|Summer 2013 Seasonal SST Anomaly|
to say "La Nada", that currently exist in the tropical Pacific are expected to continue to exist through much of the upcoming winter. Some slow warming is forecast and it is possible, that waters will warm to near weak El Nino levels during Spring 2014.
|State Climate Office of North Carolina|
Since it is early September, it is still a bit early to begin utilizing the current sea surface temperature (SST) anomaly pattern, here, to begin predicting whether the NAO will trend in the positive or negative phase. This can be more confidently done beginning in mid to late October. Current SST trends would indicate the beginning of the winter will begin with a Positive NAO phase. However, the phase can fluctuate through the winter and I anticipate the phase to shift negative during the second half of the winter, just in time for the traditionally coldest period of the year.
After reviewing current/recent ENSO values and those that are predicted into mid 2014, I have selected several previous years of reference for this year's winter outlook. These winter seasons (November-February) include:
(* indicates seasons with highest influence in this year's forecast)
A couple of these reference years, particularly, had some stretches of bitter cold and increased snowfall, 1978-79 and 1981-82, across most of the eastern half of the U.S. This does have an implication into the forecast I am issuing. However, several of the other years utilized help to subdue those year's impacts to some degree. I am following a similar pattern, though, of these winters. That implies, the coldest temperatures, with reference to normal, will affect the northern Plains into the Mid-Mississippi and western Ohio Valleys. Overall, temperatures are likely to be near to slightly below normal for much of the U.S. east of the Rockies with only a slim area of "slightly above normal" for portions of the South and along the Eastern Seaboard.
Valley and some ridging off the East Cost, I am forecasting an increased number of "Clipper" like systems dropping southeast out of the Plains of Canada into the Heartland and then making the turn along the Eastern Seaboard. This will provide a risk of above normal snowfall for much of the Mississippi Valley and Upper Midwest and also from the Deep South northeastward along the Appalachians. Additionally, several of these will have the ability to develop into a Nor'Easter which could easily skew forecast snowfall from the Mid-Atlantic to New England and west into the interior Appalachians.
Regionally Specific Snowfall Forecasts
For city specific total winter snowfall for 2013-14, please refer to the individual regional forecast groups. The map to the right provides a geographic highlight of the individual regions for reference.