Large Dome of High Pressure

At present, the vast majority of the CONUS is enjoying rather tranquil wx for what can be a stormy time of year. As we transition from late summer/early autumn into late autumn/early winter, we begin to see the jet stream become a bit more convoluted and as a result, the sensible wx becomes more and more unsettled. It might seem hard to believe that the wx can become more "feisty" than it has been of late, but winter is prime time for mid-latitude cyclones to develop and bring their wrath to those who inhabit in the temperate zones of the earth.  However, for the recent past and into the end of next week, it appears that the wx in these parts will be controlled by High Pressure or what are commonly referred to as Anticyclones.  The graphic below shows a lack of watches and warnings verifying the relative tranquillity of the atmosphere in the eastern 2/3 of the CONUS.

The pink region you see off the Carolina coast is a result of high seas and rough surf thanks to a developing system that will be far enough away from the east coast to cause us at KMDT any wx problems.  However, high winds and surf will once again pound the eastern seaboard as the storm develops, strengthens, and moves slowly NE and then ENE and away from the coast by Turkey Day.  

Here is a cloud photograph showing that developing system off the Carolinas and a nice cyclone getting ready to invade the Pacific NW.  But other than that, it is VFR (clear sailing) across the bulk of the CONUS east of the Rockies.

High-pressure weather systems often bring fair weather and relatively clear skies. In June 2012, a High Pressure system off the coast of Tasmania did just that…and in spectacular fashion. A NASA satellite caught this view of a hole in a cloud formation over the Great Australian Bight.  The subsiding air associated with High Pressure cut out the oval-shaped hole from a blanket of marine stratocumulus clouds. The cloud hole, with a diameter that stretched as far as 1,000 kilometers (620 miles) across, was caused as sinking air compresses and warms adiabatically to the tune of ~5.5F/1000'.  The clouds were evaporated as the air temp rose above the dew point temperature and voila.....clear skies!  Awesome photograph!

"Normal" sea level pressure is 1013.2 mb.  The wx is being dominated here in the east presently by a large O Canadian High centered over SW Quebec...and it is strong (1039 mb)!

Picture that High Pressure system in Quebec like the diagram below...a large dome of air that is slowly sinking towards the surface of the earth keeping most clouds and precipitation at bay.

And it will strengthen (1042 mb) through tomorrow and slowly migrate off the continent by Monday.  Lows in ME tonight will be quite chilly as the High sits right on top of Mt. Katahdin!

And even at the upper levels, a large anticyclonic flow exists.  The map below is for ~1 mile up...However, note the large Gulf of Alaska cyclone getting ready to wreak havoc on the PAC NW.

But we are protected by a huge dome of High Pressure not too different than these 2 young men who were also being protected by a slightly different variant of a Dome of High Pressure!  The pic below went viral as it was re-tweeted in the twitter-sphere over 70 times within a day!  Thanks to a heads-up move by one of our fearless leaders who, I might add, has a great sense of humor about all of this, protected these 2 combatant individuals who wanted to inflict pain upon each other.  The high pressure which he invoked rendered both individuals safe from harmful conditions much like these sprawling areas of high pressure do to the surface dwellers of planet earth!

Note the resemblance!

So being under pressure isn't all that bad.  In fact, it keeps potentially volatile situations stable!  So I will leave y'all with this Queen & Bowie classic who have their own take on Pressure!

Enjoy your High Pressure wx filled week's end!

Smitty

AA:  High pressure to rule the wx well into next week.  And we are also safe with high pressure protectors walking our building!