11/12/14: No End to the Cold

Although most would agree that for the middle of November it is already cold enough, another cold front is passing through the area today.  There has been some very light snow associated with this front passage, plus, a weak upper air disturbance is passing overhead today as well.  Liquid equivalency of moisture looks to be only in the few one-hundreds of an inch, but that will be enough for a light accumulation of snow.

 

8:00 AM Surface Analysis

8:00 AM Surface Analysis

 

Below is a representation of the HRRR take on possible radar returns today.    The narrow streaks are lake effect snows from Lakes Winnipeg and Manitoba that will likely not occur to the degree represented below, but otherwise, the light on and off snow in the area will like occur, but accumulations remaining light.

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HRRR Radar Projection for today

 

The main story in the forecast is the continued cold with temperatures in the 10 to 20 degree below average range.  The persistent north or northwesterly flow aloft appears to be lasting well into next week.  There will be reinforcing shots of cold air through this stretch.  This pattern is not conducive to much moisture so any snow events would be very similar to what is occurring today.

 

500 mb heights and anomolies.  ECMWF WMO Essential

500 mb heights and anomolies. ECMWF WMO Essential

 

The Arctic Oscillation (AO) that deals with pressure differences from the Arctic to the mid-latitudes.  Although there are exceptions, when the AO is negative, colder than average temperatures are common in our area.

 

Projected Arctic Oscillation Index through November 21

Projected Arctic Oscillation Index through November 21

 

 

It appears that an -AO will be with us for an extended period of time.  Therefore, cold and mostly dry until perhaps some time near Thanksgiving with no major snow storms foreseen.

Daryl Ritchison

 

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