Dr. Jeff Masters' WunderBlog

just wondering if anyone has the model forecast 1 week ago, before this weekend's mesosubextraitisitisntstorm 93L to see which one was closest to what actually happened.

Quoting Skyepony:
93L was closed. I had the west winds here. The surface center was ~40miles west of what was seen on radar (midlevels). It was somewhat elongated & sloppy at the surface. The center was north of me already on land before what was on radar hit KSC, it was within a very short time of it spinning up on radar. The center was on land from nearly if not the beginning..one of the many areas to look closely at all the data. The showers streaming in from the east flew over the obviously very shallow vorticity on radar..like a MCV. It was so small & ill stacked, the west side with convection was cold, the dry air it was sucking in the east side was warm. I stood in both. The rainband was cold the dry slot that arrived the next day was warm. It was bore out of a large area with other vorticity like a MCV out of a Mesoscale Convective System. We saw the ULL reflect on the surface of the east GOM finally on Oceansat that evening..weak & broad but the center of the MCS, that died sometime in the night. East coast one got in that sweet spot next to FL that spins things up.. Maybe had it had more time over water. It was a cyclone seed, tossed on land, but I'm not sure if it wasn't anything more than a mesoscale convective vortex.

Hold on a minute there, sky.

The radar was not looking into the mid levels of the system. Mid levels of the troposphere are usually defined around 850/800mbs up to around 500mbs.

Look at the radar loop below and you will see the circulation is only 10 or 20 miles from the radar location (denoted by the white plus sign). At 10-20 miles (no, not 40 miles, check Google Earth if you don't believe me), the radar beam is less than 2,000 feet above the surface of the earth, which is absolutely not the mid levels of the Earth. It was looking aroud the 950mb level, which is the low levels of the atmosphere.





Regardless, surface observations found that the circulation was closed at the surface. Surface observations also support the fact that the circulation was not hanging around over land the whole time like you say.



Melbourne International Airport



Ocean Drive, Vero Beach

Quoting robert88:


I thought for sure the CONUS would of seen a Charley or Ivan etc. The Caribbean was shut down for business. Very stable and hostile conditions down there this season. I sure didn't expect that in a neutral to La Nina season.

NOT over yet as i was just in the GOM and its still plenty warm yet. Fingers crossed!

I see we are still discussing the mess that was 93, as it will always be remembered. It was an aborted attempt at a subtropical system. It did not obtain a clear closed circulation and should go in the pile where invests go. NHC, do NOT name this system!

Quoting FrankZapper:
I see we are still discussing the mess that was 93, as it will always be remembered. It was an aborted attempt at a subtropical system. It did not obtain a clear closed circulation and should go in the pile where invests go. NHC, do NOT name this system!

I'm way over 93L to.

Quoting Skyepony:


MCV can be closed at the surface. They aren't nicknamed landcanes for being midlevel..

Subtropical storms come from ULLs that make it to the surface, extratropical storms & from Mesoscale lows. The later used to be caused a neutercane.


So if it was a Subtropical Cyclone what was it bore out of? & how long was it that before you think it should have been called a Subtropical storm & what about the Low reflecting on the surface of the GOM at the same time on Oceansat?.. 93L the tiny low was wrapped up in all that, then became the dominant low after landfall..Isn't that part of the definition of a MCC & it's MCV?

While we are at it and just for fun, here is an interesting radar image of the somewhat famous MCV in May of 2009. This guy was pretty much a land-cane, but obviously was never designated a true tropical system. Stu Ostro had a good blog on it.
Link

Quoting robert88:
93L was a extratropical mid latitiude cyclone. It wasn't subtropical or tropical...therefore it didn't warrant a name. Dry air getting sucked into the system blew up some powerful supercell T-storms over the gulfstream which brought the winds down to the surface. If you removed all the UL energy that was down there could the system still of powered itself? Nope....because There was no anticyclone sitting over it...so the air couldn't come over the center and come out at the top.

Which is exactly why it's subtropical...subtropical meaning it is a hybrid of both tropical and extratropical processes. It had convection at the surface and was indeed a warm core system according to all AMSU satellite passes and model cyclone phase diagrams, but it was being supported by divergence aloft.

Quoting FrankZapper:
I see we are still discussing the mess that was 93, as it will always be remembered. It was an aborted attempt at a subtropical system. It did not obtain a clear closed circulation and should go in the pile where invests go. NHC, do NOT name this system!

It absolutely did obtain a closed surface circulation. Surface observations and radar (radar at the low levels) confirm this.

93L clearly had a closed circulation, observations showed it. Those who chose to ignore the facts and blindly follow the NHC need to get some new glasses

I am one of the last to blast the NHC most of the time, but they missed the boat on this one. The impact this system had on parts of Florida is bigger then some realize.

Quoting washingtonian115:
I'm way over 93L to.

Yeah, the discussion was interesting and warranted, but there are bigger things going on right now.

Like Jova, which is about to slam into Mexico.

Quoting robert88:


Your opinion...not the experts ;)

Really? Why did the NHC have it listed as a subtropical storm then?

From the 18z ATCF file

AL, 93, 2011100918, , BEST, 0, 274N, 794W, 35, 1007, SS




No, they did not name it at this time, but they did believe it was subtropical.

I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC's Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don't always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system's non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both non-tropical and tropical characteristics. In other words, they acknowledge that it was at least partially warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Um yeah 93L=dead.Move along people nothing to see here.

The NHC has generational experience that DIRECTLY impacts their reasoning and issuance's.

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC%u2019s Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don%u2019t always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system%u2019s non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both subtropical and tropical characteristics. In other words, they acknowledge that it was warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Not to quote someone who was on the other side of the fence last night but

"That;s good enough for me"

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC’s Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don’t always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system’s non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both subtropical and tropical characteristics. In other words, they acknowledge that it was warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep their best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Thank you for sharing, Levi

Quoting TomTaylor:

Hold on a minute there, sky.

The radar was not looking into the mid levels of the system. Mid levels of the troposphere are usually defined around 850/800mbs up to around 500mbs.

Look at the radar loop below and you will see the circulation is only 10 or 20 miles from the radar location (denoted by the white plus sign). At 10-20 miles (no, not 40 miles, check Google Earth if you don't believe me), the radar beam is less than 2,000 feet above the surface of the earth, which is absolutely not the mid levels of the Earth. It was looking aroud the 950mb level, which is the low levels of the atmosphere.





Regardless, surface observations found that the circulation was closed at the surface. Surface observations also support the fact that the circulation was not hanging around over land the whole time like you say.



Melbourne International Airport



Ocean Drive, Vero Beach

Forgot to post station TRDF1- Trident Pier, located in Port Canaveral. It showed a surface pressure of 999.5 mb and NNW winds of 2kt at 11:42pm, followed by a pressure of 999.9mb and W winds at 1kt at 11:48pm, then a pressure of 1000.0mb and SW winds at 6kt at 11:54pm. Closed circulation. Air temp went from 21C to 24C.

EP102011 - Hurricane JOVA


Storm Relative 1km Geostationary Visible Imagery

the GFS ecwmf and the canadian models all have a Tropical depression forming in around 110 Hrs and moving it towards western cuba and South Florida , so something to keep a close eye on

JOVA

Enhanced Infrared (IR) Imagery (4 km Mercator)

..click image for Loop

Quoting Skyepony:


MCV can be closed at the surface. They aren't nicknamed landcanes for being midlevel..

Subtropical storms come from ULLs that make it to the surface, extratropical storms & from Mesoscale lows. The later used to be caused a neutercane.


So if it was a Subtropical Cyclone what was it bore out of? & how long was it that before you think it should have been called a Subtropical storm & what about the Low reflecting on the surface of the GOM at the same time on Oceansat?.. 93L the tiny low was wrapped up in all that, then became the dominant low after landfall..Isn't that part of the definition of a MCC & it's MCV?

It bore out of an upper level trough over the eastern Gulf of Mexico creating divergence aloft which naturally favors rising air or convection.

Also, you forget to mention that subtropical lows can form with ULLs nearby, they do not have to be stacked over the system.

18z GFS has my first Alberta Clipper for Oct. 26! Wohoo, snow before Halloween, I live in southern New England... but it also backed off on the winter storm idea for the most part for the 19th.

I think what the GFS is moreso hinting at is a colder pattern for the end of the month and on into Nov.

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC's Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don't always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system's non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both non-tropical and tropical characteristics. In other words, they acknowledge that it was at least partially warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Which goes well with my line of thinking when I posted a link to a previous storm and their decisions not to issue warnings (Olga 2007) for Puerto Rico. It (93L) was well handled by the WFO out of Melbourne. They issued Special Weather Statements, High Wind Warnings, Flood Warnings, etc. And that would have possibly disrupted the flow of information given out to the public at that point.

I did take a moment on Facebook to recognize the NWS Melbourne for all their hard work on this system as it came calling. They acted very quick to get information to the public as soon as things started to unfold.

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC's Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don't always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system's non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both non-tropical and tropical characteristics. In other words, they acknowledge that it was at least partially warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Very cool to see the NHC respond to the public like that, props to them.

Also looks like they also believe it was subtropical too, they just didn't upgrade it for the sake of not wasting warnings on a storm that would be overland in an hour. No surprise there.

Quoting TomTaylor:
Very cool to see the NHC respond to the public like that, props to them.

Also looks like they also believe it was subtropical too, they just didn't upgrade it for the sake of not wasting warnings on a storm that would be overland in an hour. No surprise there.

Id like to know what robert88 and Frank have to say about the NHCs response. They basically justified all of us who felt this should have been classified

and it will be in post-season

Why does the NHC advisory say Jova is at 100 MPH and the Wunderground one say's 95 MPH? It's the same advisory.

Good evening.

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,................
Notice how he says that 93L exhibited both non-tropical and tropical characteristics. In other words, they acknowledge that it was at least partially warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Cool how they actually responded. I'm pretty darn sure that 93L will be upgraded in post-season analysis.

If you believe the NHC, which I do, given the short amount of time that invest 93 might have become a named system, they elected not to name the system and thereby interrupt the local warning system that was already active. Some people on this blog hammered NHC for not making the correct technical call as soon as they might have, but in retrospect NHC appears to have made the best decision consistent with its mission of helping to protect lives and property. Do people agree? Thank you, Levi for your post.

Quoting Hurricanes101:


Id like to know what robert88 and Frank have to say about the NHCs response. They basically justified all of us who felt this should have been classified

and it will be in post-season

Yeah, and they way they went about it did make sense. All of those warnings, watches, and advisories were already out.

To be honest, even though it wasn't named, people down there had the same amount of warning, the potential was talked about for days by private and public sectors alike, and the NWS offices did a great job covering the situation and doing what needed to be done.

jova still 100mph. u guys think she will be this strong at landfall?

Seems like every year, at some point I post a copy of the NHC Mission statement... I will bold a part I think some people forget:


Mission
(Why We Exist)

To save lives, mitigate property loss, and improve economic

efficiency by issuing the best watches, warnings,

forecasts and analyses of hazardous tropical

weather, and by increasing understanding of these hazards.

Vision
(What We Hope to Achieve)

To be America's calm, clear and trusted

voice in the eye of the storm,

and, with our partners, enable communities

to be safe from tropical weather threats.

================================

There have been scholarly papers written on the "cost per mile" to the economy caused by Hurricane warnings. I am confident that costs are incurred due to lost productivity etc. even from "Tropical storm warnings". In years past, the NHC suffered very strong criticism by both the Bahamas and the Florida Keys (two that I know of) for substantial economic damage done to their tourist based economies, after warnings were issued for systems which were "marginal".

It behooves the forecasters... since it IS a part of the official Mission Statement, to take economic and other factors into consideration when naming a system. Ivory Tower meteorologists may want an exact criteria to be followed in naming systems, however, in my opinion, the NHC MUST take other factors into consideration... and sort out any questionable definition details in later analysis.

Quoting wunderweatherman123:
jova still 100mph. u guys think she will be this strong at landfall?

I think it will be. Maybe slightly weaker, but not by much, so it won't make much of a difference for Mexico.

Is Jova going to bring rain to drought-stricken Western Texas?

Just want to throw in my 2 cents on 93L, I'm no expert by any means, but I think 93L was handled appropriately by the NHC, it was one those systems that you're damn if you do and damned if you don't, frankly to me it only looked like a STS after it was over land and they(NHC) did issued gale warnings as is appropriate for any hybrid/cold/warm core system, but just for arguments sake it can be said" a rose by any other name is still a rose" , just some roses smell a little better than others :)

000
ABNT20 KNHC 112333
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT TUE OCT 11 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER CANGIALOSI






Why? WHYYYYYYY??

Quoting TampaSpin:



NOT over yet as i was just in the GOM and its still plenty warm yet. Fingers crossed!

I say the same, but the shear has to let up somewhere for something to form, it's been kicking every storms butt this year. Still, only little pockets open for any kind of development.

Quoting Levi32:
I feel it is appropriate to share this response which I received from James Franklin, one of the NHC forecasters, after I inquired on the issue of 93L and why it was not named on the spot. I feel that it is ok for me to share this since they have developed this response for all questions related to 93L's treatment by the NHC.

Dear Levi,

We've gotten a few inquiries on this, and prepared the following by way of response:

During the weekend of 8-9 October, the state of Florida was affected by a large and complex weather system, one that was not designated as a tropical or subtropical cyclone operationally by the National Hurricane Center (NHC). Watches, warnings, and forecasts for this system were provided by local National Weather Service (NWS) Weather Forecast Offices (WFOs), most notably WFO Melbourne and WFO Jacksonville, while marine analyses and forecasts were provided by NHC's Tropical Analysis and Forecast Branch (TAFB).

There have been a number of inquiries as to whether this system was a tropical or subtropical cyclone. It is not uncommon for NHC to reclassify a system after an event based on a post-storm analysis, adding it to the historical record as an unnamed tropical or subtropical cyclone. A post-storm analysis is planned for this system to see whether it met either of the following definitions:

Tropical cyclone - A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere.

Subtropical cyclone - A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. This system is typically an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection.

Nature is capable of generating a wide spectrum of low-pressure systems that don't always neatly fit into the classification systems developed by meteorologists. The weather system that affected Florida this weekend contained characteristics of both tropical and non-tropical weather systems, making its classification difficult. Because of the system's non-tropical origins, the initial warning products on the system originated from NWS WFOs, and in fact the potential impacts of this event had been advertised in WFO products up to a week in advance.

During the afternoon of 9 October, a broad area of low pressure developed off the Florida east coast. Even before this time, gale-force winds were occurring over a large area offshore, and reached the coast by the late afternoon. In some respects the system resembled a subtropical cyclone at this time. During the evening, however, the low became better defined and strengthened near the Florida coast, briefly accompanied by a very small core of strong winds more characteristic of a tropical cyclone. These winds affected the Cape Canaveral area. During the event, WFO Melbourne issued a High Wind Warning for several coastal counties and a Storm Warning for the coastal waters -both rare issuances.

The overriding consideration for NHC not to name this system during the late afternoon or evening hours was a desire to preserve the flow of watch/warning/hazard information that had been coming from the NWS WFOs. NHC coordinated warning options with the affected WFOs throughout the day Sunday. Because the hazardous weather conditions were already occurring by the time the cyclone and its circulation had become well defined, it was agreed that users would be best served by not abruptly changing the product/warning suite to tropical/subtropical issuances, with the ultimate status of the system to be determined from a post-storm analysis.

I hope this is helpful in explaining how this system was handled.

Regards,

James
--
James L. Franklin

Branch Chief, Hurricane Specialist Unit
NOAA/NWS/National Hurricane Center

Notice how he says that 93L exhibited both non-tropical and tropical characteristics. In other words, they acknowledge that it was at least partially warm-core, and likely deserves some sort of classification, but they decided to wait until after the fact in order to avoid disrupting the flow of warning products being given to the public through the local NWS WFOs. I can understand this line of reasoning, and obviously we don't know anything about how coordination between offices works and the dynamics of communicating with the public. I'm sure they were trying to keep the public's best interest in mind. I fully expect them to upgrade invest 93L to an unnamed subtropical or tropical storm after post-analysis.

Thank you Levi for sharing that...Looks like it will be upgraded in post-season.

mexico radar not on the website

Jova firing off some very cold cloud tops over the center as landfall approaches.

Quoting KipHansen:
Is Jova going to bring rain to drought-stricken Western Texas?

I don't think so. A cold front is forecast for the high plains/west Texas. Some rain from Jova possible in deep south Texas. (Brownsville, Laredo etc)

Winds still 35 mph; Pressure still 1006 mbar.

EP, 99, 2011101200, , BEST, 0, 137N, 941W, 30, 1006, LO, 34, NEQ, 0, 0, 0, 0, 1009, 200, 60, 0, 0, E, 0, , 0, 0, INVEST, S,

Jova has not changed;

EP, 10, 2011101200, , BEST, 0, 186N, 1052W, 85, 973, HU, 64, NEQ, 15, 15, 15, 15, 1006, 180, 10, 0, 0, E, 0, , 0, 0, JOVA, D,

Quoting TropicalAnalystwx13:
Jova has not changed;

EP, 10, 2011101200, , BEST, 0, 186N, 1052W, 85, 973, HU, 64, NEQ, 15, 15, 15, 15, 1006, 180, 10, 0, 0, E, 0, , 0, 0, JOVA, D,

so the 11pm still will be 100mph? figured a cat 2 at landfall... those are pretty rare for mexico and dangerous

212. There you have it folks, we can stop bashing the NHC now, they'll upgrade it post-season.

So whatever our total is come Jan 1st, you can add +1 to that total.

I am on Providenciales, the triangle shaped island in the white area North of Hispaniola.

We have had light winds all day, just now the breeze has sprung up from the South, 15 to 18 mph, I will watch the Barometer overnight... when I tapped it now, it is steady.

What a hopeless group with their " warning products and suites". What becomes apparent is that there is a lot of duplication between the NHC and NWS, with an abundance of "branch managers" all trying to protect their turf.

Now they will have this "summit" in order to give the appearance they are performing a task of a natural security nature deciding what this stupid 93 was.

This is of no importance to the country in these hard times and should be wrapped up NOW.

Quoting wunderweatherman123:
so the 11pm still will be 100mph? figured a cat 2 at landfall... those are pretty rare for mexico and dangerous

Well, the NHC does differ from the ATCF file every once in a while, but there is about a 9/10 chance of it being the same intensity at 11PM.