October 25th and January 3rd - Similarities

  • Snow levels fell in both cases despite lack of cold advection (weak low-level warm advection in both cases).

  • Primary low to mid-level isentropic lift was forecast just south of the area of interest in both cases.

  • Snow levels fell despite a lack of low-level upward vertical motion.

  • In both cases the RUC appeared to do a better job in showing the deep isothermal zero degree layer.

  • Neither model showed much mid-level cooling during falling snow-levels.

  • In both cases, temperatures fell to near or just above freezing, but did not fall below freezing.

  • Both systems were associated with deep upper lows / cold air aloft.

  • Both systems were associated with closed lows at 700 mb and strong mid-level frontogenesis.

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