Debate

[Bailey1777]

I have seen many opinions on this site about storms that shouldn't have been named and even storms that should have been named. What is the official basic criteria for when a tropical system should be named? Also, and I would like to hear from the pro's, should this criteria be changed, updated, or just scrutinized more?

[Evil Jeremy]

Even though there is a set criteria for naming systems, I think the NHC just names them when they want to, as there have been storms that, as your said, should not of been designated a storm, and there are some that should of. I think the criteria that the NHC goes by now is that if it is organized and has winds of 30 MPH or more, its a storm, regardless of if it should really be one or not, but thats just my opinion.

[HURAKAN]

This is how the NHC defines a tropical cyclone:

"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."

When that tropical cyclone reached 33 knots, it's named.

[Derek Ortt]

Even though there is a set criteria for naming systems, I think the NHC just names them when they want to, as there have been storms that, as your said, should not of been designated a storm, and there are some that should of. I think the criteria that the NHC goes by now is that if it is organized and has winds of 30 MPH or more, its a storm, regardless of if it should really be one or not, but thats just my opinion.

Jeremy,

to be honest, you do not know what you are talking about. NHC follows their criterian to a tee. There were no missed storms (unless you think frontal lows are tropical cyclones)

Do I totally agree with their criterion? No... but I will say that scientifically, it is far better than that from the Niel Frank NHC, which we all know did miss many short lived storms. I'd like to seemore systems that immediately move off of Africa classified if they do have a closed surface circulation, even if they are going to dissipate within 24

[Bailey1777]

How high up the chain at the NHC does the decision to name a storm go (who makes the call?)

[Hurricaneman]

How high up the chain at the NHC does the decision to name a storm go (who makes the call?)

I would think the director, but not too sure

[Ed Mahmoud]

The Carolina low that has Joe Bastardi so worked up, that was supposeldy frontal, may indeed had a occluded front with it, but there was not a pronounced wind shift with that occlusion, the temperature and dewpoint gradient was fading, and it is possible the occlusion wasn't at the surface at all anymore, and, IIRC, aircraft at low level found a warm core.

It may not have been purely tropical, but that is supposedly why they have sub-tropical storms. Bastardi also asserts worse looking storms on satellite have been named far out to sea without aircraft recon.

Bastardi's opinion, because it hadn't been identified ahead of time in the TWOAT, they decided to call it frontal and ignore it. He doesn't explain why they tasked an aircraft for a system they had decided they were going to ignore. One possible explanation, it was one forecaster who requested recon and a different forecaster on duty when recon was in the system.


I don't think anyone denies a suspicious system near land gets an invest tag before a system of similar appearance way offshore.


Anyway, it becomes pretty clear if you read Bastardi the only NHC forecaster he trusts is Stewart, and he is being sent off to Afghanistan this Summer by the Navy, so I see another season of Bastardi second guessing the NHC. Bastardi does agree NHC does very well with clearly tropical systems headed West or West-Northwest in the deep tropics.


Bastardi could be wrong on some things, but he is a paid professional meteorologist, granted, not one with a doctorate, but if he can blow a call, so could a pro met at NHC.

Medical doctors make mistakes, I know petroleum engineers do. Referees in sports blow calls, and some calls are so close it is impossible to call.


I will say, in my humble and unprofessional opinion, Bastardi could be right on the Carolina system, but I don't remember any egregious blown forecasts from NHC last Summer.

[caneflyer]

Not sure why it would matter if the occlusion were off the surface. It would still be frontal, and therefore not qualify as even a subtropical cyclone.

[Ed Mahmoud]

Not sure why it would matter if the occlusion were off the surface. It would still be frontal, and therefore not qualify as even a subtropical cyclone.

You realize an occluded front is basically when a cold front overtakes a warm front, and the occluded front itself separates two 'cold' airmasses, right. Now, the aircraft, best I could tell, did not find either an airmass change or wind shift at flight level meaning the front no longer existed at surface. The front no longer exists when there is no wind shift or change in airmass across the front.

Now, I'm no professional, but if there isn't a clearly defined front to be found near the surface, the isobars are circular, and the system is clearly warm core at flight level, with gales, it isn't even a subtropical storm because some remnant of the occluded front might still exist aloft?



Anyway, I suspect they'll always be debate on not just this, but other systems that originate from non-tropical origins. At what point is it tropical enough to deserve at least the title 'sub-tropical'?

Are the winds concentrated enough near the surface, for example? That is a subjective call, best I can tell.

[brunota2003]

Subject: A6) What is a sub-tropical cyclone?

Contributed by Chris Landsea

A sub-tropical cyclone is a low-pressure system existing in the tropical or subtropical latitudes (anywhere from the equator to about 50°N) that has characteristics of both tropical cyclones and mid-latitude (or extratropical) cyclones. Therefore, many of these cyclones exist in a weak to moderate horizontal temperature gradient region (like mid-latitude cyclones), but also receive much of their energy from convective clouds (like tropical cyclones). Often, these storms have a radius of maximum winds which is farther out (on the order of 100-200 km [60-125 miles] from the center) than what is observed for purely "tropical" systems. Additionally, the maximum sustained winds for sub-tropical cyclones have not been observed to be stronger than about 33 m/s (64 kts, 74 mph)).

(more on the link)

Link:
http://www.aoml.noaa.gov/hrd/tcfaq/A6.html

[Derek Ortt]

How high up the chain at the NHC does the decision to name a storm go (who makes the call?)

the forecaster on duty

[mitchell]

NHC follows their criterian to a tee. There were no missed storms (unless you think frontal lows are tropical cyclones)...<snip>... I'd like to seemore systems that immediately move off of Africa classified if they do have a closed surface circulation, even if they are going to dissipate within 24

Derek,

This seems like a contradiction. you say there areno missed storms but seem to be saying short lived systems may be missed?