Winter Forecast 12-13

Well, well , well--


For a time,  it seemed the winter outlook would fall on the easy side of things with a close to moderate el nino . Those for winters have pretty strong correlation to cold and snow, at least relative to our norms. The Nino faded and now we are left making strong judgement calls to what this winter holds.

Winter outlook for Lynchburg, Roanoke, Danville, Blacksburg Virginia-

Quick thoughts.

1. Won't be as mild as last winter.

2. Won't be as snowy as 09-10.

3. Should be a tad drier than normal

Quick view.

Winter temp average 1-2f colder than normal.

Precipitation 15% below normal

Snowfall- Take your local and subtract 5. Your range will be in that 5.

Example- Lynchburg is listed as 18 inches - so 13-18 inches. Roanoke is 21 so lets go 16-21 for the winter.

Monthly break down temp wise--

December - 1
January +2
February -3.


Thought process 
(Google these indices or email me a question)

Losing the El Nino hurt-- as that seems to usually trump other global patterns. This will be a neutral warm el nino, meaning it's not a nino, but temps are above normal in that region.

QBO- Has been very negative and should begin to move towards positive. This should allow for some blocking towards the North Pole.

PDO- Negative to very negative. This isn't a good sign for cold and snow, especially south of the mason dixon line. Oddly, when the trend is negative, but spikes positive for the winter they trend to be snowier. This will NOT be the case.

Long range model- Both the CFSv2 and ECMWF have been all over the place, but both don't see VERY cold winters.

SOI- Index that measures pressures in Darwin and Tahiti- More La Nina like, than El Nino.

Snow cover- snow cover in Eurasia has been demonstrated to be a harbinger of the Arctic oscillation, where as when the snow cover advances rapidly, the chain of events leads to more blocking at the pole. This year was THIRD on the list behind 09-10 and 1976-77, both that had TREMENDOUS cold snaps. The biggest difference in those two was the EL Nino in 09-10 leading to all the snow cover.  I weighted this the most.

The biggest issue with snowfall will NOT be cold, but lack of a sub tropical jet. My guess is 4-5 days out systems may look to have potential but unless we have strong blocking, these will end up being events NORTH of DC-- or we get much less than modeled due to downsloping, etc. (Especially east of the Blue Ridge)  I can see several events where we get 2-4 inches of snow with the nice glaze of sleet and freezing rain on top.