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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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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Quoting 1377. KEEPEROFTHEGATE:
felix was the last one to get cat 5


Yep, I was the last Cat 5 storm in the Atlantic.
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Hot spot -western GOM
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Quoting 1408. wxgeek723:
2003, on a similar pace with this season, actually experienced a lull during the first half of August.

There was a 3 week gap of named storms between July 21 and August 14.


Another year like 2003 will work just fine for me, nothing in the Bahamas for a change!
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Quoting 1423. Levi32:


That model is obsessed with the monsoon circulation. It spins up any lobe of vorticity in that region. I've been plotting it for a long time. That's not to say we won't necessarily get development here, but I'm just making sure the model biases are out in the open.



Levi you are probably correct....I have not plotted models nor looked at stats...I just don't remember seeing the Navy Models showing something that normally doesn't have a good chance. I except your observation as a fact tho.
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1431. ncstorm
Quoting 1423. Levi32:


That model is obsessed with the monsoon circulation. It spins up any lobe of vorticity in that region. I've been plotting it for a long time. That's not to say we won't necessarily get development here, but I'm just making sure the model biases are out in the open.


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..
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Quoting 1418. ProphetessofDoom:



Late response to this, I know! I taught social studies for 15 years here in South Fla. always had to teach plate tectonics, climate and the like in my geography class - even had a whole project designed to around the concepts. And hurricane season was (and still will be when I go back!) the best tool for teaching latitude and longitude!


Hurricane season is great for teaching longitude and latitude along with geography.
I also taught a weather and climate class where the kids used a lot of the same tools we use in this forum for forecasting.
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Quoting 1415. Levi32:


Actually it is the complete opposite when it comes to the Caribbean. It develops everything in the western Caribbean.



here the storm u was talking about on your video before
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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.
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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.
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Glad to see Henriette became a Category 2 hurricane overnight. Convection around the center has shrunk recently, but the eye temperature has become warmer. May have strengthened ever so slightly.


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Henriette looks like Lisa, so small with a nice eye!
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1424. KORBIN
I hope in all honesty that it doesn't impact central florida, with the rain we have had it would be a sloppy mess!

From Dr. Masters post you can see that the intensity forecasts this far our are often wrong and with the gulf nearing 90 degrees in temp it's worry some to have anything spinning around out there.
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1423. Levi32
Quoting 1417. TampaSpin:



Not to oppose you, but I don't remember seeing that from the Navy Model....could be wrong.


That model is obsessed with the monsoon circulation. It spins up any lobe of vorticity in that region. I've been plotting it for a long time. That's not to say we won't necessarily get development here, but I'm just making sure the model biases are out in the open.
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Quoting 1415. Levi32:


Actually it is the complete opposite when it comes to the Caribbean. It develops everything in the western Caribbean.

Did you see the post earlier on the ASO pressures?
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1421. Gearsts
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In reguards to 1401, we definately don't need any more rain here in Chiefland, FL. We're overflowing here. Andrea sure helped alot...We've had rain everyday. And in the past week we've had funnel clouds over my house twice. One of which I could look up and see it spinning...freaky.
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Quoting 1195. Sfloridacat5:



I teach 6 grade science and I've had this discussion with them. It's funny that they think WWE is real. I ask them "how can they punch each other in the face 50 times during a match and they don't have one mark on their face?

Where as MMA, their faces start bleeding with the first elbow or solid punch.

And I have to teach these kids about Plate tectonics, weather and climate (and yes global warming), etc.
It's not easy.



Late response to this, I know! I taught social studies for 15 years here in South Fla. always had to teach plate tectonics, climate and the like in my geography class - even had a whole project designed to around the concepts. And hurricane season was (and still will be when I go back!) the best tool for teaching latitude and longitude!
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Quoting 1415. Levi32:


Actually it is the complete opposite when it comes to the Caribbean. It develops everything in the western Caribbean.



Not to oppose you, but I don't remember seeing that from the Navy Model....could be wrong.
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Quoting 1400. Sfloridacat5:
Being in S.W. Florida this system interests me the most.
It forms in the Western Caribbean and moves up into the Eastern GOM.
I forgot one 2005 Wilma, although that occurred later in the season during the secondary peak and breeding grounds of the Western Caribbean.
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1415. Levi32
Quoting 1409. TampaSpin:



That I 100% correct...the NAVY MODEL NEVER shows something unless it happens.....very conservative model.


Actually it is the complete opposite when it comes to the Caribbean. It develops everything in the western Caribbean.
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Repost from earlier...
1999 could be a good example of where we are now....
We only had one named storm by August 15.
We then had 4 storms in the second half of August (3 hurricanes and 2 majors)
Notably storms include Floyd and Lenny. The season only brought 12 storms, but 8 were hurricanes and 5 were majors.

And 2010...we didn't even have the D storm yet. But we ended the season with 19 storms, 12 hurricanes, and 5 majors. We ended the season with 5 straight hurricanes...all in October.

I'm not saying it won't be a bust...but look at these seasons for a reference. We would be beating both seasons right now.


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this look like a storm maybe hit the northeast!
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When you look at the frequently posted NOAA "most likely" area for August tropical storm development (which is in Orange on the chart), the Orange field starts a little East of the Lesser Antilles, through the Antilles, and forms a "y" pattern to the South and North of Puerto Rico/Bahamas area.

This coincides nicely with Cape Verde waves that form into tropical depressions while crossing the Central Atlantic and start to develop further closer to or passing through the Lesser Antilles where SAL issues start to diminish.........Your classic long-track storms.

No viable waves at the moment in the Central-Atlantic but the African Continent is starting to warm up in the breeding grounds; only a matter of a few weeks before the ITCZ really starts to send a steady stream of waves towards the Atlantic:

Link

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1411. ncstorm
12z CMC..doesnt strengthen the low until off the east coast..







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Quoting 1403. GTstormChaserCaleb:
When the NAVGEM is showing something know that something is up.




That I 100% correct...the NAVY MODEL NEVER shows something unless it happens.....very conservative model.
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2003, on a similar pace with this season, actually experienced a lull during the first half of August.

There was a 3 week gap of named storms between July 21 and August 14.
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Quoting 1386. TropicalAnalystwx13:
Recurving 'Hurricane Erin' at the end.

only maybe!!
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Here's a stat I was just reading on the NHC website.

"NHC statistics show 40 percent of all U.S. and major hurricanes hit Florida. Eighty-three percent of category 4 or higher hurricane strikes have hit either Florida or Texas; both Florida and Texas have extensive coastlines, which is reflected in the number of occurrences."

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Quoting 1400. Sfloridacat5:
Being in S.W. Florida this system interests me the most.
It forms in the Western Caribbean and moves up into the Eastern GOM.
We have seen these all too often. 2000 Gordon, 2001 Gabrielle, 2004 Charley, 2007 Barry, 2008 Fay, 2012 Debby, and 2013 Andrea.
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Quoting 1396. seer2012:


Looks like Austin was right in the bulls-eye of this weather!!


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.
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When the NAVGEM is showing something know that something is up.

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1402. ncstorm
total precip up to 384 hours
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1401. ncstorm
Florida looks to be up first..
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Being in S.W. Florida this system interests me the most.
It forms in the Western Caribbean and moves up into the Eastern GOM.
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1399. ncstorm
12z Navgem-last frame 180 hour

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1398. Patrap
NOAA: Atlantic hurricane season on track to be above-normal

August 8, 2013



Image of Tropical Storm Dorian on July 24, 2013, from NOAA's GOES East satellite.
High resolution (Credit: NOAA)

NOAA issued its updated Atlantic hurricane season outlook today saying the season is shaping up to be above normal with the possibility that it could be very active. The season has already produced four named storms, with the peak of the season mid-August through October yet to come.

Our confidence for an above-normal season is still high because the predicted atmospheric and oceanic conditions that are favorable for storm development have materialized, said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA's Climate Prediction Center, a division of the National Weather Service. Also, two of the four named storms to-date formed in the deep tropical Atlantic, which historically is an indicator of an active season.

The conditions in place now are similar to those that have produced many active Atlantic hurricane seasons since 1995, and include above-average Atlantic sea surface temperatures and a stronger rainy season in West Africa, which produces wind patterns that help turn storm systems there into tropical storms and hurricanes.

The updated outlook calls for a 70 percent chance of an above-normal season. Across the Atlantic Basin for the entire season June 1 to November 30 NOAA's updated seasonal outlook (which includes the activity to date of tropical storms Andrea, Barry, Chantal, and Dorian) projects a 70 percent chance for each of the following ranges:

13 to 19 named storms (top winds of 39 mph or higher), including
6 to 9 hurricanes (top winds of 74 mph or higher), of which
3 to 5 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph)
These ranges are above the 30-year seasonal averages of 12 named storms, six hurricanes and three major hurricanes.

The updated outlook is similar to the pre-season outlook issued in May, but with a reduced expectation for extreme levels of activity. Motivating this change is a decreased likelihood that La Nina will develop and bring its reduced wind shear that further strengthens the hurricane season. Other factors are the lack of hurricanes through July, more variability in the wind patterns across the tropical Atlantic Ocean and slightly lower hurricane season model predictions. In May, the outlook called for 13-20 named storms, 7-11 hurricanes and 3-6 major hurricanes.

The peak of the hurricane season is almost upon us and it's important to remain prepared for hurricanes through November," said Joe Nimmich, FEMA Associate Administrator for Response and Recovery. "Make sure to review your family emergency plan, check that your emergency kit is stocked and consider insurance options. Learn more about how you can prepare for hurricanes at www.ready.gov/hurricanes.
NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook, Twitter and our other social media channels.
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Quoting 1377. KEEPEROFTHEGATE:
felix was the last one to get cat 5
Yup.
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Quoting 1375. 1900hurricane:

Hermine did pretty well for herself in 2010, but nowhere near the areal extent of Beulah. I might have to poke around a little bit now to see if there is a larger scale rainfall area than that in the recent past.



Looks like Austin was right in the bulls-eye of this weather!!
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Quoting 1393. GTstormChaserCaleb:
Yep and Fernand in the Gulf. Crow will be ready to serve for those who forecast a bust of a season and saying we won't get anything until after August 20th.



Regardless of future runs this is exactly why you don't speculate 16 days out based on one run that nothing will happen.
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1394. Patrap
Bogeys inbound from the Neast.

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Quoting 1386. TropicalAnalystwx13:
Recurving 'Hurricane Erin' at the end.

Yep and Fernand in the Gulf. Crow will be ready to serve for those who forecast a bust of a season and saying we won't get anything until after August 20th.


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Quoting 1388. ncstorm:
is the hurricane recurving because of the storm that crosses off the east coast and heading out to sea?..will it be all about timing?

Timing I am pretty sure regardless of the run itself there will be a system threatening some landmass.
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Quoting 1360. redwagon:


For Austin, another Beulah would get it wet enough downstream that the rice farmers could pull their straw out of Travis for a month or so... that plus the 7" Travis got would help maybe four or five feet rise, given the aquifer's emptiness. But it looks like TX might be up for two or even three storms before the clock runs out on us. Fingers, toes and eyes crossed.


I was watching the news last night and it showed a daily time lapse of Sometimes Island grow larger right before my very eyes as the lake level continued to drop. For those unfamiliar, Sometimes Island is a land mass in the middle of the lake that becomes exposed when the lake levels drop. I'm thinking they need to rename it to "West Austin 2.0" :)
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1390. Patrap
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1389. ncstorm
Quoting 1387. GTstormChaserCaleb:
Nice use of sarcasm there. :P


LOL..I wasnt being sarcastic..I scroll down real fast and didnt see any images..sorry..
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1388. ncstorm
is the hurricane recurving because of the storm that crosses off the east coast and heading out to sea?..will it be all about timing?
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Quoting 1380. ncstorm:
Is anyone not posting the 12z GFS run..wow

Nice use of sarcasm there. :P
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Recurving 'Hurricane Erin' at the end.

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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