Erin NHC Report is up (Read it on page 3)

[Chacor]

The public ATCF folder has been updated:

Posted as of Jan 31, 2008
-------------------------
Final '07 season best track, guidance and fix information has been posted. Additional
guidance (OCD5 and BCD5) has been merged into the the A-decks. Data is avalaible in the
real-time data sub-directories and is also in compressed form in the archived area.

The Erin file: ftp://ftp.tpc.ncep.noaa.gov/atcf/btk/bal052007.dat

Code: Select all

AL, 05, 2007081500,   , BEST,   0, 237N,  907W,  25, 1006, TD,   0,    ,    0,    0,    0,    0, 1010,  175,  60,  35,   0,   L,   0,    ,   0,   0,       FIVE, M,
AL, 05, 2007081506,   , BEST,   0, 245N,  918W,  25, 1006, TD,   0,    ,    0,    0,    0,    0, 1010,  175,  60,  35,   0,   L,   0,    ,   0,   0,       FIVE, M,
AL, 05, 2007081512,   , BEST,   0, 252N,  929W,  30, 1005, TD,   0,    ,    0,    0,    0,    0, 1010,  175,  60,  35,   0,   L,   0,    ,   0,   0,       FIVE, M,
AL, 05, 2007081518,   , BEST,   0, 258N,  940W,  35, 1004, TS,  34, NEQ,   60,    0,    0,    0, 1010,  175,  60,  45,   0,   L,   0,    ,   0,   0,       ERIN, M,
AL, 05, 2007081600,   , BEST,   0, 263N,  952W,  35, 1003, TS,  34, NEQ,   75,    0,    0,    0, 1010,  150,  60,  45,   0,   L,   0,    ,   0,   0,       ERIN, M,
AL, 05, 2007081606,   , BEST,   0, 272N,  962W,  35, 1005, TS,  34, NEQ,   75,    0,    0,    0, 1010,  150,  60,  45,   0,   L,   0,    ,   0,   0,       ERIN, M,
AL, 05, 2007081612,   , BEST,   0, 281N,  971W,  30, 1006, TD,   0,    ,    0,    0,    0,    0, 1010,  150,  60,  40,   0,   L,   0,    ,   0,   0,       ERIN, M,
AL, 05, 2007081618,   , BEST,   0, 288N,  978W,  25, 1006, TD,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081700,   , BEST,   0, 294N,  986W,  25, 1006, TD,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081706,   , BEST,   0, 300N,  995W,  25, 1007, TD,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081712,   , BEST,   0, 305N, 1006W,  20, 1008, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081718,   , BEST,   0, 311N, 1014W,  20, 1008, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081800,   , BEST,   0, 318N, 1018W,  20, 1008, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081806,   , BEST,   0, 325N, 1018W,  20, 1008, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081812,   , BEST,   0, 332N, 1015W,  20, 1008, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081818,   , BEST,   0, 340N, 1010W,  20, 1007, LO,   0,    ,    0,    0,    0,    0,
AL, 05, 2007081900,   , BEST,   0, 348N, 1001W,  25, 1004, LO,   0,    ,    0,    0,    0,    0,    <-----
AL, 05, 2007081906,   , BEST,   0, 356N,  988W,  50,  995, LO,  34, NEQ,   45,   45,    0,    0,    <-----
AL, 05, 2007081906,   , BEST,   0, 356N,  988W,  50,  995, LO,  50, NEQ,   15,    0,    0,    0,    <-----
AL, 05, 2007081912,   , BEST,   0, 356N,  977W,  35, 1002, LO,  34, NEQ,    0,   10,    0,    0,    <-----
AL, 05, 2007081918,   , BEST,   0, 359N,  965W,  20, 1007, LO,   0,    ,    0,    0,    0,    0,

The BT brings Erin to a 50 kt LOW inland, it appears it will not be upgraded to a tropical cyclone overland.

[Coredesat]

The BT seems to be written strategically to make Erin a 20 kt remnant low very quickly after landfall, so they might be trying to dodge the issue of what Erin was over Oklahoma.

[Matt-hurricanewatcher]

It would not suprize me at all if they did nothing with it, but it was a interesting event none the less.

[Cyclenall]

I hope this issue isn't brushed aside and ignored.

[Derek Ortt]

I've seen it

if it is not extra-tropical, a 50KT low makes no sense at all from a scientific vantagepoint

[CrazyC83]

It was definitely not a "tropical low". That makes the least sense of any of the conclusions...it had a clearly-defined circulation. It was definitely a cyclone, although it can be debated if it was extratropical, subtropical or tropical. (IMO it was subtropical)

[wxman57]

The BT seems to be written strategically to make Erin a 20 kt remnant low very quickly after landfall, so they might be trying to dodge the issue of what Erin was over Oklahoma.

Erin was a 20kt remnant low very shortly after landfall. It was a very poorly-organized tropical storm with perhaps a tiny area of 35kt winds in a few squalls over water. Max winds on the coast were probably in the 20-25 kt range at landfall (1 min sustained). The question is, what happened to the remnant circulation as it moved northward and interacted with a mid-latitude feature? I don't think one can make a good argument that we saw tropical storm development over Oklahoma. It appeared to be some type of hybrid subtropical storm. The discussion part of the report should be out soon. Let's see what the NHC has to say about Erin's stronger winds well inland.

[brunota2003]

Or perhaps, like the rest of us, they just dont know what the heck that thing was?

[Squarethecircle]

Quite likely.

[Cyclone1]

50kt LOW?

Isn't that the same as saying like... 160mph Category 3?

[Squarethecircle]

Not really. Lows can be any intensity (in theory). As previously stated, it seems nobody really knows precisely what it was.

[Chacor]

They've issued this before the Erin TCR.

[HURAKAN]

I was expecting a least one more system to be addead, but it seems that won't happen. Interesting.

[Derek Ortt]

I do not understand that one? Is it ET or is it not. If not, it is a storm by definition, not a mere low

[caneflyer]

I do not understand that one? Is it ET or is it not. If not, it is a storm by definition, not a mere low

Who says the only categories of lows are extratropical and tropical? Tropical cyclones that lose their convection over cold water in the east Pacific become (remnant) lows. They're no longer tropical cyclones, but there's nothing extratropical about them either.

Clearly, the remnants of Erin are not considered to be a tropical cyclone by NHC, perhaps because the convective structure/organization over Oklahoma was relatively short lived (indicating it was more a mesoscale phenomenon than a synoptic scale cyclone), perhaps because the energetics weren't typical of a tropical cyclone (i.e., no sensible/latent heat transports from underlying surface), etc. And without frontal structures, they probably didn't consider it ET. So it's a low that qualifies neither as a tropical cyclone nor an extratropical cyclone. Nothing wrong with that, really.

[Coredesat]

So it's a low that qualifies neither as a tropical cyclone nor an extratropical cyclone. Nothing wrong with that, really.

By default, a closed low pressure area that is not tropical, subtropical, or polar is extratropical ("non-tropical"). "Remnant low" is used to refer to a system that has no longer has enough convection to be considered a tropical cyclone. Erin was most definitely not a remnant low. My theory is that the NHC thinks it was a mesoscale feature, like what you suggest.

[caneflyer]

So it's a low that qualifies neither as a tropical cyclone nor an extratropical cyclone. Nothing wrong with that, really.

By default, a closed low pressure area that is not tropical, subtropical, or polar is extratropical ("non-tropical").

No, I'd suggest that there really is no such thing as a default. At least, nature is not the least bit interested in man's attempts at putting a spectrum of possibilities into a small number of categories.

A "low" is a generic term that simply means an area of closed low pressure. If a low meets the definition of some particular class of low, then great. But there is no rule that says every low has to be either a tropical cyclone, subtropical cyclone, polar low, or extratropical cyclone.

Not to put too fine a point on it, but into which category (tropical, subtropical, polar, or extratropical) would you place a tornado? Or a monsoon depression? (This last one is tropical, to be sure, but it's not a tropical cyclone.)

[Derek Ortt]

I will wait for the TCR. However, looking at the synoptic pattern and structure, it looks similar to Allison when it intensified quickly over central Mississippi in 2001. It was classified as an STS

[HurricaneRobert]

I don't think that's the "final" say since its been almost two weeks and the TCR is still not out.

[Ed Mahmoud]

Well, as soon as an inland tropical cyclone drops below tropical storm strength, NHC passes it to HPC and at least by bureaucratic definition, unless it approaches the coast again, its a remnant low, even though I believe HPC continues to refer to them sometimes as tropical depressions.

If I understand the system correctly.


Of course, tropical rainstorm Allison, whose name has been retired, did all (well, most) of the big raining on Texas after it had been handed off to HPC, so I almost wonder why they retired the name. It wasn't technically a named system anymore, was it?