Thursday 14 May 20 – Early – Cumulus

Today is a day when you can watch the clouds develop.  The aristream is unstable with respect to sea surface temperatures.  There is a hard edge to the lifting condensation level and spirals of cumulus development are evident.  Within the space of 5 minutes you can witness cloud currents grow, mature and fade.


Tornadoes and Storms hit Central USA, 26 Apr 16

A vigorous storm brought tornadoes and massive hail stones the central USA yesterday, 26 Apr 16.

Cloud top pressure, courtesy of EOSDIS, computed from satellite imagery shows pressure of highest cloud visible to the sensor; the lower the pressure the higher the cloud.

Desktop meteorologists can get a quick view of the tornadoes and convective storms that hit central USA yesterday, 26 Apr 16, by using NASA’s EOSDIS presented as the featured image to this blog.  The purple mass in the top right hand area of the picture is very high cloud associated with this active storm system.

Visual imagery is presented below.

EOSDIS Satellite 26 Apr 16

A look at the wind flow at 250 mb /30,000ft ish, using the Earth website, shows the region overlain by the exit of a powerful jet stream.  Mathematical dynamics predict this to be aan area of strong divergence the result of which being the air is literally sucked up through the atmosphere from the surface causing these vigorous storms.

250mb flow 26 Apr 16

Open Cell Convection in the Davis Straits and Labrador Sea

Sweep of cold polar air pull down Davis Straits into the Labrador Sea by major complex depression in NE Atlantic on 28 Mar 16 forms regular pattern of open cell convection.  Convection patterns only became apparent with the advent of satellite meteorology, now they reach our desk tops every day.

This is cold air over relatively warmer sea surface.  Convection and condensation results but there is a weight of cold air above which is subsiding over a big area and the convection mixes in with this to limit vertical extent. Air descends in the open cells of the pattern.

A search for radiosonde data in this region to check the atmospheric structure is difficult.  I came up with a model ascent from Aasiaat (west coast of Greenland just to the NE of this picture).  Which does show some subsidence at about 7,000ft and is consistent with the thoughts for open cell convection.

GFS Sounding Aasiaat 28 Mar 12