.. Both with and within this topic, I'll be working to note different points at which I've appreciated a maximum level, or fuller extent, of general consolidation of main cold air mass set up through and over its main higher latitudes source regions and areas, to be in effect. This, with considering the broader and fuller Northern Hemispheric scope.
— A point that I've noted, with much study, that appears to be reached with regularity, i.e. cyclically, in line with what I've noted as an also apparent cyclical both general expansion of main cold/er air mass more southward—outward and down from its main higher latitudes source areas—looked at together with its opposite general regress, or the general retraction of that main cold's spread more southward: this cycle of main cold's more general distribution more latitudinal being per my observation, both inner-seasonal and taking place regularly, even irrespective of season, with its main period-length being near to [more] month-long. ... In fact an idea that I've worked to show with time here within this forum with my having submitted regular projections connected to it.
And so, ...
.. With main colder air, looked at more broadly, more fully east to west, main Northern Hemisphere, having been in general regress for the past near to two-weeks / since the 5th of February, this following its previous general expansion, daily more southward, having taken place more through to that point and having being back on the 21st of January - http://theweatherforums.com/index.php/topic/1133-winter-2015-16-colder-air-mass-movement-and-distribution-projections/?p=118130 .. The 21st of Jan. then having been the most recent, past point, where main and broader cold had been at its most consolidated, likely "the most" consolidated for this current colder season, ...
.. Here below I've tacked in three different main images working to illustrate the main idea that I've suggested above.
— First here more just below, two showing the general circumstance where looking at main "Surface Temperature", where considering the greater Northern American scope, and as depicted as main 10° separation, temperature "contours". .. One for at 19z for today's date. And the other for 12z, earlier, and more in line with the image below these two showing a broader, more hemispheric scope view of the "850mb" both temperature and more general pressure height also for 12z. (Click on each of these smaller images here below to view the full sized representations.)
.. source: Unisys Weather: N. Amer. Temp Contours / 850mb Temp/Heights
Fuller Cold Air Mass Consolidation ..
Posted 18 February 2016 - 01:16 PM
Posted 16 March 2016 - 12:47 PM
At about 12z earlier today, colder air mass looked at more broadly, was at its strongest north where gathered and sitting over and through its main higher latitude source regions and areas.
.. This, with and since its last, or most recent and previous fuller consolidation north, on the 18th of February (See the initial post to this thread above.), its having been caused to expand (move and spread)—more inner-seasonally—fuller hemispheric both scale and scope, daily more southward through the 3rd of March, before then and more since that point and through to near to 12z today its having been in general regress, back more northward daily, lending to its most dense consolidation.
http://weather.unisys.com/upper air/ua hem.php?plot=n8&inv=0&t=cur
Graphic images more static, one for the fuller North American Surface Temperature Contour parameter, and one depicting the temperatures / general state pressure wise at the 850mb height level, both for 12z for today's date. (Click on the images below to view their main fuller-sized versions.)
Reviewable as animated loops using graphics similar to those here above accessible here below further, note the general expansion of colder air, shown moving and spreading more southward from the 18th of February forward through the 3rd of March, first as changes where considering main Surface Temperature depicted as 10° F Contours where looking at greater North America, and then, with also checking the 12-hourly changes where looking the 850m Height Temperatures, more hemispheric.
16021812-16030312z 12-hrly tcm sfc na.gif
16021812z-16030312z nhem 850.gif
And then, with considering these same to parameters, also the general regress of cold that I've suggested as having taken place more from the 3rd of March through to earlier today.
16030312-16031612z 12-hrly tcm sfc na.gif
16030312z-16031612z nhem 850.gif
— The regress documented here just above certainly somewhat in line with what might be expected more generally, more seasonally. The expansion, more above it, somewhat less.
— Also note with reviewing these changes, that in addition to this more latitudinal element or component of colder air's movement and distribution, that there is also a more longitudinal one. .. At work at the same time, and so at times working to obscure cold's general either whether expansion of regress more latitudinal.