Friday, April 20, 2018

A Colorado Low

During the spring, an upper level low often develops over the Four Corners region and moves eastward onto the High Plains.  In concert, its cold front bows southeastward from the central zone of low pressure, separating dry air, to its west, from warm, humid air, to its east.

Known as the Dry Line, this frontal boundary often ignites supercell thunderstorms across the Southern High Plains, from eastern New Mexico to West Texas and Oklahoma.  North of the low, counterclockwise winds push moisture toward the Front Range, producing cold rain or snow as the air is forced to rise by the terrain.

This scenario is playing out this evening.  The Dry Line and its attendant thunderstorms stretch along the New Mexico-Texas line and are moving eastward; hail is expected and tornadoes may develop.  Here in Metro Denver, chilly rain is falling which will likely change to snow overnight.  Since it has been very warm along the Front Range, significant accumulation is unlikely and the precipitation is more than welcome.