The Only Certainty in the Winter Outlook is the UncertaintyOctober 18th, 2012 at 8:06 pm by Don Paul under 4 Warn Weather
We are, frankly, in scientific nowheresville when it comes to the predictability of the upcoming winter. NOAA/CPC issued their new Winter Outlook this afternoon (October 18th), and we have seen quite a change from previous CPC outlooks for the eastern U.S. from modest anomalies projecting a warmer than average winter to what most our bloggers have seen before–”EC”. That’s Equal Chances. It could go either way, temperatures and precipitation. That’s tied to what I’ve been posting about for some weeks now. In layman’s terms, it’s the lack of anything upon which to hang a hat. We’ve gone from modeled projections of a weak to moderate el nino which was supposed to have set up by late summer to a currently nonexistent el nino (neutral ENSO). Many models are still projecting a limited chance for a weak el nino to develop this autumn and then fade away in the winter. But there is no sign of that happening at this time.
IMPO, the CPC had no choice but to broaden the EC coverage because of the neutral ENSO, and because other models they use show only a modestly better than even chance for milder than average conditions in parts of the central and western US, with a stronger chance of warmer than average temperatures in northern Alaska in November, and in the Alaska panhandle in Dec-January. With the unpredictability of the NAO, AO, PNA, and MJO beyond a couple of weeks, the uncertainties in the east central and much of the eastern US have increased. CPC was hoping for a better el nino signal so they could at least tie into el nino climatology. Without even that weak signal, EC was definitely the way to go. It probably won’t be until we get very close to the cold weather season when we can even venture a guess as to whether or not a prevalent trend may begin to show for the AO and/or the NAO.
As I’ve posted several times, research done by Bob Hamilton of the NWS Buffalo Office shows that weak el ninos tend to be associated with normal to below normal temperatures in WNY winters, with no correlation shown for snow. However, the original date of his research was in 2004, when Judah Cohen’s work was in its infancy, and even less was known about the MJO than is known now–which isn’t that much. The other variables being unknowns at this point reinforces the need for EC locally as well, even if that’s not what most of the public wants to hear. WE. DON’T. KNOW.