NOAA predicts a near-normal Atlantic hurricane season

By: Dr. Jeff Masters , 9:17 PM GMT on May 24, 2012

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NOAA forecasts a near-normal Atlantic hurricane season in 2012, in their May 24 outlook. They give a 50% chance of a near-normal season, a 25% chance of an above-normal season, and a 25% chance of a below-normal season. They predict a 70% chance that there will be 9 - 15 named storms, 4 - 8 hurricanes, and 1 - 3 major hurricanes, with an Accumulated Cyclone Energy (ACE) 65% - 140% of the median. If we take the midpoint of these numbers, NOAA is calling for 12 named storms, 6 hurricanes, 2 major hurricanes, and an ACE index 102% of normal. This is very close to the 1981 - 2010 average of 12 named storms, 6 hurricanes, and 3 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2011 have averaged 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 153% of the median. Only five seasons since 1995 have not been above normal--including four El Niño years (1997, 2002, 2006, and 2009), and the neutral 2007 season.


Figure 1. The strongest Atlantic hurricane of 2011, Ophelia, as seen at 1:40 pm EDT October 1, 2011. At the time, Ophelia was a Category 3 hurricane with 120 mph winds. At 11 pm that night, Ophelia peaked at Category 4 strength with 140 mph winds. Image credit: NASA.

The forecasters cited the following main factors that will influence the coming season:

1) Near-average sea surface temperatures (SSTs) are expected in the hurricane Main Development Region (MDR), from the Caribbean to the coast of Africa between between 10°N and 20°N. SSTs in the MDR during April were near-average, and are expected to remain so during hurricane season, based on current observations, climatology, and long-range model forecasts.

2) We are in an active period of hurricane activity that began in 1995, thanks to a natural decades-long cycle in hurricane activity called the Atlantic Multidecadal Oscillation (AMO): "During 1995-2010, some key aspects of the tropical multi-decadal signal within the MDR have included reduced vertical wind shear and weaker easterly trade winds, below-average sea-level pressure, a configuration of the African easterly jet that is more conducive to hurricane development from tropical cloud systems (aka Easterly waves) moving off the African coast, and warmer than average SSTs."

3) An El Niño event may occur this year: "Another climate factor known to significantly impact Atlantic hurricane activity is the El Niño-Southern Oscillation (ENSO.) The three phases of ENSO are El Niño, La Niña, and ENSO-Neutral. El Niño events tend to suppress Atlantic hurricane activity, while La Niña events tend to enhance it (Gray 1984). If El Niño fails to develop, the probability of an above-normal Atlantic hurricane season will be higher and the actual seasonal activity will likely be toward the upper end of our predicted ranges." There is currently of lot of uncertainty whether or not an El Niño event will develop in time for the August - September - October peak of hurricane season--the latest NOAA El Niño discussion is giving a 41% chance of an El Niño event during hurricane season, and a 48% chance of neutral conditions.

4) NOAA is increasingly using output from ultra-long range runs of the computer forecast models we rely on to make day-to-day weather forecasts, for their seasonal hurricane forecasts: "The outlook also takes into account dynamical model predictions from the NOAA Climate Forecast System (CFS), the European Centre for Medium Range Weather Forecasting (ECMWF), the United Kingdom Meteorology (UKMET) office, and the EUROpean Seasonal to Inter-annual Prediction (EUROSIP) ensemble. These models show large spreads in the ENSO forecasts for ASO, ranging from ENSO-Neutral to a moderate-strength El Niño episode. As a result, their forecasts for the Atlantic hurricane season also show a considerable spread, ranging from slightly above normal to slightly below normal."

How accurate are the NOAA seasonal hurricane forecasts?
A talk presented by NHC's Eric Blake at the 2010 29th Annual AMS Conference on Hurricanes and Tropical Meteorology studied the accuracy of NOAA's late May seasonal Atlantic hurricane forecasts, using the mid-point of the range given for the number of named storms, hurricanes, intense hurricanes, and ACE index. Over the past twelve years, a forecast made using climatology was in error, on average, by 3.6 named storms, 2.5 hurricanes, and 1.7 intense hurricanes. NOAA's May forecast was not significantly better than climatology for these quantities, with average errors of 3.5 named storms, 2.3 hurricanes, and 1.4 intense hurricanes. Only NOAA's May ACE forecast was significantly better than climatology, averaging 58 ACE units off, compared to the 74 for climatology. Using another way to measure skill, the Mean Squared Error, May NOAA forecasts for named storms, hurricanes, and intense hurricanes had a skill of between 5% and 21% over a climatology forecast. Not surprisingly, NOAA's August forecasts were much better than the May forecasts, and did significantly better than a climatology forecast.


Figure 2. Mean absolute error for the May and August NOAA seasonal hurricane forecasts (1999 - 2009 for May, 1998 - 2009 for August), and for forecasts made using climatology from the past five years. A forecast made using climatology was in error, on average, by 3.6 named storms, 2.5 hurricanes, and 1.7 intense hurricanes. NOAA's May forecast was not significantly better than climatology for these quantities, with average errors of 3.5 named storms, 2.3 hurricanes, and 1.4 intense hurricanes. Only NOAA's May ACE forecast was significantly better than climatology, averaging 58 ACE units off, compared to the 74 for climatology. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

I'll have an update on Hurricane Bud and Invest 94L Friday morning.

Jeff Masters

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Quoting LargoFl:
it was strange last night, the storms were coming down the coast, right towards largo,madiera beach etc, then stopped, and moved east out into the bay and sat there, while yet another one, sat on top of st Pete and dumped tons of rain..as the storms died out, I got just enough rain, to slightly wet the grass..gee



It was strange! I thought we were going to get hammered or at least get something out of it. I have noticed St Pete gets hit a lot lately and points north of here like Clearwater as well.
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Quoting StormTracker2K:


any rain by you yesterday afternoon?
just enough to slightly wet the grass, although st pete got almost 5 inches in almost an hour gee
Member Since: August 6, 2011 Posts: 4 Comments: 42120
Quoting intampa:
hmmm does this "predicted" track mean tampa bay may get skunked on the rainfall...
if the track holds we will be on the south side of it,maybe thats why they have us at a 50% chance of rain..this storm is going to be a rain maker with some wind.outside of it forming in may, its no big deal..50 mph maybe 60 mph gusts at times up in north florida..but hopefully tons of rain..north florida needs it badly, dunno if the fires are still going on up there
Member Since: August 6, 2011 Posts: 4 Comments: 42120
AL 94 2012052506 BEST 0 281N 781W 30 1009 LO
AL 94 2012052512 BEST 0 314N 763W 30 1011 LO
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Quoting icmoore:
Not a drop of rain last night in Madeira Beach although Mother Nature provided quite a light show and the radar was lit up all around the area.
it was strange last night, the storms were coming down the coast, right towards largo,madiera beach etc, then stopped, and moved east out into the bay and sat there, while yet another one, sat on top of st Pete and dumped tons of rain..as the storms died out, I got just enough rain, to slightly wet the grass..gee
Member Since: August 6, 2011 Posts: 4 Comments: 42120
700mb


925mb


1000mb (Surface)


Click images for lagers image.
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Quoting ILwthrfan:

Yeah, it's really sad, I used to watched that channel and that channel only...lol as I was growing up as a kid in the late 80's and 90's. Now it's a complete joke.


Exactly, whenever I do turn it on it is usually two giggly anchors barely talking about weather. They will talk about cars, grilling tips, flowers etc. etc. and when they do talk about weather, they have like 2 minute left before a commercial break. Forbes is about all that is left of the golden era, and the only one I have ever seen put arrogant Jim Cantore in his place.
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Quoting biff4ugo:


and Of those 6, 4 hit Florida...Charley, Frances,Ivan, Jeanne. Some more than once.


Yeah, Ivan's track still makes me laugh a bit. Looks like something drawn as a joke on here.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Quoting NICycloneChaser:


2004 Season:

Of 15 named storms, 8 either made landfall on the US, or brought storm force conditions to the US (Alex, Bonnie, Charley, Frances, Gaston, Ivan, Jeanne, Matthew).

Of these 8, 6 were hurricanes at landfall/closest pass (Alex, Charley, Frances, Gaston, Ivan, Jeanne).


and Of those 6, 4 hit Florida...Charley, Frances,Ivan, Jeanne. Some more than once.
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Oh and Jeff... I'm not kidding..

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Quoting jeffs713:

Please tell me you are kidding...

Its getting ripped apart by shear, filled with dry air, has no evident CoC... we're magically going to get a TS? Wow.


Good model support, weakening shear, and a 70% probability from the NHC means it's fairly likely that it will become TS Beryl. Far from a foregone conclusion, but it's likely. Not magic, just how the weather works.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Quoting jeffs713:

Please tell me you are kidding...

Its getting ripped apart by shear, filled with dry air, has no evident CoC... we're magically going to get a TS? Wow.


Ok Jeff, then if you believe I'm crazy, you must believe the officials are to.. a 70% chance for development over the next 48 hours. Conditions are EXPECTED to become much more favorable (per NHC) for development.
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Quoting MrstormX:


That died years ago buddy, it is now the home and life network. Even the weather talk is completely dumbed down and inadequate.
Yeah, it's really sad, I used to watched that channel and that channel only...lol...as a kid when I was growing up in the late 80's and 90's.  Now it's a complete joke.
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Quoting StormTracker2K:
I would not be surprised if the US see's a lot of landfalling Tropical Systems this year as we have been very lucky in regards to the lack of storms hitting the US for the last several years. Weak El-Nino tends to favor this. 2004 featured I believe 15 named storms but most hit the US that year and that was an El-Nino year.


2004 Season:

Of 15 named storms, 8 either made landfall on the US, or brought storm force conditions to the US (Alex, Bonnie, Charley, Frances, Gaston, Ivan, Jeanne, Matthew).

Of these 8, 6 were hurricanes at landfall/closest pass (Alex, Charley, Frances, Gaston, Ivan, Jeanne).
Member Since: August 10, 2010 Posts: 2 Comments: 1971
june 5th 2012 venus will cross in front of the sun,this only happens every few hundred years and happens in pairs about 8yrs apart,so it happened in 2004 and will happen again this june 5th.Im a big believer that everything is connected to the cosmos,IMO this years pattern will be almost identical to 2004 tc season patternwise.
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Quoting reedzone:
As Beryl forms tomorrow, it will be a historical storm.. Historical in being the second named storm before the official start date since 1887..

Please tell me you are kidding...

Its getting ripped apart by shear, filled with dry air, has no evident CoC... we're magically going to get a TS? Wow.
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Quoting MrstormX:


That died years ago buddy, it is now the home and life network. Even the weather talk is completely dumbed down and inadequate.


Like listening to John Madden talk about football. :-)
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712. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #31
SEVERE TROPICAL STORM SANVU (T1202)
21:00 PM JST May 25 2012
=================================

SUBJECT: Category Two Typhoon In Sea South Of Japan

At 12:00 PM UTC, Severe Tropical Storm Sanvu (975 hPa) located at 23.7N 139.9E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The cyclone is reported as moving north northeast at 7 knots.

Dvorak Intensity: T3.5

Storm Force Winds
=================
40 NM from the center

Gale Force Winds
================
170 NM from the center in northeastern quadrant
130 NM from the center in southwestern quadrant

Forecast and Intensity
=========================

24 HRS: 25.5N 142.6E - 60 knots (CAT 2/Severe Tropical Storm)
48 HRS: 28.5N 146.9E - 50 knots (CAT 2/Severe Tropical Storm)
72 HRS: 33.0N 152.9E - 45 knots (CAT 1/Tropical Storm)
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Quoting lobdelse81:
I see that on TWC they are now demonstrating cooking utensils for the holiday weekend. What ever happened to weather-related stuff, lol? I almost thought it was an info-mercial


That died years ago buddy, it is now the home and life network. Even the weather talk is completely dumbed down and inadequate.
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Quoting lobdelse81:
I see that on TWC they are now demonstrating cooking utensils for the holiday weekend. What ever happened to weather-related stuff, lol? I almost thought it was an info-mercial
Yeah, the "W" in "TWC" nowadays means about as much as the "M" in "MTV". But they're just giving the people what they want; I would imagine that somewhere in this huge nation, there's a group of barbecue enthusiasts that begged for less of that boring weather stuff and more outdoor grilling tips... :-\

Big heat wave in the Midwest expected this weekend, while winter still hangs around the northern Rockies; triple-digit temperatures are expected for parts of the Ohio River Valley. Next week, that flip-flops, with major heat in the Desert Southwest, but a temporary cooldown in the upper Midwest. By way of example: Madison, WI, is expected to reach 95 on Sunday, while Tuesday's high will be in the 60s.
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Just FYI

94L Floater
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As Beryl forms tomorrow, it will be a historical storm.. Historical in being the second named storm before the official start date since 1887..
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Not a drop of rain last night in Madeira Beach although Mother Nature provided quite a light show and the radar was lit up all around the area.
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hmmm does this "predicted" track mean tampa bay may get skunked on the rainfall...
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Looking NNW from Odessa, Fl shortly after receiving pea size hail at 7:26pm yesterday
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Quoting gatorchomp:
Good morning!

Nothing impressive about 94L yet, huh?

This things needs to do something interesting, fast!
look at the latest visible its starting to get its act together quick
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I see that on TWC they are now demonstrating cooking utensils for the holiday weekend. What ever happened to weather-related stuff, lol? I almost thought it was an info-mercial
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701. 7544
Quoting K8eCane:
I think we are seeing history in the making! 94L will have an unprecedented track


yeap it be fun to see where the west turn takes place and how strong it will be and if we could get our B strom to make two in may wait watch and see
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Quoting severstorm:
Morning, West coast of FL finally got a lot of rain, zephyrhills is still high and DRY go figure.
Good thing you have springs :p
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I think we are seeing history in the making! 94L will have an unprecedented track
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I hope the predictions are right. We are desperate for rain.
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Quoting BahaHurican:
Morning CI... from your house to mine.... lol Looks like we'll be dealing with this off and on all day...



my parents said there was a huge storm at around 4:30 this morning. There was another mini one at around 7ish that I heard. Had I not have school today, I'd still be sleeping -_-

Good morning erryone! Expecting more crappy weather today.
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NHC is going to have to move their circle north and i think they will go to 80% when they do.
Member Since: February 11, 2012 Posts: 0 Comments: 9760
Quoting Cayman2010:
Good morning CI, yes we had thunderstorms most of the night and it certainly doesn't look to be going anywhere fast.
I know. It is very overcast still and looks just about stationary. Looks like moisture moving into the Caribbean down around Panama.
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Quoting Grothar:


This image is a few minutes old,so I expect the centerto be a few feet further North.



Posting old maps again I see, sheesh Gro?

I see the red circle has expanded quite a bit to the South. Trailing energy has to make you wonder.
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Morning, West coast of FL finally got a lot of rain, zephyrhills is still high and DRY go figure.
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Good morning all.
Very close shave by a newly discoverd asteroid on Monday. 2012KP24 will pass .1 lunar distance from earth. At 26 meters across one this size probably wouldn't make it to the surface but it could make quite an explosion.

Link

Link
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Quoting stormwatcherCI:
Good morning. I think you are right. We have had a couple heavy showers already this morning. Doesn't seem to be going anywhere too fast.
Good morning CI, yes we had thunderstorms most of the night and it certainly doesn't look to be going anywhere fast.
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Quoting StormTracker2K:
This piece of energy hanging back in the NW Caribbean could form another tropical system come mid next week. The models have been showing this on and off now for a week.

if 94 gets cranking it might suck in all that "leftover" moisture from the nw carib.
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Quoting StormTracker2K:
This piece of energy hanging back in the NW Caribbean could form another tropical system come mid next week. The models have been showing this on and off now for a week.

One thing the models have been consistent with though is lowering pressures.Which leads to more convection.
Member Since: August 14, 2010 Posts: 10 Comments: 17814
I would not be surprised if the US see's a lot of landfalling Tropical Systems this year as we have been very lucky in regards to the lack of storms hitting the US for the last several years. Weak El-Nino tends to favor this. 2004 featured I believe 15 named storms but most hit the US that year and that was an El-Nino year.
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This piece of energy hanging back in the NW Caribbean could form another tropical system come mid next week. The models have been showing this on and off now for a week.

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Quoting Autistic2:
Is there a center of circulation forming anywhere for 94? All I can see is a big blob.


This image is a few minutes old,so I expect the centerto be a few feet further North.

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Quoting LargoFl:


any rain by you yesterday afternoon?
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94? a big one. the drought smasher?
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Quoting BahaHurican:
Morning CI... from your house to mine.... lol Looks like we'll be dealing with this off and on all day...

Good morning. I think you are right. We have had a couple heavy showers already this morning. Doesn't seem to be going anywhere too fast.
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Member Since: July 6, 2010 Posts: 113 Comments: 32830

Good Morning.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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