There is no real cold air now over the Lower 48 and doesn’t look like we’ll see it’s return until next autumn. That doesn’t mean to say we won’t see cool and below normal temperatures return, in fact modeling suggests more troughiness over the East in coming weeks but the air which comes down from Canada won’t be ARCTIC. The negative NAO supports more cool shots into the East through the second half of May extending into June but they will be your more typical of late spring, early summer.

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Now that the real cold is now kicked out, heat is now allowed to cover more ground and with system pushing into the country from off the Pacific, that means the severe weather potential is significantly increasing and we’ll see just how significant the severe risk will increase by this weekend. A system riding a fast flowing Pacific jet will carve out a new trough over the West this weekend and as it does so, this shall cool things down over California, Nevada into the Rockies but out ahead of this trough, ridging will build and so too will both heat and humidity. It’s as the system pushes across the Rockies does the air get forced to rise further east and so thunderstorms will develop over the western High Plains Saturday.

During Sunday the risk of thunderstorms turning severe increases as the cold overlaps the increasingly warm, humid air beneath, also the jet stream splits and like a arms spreading apart in a bath tub, the water from beneath gets forced upwards faster. This process draws air from surrounding areas inwards, replacing the air being forced to rise vigorously. All this should increase thunderstorm development ten fold along and ahead of the front which by Sunday afternoon will be crossing the Plains. The turning of winds with height is the concern and will transition these storms into rotating supercells.

Below is the risk areas through this weekend into early next week according to AccuWeather

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