12/3/2014: Pattern Shift

It has been exceptionally cold the past few weeks with negative temperature anomalies in the 10 to 15 degree range.

 

Departure from Average from 11/10/14 through 12/2/14

Departure from Average from 11/10/14 through 12/2/14

 

Although in the short term, the next 5 days through the weekend will continue to see some fluctuation in the temperatures, with the general trend  for improvement in the temperatures (warmer).  Next threat of precipitation outside of the normal flurries that may come out of any given cloud in the winter will be on Sunday.  A Pacific Low pressure system will move near the US / Canadian border.  Any precipitation (snow) looks light at the moment with the highest potential near the International Border, but this system will also usher in some very mild air.

 

Surface Pressure and precipitation for Sunday PM

Surface Pressure and precipitation for Sunday PM

 

The clipper will be riding on the edge of a pool of mild Pacific Air that will then in turn bring in the warmest air the north central part of the United States has recorded since early November.  Atmospheric heights will build (ridge of high pressure) and in turn above average temperatures will probably hold strong to the region for most of next week.

 

500 mb heights and anamolies

500 mb heights and anamolies for next 10 days

 

Snow cover will temper the potential highs for next week as well as the low sun angle this time of year, but positive temperature anomalies in the 5 to 10 degree range can be expected and there is certainly potential for even warmer temperatures in locations with little snow cover.  This should translate into highs at least in the 30s.

Projected Temperature anomaly for December 7 through 12

Projected Temperature anomaly for December 7 through 12

At the moment I feel that temperatures will go back below normal for the last week to ten days of the month (during the holidays), but in the near future, warmer air is likely and will give us a break from the unseasonably cold weather as of late.  Precipitation look very light during the next 7 to 10 days, so a pleasant weather period is expected.

Daryl Ritchison

 

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