My hurricane forecast and Florida’s Severe Weather Outlook

The forecast is out by the National Hurricane Center and NOAA, but how exactly will this season work out…and more importantly, will you get hit?  Also, Invest 94L is better developed and it looks like there will be a second storm this month before hurricane season begins.  The air outside is ripe enough to wear, does that mean severe weather today? Find that out below as well.

National Oceanic and Atmospheric Administration — Hurricane Forecast:

The Forecast, with a 70% confidence:

  • 9-15 Named Storms
  • 4-8 of which will become Hurricanes
  • 1-3 of which will become Hurricanes with winds of greater than 111 miles per hour

A point of accuracy with this forecast is that in fact it is a range of possibility with unabsolute confidence. Within the parameters of this blog I will not be breaking these numbers down to a single number because there is a loss of point associated with that reduction. What I do plan on doing is breaking down a general area that is more likely to get hit this hurricane season and the possible reasoning for the numbers above.

Point #1: The Atlantic “Main Development Region”, which is the area between the Caribbean Lesser Antilles and Africa, is cooler than normal. These anomalies are only slightly below normal, but they expand nearly two-thirds of this span. Cooler than normal water temperatures also reach into the Bermuda Triangle. The Gulf of Mexico  and the Caribbean are generally at average and a few isolated spots are above average. Oceanic Heat Content, the variable that really drives the strongest tropical cyclones, is on track to be on average this season.

  • Why it matters: Cooler temps out in the MDR may keep storms from developing out there, and allow development closer to home.

Point #2: The development of El Nino. The Climate Prediction Center is currently forecasting a slow development of El Nino near the peak of the hurricane season, which occurs during the first half of September. I believe based on looking at the models released by the CPC that this transition from neutral to El Nino may come slower than currently forecast. With El Nino, an increase in vertical shear is soon to follow, which limits hurricane potential. Also found with El Nino is slightly drier and more stable air in the Caribbean.

  • Why it matters: higher shear and drier air later in the season may “front-load” the season and slow down the frequency in storms later in the season, which would allow for a peak more likely in August rather than in September. Higher shear may also limit the number of stronger storms such as category 3, 4, and 5 hurricanes.

Point #3: The Atlantic Multi-Decadal Oscillation may begin to wind down over the next few years. The most recent uptick in AMO began in 1995, peaked in 2005 with 28 named storms and generally AMO upticks last between 15 and 20 years. This is purely climatological evidence, but it could have meteorological impacts over the next few years.

  • Why it matters: The general number of named storms may very gradually drop over the next 10-15 years as the AMO drops.

Point #4: Better detection of weak tropical storms and better observing of all cyclones. Although the effects of a subtropical storm and an unnamed summertime storm may be exactly the same to the normal person, when scientists look at the data 10 years from now they will look at final numbers, and that is where the difference is. Small, weaker tropical storms are being named, and hurricanes are being better analyzed. Also, new to the Atlantic this year is a hurricane hunter unmanned drone, which has been in testing over the last couple of years. I have been told that this year will be the first year that the drone will be in use operationally, but there has been no press release on this yet, so I’m not entirely sure that this will be the case. I will be investigating this over the next couple of weeks. This drone has a much larger range in reach across the Atlantic and can stay in hurricanes much longer than the normal Hurricane Hunters can due to less fuel use.

  • Why it matters: Weaker storms and storms that are not close to the USA may get named this year, which may boost the long term average by a storm or two.

The Real Point #1: It only takes one storm to make a hurricane season. This year is the 20th anniversary of Hurricane Andrew, which struck south Florida in August of 1992 and continues to be one of the most recognized names across the US. From the bent trees at Islands of Adventure’s Suess Landing, which were recovered after Andrew in Dade County, to the huge increase in building codes which are still in effect across most of the Florida coastline…Andrew continues to impact life in Florida, if nothing else than a reminder that IT ONLY TAKES ONE!

The Real Point #2: The time is NOW to prepare. Over the next few days I will be gathering data on local news hurricane specials and regional hurricane expos. I challenge each of you to watch at least one special or attend one expo. I will post these above in the active notices section.

Invest 94L — An Update:

Invest 94L is still a lopsided area of low pressure with winds of roughly 35 mph, mainly removed from the 1011 millibar center to the east. The center of circulation is located about 350 miles north-northeast of Grand Bahama. 94L continues to reside along a very elongated area of low pressure in an area of 60-70 mph upper-level shear, which generally is prohibitive of any development, but 94L is persistent. The NHC has given 94L a 70% chance of development within 48 hours. I believe that the window truly opens in about 12-24 hours when shear takes a nose dive down to about 15-25 mph. 94L will have about 24 hours before that window closes to become tropical storm Beryl. This will most likely occur somewhere off the coast of the Carolinas.  With the consistent shear and current organization, I am expecting 94L to make numerous relocations over the next 18 hours.

When the models latched on to the current center this morning they were trending toward a hybrid case between the two cases I showed yesterday, in which Beryl would move northward through tomorrow afternoon along mean flow. After that point, high pressure over the US will build in and shunt the low pressure center to the southwest toward South Carolina or Georgia.  Exactly where that turn occurs and how early will depend on the location of landfall.

The impacts of 94L are yet to be determined, but heavy rain over the Carolinas, Georgia, and north Florida is likely a good bet.

Hurricane Hunters will be in 94L around this time tomorrow in time for the above mentioned window to open.

Eye on Florida:

Based on yesterday’s hail around the area and tornado in North Port, I am forecasting that there is an isolated chance of severe weather this evening along the sea breeze. The sea breeze tonight could very well be stronger than normal this evening with the energy that is out there. Drier air north of Tampa Bay and across south Florida should limit activity there, but the conditions are good to go for an area from Ruskin down to Everglades City along the coast after 4pm.

If you have any pictures from yesterday’s severe weather or today’s storms, tweet me @JonathanBelles and I will host your pictures here.



Posted on Friday, May 25th, 2012, in Florida Weather, Severe Weather, Tropical Weather. Bookmark the permalink. 2 Comments.

  1. Hey Jonathan, I have to say I’m lovin this blog. I’ve been reading all of them hah. Keep up the good work man. Very informative and fun to read. Btw, I found another really good blog about Florida weather: ..for a fellow Florida weather follower : )


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