A strong subsurface warm anomaly known as a Kelvin Wave continues to shift eastward in the equatorial Pacific eroding cool waters needed to sustain La Nina. The 2021-22 La Nina is definitely weakening!
The 12Z GFS indicates a long-duration snowfall event along and trailing a cold front which shifts eastward slowly this week. The snow begins tomorrow night in the south/east Great Plains and stretches to the Ohio Valley and then eastward into New England for later this week. GFS grinds out 1-2 feet of snow across this large area - which is likely excessive, but the model certainly makes its point.
Traditionally, a “bomb cyclone” is a low-pressure system deepening (strengthening) by more than 24 MB over a 24-hour period. The definition usually applies to middle/upper middle latitude. Although a “bomb cyclone” is not a tropical cyclone, these systems can reach category-1 hurricane force on the Saffir Simpson Scale.
An arctic outbreak plows into a slow-moving frontal system in the Central U.S. middle of next week and lays a nearby carpet of snow for the air mass to shift south into Texas with limited moderation causing two mornings (next FRI/SAT A.M.) of temperatures in the frigid 20's!