The notion, right or wrong, came from this discussion from the NWS...
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
143 PM EDT THU JUL 28 2005
VALID 12Z SUN JUL 31 2005 - 12Z THU AUG 04 2005
SOUTHEAST LATE IN THE PD...
AS FOR THE TROPICAL FEATURE IS EXPECTED TO MOVE THRU THE
BAHAMAS...WITH RIDGING BUILDING TO ITS NORTH AHEAD OF THE
EVER-WEAKER TROUGH PROGRESSING THRU CNTRL CAN AND A DVLPG WEAKNESS
IN THE UPR PATTERN IN THE CNTRL/WRN GULF OF MEXICO...IT IS LOOKING
MORE LIKELY THAT IF THERE WAS AN ORGANIZED TC...THAT IT WOULD
RETROGRADE INTO FL OR THE SOUTHEAST US SOMETIME BETWEEN AUG 3-5.
MOST OF THE GUIDANCE NOW TAKES THE SYSTEM THROUGH THE FL STRAITS
INTO THE ERN GULF OF MEXICO. THE 12Z UKMET WAS THE FARTHEST NE...
LEAVING THE SYSTEM JUST NE OF THE BAHAMAS. MADE SLIGHT CHANGES IN
THAT DIRECTION FROM CONTINUITY PER COORDINATION W/TPC...WHICH IS
CLOSE TO THE 12Z ECMWF.
GOM and 92L
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frederic79
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deltadog03
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look, it all depends on the ridge....CLEARLY the better global models are handling this very well and they are a heck of a lot more dependable than the GFS. I mean just read all of the NWS and HPC/TPC discussions....don't look at the tropical models so much, as most if not all are GFS based. There is plenty of time to watch this. Yes, my honest opinion its a florida straits to GOM....
Last edited by deltadog03 on Thu Jul 28, 2005 4:36 pm, edited 1 time in total.
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Ivanhater
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MORE LIKELY THAT IF THERE WAS AN ORGANIZED TC...THAT IT WOULD
RETROGRADE INTO FL OR THE SOUTHEAST US SOMETIME BETWEEN AUG 3-5.
MOST OF THE GUIDANCE NOW TAKES THE SYSTEM THROUGH THE FL STRAITS INTO THE ERN GULF OF MEXICO.
so they must be -removed-?...personally i think it will cross the peninsula and go in the gulf instead of the straits, but to be fair to the gommers its more than "-removed-" which i try to stay out of
RETROGRADE INTO FL OR THE SOUTHEAST US SOMETIME BETWEEN AUG 3-5.
MOST OF THE GUIDANCE NOW TAKES THE SYSTEM THROUGH THE FL STRAITS INTO THE ERN GULF OF MEXICO.
so they must be -removed-?...personally i think it will cross the peninsula and go in the gulf instead of the straits, but to be fair to the gommers its more than "-removed-" which i try to stay out of
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frederic79
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Opal storm
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gkrangers
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gkrangers
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deltadog03
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>>look, it all depends on the ridge....CLEARLY the better global models are handling this very well and they are a heck of a lot more dependable than the GFS. I mean just read all of the NWS and HPC/TPC discussions....don't look at the tropical models so much, as most if not all are GFS based. There is plenty of time to watch this. Yes, my honest opinion its a florida straits to GOM....
Well the GFS is a global model, but you might find this discussion posted by Clark Evans interesting (assistant researcher at Florida State University and mod over at flhurricane.com - he has a pretty good blog over there along with Jason Kelley of Panama City Beach tv). He wrote the following:
As another heads-up, tropical-wise, the FSU Superensemble has been the best performing model for two years running. Of course, it's not publically available, so we can't use the output to make forecasts...only the NHC can. The NOGAPS model was best in 2002 and has remained near the top ever since; the UKMET was best in 2001 yet has been one of the worst since then. It was negatively influenced by 1 storm in 2002, but no such excuses can be made for the past two years. The UK Met Office apparently made some changes to the model during that time which hasn't resulted quite as favorably as they would've hoped or expected. The GFS is always near the middle of the pack, while the GFDL is similar (it's run off of the GFS initial conditions). The GFDN, or the GFDL run off of the NOGAPS initial conditions, generally performs slightly better. Both are usually either too low or too high with intensity. The Canadian (CMC) and European Center (ECMWF) models aren't run as much for tropical activity, though the latter does quite well and the former has its moments...particularly with recurving storms.
On a global scale, the ECMWF model has been the best for some time. The UKMET model is up there as well, as is the Japanese (JMA) model. The GFS is towards the middle-end of the pack as far as global models go, but improving. Note that many of the tropical models are just mesoscale models -- this includes the GFDL and various flavors of both the WRF and MM5, plus all of the steering layer (e.g. BAM-series, LBAR, A98E) and statistical (e.g. CLIPER) models -- and thus not relevant to this part of the discussion.
In this decade, the dynamical models (GFS, GFDL, ECMWF, UKMET, and so on) heavily outperform the limited-area/statistical-dynamical models (BAM-series, LBAR, etc.) and are even better than the statistical/persistence models. This wasn't always the case. Until the mid-90s, when the global models improved in the tropics to the point of relevancy, the statistical-dynamical models were relied upon for track and intensity forecasting; back into the 80s and prior, it was down to forecaster experience, looking at the flow regimes (as best as they could tell from water vapor; satellite analyses such as the UWisconsin products weren't around back then), and the statistical/persistence models. Kinda funny how we've come full circle, with a statistical model (FSU Superensemble) at the head of the pack, though it really is better classified as a dynamical model with statistical modifications.
Obviously, models change from year to year (and occasionally more frequently than that), whether in terms of their resolution, the physics they employ, or even how they ingest data. That's why it's important to use past performance as just a tool until you can determine how a given model is doing with any given storm or any given season/environmental regime. It's also why the FSU Superensemble -- heavily based upon prior model performance -- tends to struggle early in the season; the changes in the model aren't always able to be accounted for, making the first few storms' forecasts not as accurate as they could be.
Hope this sheds some light on the model questions...
Steve
Well the GFS is a global model, but you might find this discussion posted by Clark Evans interesting (assistant researcher at Florida State University and mod over at flhurricane.com - he has a pretty good blog over there along with Jason Kelley of Panama City Beach tv). He wrote the following:
As another heads-up, tropical-wise, the FSU Superensemble has been the best performing model for two years running. Of course, it's not publically available, so we can't use the output to make forecasts...only the NHC can. The NOGAPS model was best in 2002 and has remained near the top ever since; the UKMET was best in 2001 yet has been one of the worst since then. It was negatively influenced by 1 storm in 2002, but no such excuses can be made for the past two years. The UK Met Office apparently made some changes to the model during that time which hasn't resulted quite as favorably as they would've hoped or expected. The GFS is always near the middle of the pack, while the GFDL is similar (it's run off of the GFS initial conditions). The GFDN, or the GFDL run off of the NOGAPS initial conditions, generally performs slightly better. Both are usually either too low or too high with intensity. The Canadian (CMC) and European Center (ECMWF) models aren't run as much for tropical activity, though the latter does quite well and the former has its moments...particularly with recurving storms.
On a global scale, the ECMWF model has been the best for some time. The UKMET model is up there as well, as is the Japanese (JMA) model. The GFS is towards the middle-end of the pack as far as global models go, but improving. Note that many of the tropical models are just mesoscale models -- this includes the GFDL and various flavors of both the WRF and MM5, plus all of the steering layer (e.g. BAM-series, LBAR, A98E) and statistical (e.g. CLIPER) models -- and thus not relevant to this part of the discussion.
In this decade, the dynamical models (GFS, GFDL, ECMWF, UKMET, and so on) heavily outperform the limited-area/statistical-dynamical models (BAM-series, LBAR, etc.) and are even better than the statistical/persistence models. This wasn't always the case. Until the mid-90s, when the global models improved in the tropics to the point of relevancy, the statistical-dynamical models were relied upon for track and intensity forecasting; back into the 80s and prior, it was down to forecaster experience, looking at the flow regimes (as best as they could tell from water vapor; satellite analyses such as the UWisconsin products weren't around back then), and the statistical/persistence models. Kinda funny how we've come full circle, with a statistical model (FSU Superensemble) at the head of the pack, though it really is better classified as a dynamical model with statistical modifications.
Obviously, models change from year to year (and occasionally more frequently than that), whether in terms of their resolution, the physics they employ, or even how they ingest data. That's why it's important to use past performance as just a tool until you can determine how a given model is doing with any given storm or any given season/environmental regime. It's also why the FSU Superensemble -- heavily based upon prior model performance -- tends to struggle early in the season; the changes in the model aren't always able to be accounted for, making the first few storms' forecasts not as accurate as they could be.
Hope this sheds some light on the model questions...
Steve
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deltadog03
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No problem delta. Check out his blog sometime over at that site. He usually only updates it when there is threatening action, but he's pretty good.
I can't make heads or tails of what the ECMWF wants to do. It looks like it brings a hump toward SE FL but I can't guess if it's going to turn it up or into the Gulf based on that run.
Steve
I can't make heads or tails of what the ECMWF wants to do. It looks like it brings a hump toward SE FL but I can't guess if it's going to turn it up or into the Gulf based on that run.
Steve
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gkrangers
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deltadog03
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A couple of comments on the Clark Evans post
I would like to see the verification for that. FSUSE was the best performing model last year, but in 2003 it was neither the best performing track model (GFDL was tops) nor the best performing intensity model (DSHIPS was). As far as NHC is concerned, no model has been the top performer two years in a row.
And as recently as last year, NHC couldn't really; the output wasn't timely enough. They got it right before the advisory was due, so all they could do was look at their forecast and compare it to the SE forecast. They didn't get it in time to make it part of their decision making proccess. I believe however, that it has become more timely this year.
Sources:
2003 Verification
http://www.ofcm.gov/ihc04/presentations ... jgross.ppt
2004 Verification
http://www.tpc.ncep.noaa.gov/verification/pdfs/2004.pdf
2004 Superensemble Performance
http://www.ofcm.gov/ihc05/Presentations ... mackey.ppt
As another heads-up, tropical-wise, the FSU Superensemble has been the best performing model for two years running.
I would like to see the verification for that. FSUSE was the best performing model last year, but in 2003 it was neither the best performing track model (GFDL was tops) nor the best performing intensity model (DSHIPS was). As far as NHC is concerned, no model has been the top performer two years in a row.
Of course, it's not publically available, so we can't use the output to make forecasts...only the NHC can.
And as recently as last year, NHC couldn't really; the output wasn't timely enough. They got it right before the advisory was due, so all they could do was look at their forecast and compare it to the SE forecast. They didn't get it in time to make it part of their decision making proccess. I believe however, that it has become more timely this year.
Sources:
2003 Verification
http://www.ofcm.gov/ihc04/presentations ... jgross.ppt
2004 Verification
http://www.tpc.ncep.noaa.gov/verification/pdfs/2004.pdf
2004 Superensemble Performance
http://www.ofcm.gov/ihc05/Presentations ... mackey.ppt
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On the ECMWF... let's look at the final lines of the HPC discussion
So their forecast is similar to the 12Z ECMWF...
...so let's look at the HPC forecast...
http://www.hpc.ncep.noaa.gov/medr/5dayfcst_bw.gif
It doesn't put the low anywhere near the Florida Straits.
MADE SLIGHT CHANGES IN
THAT DIRECTION FROM CONTINUITY PER COORDINATION W/TPC...WHICH IS
CLOSE TO THE 12Z ECMWF.
So their forecast is similar to the 12Z ECMWF...
...so let's look at the HPC forecast...
http://www.hpc.ncep.noaa.gov/medr/5dayfcst_bw.gif
It doesn't put the low anywhere near the Florida Straits.
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Take it up with Clark, not me. He's the research scientist. I'm not sure in what context he's discussing nor in comparison to what sample. I'm sure he'd hook you up. I'll go ahead and call him over (he may have an account here, if not, he can create one). Maybe he'll explain what he was saying.
Steve
Steve
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