A mere 12 hours after being declared a tropical depression, Tropical Storm Aletta formed Monday evening in the east Pacific Ocean. It is the basin's first of the 2012 season (which by the way, doesn't officially start until today, May 15). Since hurricane records began in 1949, only 2 other storms have reached tropical storm strength at such an early date: Hurricane Alma (1990) and an unnamed 1996 storm.

While Aletta may strengthen through Tuesday, it's unlikely the storm will reach hurricane strength. It is forecast to continue tracking west over open waters, therefore posing no threat to land areas.

Yes...it's that time of year again! Tomorrow kicks off the first day of the Eastern Pacific hurricane season. Even at this early date, the waters are already teeming with convective activity. The above is a satellite image of an area of disturbed weather roughly 600 miles (966 km) southwest of Manzanillo, Mexico. The system has become better organized over the last 24 hours and stands a 60% chance of becoming a tropical cyclone within the next 2 days, advises the National Hurricane Center (NHC).

In another few weeks, the other basin monitored by NHC officials, the Atlantic, will fire up. Hurricanes occurring in the central Pacific share a June 1 season start with that of the Atlantic, but monitoring responsibilities for these storms falls under NOAA's Central Pacific Hurricane Center (CPHC). All three seasons share a close date of November 30.

Image credit: NASA

Cooler-than-normal sea surface temperatures (SSTs) have begun warming across the equatorial Pacific Ocean, signaling the end of a nearly 2-year La Niña event. According to Climate Prediction Center (CPC) model forecasts, ENSO-neutral conditions (that is, no active La Niña or El Niño) will now resume, with a near 50% chance of El Niño building by mid-summer/early fall.

There are generally two times a year when all eyes turn toward ENSO conditions: winter and hurricane season. If the CPC forecast proves accurate, El Niño's warmer-than-normal ocean waters could mean increased hurricane activity in the eastern Pacific. Since El Niño tends to increase wind shear (a "hurricane killer") across the Atlantic, a decline in activity may be in store for the Atlantic, Caribbean, and Gulf waters.

A nationally-averaged temperature of 55 °F (3.6 °F above normal) ranks April 2012 as the third warmest April, says NOAA's National Climatic Data Center.

At first glance, this news may pale in comparison to last month's reveal as the warmest March since record keeping began in 1895; however there's a deeper significance behind April's warmth. With January, February, and March all boasting above average temperatures, April is the addition that tips the scale. It qualifies 2012 as the warmest year (to date) and the period of May 2011-April 2012 as the warmest 12-month period ever. (The previous record for warmest 12-month period was November 1999 to October 2000.) Kind of gives new meaning to the expression "hot streak" don't you think? It also raises two quintessential questions: why is this occurring and can we expect more of the same?

The warm winter and spring are largely attributed to the Arctic and North Atlantic Oscillations (climate patterns that describe pressure differences in northern latitudes and their effects on temperature and storm tracks). All winter long, one of these two has been extremely positive (positive values are equated to the retreat of cold arctic air and the jet stream far north of U.S. territory). Could climate change also be to blame for this winter's extreme deviation? Quite possibly.

As for whether or not the heatwave will continue, the Climate Prediction Center suggests temperatures will turn a touch more seasonable, especially for the upper tier of the U.S. However, for lower tier states there's a 33-50% chance that temperatures will remain above the 1981-2010 average.