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Heavy Mountain Snow in the Northwest U.S.; Wintry Mix in the Northeast U.S.

Two more cold fronts will pass through the Northwest U.S. this week with heavy mountain snow continuing across the Cascades, and northern Rockies. A quick moving storm system will bring mixed precipitation including some freezing rain across the Northeast U.S. overnight into Wednesday. Read More >

Overview

A strong area of low pressure aloft moved up into the northern Plains as an associated mid level jet advanced over the southern Plains. The right entrance region of this jet was situated over the eastern Panhandles on top of a dryline which helped bolster deep convection. A weak lee low developed over southeastern CO helping to increase convergence along the dryline during the afternoon where Thunderstorms initiated and quickly became severe. Deep layer shear vectors were normal to the boundary at around 40-50 knots resulting in discrete supercell structures. SBCAPE on the order of 3500 J/kg supported very large to giant hail. Canadian was one of the main targets in this event as the north side of town got beat up with golf ball to baseball size hail due to a "right mover". A "left mover" moved up into Beaver County at 60 mph and also dropped very large hail east of Elmwood, OK.

Fig 1: This is a base radar reflectivity loop of the June 13th event. 

 

Fig 2: GOES 16 Cloud Top Phase IR Band for June 13th event (non-operational, preliminary data).

 

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