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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Im just sitting over here chuckling..I for one know that you have to kick the tires before a test drive..as we already saw two Cape Verde systems before August, thats exactly we saw in regards so far to this season..kicking of the tires..

The test drive is next..whose ready

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This lull would be more bearable if the WPAC didn't suck.

Honestly Soulik is the only major hurricane, only category 2, since March. 2013 in itself is a bust.
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Quoting 59. catastropheadjuster:


MP- just wondering all that brown on the image, is that the SAL?

sheri


There is Saharan sand in the brown part of the image, yes.
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Quoting 70. catastropheadjuster:


Taco, Thanks and great to see ya to, I am always on here in the morning and reading. But it's great to see you again. Well we found out from all that rain that we have 5 leaks in the roof, not good. Hubby said it's time for a roof so know I gotta go price shingles and all that good stuff. Not going to be fun.

sheri

It "Never Is" when you have to deal with a roof Sweetie.... I know I replaced 4 on my street back in 04 after Ivan blew off shingles everywhere.... I'm on right now because I had Neck surgery back in June but hope to be back at work next Tuesday.... Don't let the prices scare you because they are so much higher now than what they were back in 04....

Taco :o)
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Quoting 64. washingtonian115:
The only storm that was remotely interesting thus far was Andrea.The other one was your typical June storm..an then you had two wanna be short lived cape verde storms that suffocated on dry air and then died a miserable death later as shear got to them.


ACE is very low 6.555 and that is below average for August 7.
Quoting 74. weathermanwannabe:
The less experienced bloggers or trolls always get impatient or provocative during the August lull; fact of the matter is that the past several years have all been "above average" seasons and no reason to think that trend, based upon the current active multi-decadal signal, will change.

I would expect at least around 7 storms or hurricanes by the end of October.


That would be below what the experts are forecasting. August with 3 and September with a big burst of activity (7-8) and with 1-2 in October is what I see.
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Here is the deal stick to your forecasts, if you originally thought the season was going to be a bust, then stick to that and vice-versa, don't change it based on current conditions. Also, hopefully no one runs away and cries in a corner when their prediction busts. I know for one right or wrong I will still be here at the end of the season. Hopefully you all will too. :)
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Quoting 78. sporteguy03:

No that belongs to CybrTeddy he gives the best speeches. :)


You flatter me. :P
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Quoting 72. washingtonian115:
The infamous Wu speech during hurricane season..

No that belongs to CybrTeddy he gives the best speeches. :)
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Quoting 76. CybrTeddy:


Why is it infamous? If anything is infamous it's the bellyaching speeches that we see around this time. Sporteguy03's dead on.
Because we hear it every year during a lull :).It's a joke Ted.
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Quoting 72. washingtonian115:
The infamous Wu speech during hurricane season..


Why is it infamous? If anything is infamous it's the bellyaching speeches that we see around this time. Sporteguy03's dead on.
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A lot of you have been around longer than me tracking the Tropics and should know better not to call this season a bust being that we are only 1 week into August with the Climatoligcal peak not occurring until the 2nd week in September. In fact a lot of bad hurricanes have occurred more often in September than in August. Also every season including the most active season on record 2005 had its lull. I checked the EL-Nino forecast and only a few models suggest we would see El-Nino conditions which wouldn't be until Winter time at best, but I'm starting to believe those models are out to lunch and that we will remain in a Neutral to weak La-Nina. SAL will thin out once the high retreats north and weakens, are we even at summer solstice yet? These ULL features you are seeing now will be carried out of the way with the rise in motion from the MJO and there will be a period in which the troughs will stop pushing off the East Coast. In that period is when the Atlantic should see an explosion of activity. This might be a second half season as well.
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The less experienced bloggers or trolls always get impatient or provocative during the August lull; fact of the matter is that the past several years have all been "above average" seasons and no reason to think that trend, based upon the current active multi-decadal signal, will change.

I would expect at least around 7 storms or hurricanes by the end of October.
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The attitude on here is so much like it was in August 2010 it's actually funny. People then too were backtracking their forecasts, stating the season wouldn't live up to expectations, and we weren't on the "D" storm yet like we are right now. The CSU and TSR haven't dropped their predictions and to be honest neither have I. People please for once have patience. This isn't sports, you have to wait for things to happen. This season will be an August 20th - October 10th season in terms of activity.
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Quoting 66. sporteguy03:
That is sad if a person has their feelings hurt by the weather because the amount of storms out there. I just don't get it on here sometimes it seems some bloggers are upset that there is no hurricane by the first week of August. There is plenty of time left in the season. As far as the models go they are guidance only especially long range, use climatology and the chart will tell you that the season is nearing the heart of the season. If you think this season is over go back and read previous years of Dr.M's blog where the same thing was said over and over again.
The infamous Wu speech during hurricane season..
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Quoting 58. taco2me61:

Good Morning Sheri :o)

we did not have that much rain last night (0.54") but on Monday night had (2.88").... You all out in West Mobile got it all last night.... Now I too was thinking we were going to have close to 19 named storms, but as I see it right now I think we will get close to that number.... I am afraid that the GOM will get at least 2 of them between now and the end of September.... Good to see you on this morning

Taco :o)


Taco, Thanks and great to see ya to, I am always on here in the morning and reading. But it's great to see you again. Well we found out from all that rain that we have 5 leaks in the roof, not good. Hubby said it's time for a roof so know I gotta go price shingles and all that good stuff. Not going to be fun.

sheri
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Quoting 65. Kyon5:
The 2010 hurricane season got serious by August 23. There were only 3 named storms by the time. Still, it managed to produce 19 storms. All we have to do is wait.


Yep, a lot can change in two weeks!
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Quoting 63. Beachfoxx:
Great blog,thanks Dr. M.


Hey stranger, good to see you posting here!
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Quoting 5. StormPro:
Good morning all, heat advisory here again in NOLA although I'm not quite sure what is different about today than the last 200 august 7ths lol. Have a great day
From the NWS:

A HEAT ADVISORY MEANS THAT A PERIOD OF HOT TEMPERATURES IS
EXPECTED. THE COMBINATION OF HOT TEMPERATURES AND HIGH HUMIDITY
WILL COMBINE TO CREATE A SITUATION IN WHICH HEAT ILLNESSES ARE
POSSIBLE.

IOW, the weather needn't necessarily be any hotter than normal to warrant such an advisory; it's issued to make people aware of the danger, that's all.
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That is sad if a person has their feelings hurt by the weather because the amount of storms out there. I just don't get it on here sometimes it seems some bloggers are upset that there is no hurricane by the first week of August. There is plenty of time left in the season. As far as the models go they are guidance only especially long range, use climatology and the chart will tell you that the season is nearing the heart of the season. If you think this season is over go back and read previous years of Dr.M's blog where the same thing was said over and over again.
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Quoting 52. Tazmanian:
Well if we don't see any storms by Augs 20th am calling this season a bust
The 2010 hurricane season got serious by August 23. There were only 3 named storms by the time. Still, it managed to produce 19 storms. All we have to do is wait.
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The only storm that was remotely interesting thus far was Andrea.The other one was your typical June storm..an then you had two wanna be short lived cape verde storms that suffocated on dry air and then died a miserable death later as shear got to them.
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Great blog,thanks Dr. M.
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Just a little wet in the MID WEST.....Watch those flooding maps explode.
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Well probably have two storms by the 20th .so no bust folks. Stop giving up on the season yet . You all got to have patience which some of u can't handle.
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Blob
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Quoting 57. MisterPerfect:


MP- just wondering all that brown on the image, is that the SAL?

sheri
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Quoting 50. catastropheadjuster:


Taco Hey how r you? What did you think about all that rain last night? It did some serious raining. So what's your thoughts about the season, earlier in the season everyone was saying it was going to be like 2004 know some r saying where not gonna have much of a season.

sheri

Good Morning Sheri :o)

we did not have that much rain last night (0.54") but on Monday night had (2.88").... You all out in West Mobile got it all last night.... Now I too was thinking we were going to have close to 19 named storms, but as I see it right now I think we will get close to that number.... I am afraid that the GOM will get at least 2 of them between now and the end of September.... Good to see you on this morning

Taco :o)
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Quoting 24. SouthernIllinois:

Exactly what I was looking for. Thanks so much! :P


Girl check your WU mail, you have some questions to answer LOL!
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Until a storm is physically out there I'm not believing anything.Some peoples feelings were hurt because they felt as though this was going to be a quick starting season with some nice storms already to track.You all were sadly mistaken.Sorry this isn't 2008 part two.And honestly if the instability doesn't let up anytime soon I think we will continue to see weak storms struggling with dry air.Like 2012 for a example.
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GFS cant make up its mind.
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Well if we don't see any storms by Augs 20th am calling this season a bust
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African dust has settled over TX, hazy, hot and humid with heat indicies as high as 115 in isolated locations....in the shade
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Quoting 33. taco2me61:

Mobile Alabama not to far from you I think :o)

Taco :o)


Taco Hey how r you? What did you think about all that rain last night? It did some serious raining. So what's your thoughts about the season, earlier in the season everyone was saying it was going to be like 2004 know some r saying where not gonna have much of a season.

sheri
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Thanks doc!
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Quoting 35. GTstormChaserCaleb:
You're welcome. :) Here is a look at the lower resolution FIM-7 which goes out to the longer ranges.



And continues to show a Tropical Storm in the GOM.



Glad that is 336hr out and not 72hr...
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Quoting 44. taco2me61:


That's a long way out for a model to predict a "Storm" in the GOM. But if it does we will have Tidal Flooding here along the North Gulf Coast :o(

Taco :o)


Spittin out junk, not gonna be storm out there anyway
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Quoting 18. hurricanes2018:
Quiet in the Atlantic on august 7 2013
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.


maybe no storm this august!


I gave my reasoning the other night on a heated discussion about why we might not see the forecasted amounted of storms this year. Keep in mind IT ONLY TAKES ONE STORM TO REMEMBER A SEASON! Below is what I posted on my blog!

I would suggest we might not see as many Hurricanes this year than was previously forecast. We had this conversation on my FB page. Yes, we can still get to 15 without any problems. But, thus far this year is the year of SAL with very dry Dusty air in the MDR leaving the Atlantic somewhat cooler than some years. Also, ULL's have also dominated the Western side of the Atlantic. Let me remind all that the Early arrival of WINTER in the Artic could easily cause many troughs thus creating a lot of ULL with wind Shear. Again, I am only pointing out the reasons we might not see the forecast of 15 named storms.

An active Pacific side is usually a Lull in the Atlantic. Seldom do we ever see both sides active at the same time. SELDOM does that happen!
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Quoting 42. moonlightcowboy:
...shear shield


Looks like the ULL will get pinched off by the building high off the East Coast which should resume a more east to west motion for tropical waves entering the Caribbean.
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Quoting 35. GTstormChaserCaleb:
You're welcome. :) Here is a look at the lower resolution FIM-7 which goes out to the longer ranges.



And continues to show a Tropical Storm in the GOM.



That's a long way out for a model to predict a "Storm" in the GOM. But if it does we will have Tidal Flooding here along the North Gulf Coast :o(

Taco :o)
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Quoting 38. CaribBoy:
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.

If nothing change within the next two weeks... well... you can guess the end of my thinking.
I don't know about all that at the end of the 6-7 day period we may have something to watch in the Western Caribbean and both the GFS and ECMWF is showing a broad low emerging off the coast of Africa in 3-5 days. I'd say odds are good we get something between now and the 20th.
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...shear shield


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i see the new tropical wave on here
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Broad low in the SW Caribbean around 150 hrs. We may see something try to get going down there, but it might take awhile, especially knowing monsoonal development.

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Quoting 33. taco2me61:

Mobile Alabama not to far from you I think :o)

Taco :o)


Yep, Fort Walton Beach here. Amazing how close we are but how different rain amounts can be. Some days you'll get rain and we won't and then we'll get rain on the days you don't. I guess that's why they use the terms scattered and isolated thunderstorms in the forecast!
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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.

If nothing change within the next two weeks... well... you can guess the end of my thinking.
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Gonna be another scorcher today folks, highs in the 100s, and not a drop of rain around for a thousand miles
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Enjoyed learning about the models. Thanks Dr. M!!
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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