Tiffany's Weather Blog

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.

As a basic piece of protective gear, helmets save bikers, climbers, and all manner of athletes from fatal injury every day. Prepare to add storm goers to that list.

While the thought of grabbing a helmet during severe weather may seem outlandish to some, one 8-year old Oklahoman storm survivor owes his life to the hard-shelled hat.

Emergency officials have yet to endorse helmet use, but given that the majority of tornado-related deaths result from head and neck injuries, a helmet seems a logical protective measure. (Not to mention it's more durable than using one's bare arms--the current accepted method.) In any case, it certainly can't do any harm. Adding a helmet to safety preparations might even help residents feel a bit more secure when those tornado sirens do sound up.

What do you say: ill-advised or ingenious?

Take the poll

This past week, NOAA and FEMA urged the nation's public to educate their families and neighbors on severe weather risks, as well as to take immediate action when severe weather hits. The requests were main themes of the very first National Severe Weather Preparedness Week.

It's no coincidence that the SWPW's dates just happen to align with last year's April 25-28 super tornado outbreak--one of the largest in U.S. history--during which a confirmed 358 tornadoes wreaked havoc across 21 states over a mere 3 days. Like the tornado warning updates put into practice earlier this month, Severe Weather Preparedness Week is the latest attempt at remedying the public's often blasé attitude on severe weather threats. If successful, such campaigns could protect against the future loss of 325 lives and $11 billion in damages, the likes of which were seen last April.

Are you sometimes guilty of taking storm warnings 'with a grain of salt'? If so, make a pledge to yourself and your loved ones to start being more weather aware.

While Earth Day may have roots dating back to the late 1960s, there's never been a time when its cause--raising political awareness of environmental concerns around the globe--has held more significance.

What acts of green will you participate in? Visit earthday.org for scheduled events, and be sure to share your plans in the comments section!

For residents across the Central U.S., it was indeed an unlucky Friday the 13th. Nearly 200 preliminary tornado reports were logged for the Central and Great Lakes regions of the U.S. for April 13-16, 2012. Woodward, OK was one of the hardest hit areas; a deadly EF-3 storm roared through the town near midnight on April 15, claiming 6 lives. Casualties could have been much higher if not for the Storm Prediction Center (SPC). Thanks to their efforts, severe weather forecasts came nearly 2 days prior--the second time in U.S. history that the center has successfully issued high risk warnings more than 24 hours in advance.

Update: As of April 20, 71 tornadoes have been confirmed. This count includes: 33 EF-0, 19 EF-1, 3 EF-2, 5 EF-3, and an EF-4 storm near Marquette, KS; the 10 additional storms have not yet been assigned an intensity rating.

100 years ago to the day, the grandiose R.M.S. Titanic passed honorably beneath the icy waters of the North Atlantic. You may be asking yourself what does weather have to do with the Titanic? Well, besides my personal fascination with the event, the answer is quite a lot actually. Based on historic ship weather records and investigative accounts for April 14-15, 1912, it is believed that the night's seemingly fair conditions--clear skies, cold temperatures, variable winds, and light fog--were a catalyst for the ship's demise. Had Arctic high pressure not created a placid, glassy ocean surface and a still black-lit horizon, visual signs of surrounding icebergs may have been easier to spot at a greater distance.

Even if you consider yourself to be "weather challenged," chances are you probably know that weather warnings are meant to alert of danger from an approaching storm. But when it comes to a tornado warning, this same line of thinking isn't necessarily true. Because tornado warnings can be issued if rotation within a thunderstorm (not necessarily a tornado itself) is detected, tornado "false-positives" frequently result. While issuing a warning prior to actual development allows additional evacuation time in the event that a tornado does form, it has also desensitized residents in locations prone to tornadic activity. In an effort to eliminate this "cry wolf" effect, the NWS is now beta-testing a new form of warning.

The new warnings, which took effect April 2, will look much the same except for the below addenda which are meant to convey an additional level of urgency:

Tornado...Possible
Tornado...Radar Indicated
Tornado...Observed

Tornado Damage Threat...Significant
Tornado Damage Threat...Catastrophic

For now, only the following NWS Forecast Offices will participate:

Wichita, KS
Topeka, KS
Kansas City/Pleasant Hill, MO
Springhill, MO
Saint Louis, MO

The experiment will run through late fall. After results are analyzed, a decision will be made as to whether or not the new system will take permanent effect across the U.S.

Image: A mesocyclone tornado © NOAA