91C.Invest - Very far to the north (42.5 N, 146.5 W)

[senorpepr]

I would concur with you there, sir. Definitely not "polar," the mid-troposphere was plenty warm. I'm still placing my chips on the "frontal wave" spot.

[Coredesat]

I don't think the upper atmosphere was really cold enough for a polar low anyway. Around my area the 500hPa temperature needs to be around -40C with SSTs maybe 7C or so lower than in this case, but if you look at the initialisation of the GFS from just after this appeared on the NRL it was way below this at around -18C. Don't quote me on that temperature being the correct one for this area though.

Why does that map's title say the temperatures are in kelvins, when they're really in degrees Celsius? I'd be worried if the mid-level temperatures were -18K.

[P.K.]

That would be a little cold.

The default is K but I changed the units to C but didn't change the title from default hence the result you see there.

[Chacor]

NASA has called this a subtropical storm.

Subtropical Storm off the Coast of Oregon

This photo-like image of a rare subtropical storm in the Pacific Ocean was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on November 1, 2006. Located 900 miles off the coast of Oregon in the northwestern Pacific, this storm system looks like a hurricane, but it is located far from any of the typical hurricane formation areas. The storm originally formed from a cold-cored extratropical storm, but after spending two days over unusually warm water (perhaps as much as 2 degrees Celsius above normal for the time of year), it developed a warm center, and hurricane characteristics, such as a cloud-free eye and an eyewall of thunderstorms. With satellite-observed winds as high as 50 knots on November 2, the storm was strong enough to have been named if it had been in one of the routinely monitored hurricane basins. Because it formed outside the territory of any monitoring organizations, however, it was not named. The storm was being referred to as “Storm 91C” by the U.S. Navy.

What is interesting and should be noted is that the CPHC do not issue advisories on subtropical cyclones (as proven by the "CPHC Products Help" link on their website - "Public advisories are issued for all Central Pacific tropical cyclones, Atlantic tropical or subtropical cyclones, and for eastern Pacific tropical or subtropical cyclones")

[P.K.]

I noticed that page last night, however it did cross from RSMC Honolulu's AOR to RSMC Miami's AOR without any note anywhere.

[Floodo_Is_My_Hero]

I can finally add an avatar that is appropriate for this forum...kinda sad when us Oregonians are getting more action then Florida and the Gulf Coast

[Matt-hurricanewatcher]

The thing hit to my north, hell I never thought I would be hit with a tropical cyclone. But guest they can form if things match up.

[Coredesat]

Interesting post from Jeff Masters on the storm. It contains an e-mail from James Franklin:

The system was of frontal origin, that much is clear. But I believe the frontal structure was eventually lost (no way to know for sure). The convective structure resembled a tropical, rather than subtropical cyclone, and the radius of maximum winds (based on QuikSCAT) was very close to the center, also more typical of tropical cyclones. It was, for most of its existence, under an upper low, typical of subtropical cyclones. However, it was developing a modest mid to upper lever warm core, moving toward tropical structure. So structurally, on balance, it was more tropical than subtropical.

However - it was over sub 18C water, and part of the definition of a tropical cyclone is that it originates over tropical or subtropical waters. This one didn't, so it's not a tropical cyclone by our operational definition, even though it had some of the characteristics of one.

Our classification system is a convenience for man, but Nature is not the slightest bit interested in our classifications of cyclones. There is a complete spectrum of storms between extratropical and tropical. There are cyclones that have similarities to tropical cyclones in structure - even share some of their energetics, polar lows are an example of such a beast, and maybe it is unfair to exclude them based on their location of origin. I, however, don't sense a groundswell of opinion to strike the "originates over tropical or subtropical waters" from our definition. It has, on the whole, served us well.