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 TropicalAnalystwx13:
I just have a feeling it will look much better organized when I wake up in the morning.

Here is what it was at 2pm..........Last advisory update: 2:00 PM EDT, Thu May 24 2012
Lat: 25.3 N Long: 80.4 W
Winds: 40 mph (35 knots)
Pressure: 29.77 inches (1008 mb
Member Since: August 6, 2011 Posts: 4 Comments: 39349
Personally think the low is east of Biscayne Bay.
Member Since: August 19, 2005 Posts: 5 Comments: 5450
Quoting K8eCane:
It was 1984 we got hit twice by Diana. It had a funny track, but not like this one



Beryl would give NC a day or 2 in between.
Member Since: February 11, 2012 Posts: 0 Comments: 9731
From an April blog by Dr. Masters:

Dr. Pat Fitzpatrick of the Stennis Space Center in Mississippi discussed how landfalling tropical storms and hurricanes can alleviate drought. The biggest winner tends to be the Southeast U.S. states of Florida, Georgia, South Carolina, and North Carolina, where about 20% - 50% of all droughts between 1960 - 2009 were busted by a landfalling tropical storm or hurricane. It is uncommon for Texas to see a drought busted; less than 10% of all Texas droughts have been ended by a hurricane or tropical storm. This occurs because the Southeast U.S. can receive heavy rains from hurricanes moving up the East Coast, or moving through the Gulf of Mexico, while relatively few storms track over Texas. Over the course of a year, hurricanes and tropical storms contribute 15 - 20% of rain along the Gulf Coast, and 3 - 16% along the East Coast. The length of a drought does not seem to affect whether a drought can be ended by a hurricane or not. Hurricanes have been able to end both short ( 12 month droughts) equally well.


He was saying how Alberto tended to bring heavy rains recently, but could Beryl take this drought busting role this year?
How much rain could N FL and S GA expect?
Member Since: February 11, 2012 Posts: 0 Comments: 9731
I just have a feeling it will look much better organized when I wake up in the morning.

Member Since: July 6, 2010 Posts: 113 Comments: 32292
Kinda contradicts this map, which was posted a couple hours earlier however.

Member Since: August 19, 2005 Posts: 5 Comments: 5450
OK.. My 5th year on here begins... Welcome back all!

My predictions 18-7-4... because nature has the upper hand over NHC or anyone else.. Bud was meant to peak at 90mph and Beryl was a 0% possibility just yesterday... Enjoy the season folks!!!
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Member Since: August 6, 2011 Posts: 4 Comments: 39349
It was 1984 we got hit twice by Diana. It had a funny track, but not like this one
Member Since: April 26, 2006 Posts: 5 Comments: 3210
Link

Brownsville Radar malfunction...or Cumulonimbowolves circling the victim
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Quoting cg2916:


I'm actually kind of skeptical as well on 94L. It's got a nice shot, but nothing's even close to guaranteed.


It certainly has a chance, and it does have reasonable model support, but a little east and the waters are too cool, a little west and it's over land... And with the decoupling going on at the minute, it can't be certain that it will ever become stacked again.

Health warning: I am not saying that 94L will not develop, just that it might not.
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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
559 PM EDT THU MAY 24 2012

FLZ042-048>051-242245-
CITRUS-HERNANDO-PASCO-HILLSBOROUGH-PINELLAS-
559 PM EDT THU MAY 24 2012

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR NORTHERN
PINELLAS...NORTHWESTERN HILLSBOROUGH...SOUTHERN CITRUS...WESTERN
HERNANDO AND WESTERN PASCO COUNTIES FOR A LINE OF STRONG
THUNDERSTORMS WITH HAIL AND STRONG WIND GUSTS VALID UNTIL 645 PM
EDT...

AT 558 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATES A
LINE OF STRONG THUNDERSTORMS LOCATED ALONG A LINE EXTENDING FROM
HOMOSASSA SPRINGS TO LAKE FERN...OR ALONG A LINE EXTENDING FROM
HOMOSASSA SPRINGS TO 7 MILES EAST OF TARPON SPRINGS...MOVING SOUTH AT
5 MPH WILL AFFECT CRYSTAL RIVER...CRYSTAL RIVER AIRPORT...OZELLO AND
HOMOSASSA SPRINGS.

GUSTY WINDS OF 45 TO 55 MPH CAN BE EXPECTED WHICH CAN CAUSE UNSECURED
OBJECTS TO BLOW AROUND...SNAP TREE LIMBS AND CAUSE POWER OUTAGES.
FREQUENT TO CONTINUOUS LIGHTNING IS EXPECTED. IN ADDITION TO THE
STRONG WINDS HALF INCH HAIL WILL BE POSSIBLE WITH THESE STORMS. TO
BE SAFE GO INDOORS IMMEDIATELY. IF CAUGHT OUTSIDE...FIND A LOW
SPOT...AND STAY AWAY FROM TALL OBJECTS. TORRENTIAL RAINS WILL REDUCE
VISIBILITY TO NEAR ZERO AND WILL CAUSE PONDING OF WATER ON ROADWAYS.

REPORT DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY OR TO YOUR COUNTY
EMERGENCY MANAGEMENT OFFICE.

&&

LAT...LON 2822 8286 2819 8283 2822 8278 2845 8268
2859 8267 2869 8268 2871 8273 2875 8270
2878 8272 2878 8274 2892 8271 2888 8236
2797 8255 2801 8284 2808 8285 2809 8282
2806 8279 2813 8279 2818 8282 2816 8285
TIME...MOT...LOC 2158Z 346DEG 4KT 2879 8253 2811 8264

$$
Member Since: August 6, 2011 Posts: 4 Comments: 39349
Quoting NICycloneChaser:


Yeah, but I don't think it's quite guaranteed that it will be said Tropical Storm just yet.

Just brought back memories of the thousands of prefixes used with Emily last season.

Pre-Emily, Emily, Post-Emily, Ex-Emily, Reborn-Emily, Dead-Emily...


The same can be said for Ophelia, except you could add "Major Hurricane Ophelia" in there, too.

Even though she was no Irene because she didn't make any significant landfalls, she was by far the most impressive storm of 2010. At least, I think so.
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116. Gorty
Quoting Gorty:
Looks like 94l is starting to become more organized, the structure of it.


Or maybe not. idk lol.
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I went back a page, not sure if this has been posted yet. If it has, my apologies.

Member Since: August 19, 2005 Posts: 5 Comments: 5450
Quoting NICycloneChaser:


Yeah, but I don't think it's quite guaranteed that it will be said Tropical Storm just yet.

Just brought back memories of the thousands of prefixes used with Emily last season.

Pre-Emily, Emily, Post-Emily, Ex-Emily, Reborn-Emily, Dead-Emily...


I'm actually kind of skeptical as well on 94L. It's got a nice shot, but nothing's even close to guaranteed.
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I live in Southeastern NC Wilmington and in 1985 i THINK it was, Diana hit us twice
Member Since: April 26, 2006 Posts: 5 Comments: 3210
Quoting cg2916:


Better than 2010's prediction of 14-23 storms. Wow, that really helped.


Pretty much, or 2006's prediction of another adove-average season, which was proven to be our least active season in many years. They touted Ernesto to be the next Katrina, and it was a swirling mess of rainclouds by the time it got to Florida.

Not saying what this season will hold, but pre-season pridictions have been rendered less and less telling as time progressed.
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Quoting cg2916:


"Pre". It's not there yet, but... "pre".


Yeah, but I don't think it's quite guaranteed that it will be said Tropical Storm just yet.

Just brought back memories of the thousands of prefixes used with Emily last season.

Pre-Emily, Emily, Post-Emily, Ex-Emily, Reborn-Emily, Dead-Emily...
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110. Gorty
Looks like 94l is starting to become more organized, the structure of it.
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the NAM has the system peaking near the Outer Banks, and when it makes landfall near Savannah,GA, and then weakening to a rainmaker as it tracks along the N Gulf Coast.
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Quoting Gorty:


Look at over by Africa. One thing about to exit looks pretty healthy. And more action behind it.


The wave train won't come into play really until July.
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Quoting GTcooliebai:
I will look it up and post it if I come across a track like that.


okay!
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Quoting NICycloneChaser:


Oh boy, the fun we had last season with the 'pre' word.


"Pre". It's not there yet, but... "pre".
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105. Gorty
Quoting HurricaneDean07:

Shear forecasted to drop, Storm could form that day or Sunday, according to the NHC.


Look at over by Africa. One thing about to exit looks pretty healthy. And more action behind it.
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Quoting cg2916:
The Miami forecast discussion said that storm force winds were reported. That makes 94L at least a 55 mph... pre-Tropical Storm.


Oh boy, the fun we had last season with the 'pre' word.
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Quoting Gorty:


shear? or the storm?

Shear forecasted to drop, Storm could form that day or Sunday, according to the NHC.
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Just for the record. The last time we had two named storms in the month of may was 1887.

1887 Atlantic hurricane year consisted of:

5 off season storms

19 named storms

11 hurricanes

2 major hurricanes.

Could this be a possibility for this year?
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Quoting LostTomorrows:
Haha, this NOAA prediction reads more like:

"We have no idea what's going to happen anymore, so let's just see how things go."

It's certainly started out in an unpredictable manner, so it might very well stay that way.


Better than 2010's prediction of 14-23 storms. Wow, that really helped.
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Haha, this NOAA prediction reads more like:

"We have no idea what's going to happen anymore, so let's just see how things go."

It's certainly started out in an unpredictable manner, so it might very well stay that way.
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The Miami forecast discussion said that storm force winds were reported. That makes 94L at least a 55 mph... pre-Tropical Storm.
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Quoting HurricaneDean07:

Its currently at 35 kts as of now.


Yes, but it has a more tropical structure in the image i posted.

the nam has the storm hugging the gulf coastline all the way to NOLA as a possible TD
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Pretty healthy looking thing about to exit Africa. Though right now it is pretty far south.

Pretty active for this time of year in Africa, but they are a bit south right now.
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Member Since: August 6, 2011 Posts: 4 Comments: 39349
Quoting HurricaneDean07:

Forecasted to by saturday, stated by NHC.


shear? or the storm?
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Good agreement with the 12Z ECMWF Ensemble for SUN 12Z:

Member Since: August 14, 2008 Posts: 4 Comments: 4977
.....................models are changing every couple of hours, we will have to wait this one out this weekend and see what happens
Member Since: August 6, 2011 Posts: 4 Comments: 39349
Quoting GTcooliebai:
What would the comparison to 2012 be, since we're going from a weak La Nina to a weak El Nino?


2002 I would think, someone correct me if I'm wrong.
Member Since: July 8, 2005 Posts: 259 Comments: 24200
Quoting GeorgiaStormz:


35kts at surface

Its currently at 35 kts as of now.
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Quoting Gorty:


Tomorrow it should really start developing. Though not sure if shear will die down at all.

Forecasted to by saturday, stated by NHC.
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BAY AREA --
Record heat triggers scatteredthunderstorms have across the Bay area near the end of the day Thursday.

The storms have lined up with the seabreeze, predominately along the coastal counties of Pinellas, Hernando, Pasco and Citrus Counties.

Expect heavy rain and lightning in these storms. Some storms could produce small hail.

Dime-size hail was reported in Odessa and Trinity around 6 p.m.
Tampa and Bradenton set records for high temperatures. Tampa set a new record at 96 degrees and Bradenton saw a record of 95 degrees.
Member Since: August 6, 2011 Posts: 4 Comments: 39349
ECMWF has it going north, forming, moving back south off the Carolina coast into Florida, turning again, and taking almost the same path back to sea.
It peaks at 1004 mb the second time it goes north.

That would be interesting to have the same storm hit you twice.
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Quoting GTcooliebai:
Good ole afternoon seabreeze thunderstorms pinned along the beaches.
lol YESSSS!!..thunder and Lightning just north of me..hope it drifts a bit south and rains here too,looks like clearwater is getting alot of action right now
Member Since: August 6, 2011 Posts: 4 Comments: 39349
Well GTc that looks like a ball of confusion.
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Quoting GTcooliebai:
What would the comparison to 2012 be, since we're going from a weak La Nina to a weak El Nino?

That's the thing. the 2007/2008 La Nina set up into 2009 is completely different, you see.
Weren't set to go into a full blown La Nina, and it will be much more of a gradual ease into El Nino.
Look at the early 2000's where the was no LARGE swings in La Nina-El Nino and vise-versa.
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35kts at surface
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Quoting LargoFl:
Good ole afternoon seabreeze thunderstorms pinned along the beaches.
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Quoting HurricaneDean07:

Broad/weak circulation. It's forecasted by many models now to become Beryl, and then get shoved down by the High, into SE coast.


Tomorrow it should really start developing. Though not sure if shear will die down at all.
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Member Since: August 6, 2011 Posts: 4 Comments: 39349
Quoting Gorty:
Any low yet with pre-beyrl?

Broad/weak circulation. It's forecasted by many models now to become Beryl, and then get shoved down by the High, into SE coast.
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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.