Which Hurricane Forecast Model Should You Trust?

By: Dr. Jeff Masters , 1:05 PM GMT on August 07, 2013

The National Hurricane Center (NHC) set a new record in 2012 for accuracy of their 1, 2, 3, and 4-day Atlantic tropical cyclone track forecasts, but had almost no skill making intensity forecasts, according to the 2012 National Hurricane Center Forecast Verification Report, issued in March 2013. The new records for track accuracy were set despite the fact that the season’s storms were harder than average to forecast. The average error in a 1-day forecast was 46 miles, and was 79 miles for 2 days, 116 miles for 3 days, 164 miles for 4 days, and 224 miles for 5 days. The official track forecast had a westward bias of 10 - 17 miles for 1 - 3 day forecasts (i.e., the official forecast tended to fall to the west of the verifying position), and was 38 and 75 miles too far to the northeast for the 4- and 5-day forecasts, respectively.


Figure 1. Verification of official NHC hurricane track forecasts for the Atlantic, 1990 - 2012. Over the past 15 - 20 years, 1 - 3 day track forecast errors have been reduced by about 60%. Track forecast error reductions of about 50% have occurred over the past ten years for 4- and 5-day forecasts. Image credit: 2012 National Hurricane Center Forecast Verification Report.

NHC Intensity Forecasts: Little Improvement Since 1990
Official NHC intensity forecasts did better than usual in 2012, and had errors lower than the 5-year average error for 1, 2, 3, 4, and 5-day forecasts. However, 2012's storms were easier to predict than usual, due to due to a lack of rapidly intensifying hurricanes. These rapid intensifiers are typically the source of the largest forecast errors. The skill of official NHC 24-hour intensity forecasts made in 2012 for the Atlantic basin were only about 15% better than a "no-skill" forecast; 2, 3, 4, and 5-day intensity forecasts had no skill.


Figure 2. Verification of official NHC hurricane intensity forecasts for the Atlantic, 1990 - 2012. Intensity forecasts have shown little to no improvement since 1990. Image credit: 2012 National Hurricane Center Forecast Verification Report.

Which Track Model Should You Trust?
As usual, in 2012 the official NHC forecast for Atlantic storms was almost as good as or better than any individual computer models--though NOAA's GFS model did slightly better than the NHC official forecast at 12, 24, and 48-hour periods, and the European model forecast was slightly better at 12-hour forecasts. Despite all the attention given to how the European Center (ECMWF) model outperformed the GFS model for Hurricane Sandy's track at long ranges, the GFS model actually outperformed the European model in 2012 when summing up all track forecasts made for all Atlantic named storms. This occurred, in part, because the European model made a few disastrously bad forecasts for Tropical Storm Debby when it was in the Gulf of Mexico and steering currents were weak. For several runs, the model predicted a Texas landfall, but Debby ended up moving east-northeast to make a Northwest Florida landfall, like the GFS model had predicted. However, the best-performing model averaged over the past three years has been the European Center model, with the GFS model a close second. Wunderground provides a web page with computer model forecasts for many of the best-performing track models used to predict hurricane tracks. The European Center does not permit public display of tropical storm positions from their hurricane tracking module of their model, so we are unable to put ECMWF forecasts on this page. Here are some of the better models NHC regularly looks at:

ECMWF: The European Center's global forecast model
GFS: NOAA's global forecast model
NOGAPS: The Navy's global forecast model (now defunct, replaced by the NAVGEM model in 2013)
UKMET: The United Kingdom Met Office's global forecast model
GFDL: The Geophysical Fluid Dynamics Laboratory's hurricane model, initialized using GFS data
HWRF: The intended successor for the the GFDL hurricane model, also initialized using GFS data
CMC: The Canadian GEM model
BAMM: The very old Beta and Advection Model (Medium layer), which is still useful at longer ranges

If one averages together the track forecasts from the first six of these models, the NHC official forecast will rarely depart much from it. As seen in Figure 3, the HWRF and UKMET were well behind the ECMWF and GFS in forecast accuracy in 2012, but were still respectable. The simple BAMM model did well at 3, 4, and 5-day forecasts. The GFDL and CMC models did quite poorly compared to the ECMWF, GFS, UKMET, and HWRF. The Navy's NOGAPS model also did poorly in 2012, and has been retired. Its replacement for 2013 is called the NAVGEM model.


Figure 3. Skill of computer model forecasts of Atlantic named storms in 2012, compared to a "no skill" model called "CLIPER5" that uses just climatology and persistence to make a hurricane track forecast (persistence means that a storm will tend to keep going in the direction it's current going.) OFCL=Official NHC forecast; GFS=Global Forecast System model; GFDL=Geophysical Fluid Dynamic Laboratory model; HWRF=Hurricane Weather Research Forecasting model; UKMET=United Kingdom Met Office model; ECMWF=European Center for Medium Range Weather Forecasting model; TVCA=one of the consensus models that lends together several of the above models; CMC=Canadian Meteorological Center (GEM) model; BAMM=Beta Advection Model (Medium depth.) Image credit: National Hurricane Center 2012 verification report.

Which Intensity Model Should You Trust?
Don't trust any of them. NHC has two main statistical intensity models, LGEM and DSHP (the SHIPS model with inland decay of a storm factored in.) In addition, four dynamical models that are also use to track hurricanes--the GFS, ECMWF, HWRF, and GFDL models--all offer intensity forecasts. With the exception of the GFS model, which had a skill just 5% better than a "no-skill" intensity forecast for predictions going out 36 hours, all of these models had no skill in their intensity forecasts during 2012. The ECMWF and HWRF models were the worst models for intensity forecasts of 3, 4, and 5 days, with a skill of 20% - 60% lower than a "no-skill" forecast. The LGEM model, which was a decent intensity model in 2011, tanked badly in 2012 and had near-zero skill. The only model that was any good in 2012 was the IVCN "consensus" model, which averages together the intensity forecasts of two or more of the intensity models such as LGEM, GFDL, HWRF, and DSHP.

Some Promising Models From the Hurricane Forecast Improvement Project (HFIP)
Last year was the fourth year of a ten-year project, called the Hurricane Forecast Improvement Project (HFIP), aimed at reducing hurricane track and intensity errors by 50%. The new experimental models from HFIP generally performed poorly in 2012. However, the new FIM9 15-km global model was competitive with the ECMWF and GFS models for track, and the new CIRA Statistical Intensity Consensus (SPC3) model for intensity performed better than many of the traditional intensity models.

For those interested in learning more about the hurricane forecast models, NOAA has a 1-hour training video (updated for 2011.) Additional information about the guidance models used at the NHC can be found at NHC and the NOAA/HRD Hurricane FAQ.

Sources of Model Data
You can view 7-day ECMWF and 16-day GFS forecasts on wunderground's wundermap with the model layer turned on.
Longer ten-day ECMWF forecasts are available from the ECMWF web site.
FSU's experimental hurricane forecast page (CMC, ECMWF, GFDL, GFS, HWRF, and NAVGEM models)
NOAA's HFIP model comparison page (GFS, ECMWF, FIM, FIM9, UKMET, and CMC models.)
Experimental HFIP models

Quiet in the Atlantic
There are no tropical cyclone threat areas in the Atlantic to discuss today, and none of the reliable models for tropical cyclone formation is predicting development during the coming seven days. I plan on having a detailed update on Friday to discuss the latest long-range forecasts for the coming peak part of hurricane season.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

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1486. JLPR2
Impressive TCHP in the Western Caribbean, it's actually the highest in the area at this date since the record of the images start on 2005.

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lazy flash flood warning issuer....lol





huge area.
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1484. nigel20
Quoting MississippiWx:
SAL/Dust Forecast. Looks like another healthy attack of SAL.


Hi Mississippi! It seems as if it'll move a bit more north than the previous one.
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TAFB dissipates the low within 24 hours.

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Quoting 1466. wxgeek723:


Maybe you should move to San Diego and see if hurricanes follow you there :p


I lived in Chula Vista, San Diego in 2003.
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1481. nigel20
Good afternoon all!

Latest Southern Oscillation Index values

SOI values for 08 Aug 2013

Average for last 30 days 5.6
Average for last 90 days 8.9
Daily contribution to SOI calculation -3.2
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Quoting 1478. unknowncomic:
why is that?
It's the more conservative model of the major global models well at least the NOGAPS was, but from what I am reading on here this is a brand new model, so we shall see.
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1479. nash36
Quoting 1477. GTstormChaserCaleb:
I've been diagnosed with Tropical Depression.


LOL! Good one.

As they say....Patience is a virtue. Won't be much longer before we'll be busy.
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Quoting 1403. GTstormChaserCaleb:
When the NAVGEM is showing something know that something is up.

why is that?
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Quoting 1474. nash36:
Good afternoon everyone.

How's everyone hanging in with this lull in activity?
I've been diagnosed with Tropical Depression.
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Quoting 1437. SouthernIllinois:
Well nothing substantial. But that is okay because a nice moderate soaking rain is best for the ground and vegetation anyway. So far I have recorded .24". Still coming down steady though. Not disappointed by any measure since the models didn't even initially pick up on this wave of showers and thunderstorms.

Nat


I bet I get more than you before the day is over! These storms off the Gulf can dump 3"+ in less than an hour! Really wish I could send them North to you and West to Texas, enough already!

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Quoting 1471. TampaSpin:
Gotta keep this RAIN away in Tampa today...I have my golf league at 5pm with my son...but if we do get rained out....we are heading to the Bucs game against the Ravens.
Yeahhh hopefully we dethrone the Champs wish it was a regular season game. At least football is back. :)
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1474. nash36
Good afternoon everyone.

How's everyone hanging in with this lull in activity?
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Quoting 1468. MississippiWx:
SAL/Dust Forecast. Looks like another healthy attack of SAL.

Nice animation, consider it stolen ;)...The Caribbean looks dust free at the end, just in time for a system to bubble there.
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1472. Gearsts
I need something to track in the atlantic!
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Gotta keep this RAIN away in Tampa today...I have my golf league at 5pm with my son...but if we do get rained out....we are heading to the Bucs game against the Ravens.
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Good afternoon, weathergeeks! ;) Dipping in quickly for lunch and a quick look at the tropics.

Our southern Caribbean low embedded within the low amplitude surface trough keeps creeping further west in the Caribbean. And, although convection is sporadic, it's under a mid-level anticyclone which may help sustain what bit of surface vorticity it has going for it until it moves away from its proximity to Venezuela. Of course, this is the "dead zone" area and not much ever develops in this region, but given the anticyclone, vorticity, lower pressure, proper forward speed, atmosphere getting more moist, it may keep enough energy for spinning up a bit further west.

The huge ULL over the Bahamas is creating southwesterly shear further west in front of the low, but it's also helping moisten the atmosphere. As it retrogrades westwards into the GoM I suspect we'll start to see upper level shear diminish somewhat in the west Caribbean in front of the low. And, if it can create some lift and get some convection going, we might start seeing some noticeable rotation. And, it could just dissipate too. :)

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Quoting 1465. Gearsts:
And weaker smaller storms.
Yep, Flossie, Gill, and Henriette have been smaller than their predecessors.

As of today the EPAC storm totals are 8/6/0. With 2 more showing up on the GFS model.

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SAL/Dust Forecast. Looks like another healthy attack of SAL.

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1467. Thrawst
Henriette's looking good!

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Quoting 1462. CybrTeddy:


Lived there in 2003. Lived in Florida since 2004.


Maybe you should move to San Diego and see if hurricanes follow you there :p
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1465. Gearsts
Quoting 1464. GTstormChaserCaleb:
The EPAC hasn't been too bad. The trend has been for storms to develop a lot further away from the Mexican coast.

And weaker smaller storms.
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The EPAC hasn't been too bad. The trend has been for storms to develop a lot further away from the Mexican coast.

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Quoting 1457. NasBahMan:


You in North Carolina or Virgina?


Lived there in 2003. Lived in Florida since 2004.
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Quoting 1448. SouthernIllinois:

When do the TCHP's and SST's typically peak MissWx? Is it about early to mid August? I understand the peak of the hurricane season is Sept 10th but does that necessarily mean the ocean temperatures are the warmest then....or have more to do with the overall conditions of the MDR (shear, dry air potential, steering flows, etc...) all coming together at once being the most favorable?


They usually peak in September.
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Kind of weather related, but this is really cool. Check out how engineers convert humidity in the air into drinking water. Sorry if this has been posted another time. I've often thought I could drink the air here in South MS.

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Quoting 1451. Jedkins01:


This map must be fairly old, they forgot Jeanne and Wilma

Interesting though to say the least. My house in Pinellas county is under the eyewall path of 2 old strikes strikes.
I know one for sure is the 1921 Tarpon Springs Hurricane, not sure about the other one though. Our houses weren't even built yet during that time. Mine is about 30 years old. This area was sheer swamp land before the 80s.
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Quoting 1435. Felix2007:


Yep, I was the last Cat 5 storm in the Atlantic.
Too bad you're retired now.
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Quoting 1445. CybrTeddy:


I'd feel really sorry for anyone having an experience like Isabel though like I did.


You in North Carolina or Virgina?
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My opinion is we don't have enough data from the NAVGEM to characterize it strengths and weaknesses. Some treat the NAVGEM as just an upgrade to NOGAPS, but I think the changes were major enough to consider it a new model. The Navy must have also since they decided to change the name. JMO
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40%/70% for 92E:

AN AREA OF DISTURBED WEATHER IS LOCATED ABOUT 500 MILES SOUTH OF
MANZANILLO MEXICO. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE
FOR SOME DEVELOPMENT OF THIS DISTURBANCE OVER THE NEXT FEW DAYS
AS IT MOVES WESTWARD AT ABOUT 10 MPH. THIS SYSTEM HAS A MEDIUM
CHANCE...40 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AND A HIGH CHANCE...70 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 5 DAYS.



10%/30% for a separate disturbance:

A LOW PRESSURE TROUGH LOCATED ABOUT 1500 MILES SOUTHWEST OF THE
SOUTHERN TIP OF BAJA CALIFORNIA IS PRODUCING DISORGANIZED SHOWERS
AND THUNDERSTORMS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE
CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM DURING THE NEXT
SEVERAL DAYS. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A
MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 5 DAYS AS IT MOVES WESTWARD AROUND 10 MPH.



Caribbean wave at ~0%/~0%:

CLOUDINESS AND SHOWER ACTIVITY ASSOCIATED WITH A WEAK LOW PRESSURE
SYSTEM OVER THE SOUTHEASTERN CARIBBEAN SEA HAVE DECREASED.
ENVIRONMENTAL CONDITIONS ARE NOT CONDUCIVE FOR DEVELOPMENT WHILE
THE LOW MOVES WESTWARD AT 10 TO 15 MPH DURING THE NEXT SEVERAL
DAYS. THIS SYSTEM HAS A LOW CHANCE...NEAR 0 PERCENT...OF BECOMING
A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A LOW CHANCE...
NEAR 0 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5
DAYS.

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1454. Gearsts
Quoting 1446. stormchaser19:


Actually is showing the system but to the north now...
Just a broad area of low pressure.
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A lot more humid than in days past here on the Gulf Coast
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Quoting 1440. Stoopid1:


I remember being in the eye of Charley when he was a moderate category 1. That was the most eerie feeling ever when everything went quite, you knew it was going to ramp up again very soon.


it was like that the night Ike hit, as the sun went down you could see the bands start coming inland. it was very eerie
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Quoting 1364. Sfloridacat5:
Interesting to know that central Fl. (Orlando area)has had the most major hurricanes pass through its area.


This map must be fairly old, they forgot Jeanne and Wilma

Interesting though to say the least. My house in Pinellas county is under the eyewall path of 2 old strikes strikes.
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Quoting 1443. Dragod66:


Long time no see Felix!


I don't really lurk or post around here except during hurricane season, lol. I mean I use the site and all, just not really the blogs. You know I'll be around plenty during the next few months as the tropics heat up!
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Quoting 1404. calkevin77:


Yes. I live about 10 minutes South of Georgetown and during Hermine the entire Austin area had two days of training storms. Lots of flooding in the Brushy Creek area of Round Rock in an area. However, after Hermine the Austin area did not see any measurable rainfall until January of 2012...hence the inferno/drought of 2011.


Off to work, keep your fingers crossed and send good vibes to FIM7!
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1447. Thrawst
.
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Quoting 1428. Gearsts:
Beyond this time the models loses resolution and usually goes crazy, also the CMC is not showing this system like it was yesterday.


Actually is showing the system but to the north now...
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Quoting 1433. NasBahMan:


Another year like 2003 will work just fine for me, nothing in the Bahamas for a change!


I'd feel really sorry for anyone having an experience like Isabel though like I did.
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Active convection in my area today.
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Quoting 1435. Felix2007:


Yep, I was the last Cat 5 storm in the Atlantic.


Long time no see Felix!
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1442. Levi32
Quoting 1422. sporteguy03:

Did you see the post earlier on the ASO pressures?


Those forecasts have been out for 3 weeks.
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Quoting 1431. ncstorm:


yes but takes it west into the EPAC..northwards..no I havent seen that in its bias..Im probably the only here who posts the Navgem religiously so I have to disagree just a little bit there with you..


I too tend to agree with you NCS....not seen that bias from the Navy Model...and I look at all models everyday this time of year. I find the Navy as the most conservative of them all IMO. I'm sure Levi has a reason for his post and respect his post concerning. I like all MODELS....LOL
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Quoting 1427. JrWeathermanFL:
Since I've been born and alive for 14 years, I've been in Gordon (2000), Frances, Jeanne (both 2004), Fay (2008), Claudette (2009), Beryl, Debby (both 2012), and Andrea (2013). That's pretty good for 14 years! And I've been affected by a lot more including Isaac, Ike, and Alex. I've never been in a hurricane though. Nor have I ever had to travel more than 100 miles to be in the center of a storm.


I remember being in the eye of Charley when he was a moderate category 1. That was the most eerie feeling ever when everything went quite, you knew it was going to ramp up again very soon.
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Meanwhile bye Ivo and welcome Juliette. Ivo may stay far enough south to make its way to the International Date Line.



Here it comes:



And there it goes:



These are cool the ones that cross basin.
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1438. Gearsts
GEM yesterday showing our future storm.

Today
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The Gulf and Caribbean are primed for a tropical cyclone. Now, we just wait for an actual storm and favorable upper level conditions. It has been a while since we've had a real Caribbean cruiser.

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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather