Wednesday, December 09, 2015

Warmth Continues...When Will It Flip To Winter?

No one is complaining about the above normal temperatures after the two past harsh winters. Above normal temperatures across the eastern 1/2 of the US.  This warmth is not unexpected given the strong El Nino reaching peak strength though I am somewhat surprised that the warmth has been this consistent.

It can't last forever.  So when will it flip or at least trend colder with higher chances of snow!

Remember our preliminary December outlook issued back in early September showed the core of the high pressure/warmth across the northern states into Canada with the core of the low pressure centers across the south (panhandle low type systems).
Through the first week or so, the core of each HIGH and LOW is much stronger than anticipated yet they are roughly in the same position as our forecast 3 months ago indicated. However, the southern lows (Panhandle type) are far weaker and, as of this writing--December 8th--are just now showing signs of developing. (see the smaller "Ls").
Since November, the warmth has been extensive with below normal temperatures in the west. Warmer colors indicate above normal temperatures, cooler colors below normal temperatures.

Some computer model projections have been bullish in tracking these southern lows further east and the warm ridge further north into Canada by the beginning of Christmas week.

The big questions for the end of the month and Christmas week: 1) How fast will the ridge lift north and 2) how strong will the low in the southwest/panhandle region push east?

We do know this: Any easterly migration of the southwest low along the southern jet stream will increase our chances of a wet panhandle-type snow by month's end. 

The chances we will receive wet snow from a panhandle low will climb further after the first of the year.