Restoring confidence in NHC
There are no threat areas in the tropical Atlantic to discuss, and none of the computer models are forecasting tropical storm formation over the coming week. In the Pacific, an exceptionally large Category 4 typhoon, Man-Yi, will pass close to Okinawa on Friday, and hit Japan on Saturday. Winds at Okinawa have been as high as 50 mph with gusts to 70 mph.
Some links on Man-Yi, sent to me by Jim Edds:
Live camera feed from Southern Okinawa:
click on the pic arrow on the bottom right.
Okinawa radar.
click on Okinawa to zoom in - awesome shot
Camera feed with some audio.
click on the first "no image" box then select "report 17/66"
Latest satellite image of Typhoon Man-Yi, courtesy of NOAA.
Restoring confidence in the NHC
Interim National Hurricane Director Dr. Ed Rappaport has two immediate tasks--restoring morale fractured by Bill Proenza's turbulent 6-month tenure, and restoring public confidence in the Hurricane Center's ability to do their job. With the steadying influence of Dr. Rappaport, a highly respected and talented hurricane scientist, I expect that the staff of NHC will put out their best hurricane forecasts ever this season. Aiding in this endeavor will be the availability of a new hurricane tracking, intensity, and storm surge model called the HWRF--Hurricane Weather and Research Forecast Model. In addition, several of the other reliable models used by the forecasters, such as the GFS and GFDL, have had upgrades since last hurricane season. Furthermore, the Air Force Hurricane Hunters will be carrying the SFMR instrument for the first time, which can measure winds speeds at the ocean surface everywhere the aircraft fly.
Forecasters at the National Hurricane Center made their best track forecasts ever for storms in the Atlantic in 2006. The mean track errors for 12 to 72 hour forecasts were 15% - 20% lower than during 2001-2005. Track errors for Atlantic storms have improved about 50% in the past 15 years (Figure 1), a remarkable achievement that has undoubtedly saved lives and hundreds of millions of dollars. The track error in 2006 for a 24 hour forecast was 58 miles; 112 miles for a 48 hour forecast; and 171 miles for a 72 hour forecast. Track errors for 96 and 120 hour forecasts were 236 miles and 305 miles--the second best on record (2003 set the record). NHC's long-range 120 hour forecasts had a significant bias to the west of 94 miles--about double the bias of what the computer models were forecasting. Thus, when the models correctly called for systems to recurve out to sea, NHC human forecasters tended to resist following what the models were saying.
Figure 1. Track forecast skill since 1990 in the Atlantic for the official NHC forecasts. Track errors are given in nautical miles (100 n mi = 115 miles). Skill is rated compared to a "zero skill" forecast using NHC's CLIPER5 model. The CLIPER model (short for CLImatology and PERsistence) is a model that makes a forecast based on historical paths hurricane have taken, along with the fact that hurricanes tend to keep moving in the direction they are going (i.e., their current motion persists).
Intensity forecasts
Intensity forecasts since 1990 have shown little or no improvement, and 2006 was no exception (Figure 2). One encouraging result was the emergence of the GFDL's intensity model as the best intensity model for 2006. This is the first time that a non-statistical model has made the best intensity forecasts. With the major improvements that were added for the 2007 version of the GFDL, plus the availability of the HWRF model, I am hopeful that this year will see the first noticeable improvement in intensity forecasts since 1990.
Figure 2. Intensity forecast skill since 1990 of the official NHC Atlantic forecasts. Intensity errors are given in knots (10 knots = 11.5 mph).
Jeff Masters
Reader Comments
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Join us in
Storm Chat during the show!
The Barometer Bob Show for July 12, 2007!
Bobs guest will be Dr Robert Atlas, Dr. Robert Atlas is the former Chief Meteorologist at NASA's Goddard Space Flight Center (GSFC), and is currently the Director of the National Oceanic and Atmospheric Administration's (NOAA) Atlantic Oceanographic and Meteorological Laboratory in Miami, Fla. Some of the areas he focuses his current research on include the prediction, movement and strengthening of hurricanes. Atlas has worked with both satellite data and computer models as a means to study these hurricane behaviors.
We will discuss the QuickScat Satelitte, what it is, what it does, and about the studies on it's performance.
Hey!!
Welcome CRS!!!
Tnx...
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HurricaneGeek
I heard tht the GEM and CMC were the same!!
See:
Posted By: MichaelSTL at 7:05 PM GMT on July 12, 2007.
So is that 2 models now venturing out 144 hours to stir up some media attention???
Actually only one model (the CMC and GEM are the same, just a different name; the GEM is the CMC's global model, just as the GFS is the NCEP's global model).
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Reload time here VERY SLOW w/ 1400 posts & grafics...
CRS
A disorganised wave at about 38 w, that some models predict will become a hurricane in Florida. Thats cool. But what would realy be nice, is for one of the people reading the models that result in this prediction, to say what that forecast is based upon.
Surely, it would be possible to make a written synopsis of the information, so that others could at least see the reasoning ??
Where do we get this info ?
This site has also been added to the Quick Links page.
Please see my post a few mins ago.
Any comment on this ??
thanks..........
So, what have we got ??
A disorganised wave at about 38 w, that some models predict will become a hurricane in Florida. Thats cool. But what would realy be nice, is for one of the people reading the models that result in this prediction, to say what that forecast is based upon.
Surely, it would be possible to make a written synopsis of the information, so that others could at least see the reasoning ??
Where do we get this info ?
From CMC link 850mb vorticity
Which shows the little yellow blob @ 38W turning into a red blob with yellow on the edges which is probably a TS @ least.
Link on Vorticity
Or we have the graphical forecastLink which shows the pressure @ 1008 entering FL which doesn't seem like much but as someone mentioned earlier the low pressure in a hurricane is VERY close to the eye.
This is VERY simplified if you want more complicated ask StormyW, IKE, Nash, Drakoen, ect. etc.
As for the models, that is a long way out and it is basically something to watch the models toy with for right now. If they hold on to the feature through the next 8 runs or so then I'll believe them a little more.
THANKS!... now set to 50 (duh.... I catch on fast no matter how long it takes) and sorrry about all the "whitespace" CRS
So, what have we got ??
A disorganised wave at about 38 w, that some models predict will become a hurricane in Florida. Thats cool. But what would realy be nice, is for one of the people reading the models that result in this prediction, to say what that forecast is based upon.
Surely, it would be possible to make a written synopsis of the information, so that others could at least see the reasoning ??
Where do we get this info ?
Only one model the CMC/GEM shows a system developing TS or Hurricane strength. The model base thing on the what they think the atomospheric conditions will be. The CMC shows the system 144 hours out. Which is a long way out. Usually we look for model agreement. Before we buy into this. THe GFS 18z does really show anything but moisture in Florida. I think there are a number of sites that provide a synopsis of the models. The TCHP, NWS, etc.
I have a question as a newbie. There is a group of storms just south of al/fl panhandle that came off last night. (I know this as I huddled in the hallway with five kids with tornadoes all around last night). What is to stop development of the system now in the gulf?
Drak, you think the cmc model may be right?
Too far out to tell. We need more model agreement.
Thank you Drakoen.
No problem.
Sheri
Welcome CRS
Thanks CRS
well if the cmc model is to be correct then it should be a depression by monday correct.
No. Somewhere around the 120 hours time frame which is 5 days from now.By that time it should be west Cuba.
I hope it swings north before it gets to 11 n 61 w in any event. We have had loads of rain here the past week.
What's the forecast shear for this wave.
Low to moderate shear.
If the CMC sticks with it for several more runs, then we have something to watch...
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