early fall.   See map below courtesy of NOAA.

Rising, cooling air releases a lot of latent heat when water is condensing, building up the existing ridge to is east.  Temperature difference at 850 mb (about 5000 feet in the atmosphere) is strong.  Temperatures are as low at -4.5C (mid 20's F) near the low center and +15C (upper 50's F) over eastern mainland Alaska!  See below 850 mb map courtesy of Ventusky:

Here's the corresponding surface temperatures, quite toasty over the majority of the state! 70's, 80's and perhaps a few 90's in the 40-mile country.  Even the arctic coast will get in on some of the action depending on prevailing wind direction. Southeast or south surface winds are conducive of warmth.

Durning these next few exciting weather days I noticed the upper atmosphere was getting into a stable pattern called an Omega block.  These can hang around for quite some time before breaking down.  Here is the basic definition courtesy of NOAA: Omega blocks are a combination of two cutoff lows with one blocking high sandwiched between them. Because of their size, Omega blocks are often quite persistent. So basically, warm and dry lingering in location while wet and stormy conditions remain day after day.  See computer model below of the forecasted Omega block at 700 mb or 10,000 feet.  Our second low pressure system (which is much weaker in comparison) is located off coast of the Pacific Northwest.  Seattle should have some cool weather the next few days.  Thanks for reading!