.. Greater cold air mass will slow its pace east on the 10th, ...
As shown within the "gif loop" accessible here following just below, after previously having been moving as a whole more swiftly eastward from the 2nd of May through the 10th, starting on the 10th greater cold air mass
* did in fact begin to slow its over-all pace eastward. (
Click on the image here just below, as with on those also following each main section of text further below. Allow time for loops to load in fully.)
The 700mb pressure-height level occurrs generally at near to 10,000 ft of elevation.
… and spread more south again beginning on the 13th of May.
Shown more main focus within the loop next following accessible, as a result of this general slow-down in and of greater cold air's more eastward movement, .. between the 10th and the 13th of May, where provided different more specific pathways south (both more basic topography, along with established pressure related.), some amount of more primary cold was steered more southward
—i.e. previous to the 13th and if with more primary cold looked at more over-all having still been retracting more northward by degrees daily.
And shown within this next loop following, nearer to the present, …
Since the 13th, greater cold has in fact been continuing to move and spread steadily more southward daily where looked at as a whole.
With continuing to slow its main movement east through the 22nd or so of May, greater cold air mass should move through a short period of more stepped up pace east from the 23rd through the 25th or so before slowing again.
This, while continuing to spread more southward through May 25th, before beginning to regress more back toward the north for several days.
Source for the graphic depictions used above. -
http://www.osdpd.noaa.gov/ml/mirs/Poes.html(
Check "product", for "Temperature Profile" / 700mb. Runs a day behind, generally.)
* .. All, of the bluer areas within these depictions: .. the darker, more primary, the lighter, if at one point more primary, more "secondary"; .. and where considered together "greater" cold.