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 1267. RitaEvac:
Everybody talkin' bout rain in the Gulf heading for TX,

There's a feast on the table, but nuttin on the plate.


No joke. Alanis Morissette could have written a song about our weather here.
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1285. KEEPEROFTHEGATE (Mod)
Quoting 1282. RitaEvac:


That's where I'm staying in Vegas
nice
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@1269.
2001 we had 4 straight TS- We ended 15-9-4 with our first hurricane on Sep. 9th

2002 we had six straight in a season with 12 storms and 2 majors- The majors were Isidore and Lili.

I would've thought the same but there's always time lol
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Quoting 1267. RitaEvac:
Everybody talkin' bout rain in the Gulf heading for TX,

There's a feast on the table, but nuttin on the plate.


texas death ridge for ya. the first part of summer wasn't bad nothing like last summer. the heat this week is just oppressive.
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Quoting 1278. KEEPEROFTHEGATE:
a mirage


That's where I'm staying in Vegas
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1281. Skyepony (Mod)
Wisconsin storms packing high winds of more than 100 mph and two tornadoes caused at least one weather-related fatality, injured 3, destroyed a church, barns and other buildings and cut power to tens of thousands of people in central and northeastern Wisconsin on early Wednesday morning, on August 7, 2013.

There is some pics in there..manufactured homes didn't fair as well.

Hard not to repost the...we will rebuild, somehow..pic..



Quoting 1227. Tropicsweatherpr:
NOAA continues to see an active 2013 North Atlantic Season

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)

I had 19-10-3 back in maybe April...nice to see them getting closer to my numbers:P

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Baseball- and softball-sized hail today in Germany: http://www.liveleak.com/view?i=95a_1375948831
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If this MJO forecast is right then the Cape Verde season is about to kick into high gear.

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1278. KEEPEROFTHEGATE (Mod)
Quoting 1237. RitaEvac:


Nah, it's the same concept when your overheated in the desert and off on the horizon you think there's water because it looks like water, it's just the heat reflecting off the ground....nothing to see here, move along.
a mirage
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Quoting 1274. nrtiwlnvragn:
Experimental basin scale HWRF has the East Pacific spit-em out. It seems to work its way from East to West.

A teleconnection may suggest the Western Caribbean also gets one with a pattern like this.
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1276. LargoFl
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Quoting 1274. nrtiwlnvragn:
Experimental basin scale HWRF has the East Pacific spit-em out.





I am a STRONG believer that when the Eastern Pacific is busy the Atlantic stays Quite. Seen it too often it seems.
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Experimental basin scale HWRF has the East Pacific spit-em out.


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Quoting 1260. Sfloridacat5:


Think we're starting to break down the pattern. Most the meteorologists have been stating the topics should get active in about 7 days or so.


Still a lot of Dust and Dry air out there....UNTIL we get a good UpLift from MJO then not much will happen....NOW that could be coming if this forecast is correct....BUT IT WAS WRONG ABOUT A MONTH AGO TOO!

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1272. Grothar
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Quoting 1261. EyEtoEyE:
. GT I was saying the heart of the season , I know we have had A thru D !
I know I was just messing with you...Que the date August 20th. That should be when the lid comes off.
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1270. Grothar
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Quoting 1257. JrWeathermanFL:
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.
So far we have had 4 Tropical Storms, 2 of which formed in the MDR, 1 in the Western Caribbean, and 1 in the Gulf. The only thing I thought was we would have at least had 1 hurricane by now.
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1268. Patrap
From a Texas pyrate I know...

www.nrlmry.navy.mil/aerosol_web/loop


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Everybody talkin' bout rain in the Gulf heading for TX,

There's a feast on the table, but nuttin on the plate.
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1266. LargoFl
I really don't know why so many live here..110 degree's?...
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Quoting 1185. SouthernIllinois:

Yup. Bring it! I want my 2-3".


Wish I could box it up and send it to you!
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1264. Grothar
Quoting 1254. Sfloridacat5:


Thanks. It gets harder every year.


Glad you modified that. See, I was a teacher, too!! :)
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Quoting 1237. RitaEvac:


Nah, it's the same concept when your overheated in the desert and off on the horizon you think there's water because it looks like water, it's just the heat reflecting off the ground....nothing to see here, move along.


Technically, a mirage is caused from steep lapse rates near the surface. This happens because air is a relatively poor conductor of heat, and since the ground gets much hotter than the air above, the air right near ground level is able to be much hotter, the temperature rapidly drops off over a distance of 1 ft which represents steep lapse rates. This rapid change in temperature causes light to refract significantly in a way that when the light reaches our brain we see that watery appearance.

You'll notice that air just above a fire looks similar even from up close, it will have watery of gelatin appearance to it.


:)
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Quoting 1252. LargoFl:
well at least its some rain huh..


Honestly I'd rather it not rain if that's the case
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Quoting 1249. GTstormChaserCaleb:
Huh, I thought the season began with Andrea? And yes I still believe we see something next week, particularly closer to home.
. GT I was saying the heart of the season , I know we have had A thru D !
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Quoting 1251. TampaSpin:


Clearly shows the ULL finally moving...Might still wanna watch it close for getting to the surface tho as the 700mb Vorticity has enhanced some. JUST something to watch.


Think we're starting to break down the pattern. Most the meteorologists have been stating the topics should get active in about 7 days or so.
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1259. LargoFl
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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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Quoting 1241. LargoFl:
rita check out Monday............................
Not bad could be the ULL combines with the system Pat shows in 1242.
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Quoting 1232. LargoFl:
this huge moisture blob in the gulf seems to be headed to Texas...
Not necessarily !
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Quoting 1234. Grothar:


Good Luck. I'm glad those days are over.


Thanks. It gets harder every year.
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1253. LargoFl
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1252. LargoFl
Quoting 1247. RitaEvac:


Niiiiice....but I'm in the 0.05" shading....
well at least its some rain huh..
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Quoting 1242. Patrap:


Clearly shows the ULL finally moving...Might still wanna watch it close for getting to the surface tho as the 700mb Vorticity has enhanced some. JUST something to watch.
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Quoting 1227. Tropicsweatherpr:
NOAA continues to see an active 2013 North Atlantic Season

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)
I see NOAA isn't budging off there forecast , I figured that much , I guess they are seeing things , we are not ! What I don't know , they are the experts , and we are not.
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Quoting 1228. EyEtoEyE:
GT , I totally agree with you , doubt if at all on recurves this year , do you think the season truly and honestly begins next week?
Huh, I thought the season began with Andrea? And yes I still believe we see something next week, particularly closer to home.
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Quoting 1227. Tropicsweatherpr:
NOAA continues to see an active 2013 North Atlantic Season

13 to 19 named storms (top winds of 39 mph or higher), including %u25E66 to 9 hurricanes (top winds of 74 mph or higher), of which
%u25E63 to 5 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph)



Although this updated outlook is consistent with the pre-season outlook issued in May, all of the updated predicted ranges of activity have been lowered and narrowed slightly. These changes reflect: 1) The lack of hurricanes during June and July; 2) The latest CPC/ IRI ENSO forecast and many climate models which predict that La Niña is less likely to develop and further enhance the season; and 3) Some models are more conservative in their predictions of Atlantic hurricane activity.



Link
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Quoting 1241. LargoFl:
rita check out Monday............................


Niiiiice....but I'm in the 0.05" shading....
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1246. Patrap
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goes satellite showing some SAL dust in Houston. The skies have been hazy for days. hopefully any rain in the GOM will clear it out this weekend.
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1244. Grothar
Quoting 1231. Jedkins01:


You know, considering I'm not sure what you're implying, I probably didn't see whatever movie it is that you speak of, lol.


Famous line (paraphrased) from the movie "Presumed Innocent". I just have this mind that remembers dialogues from TV shows and movies. I can almost recite most of the "Twilight Zone" shows from the 1950's.
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Quoting 1221. LargoFl:
showers in the gulf seem to be moving westward........


Yesterday we also had a flow from East to West across the state(at least the southern half). I'm in Ft. Myers and I kept looking to the East for T storms moving into the area.
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1242. Patrap
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1241. LargoFl
rita check out Monday............................
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Quoting 1227. Tropicsweatherpr:
NOAA continues to see an active 2013 North Atlantic Season

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)


NOAA must think the environment will change so that 'tropical hell' will bust loose soon.
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Quoting 1233. RitaEvac:
And that dang song is on again, summertime sadness..


Wish it would rain down just came on here. Very funny Phil! :P
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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.


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 Niña 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 1232. LargoFl:
this huge moisture blob in the gulf seems to be headed to Texas...


Nah, it's the same concept when your overheated in the desert and off on the horizon you think there's water because it looks like water, it's just the heat reflecting off the ground....nothing to see here, move along.
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1236. LargoFl
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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