vortex95

HU Polo is in an RI phase now, and it would not surprise me if it over-performs and gets to high-end (150-160 kt). This tends to occur in very strong El Nino. We had Patrica in 2015 and Linda in 1997. Linda never has a recon in when it was intense, sot its 160 kt peak is estimated, but it is likely it was higher than that. Look at this VIS image of Linda on 9/12/97. It was not as small as Patrica, but look at its CDO and very sharp subsidence ring around it. That is tell-tale sign of high-end intensity! Probably closer to 170 kt for a peak, but as I noted, NHC does not go above 160 kt for a TC in the absence of recon or other in situ data. The uncertainty when you get this intense is just too high, but one can say it was highly likely it was at *least* 160 kt!

This short paper from 2007 (attached) from Chris Landsea of NHC summaries well the issues w/ "missing" TCs in the Atlantic. Counting Atlantic Tropical Cyclones Back to 1900 From the paper: In particular, Landsea et al. [2004] esti- mated an undercount bias of zero to six tropical cyclones per year between 1851 and 1885 and zero to four per year between 1886 and 1910. These undercounts roughly take into account the typical size of tropical cyclones, the density of shipping tracks over the Atlantic basin, and the amount of popu- lated coastline. As one goes back further in time, the numbers of ships and shipping lanes decreases and fewer people live in the tropical and subtropical coastal regions. These factors make it increasingly likely that some tropical cyclones would not be counted the farther back in time examined. I like how he compared 1933 to 2005, which is #1 and #2 for most ACE in a season. Look at the gap out in the cntrl and ern Atlantic. The 20 storms in 1933 I bet is at least 5-8 too low. We saw what happened in 2005 when everything went "right." We were getting late- season oddballs Oct-Dec often cntrl and ern Atlantic, and that season redefined what we call a TC and expanded what was possible! He said that as to hurricanes from 1851 to about 1940, anywhere from 0 to 4 hurricanes in the Atlantic were likely missed in any given year, w/ the avg being likely close to 1. Meaning that 1914 probably had a hurricane, just never detected. When you see something like Fay recently, and tiny systems like Oscar even when not in the middle of nowhere, you see how the probability is quite high here. It is fascinating stuff to look at history and do "sleuthing!" The Hurricane Reanalysis Project displays this best. I wish other agencies would do this for TC basin worldwide. There is *lot* of data out there that could be gathered, analyzed, and much to be found. And you do not have to go the far back. Full geostationary sat coverage did not exist in the western Pacific until 1987 and not until 1989 over the IO. However, for over 25 years up to this point, we had plenty of polar imagery, and as I mentioned, the delays in transmission of polar imagery in those days was several hours or more, so it could not be used operationally to assign proper TC intensity. It's the main reason why if you want to look at trends for TCs in the IO, you really can't start until 1990, and by extension, global TCs are well. The SIO is the second most active basin globally for ACE per year. landsea-eos-may012007.pdf

Yes, you can clearly see the outflow plume on the N side getting squashed by nrly shear. It is moving steadily S now as well. S movement outside an eye wobble loop usually means not good times ahead as it takes quite strong flow to push a TC bodily S. Most of the time, the LLCC gets exposed in short order. An exception I can think of was Joaquin Oct 2015, but that was much farther S (22-23N) and over the Gulf Stream. Solid, strong banding on the E side of Fay now, but the W side convection is waning.

And there full LEAVES on the TREES! One thing @CoastalWxneeds to account for here for the winds.

One thing about lows that hook or loop back to the NW, it jacks up the winds more as it pushes against the high to NW. One reason why the Oct 2021 event was NUTZ for WINDZZZZZZZZZZ!

@CoastalWx must relent! And yes, it might just be a "COASTAL WX" sig impact event, but so was the Perfect Storm in 1991!

12z ECMWF by 132 hr showing a strong warm seclusion unfolding (-6 C at 500 and +11 C at 700). I will get way ahead of myself and say this now, and an excuse to talk about past policy and events! The problem I see here is not whether it goes ST, it is the messaging. A strong non-tropical low then going ST and getting a name when it is sitting close to the coast? That is big problem for messaging b/c non-tropical wind warnings would have to be changed to tropical wind warnings! I do not know of any case like this this close to the coast, but similar things have happened. The Perfect Storm in Oct 1991. Once it deeply occluded, it drifted S of the Gulf Stream and become a hurricane, but they did not call it such operationally *even* thought they had a recon in it and found a 981 mb pressure and 88 kt FL winds! I found that disingenuous, as it was abundantly clear what it was, but NHC did not name it, and only included it in post-season analysis. The reasoning was they did not want to confuse the public, as the public may have thought the storm was a hurricane all along and cry foul. Such would never happen today b/c of the internet and social media. Back in those days if NHC could get away w/ not declaring a high latitude or out of season TC and defer it to post-season analyses, they would. But it has gone further. In Sep 1992, there was a small hurricane that quickly developed just N of TXKF, and it passed close to Sable Island when it was starting to weaken on sat, but they still recorded 55-60 kt winds. It was not even included in post-season analysis! In the TWO, it said, "moving towards cooler waters." That was "out phrase" for NHC not to declare something back then. Again, disingenuous and I find lazy. Just b/c something only exists for a short time, does not mean it does not exist! There are 5 suspect TCs in 1992 alone that will likely get included in HURDAT once the reanalysis project gets into to the 1990s (they plan to go to 2000). And for those wondering, the pre-Christmas 1994 storm ( the @CoastalWx “how did you know about that?” event) is a likely candidate for a 70 kt hurricane, peaking at 70 kt / 969 mb near 40/70.

If this was Jan, you'd be all in at this point!

No back-pedaling allowed! Your initial approach was, "ho-hunm, maybe we can get something" said in EEYORE tone, despite strong signals in the models.

How about those 12z ECMWF rainfall totals when all is said and done? 9.95" right over Weymouth! Would be among the best Nor'easters in Sep for the region.

Yes, a dry air slot. Look at the last few EIR frames. It is possible since it has not moved much at all, some upwelling is taking place. 00z ATCF gives it 60 kt/995 mb. Hard to get a T4.0 (65 kt) from Dvorak w/o an eye or embedded center pattern. You need excellent banding and very cold cloud tops for a 4.0 when a banding pattern is applied. Tiny TCs are indeed not handled well by Dvorak, however, that largely applies when there is an eye (can't get a cold ring thickness wide enough for proper T-numbers). Also, Fay is over marginal SSTs (see attachment) and not in pure tropical environment, so the mixing down of the higher winds aloft 500-800 m up is not ideal. I'm just pointing these factors out now b/c I'm sure you'll see discussions/debate if it was a hurricane or not, pending the next 6-12 hr! Still, Fay did what can be expected for tiny systems. Models will have no clue. Recall Oscar from a few years ago.

What? The GFS and ECMWF show extended storminess, unlike anything I can recall in Sep. Even before the rain, that E fetch sets up and sticks around for almost a week? Do you know what kind of coastal flooding that will result in w/ the water piled up constantly for so long? That sprawling high stuck to the N is epic for Sep. 1036 mb? That would be excellent for the heart of winter. And the GFS and ECMWF both shows it well. And they way it tries to reload for coastals as the blocking stays in place? And then big QPF wildcard. I guess b/c it is isn't snow, @CoastalWx doesn't care? Jaded, tattered, and torn from the "boring" pattern, and when something potentially historic for an extended Nor'easter so early in the season for the NEUS shows up, he be like "MEH!" Very, very disappointed in you!

I spoke too soon. Strong anticyclonic shear is disrupting the core in the last few hr and the circulation getting elongated again. I would be surprised if they upgrade it to a TS at 03z, unless they get a good ASCAT or SAR pass showing TS-force winds.

Talk about threading the needle. That anticyclonic cirrus shear plume is right on the doorstep of the core, and yet no shearing of the convection over the core. One thing about seasons like this, the TCs are often small. TD6 exemplifies this. At first glance in vacuum, you look at the EIR image below of the Atlantic, and go, "where is it?!" Areas of convection exists sig larger than TD6 here!