Weather It Is (An Icy Night, and Much More to Come?)

Good Late Night:

A good clap of thunder (or two...) will wake up any good meteorologist from a sound sleep, and I am no exception. But, to get up (and stay up) after letting the dog go out?  This seems a bit too much.

On the other, I just noticed that temperatures dropped more than 3 C from the forecast overnight lows in the very strong thunderstorm that just occurred. It was a chilly 3 C.  This means that we're getting good mixing down from upper levels (500 mb), where temperatures are averaging about - 25.25 C. (Even lower temperatures should occur Wednesday night.)

These cold temperatures are associated with a strong winter storm that should provide us with ample late winter rain, which should finally taper off just in time for Purim day (or the day after, really).

In the meantime, we are getting stronger indications (and my apologies to the person who called me about Friday and I insisted "no" chance (of snow); actually it was 5%) that Friday evening is going to be even colder aloft than previously thought (perhaps as low as - 28C, but on average the forecast low temperature is almost -27 C).

The fly in the ointment is that we're in March, and temperatures at 850 mb are suppose to be just above freezing.  This is indicated by a relatively high thickness between 500 mb and the surface (by thickness I mean the height at the pressure level of 1000 mb subtracted from the height at the 500 mb pressure level).  Still, this type of situation, relatively warm at the surface and very cold aloft is conducive to thunderstorms (and thunderstorm snow).

Will it be a white Purim?  The plot thickens, but it grows more interesting by the day.

By the way, Purim itself may be followed immediately by another bout of rain (but again, we see a lack of upper level support for this event, as we actually originally saw for Friday night's possible snow).

I'm tired, so good night.