Restoring confidence in NHC

By: Dr. Jeff Masters , 12:24 PM GMT on July 11, 2007

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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

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1088. bobw999
1:52 PM EDT on July 12, 2007
Basically, I won't think too much of it until news people in Miami start telling everyone to panic because they will all surely die if this hits as a T.S. or Cat 1.

Katrina was a cat 1 when it hit Miami and that did some damage but lots of flooding. Thats the problem with south Florida is its all flat.
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1087. IKE
12:49 PM CDT on July 12, 2007
Posted By: vortextrance at 12:49 PM CDT on July 12, 2007.
Posted By: IKE at 5:44 PM GMT on July 12, 2007.

Posted By: vortextrance at 12:42 PM CDT on July 12, 2007.
While I am sure the CMC isn't right.

I'm not saying it's right...but...how do you know it isn't?

I have never seen a model corectly predict the path of a tropical cyclone 6 days out that hasn't even formed yet. Even if it was already a TS or hurricane we all know 6 day forecasts are mostly useless.



I agree on the path portion. I've seen models accurately predict a storm would form a few days in advance.
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1086. Tazmanian
5:52 PM GMT on July 12, 2007
ok her is are wave



this is the Station neare by the wave

Station 41041


Wind Direction (WDIR): ENE ( 70 deg true )
Wind Speed (WSPD): 15.5 kts
Wind Gust (GST): 19.4 kts
Wave Height (WVHT): 8.2 ft
Dominant Wave Period (DPD): 10 sec
Average Period (APD): 5.8 sec
Atmospheric Pressure (PRES): 29.99 in
Pressure Tendency (PTDY): -0.05 in ( Falling )
Air Temperature (ATMP): 79.2 F
Water Temperature (WTMP): 80.1 F
Dew Point (DEWP): 73.8 F
Heat Index (HEAT): 82.8 F


Station 41100

Wind Direction (WDIR): E ( 80 deg true )
Wind Speed (WSPD): 18.1 kts
Wave Height (WVHT): 7.5 ft
Dominant Wave Period (DPD): 7 sec
Atmospheric Pressure (PRES): 30.03 in
Pressure Tendency (PTDY): -0.02 in ( Falling )
Air Temperature (ATMP): 82.6 F
Dew Point (DEWP): 74.5 F
Heat Index (HEAT): 89.2 F

Station 41040

Wind Direction (WDIR): ENE ( 70 deg true )
Wind Speed (WSPD): 15.5 kts
Wind Gust (GST): 17.5 kts
Atmospheric Pressure (PRES): 29.99 in
Pressure Tendency (PTDY): -0.03 in ( Falling )
Air Temperature (ATMP): 81.5 F
Water Temperature (WTMP): 81.9 F
Dew Point (DEWP): 71.8 F
Heat Index (HEAT): 86.0 F

Member Since: May 21, 2006 Posts: 5091 Comments: 115256
1085. benirica
5:47 PM GMT on July 12, 2007
mr puerto rico, sorry i didnt answer, but yes! that was pretty intense and sudden, especially here at my house, which is up on a hill side and the wind comes straight off the ocean uninterrupted...
the wind was VERY strong, a few branches in my pool still. lol
and after it was over (the first batch) i had to go take some movies back and got hit by another batch and my car was swaying in the wind, the rain was actually falling horizontally and on the freeway everyone was going just 10mph... scary to drive in that type of thing, i usually avoid it.
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1084. bobw999
1:49 PM EDT on July 12, 2007
what does srn fla. mean

Southern Florida.
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1082. stormybil
5:50 PM GMT on July 12, 2007
my bad thanks
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1080. vortextrance
5:45 PM GMT on July 12, 2007
Posted By: IKE at 5:44 PM GMT on July 12, 2007.

Posted By: vortextrance at 12:42 PM CDT on July 12, 2007.
While I am sure the CMC isn't right.

I'm not saying it's right...but...how do you know it isn't?


I have never seen a model corectly predict the path of a tropical cyclone 6 days out that hasn't even formed yet. Even if it was already a TS or hurricane we all know 6 day forecasts are mostly useless.
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1079. stormybil
5:48 PM GMT on July 12, 2007
what does srn fla. mean
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1077. stormybil
5:45 PM GMT on July 12, 2007
got so is it that wave that out there now we need to watch like the atl one or it hasnt even been born yet .
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1074. wederwatcher555
5:44 PM GMT on July 12, 2007
what is the most number of tropical systems that occurred simultaneously in a single basin? especially the atlantic
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1073. IKE
12:43 PM CDT on July 12, 2007
Posted By: vortextrance at 12:42 PM CDT on July 12, 2007.
While I am sure the CMC isn't right.


I'm not saying it's right...but...how do you know it isn't?
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1072. hurricane23
1:42 PM EDT on July 12, 2007
Its interesting to see for sure but again i would like to see more model agreement before i buy into it.Its basic showing a strong TS or CAT1 heading into southflorida moving WNW.Dont see it moving into tampa on this run.Chances are things will change on the next run towards a weaker system more maybe stronger or infact nothing at all.We'll see.

Here is a pic of the 850mb vort.

vort
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1071. weathers4me
5:41 PM GMT on July 12, 2007
What does PD stand for in this:


RIDGE INTO THE ERN US IT WAS DEPICTING 24 HRS AGO. GEM GLOBAL
STILL INSISTS ON BRINGING HURRICANE INTO SRN FL AT THE END OF THE
PD...A SOLUTION
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1070. IKE
12:42 PM CDT on July 12, 2007
Posted By: jeanri2000 at 12:40 PM CDT on July 12, 2007.
How good is the cmc at predicting these types of events and are there any other models also showing this development? thaks


The GEM does. The NAM shows the moisture entering the Caribbean in 72-84 hours. The GFS does too.
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1069. Canesfan68
5:42 PM GMT on July 12, 2007
K good. It better not be right. I want to be able to come home lol
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1068. vortextrance
5:40 PM GMT on July 12, 2007
While I am sure the CMC isn't right. It may signal an overall change in conditions from unfavorable to favorable. It will be interesting to see if other models start developing systems over the next couple of weeks.
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1067. 0741
5:35 PM GMT on July 12, 2007
it 144 hour that most likely wont happen i donot go that many hour 144 ahead
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1066. stormybil
5:40 PM GMT on July 12, 2007
at that angle and remeber the high above it it will stay sout and go west simular to katrinas path for fla. stay tuned
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1065. jeanri2000
5:38 PM GMT on July 12, 2007
How good is the cmc at predicting these types of events and are there any other models also showing this development? thaks
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1064. Canesfan68
5:37 PM GMT on July 12, 2007
If the CMC is right, then it looks like im gonna be stuck out in the open sea for a few days on my cruise...
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1062. IKE
12:31 PM CDT on July 12, 2007
hurricane23...Is the CMC connected to the GEM?
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1061. hurricane23
13:27 EDT le 12 juillet 2007
Yea just saw that its been harping on this for a few runs now...

run
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1060. IKE
12:29 PM CDT on July 12, 2007
Posted By: stormybil at 12:29 PM CDT on July 12, 2007.
saw it too but i think its a new wave thats going form and head twoard so fla. from the bahmas does that sound right dont think its the one in the atl. now


I think it is...put the CMC on 850mb...you'll see where it starts...around 10N,40W.
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1059. Jedkins
5:27 PM GMT on July 12, 2007
Posted By: randommichael at 5:22 PM GMT on July 12, 2007.

Is it just me or is the Japan radar showing the eye becoming somewhat elongated?


Thats a mistake in the nowcast product, it doesn't know how to handle a well organized eye accurately in its forecast radar imagery.
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1058. bobw999
1:28 PM EDT on July 12, 2007
Is the CMC connected to the GEM?

Same thing I'm wondering.
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1057. hurricane91
5:28 PM GMT on July 12, 2007
look like a ts, but 6 days, thats a long time
1056. stormybil
5:27 PM GMT on July 12, 2007
saw it too but i think its a new wave thats going form and head twoard so fla. from the bahmas does that sound right dont think its the one in the atl. now

Link
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1055. IKE
12:27 PM CDT on July 12, 2007
Is the CMC connected to the GEM?
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1052. IKE
12:25 PM CDT on July 12, 2007
Posted By: Anticyclone1 at 12:18 PM CDT on July 12, 2007.
12Z CMC is now picking up on it.


I was just fixin to post it. You beat me!

Aims it at SE FL in 144 hours.
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1049. bobw999
1:22 PM EDT on July 12, 2007
12Z CMC is now picking up on it.

Sure is...................
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1047. Jedkins
4:54 PM GMT on July 12, 2007
Posted By: MichaelSTL at 4:14 PM GMT on July 12, 2007.

Convection/storms won't develop just because of a high CAPE; if there is a strong cap nothing may happen unless something (front, upper-level disturbance, seabreeze, etc) breaks it or until it weakens. Also, if there is little or no cap at all, the storms that develop are less likely to be severe than if they have to break a strong cap (a cap allows energy to build up; CAPE also isn't the only factor for storms or how strong they can get). The best way to find out what may happen is to look at the NWS discussions and what places like the SPC say (easier than trying to interpret a bunch of maps and data).





Yep you're right, capes have been 4000 or even higher past few days as they usually are this time of year. But due to an upper level ridge, hardly any of the sorms have been strong.


The other day Orlando had 1 severe Thunderstorm warning, but we get those everday around the area this time of year in central Florida.


So ya, high CAPE definitely doesn't mean you're getting severe weather for sure.

There are always so many factors that must come together for weather events to play out. Thats what makes forecasting so tough.
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1045. stormybil
5:12 PM GMT on July 12, 2007
where is this storm suppose to form to hit so. fla ? i dont see anything out there
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1043. stormybil
5:05 PM GMT on July 12, 2007
what model is showing a hurricane for so. fla i dont know the id who posted or if we can trust his word .
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1040. mrpuertorico
1:02 PM AST on July 12, 2007
hey benerica did you see the storm we had the other night i registered 38 mph wind gusts on my weather station! to bad i was sleeping when it hapened
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1039. Thundercloud01221991
5:03 PM GMT on July 12, 2007
http://www.jma.go.jp/en/radnowc/index.html?areaCode=217
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1038. gthsii
5:01 PM GMT on July 12, 2007
( dictated, and typed by a passing vagrant ) -- hehe
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.