You've asked a good question and the short answer is that there is very little correlation between current SSTs and those that can be expected later in the year. An oceanographer could probably do a better job with the answer, but large scale circulations (ocean currents) in the Atlantic Ocean are really the driving force behind SST forecasts.

A couple of definitions from CSU:

Atlantic Multi-Decadal Oscillation (AMO) â€“ A mode of natural variability that occurs in the North Atlantic Ocean and evidencing itself in fluctuations in both sea surface temperature and sea level pressure fields. The AMO is likely related to fluctuations in the strength of the thermohaline circulation.

Thermohaline Circulation (THC) â€“ A large-scale circulation in the Atlantic Ocean that is driven by fluctuations in salinity and temperature. When the THC is stronger than normal, the AMO tends to be in its warm (or positive) phase.

Yes, we could indeed have a warm Spring and make up the difference in the near shore local SSTs and in fact the latest SST Outlook (Jan 31st) does call for neutral SST anomalies in the Gulf of Mexico and the western Atlantic. However, SST anomalies in the eastern Atlantic, which were much above normal last year, are expected to be neutral this year during the 2011 hurricane season and this usually translates into fewer named storms than the activity that we saw in 2010.

Your last statement is still very correct in that forecasting SSTs is one of the more difficult and least accurate forecasts. There are still indications in the SST outlook that the current La Nina will be a multi-year event.
Cheers,
ED