Saturday, May 31, 2014

Six Key Questions for the 2014 Atlantic Hurricane Season

By: Dr. Jeff Masters , 3:18 PM GMT on May 30, 2014
The 2014 Atlantic hurricane season is officially underway on Sunday, June 1. What will this year's hurricane season bring? My top six questions for the coming season:

1) When will the first "Invest", tropical depression, and named storm of the 2014 Atlantic hurricane season form? We have a chance of all three of these events occurring in the Gulf of Mexico during the first week of hurricane season, though the models are currently hazy about this. An area of disturbed weather in the Eastern Pacific located a few hundred miles south of Southeast Mexico is forecast to move slowly northwards towards the Gulf of Mexico Sunday through Tuesday. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this system a 50% chance of developing into a tropical depression or tropical storm by Wednesday. The 06Z Friday run of the GFS model predicts that this disturbance will make landfall in Southeast Mexico on Tuesday, then spread moisture northwards over the Gulf of Mexico late in the week. The model predicts that wind shear will be light to moderate over the Gulf late in the week, potentially allowing the disturbance to spin up into a tropical depression. The 00Z Friday run of the European model has a different solution, predicting that the Eastern Pacific tropical disturbance will remain south of Mexico through Friday. However, the model suggests that moisture streaming into the Gulf of Mexico late in the week will be capable of spawning an area of low pressure with the potential to develop in the Southern Gulf of Mexico's Bay of Campeche. In any case, residents of Southeast Mexico and Western Guatemala appear at risk to undergo a multi-day period of very heavy rainfall capable of causing flash flooding and dangerous mudslides beginning as early as Monday. This disturbance may cross over Mexico and into the Gulf of Mexico and create the Atlantic's first "Invest" with the potential to develop late in the week, sometime June 5 - 7.


Figure 1. Satellite image taken at 7:45 am EDT Friday May 30, 2014, showing an area of disturbed weather a few hundred miles south of Southeast Mexico. Will this disturbance cross over into the Gulf of Mexico and create the Atlantic's first "Invest" of 2014 late in the week? Image credit: NASA/GSFC.

2) All of the major seasonal hurricane forecasts are calling for a below-average to near-average season, with 9 - 12 named storms, 3 - 6 hurricanes, and 1 - 2 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2013 averaged 15 named storms, 8 hurricanes, and 4 major hurricanes. Will an El Niño event indeed arrive, bringing reduced Atlantic hurricane activity, allowing the pre-season predictions to redeem themselves after a huge forecast bust in 2013?

3) How will the steering current pattern evolve? El Niño years tend to feature more storms that recurve out to sea and miss land; will this be the case in 2014?

4) Will the U.S. break its 2006 - 2013 eight-year run without a major hurricane landfall, the longest such streak since 1861 - 1868?

5) Will the 170,000 people still homeless and living in makeshift shelters in Haiti in the wake of the January 2010 earthquake dodge a major tropical cyclone flooding disaster for the fifth consecutive hurricane season?

6) Will the new experimental National Hurricane Center products be useful and popular? I am most looking forward to the Potential Storm Surge Flooding Maps, interactive zoomable maps that will show where the storm surge has a 10% chance of inundating the coast at 3, 6, and 9 feet above ground level. The new NHC blog (first post: May 29, 2014) and 5-day graphical weather outlook (begins July 1) should also be of interest.


Figure 2. Sample experimental NHC Potential Storm Surge Flooding Map for the Texas coast for a fictional hurricane (not Hurricane Ike), generated using using NOAA's Probabilistic Hurricane Storm Surge (P-Surge 2.0) model. P-Surge 2.0 uses multiple runs of the NWS Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model to create an ensemble of possible inundations, by varying the hurricane's landfall location, intensity, size, forward speed, and angle of approach to the coast. The image shows where the storm surge has a 10% chance of inundating the coast at 3, 6, and 9 feet above ground level. The model does not take into account wave action, freshwater flooding from rainfall, and breaching or overtopping of levees.

Cosmos takes on Climate Change
The groundbreaking Fox and National Geographic Channel series Cosmos, hosted by Neil DeGrasse Tyson, has been attracting more than 3 million viewers every Sunday night--an impressive tally for a science-based show. Cosmos has been unafraid to confront controversy, taking on creationism and industry-funded science denial, for example. This Sunday, June 1, at 9 pm EDT/8 pm CDT, Cosmos takes on climate science deniers with a full 1-hour episode devoted to climate change. According to Chris Mooney of motherjones.com, who had a chance to preview the episode, "it contains some powerful refutations of a number of global warming denier talking points, as well as some ingenious sequences that explain the planetary-scale significance of climate change. It also contains some in-situ reporting on the impacts of climate change, straight from the imperiled Arctic." I'm looking forward to seeing the legacy of Carl Sagan continue this Sunday night. For those who miss it on Sunday, Cosmos also airs Monday, June 2nd at 9 pm EDT on National Geographic Channel, with additional footage.


Video 1. Neil DeGrasse Tyson uses the analogy of walking a dog on the beach to explain the difference between climate and weather, showing that no matter how cold your winter may have been, that's no argument against global warming. Tyson travels to the Arctic to explain global warming and its effect on thawing permafrost in this Sunday's Cosmos episode (9pm EDT/8 CDT.)

Have a great weekend, everyone, and I'll be back Monday with a new post--earlier if the disturbance in the EPac looks like a significant threat.

Jeff Masters

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