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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Quoting 1013. GTstormChaserCaleb:
CMC 150 hrs. monsoon development taking time to consolidate moves over the Yucatan and emerges into the BOC:

150 hrs.



204 hrs.

Wasn`t this moving into the northern gulf instead of Mexico?Kori will be dissappoint :P lol.
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Another Massive Arctic Cyclone?

By Tom Yulsman | August 7, 2013 6:40 pm




A mosaic of images from NASA%u2019s Terra satellite reveals what appears to be a cyclone over the Arctic Ocean. (Image: NASA)

I just spotted what appears to be a massive cyclone -- bigger than all of Greenland -- in today's daily Arctic mosaic from NASA's Terra satellite.

Look for the thing that looks like a giant, white, upside down comma in the image above. (And click on the picture for a larger version.)

I've dug around a bit and found this Tweet about it from Ryan Maue, a research meteorologist with WeatherBell:

[NOTE: unable to copy Tweet shown, but it's available at link below]

Make sure to click on the link he provided to see a spectacular animation of the model's forecast for the storm.

http://blogs.discovermagazine.com/imageo/#.UgM0JW t5mSM
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20%/50% for 92E.

1. A BROAD AREA OF DISTURBED WEATHER IS LOCATED SEVERAL HUNDRED MILES
SOUTHWEST OF ACAPULCO MEXICO. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS DISTURBANCE OVER THE NEXT
FEW DAYS AS IT MOVES WESTWARD AT ABOUT 10 MPH. THIS SYSTEM HAS A
LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AND A MEDIUM CHANCE...50 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 5 DAYS.
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Southeastern Caribbean disturbance remains at 10%.

1. A WEAK LOW PRESSURE SYSTEM IS PRODUCING A SMALL AREA OF CLOUDINESS
AND SHOWERS OVER THE SOUTHEASTERN CARIBBEAN SEA. ENVIRONMENTAL
CONDITIONS DO NOT APPEAR CONDUCIVE FOR DEVELOPMENT AS THE LOW MOVES
WESTWARD AT 10 TO 15 MPH 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 LOW CHANCE...10 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.
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This low in the E. Caribbean has a day of virtually no shear to contend with and will then enter a tongue of moderate to high shear. May be traveling low enough to miss the high shear though. Dry air not allowing much to kick off right now. Down to 1009mb and if it can develop some in the next day it may survive the day or two of higher shear before moving into better conditions.
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Henriette is making one last effort at intensification.

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Quoting 1027. ProgressivePulse:



Your a FL guy, you notice changes in your local weather?
I noticed it has been hot during the day and humid at night. The East Coast seabreeze has also been a lot stronger than the West Coast seabreeze that when the collision occurs the East Coast seabreeze pushes the thunderstorms back to the West Coast of FL.
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Quoting 1022. GTstormChaserCaleb:
It's going to happen eventually, you guys have been tracking these things longer than me, so you should now when the lid comes off. How does the 20th sound for activity to really pick up? I mean I am still thinking we get a weak system either in the Atlantic or Gulf sometime between now and then.



Your a FL guy, you notice changes in your local weather?
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I've seen a lot of years where it's very slow until the last week of August and then boom, you've got a Hurricane somewhere out in the Atlantic. People, you just have to wait.
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Quoting 1022. GTstormChaserCaleb:
It's going to happen eventually, you guys have been tracking these things longer than me, so you should now when the lid comes off. How does the 20th sound for activity to really pick up? I mean I am still thinking we get a weak system either in the Atlantic or Gulf sometime between now and then.


Wave coming off Africa will gain attention. Velocities are heading our way so your Caribbean storm may have merit. Spunky wave heading in that direction from the E Caribb.
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Im telling you guys by next week and in two weeks things gonna be crazy. here we go again Patience:
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Quoting 1012. wxchaser97:
Four microwave passes in the past 6hrs and not one can get full look on Henriette.
I bet you miss QuikSCAT.
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Quoting 1021. ProgressivePulse:
Pattern Flip coming soon..
It's going to happen eventually, you guys have been tracking these things longer than me, so you should now when the lid comes off. How does the 20th sound for activity to really pick up? I mean I am still thinking we get a weak system either in the Atlantic or Gulf sometime between now and then.
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Pattern Flip coming soon..
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Quoting 1015. Gearsts:
Fim also shows it?




TCFP still calling up GOM development. Purple circle has gotten bigger in the last 24hr.
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1019. Gearsts
FIM-9 shows it
Link
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Quoting 1015. Gearsts:
Fim also shows it?
Hasn't ran yet. FIM-7 will likely complete first, kinda sucks you have to wait for it to finish the whole run before posting it. Oh well I can wait. :)
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Quoting 1011. SuperStorm093:
I kinda trust the EURO and GFS over that, until one of them show a TS/Hurricane in the Gulf, I will not believe the FIM, cause I am pretty sure the FIM showed something like that a couple weeks ago and didn't pan out.
So did the GFS and I think you're talking about with Dorian when both models were showing a hurricane recurving just offshore the East Coast. Good times. The FIM runs off of the same physics as the GFS, it may not be counted as a reliable model at least not yet, but the Doc. mentioned it right here on his blog:

"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."

Love the competition.
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Quoting 986. seer2012:


Cloud heights. A lot of 60,000 ft. clouds here!


That is a beautiful representation. Really nice.
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1015. Gearsts
Quoting 1013. GTstormChaserCaleb:
CMC 150 hrs. monsoon development taking time to consolidate moves over the Yucatan and emerges into the BOC:

150 hrs.



204 hrs.

Fim also shows it?
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Quoting 1010. KoritheMan:


Yeah, but I don't think we have much statistics on the FIM, do we?
It performed well with Ernesto last year.
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CMC 150 hrs. monsoon development taking time to consolidate moves over the Yucatan and emerges into the BOC:

150 hrs.



204 hrs.

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Four microwave passes in the past 6hrs and not one can get full look on Henriette.
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Quoting 1009. GTstormChaserCaleb:
Whereas, the Experimental FIM consistently shows a Tropical Storm in the Gulf. At this point it depends on which models you throw your cards at.
I kinda trust the EURO and GFS over that, until one of them show a TS/Hurricane in the Gulf, I will not believe the FIM, cause I am pretty sure the FIM showed something like that a couple weeks ago and didn't pan out.
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Quoting 1009. GTstormChaserCaleb:
Whereas, the Experimental FIM consistently shows a Tropical Storm in the Gulf. At this point it depends on which models you throw your cards at.


Yeah, but I don't think we have much statistics on the FIM, do we?
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Quoting 1004. SuperStorm093:
Obviously things can change, and storms can pop out of no where, but the GFS has consistently shown nothing of significance threw August 24th, getting pretty late there.
Whereas, the Experimental FIM consistently shows a Tropical Storm in the Gulf. At this point it depends on which models you throw your cards at.
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Coming around the mountain.

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Quoting 1005. KoritheMan:


How many hurricane seasons have you been through?
Tracking wise, probably my 4th. I just cant remember the last time models didnt atleast show something, only thing that scares me.
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Continuity equation


zonal wind component


meridional wind component
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Quoting 1004. SuperStorm093:
Obviously things can change, and storms can pop out of no where, but the GFS has consistently shown nothing of significance threw August 24th, getting pretty late there.


How many hurricane seasons have you been through?
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Obviously things can change, and storms can pop out of no where, but the GFS has consistently shown nothing of significance threw August 24th, getting pretty late there.
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1003. KEEPEROFTHEGATE (Mod)
Quoting 999. BaltimoreBrian:
What's a Kelvin wave? Is it different from a Fahrenheit wave or a Celsius wave?


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Quoting 988. MiamiHurricanes09:
Very impressive. The easternmost cyclone is the one that NHC has been forecasting to develop for a few days now in their extended TWOs. The western cyclone seems to develop from the ITCZ.

What's interesting about the EPAC thus far is the fact that they're under just about the same downward motion as the Atlantic basin and are still having no problems developing cyclones.
You forgot one key point they don't have the SAL to deal with. Our storms on this side have to earn their pay checks. :P
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1001. KEEPEROFTHEGATE (Mod)
4:41 AM GMT on August 08, 2013
latest full disk
12 13 am

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1000. evilpenguinshan
4:40 AM GMT on August 08, 2013
I spy, with my little eye...

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999. BaltimoreBrian
4:40 AM GMT on August 08, 2013
What's a Kelvin wave? Is it different from a Fahrenheit wave or a Celsius wave?
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998. SuperStorm093
4:38 AM GMT on August 08, 2013
Another crappy run of the GFS, no storm slamming into the Caribbean like GT said. Maybe next run.
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997. wxchaser97
4:38 AM GMT on August 08, 2013
Quoting 992. BaltimoreBrian:


1994 had 3 Cat 5 storms. That was fun to watch over and over.

I wouldn't mind watching 3 Cat-5's, but watching Cat-1 after Cat-1 do the same thing in the Epac is getting a little boring.
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996. AussieStorm
4:37 AM GMT on August 08, 2013
NW Pacific is in for another Typhoon. This time it could very well hit The Northern Philippines.







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995. KEEPEROFTHEGATE (Mod)
4:36 AM GMT on August 08, 2013
Quoting 984. GTstormChaserCaleb:
Looks like one big mess coming more headache for us to track.

yeah that kinda looks multi vortex for sure

its something just don't know what it wants to do
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994. ProgressivePulse
4:36 AM GMT on August 08, 2013
Epac is developing storms but, weak ones. Energy is in the Atlantic, it will be tapped sooner or later.
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993. TropicalAnalystwx13
4:36 AM GMT on August 08, 2013
Quoting 988. MiamiHurricanes09:
Very impressive. The easternmost cyclone is the one that NHC has been forecasting to develop for a dew days now in their extended TWOs. The western cyclone seems to develop from the ITCZ.

What's interesting about the EPAC thus far is the fact that they're under just about the same downward motion as the Atlantic basin and are still having no problems developing cyclones.

Eh...the MJO signal across the EPAC is neutral overall. They've been getting their cyclones from passing kelvin waves.

At this rate though, predictions of a below-average season are going to bust.



Quoting 989. BaltimoreBrian:


Oh snap, Lana. And the time before that?

Never.
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992. BaltimoreBrian
4:35 AM GMT on August 08, 2013
Quoting 991. wxchaser97:

Choo-Choo!
But seriously, if the next storm becomes a category 1 hurricane like the most of the other Epac storms I'm going to go a little crazy. I'm tired of seeing the same thing over and over and over again, lol.


1994 had 3 Cat 5 storms. That was fun to watch over and over.
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991. wxchaser97
4:34 AM GMT on August 08, 2013
Quoting 978. TropicalAnalystwx13:
The EPAC continues its train.


Choo-Choo!
But seriously, if the next storm becomes a category 1 hurricane like the most of the other Epac storms I'm going to go a little crazy. I'm tired of seeing the same thing over and over and over again, lol.
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990. MiamiHurricanes09
4:33 AM GMT on August 08, 2013
Quoting 981. BaltimoreBrian:


When's the last time 3 Atlantic hurricane seasons in a row had the same number of storms?
Never happened. The fact that it was 19 cyclones is very impressive.
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989. BaltimoreBrian
4:33 AM GMT on August 08, 2013
Quoting 987. TropicalAnalystwx13:

2010, 2011, and 2012.


Oh snap, Cody. And the time before that?
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988. MiamiHurricanes09
4:32 AM GMT on August 08, 2013
Quoting 978. TropicalAnalystwx13:
The EPAC continues its train.

Very impressive. The easternmost cyclone is the one that NHC has been forecasting to develop for a few days now in their extended TWOs. The western cyclone seems to develop from the ITCZ.

What's interesting about the EPAC thus far is the fact that they're under just about the same downward motion as the Atlantic basin and are still having no problems developing cyclones.
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987. TropicalAnalystwx13
4:31 AM GMT on August 08, 2013
Quoting 981. BaltimoreBrian:


When's the last time 3 Atlantic hurricane seasons in a row had the same number of storms?

2010, 2011, and 2012.
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986. seer2012
4:31 AM GMT on August 08, 2013


Cloud heights. A lot of 60,000 ft. clouds here!
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About

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