Alberta Fires

The Alberta fires, which has resulted in the evacuation of Fort McMurray,  are extremely unusual this early in the warm season.  On Monday, the fires were quite evident on the NASA MODIS high resolution imagery (see below).  You will notice there are several smoke plumes from multiple fires.

A close up from the Fort McMurray fires today is quite impressive, with dense smoke moving to the southeast.

The fires were set up by very dry conditions, as illustrated by the percent of normal precipitation during April (see below).  Some locations in the fire are had less than 25% normal precipitation.

And temperatures in the same area were 3-5C  (5-9F) above normal.

The proximate cause of all this warmth and dryness?   Here is the pressure (height) anomaly for the last 3 months in the midtroposphere (500hPa). You will notice very strong, small-scale, persistent area of high pressure (red color).   The same ridge that gave us a wet winter and warmth.

Why the ridge was there?  At this point it appears to be natural variability, but perhaps someone may find a connection with human forcing.  But that connection does not exist today.  El Nino (which is a natural cycle) could have contributed as well.

from Cliff Mass Weather Blog http://ift.tt/1OgqHY7