ATL: KIRK - Remnants - Discussion

[Aric Dunn]

I am not surprised considering how well it looked last night and this morning. Looks much improved compared to yesterday in overall structure. Will likely have this one around awhile.

Interesting. Looks less-organized to me. Time to head out on a bike ride between storms.

increased mid level turning convection building on east side and west side of circ though it is having some issues do to the forward speed and the convection trying to keep up with it. but overall the low level cloud structure is expanded and more defined.

Pretty sure the models are under doing the intensity. if it stay under 12N shear is low ( except maybe low level from the forward motion) I see no reason why we could not have a hurricane before the islands.

[toad strangler]

 https://twitter.com/AndyHazelton/status/1043530434498494464

[chaser1]

I think it's another indication of just how hostile the MDR is this season. We've had tiny Beryl form south of a SAL outbreak and small/weak Isaac dissipating as it neared the Caribbean. TD Eleven dissipating east of the Caribbean. Now Kirk, which may not survive as a TS to reach the Caribbean.

Respectfully, I think the eastern MDR has actually been quite favourable, while the western MDR, as you mentioned, has been quite hostile. Had the eastern MDR been unfavourable, we would have not witnessed four hurricanes developing in the deep tropics close to West Africa. The fact that we are seeing so many storms, albeit most weak and/or short-lived, in the MDR might be an ominous sign, given the persistence of strong vertical wind shear, subsidence, and cooler-than-average SSTs. The active African monsoon was enough to partly offset the hostile indicators. If 2019 features warmer SSTs and lower vertical wind shear, with all other factors remaining unchanged vs. 2018, we could see another hyperactive season in the MDR, similar to or even more active than 2017. Even 2017 featured only four storms in the MDR: Irma, Jose, Lee, and Maria. We have already seen five in 2018: Beryl, Florence, Helene, Isaac, and now Kirk. Due to the unfavourable western MDR, of course, none of these storms survived to reach the Caribbean. (Florence and Helene, obviously, passed well to the north and east of the Caribbean.) Bottom line: given how hostile most of the indicators have been in 2018, the fact that we are still seeing so much activity seems disconcerting.

Good points on both sides but i'd have to side with Shell Mound here. In fact, when one considers the broader question of whether the multi-year active era has ended (Tropics discussion thread) I'd suggest that over-all we are seeing an increased number of tropical cyclones evolving in recent years in spite of some year broad scale nearly basin wide conditions that would typically suggest otherwise. I think this season is a prime example of that. With higher then average surface pressures, early onset of well below SST anomalies, and an abundance of dry SAL conditions that typically would have let up by now there seems to be some other factors which at minimum seem to aid in overall cyclongenesis. In support of this argument I'd point toward the increase of non-tropical genesis systems developing far north of the MDR that eventually transition into tropical systems, AND an increase of what i'd simply call "Micro-Canes"; Smallish tight areas of vorticity which in some cases are so small that they nearly defy the definition of meso-scale. At the same time, I think there's some legitimacy to the counter argument that both of the above examples are partly a result of major advances to our own satellite and far reaching visual capacity as well as perhaps a long slowly evolving change to how we view and define the science of baroclinic verses tropical cyclones. Furthermore, the increasing need to foresee and warn an ever-increasing population and coast interests of even peripheral conditions (tide and surge related flooding, etc) has further exacerbated the unrelenting argument that politics itself does play some roll in the need to "name" (designate T.S.) some weather systems developing near populated regions (GOM especially) thus increasing the apparent number of developing tropical cyclones during some years.

(Didn't mean to continue to take this topic well off discussion thread, so feel free to copy/paste and apply to a more appropriate thread)

[Aric Dunn]

[wxman57]

I went back and checked the ASCAT and ScatSat imagery for Kirk (valid about 1100Z today) and cannot see anything but 25kt winds. Dvorak then was 2.0. I don't think Kirk qualifies as a TS. 12Z EC & GFS dissipate it near the eastern Caribbean, if not sooner.

[AutoPenalti]

Back to an open wave, didn’t take long but the LLC looks intact for the moment.

[cycloneye]

18z Best Track:

AL, 12, 2018092218, , BEST, 0, 84N, 241W, 35, 1005, TS

[Shell Mound]

I went back and checked the ASCAT and ScatSat imagery for Kirk (valid about 1100Z today) and cannot see anything but 25kt winds. Dvorak then was 2.0. I don't think Kirk qualifies as a TS. 12Z EC & GFS dissipate it near the eastern Caribbean, if not sooner.

http://wxman57.com/images/ASCAT-Kirk.JPG
http://wxman57.com/images/ScatSat-Kirk.JPG

So where did the NHC find ASCAT data confirming "an area of 30-35 kt winds northwest of the center"? Hmm...

https://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/221436.shtml

I've noticed that the NHC has become quite generous with TC classification since 2005. Does anyone know why?

Edit: the NHC does have higher-resolution satellite-derived data than are available to us outsiders...

[TropicalAnalystwx13]

I went back and checked the ASCAT and ScatSat imagery for Kirk (valid about 1100Z today) and cannot see anything but 25kt winds. Dvorak then was 2.0. I don't think Kirk qualifies as a TS. 12Z EC & GFS dissipate it near the eastern Caribbean, if not sooner.

http://wxman57.com/images/ASCAT-Kirk.JPG

http://wxman57.com/images/ScatSat-Kirk.JPG

AL, 12, 201809221048, 31, ASCT, C, , 810N, 2270W, , 2, 33, 2, , 3, , , , , , , , , , , , 3, , , , KNHC, MJB, , , , , , , , , ASCT, , , , , , , , , , , , , , , , , , , 3, ASCAT-B; PBO AMBIGUITIES

[WAcyclone]

I went back and checked the ASCAT and ScatSat imagery for Kirk (valid about 1100Z today) and cannot see anything but 25kt winds. Dvorak then was 2.0. I don't think Kirk qualifies as a TS. 12Z EC & GFS dissipate it near the eastern Caribbean, if not sooner.

http://wxman57.com/images/ASCAT-Kirk.JPG

http://wxman57.com/images/ScatSat-Kirk.JPG

AL, 12, 201809221048, 31, ASCT, C, , 810N, 2270W, , 2, 33, 2, , 3, , , , , , , , , , , , 3, , , , KNHC, MJB, , , , , , , , , ASCT, , , , , , , , , , , , , , , , , , , 3, ASCAT-B; PBO AMBIGUITIES

https://i.imgur.com/XT31y5i.png
https://i.imgur.com/Gmdp4U4.png

Note that all of the 30 and 35 kt wind barbs apparently failed the ASCAT quality control due to rain contamination:

[Aric Dunn]

This tells much more of the story. A large low to mid level moisture envelope. Very well established and defined large circulation. no doubt this is a TS. no reason for this not to strengthen except the forward speed and mid to upper level dry air per the SAL> however currently the SAL does not appear to be having much effect on the convection within the envelope.

[wxman57]

So where did the NHC find ASCAT data confirming "an area of 30-35 kt winds northwest of the center"? Hmm...

https://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/221436.shtml

I've noticed that the NHC has become quite generous with TC classification since 2005. Does anyone know why?

Edit: the NHC does have higher-resolution satellite-derived data than are available to us outsiders...

I'm not sure what they are looking at. I can assure you that we have the same data as the NHC, by the way. Dvorak down to 1.5 as of 18Z. The only thing the NHC has that we don't is the Florida State superensemble.

Classification criteria have changed quite a bit in the past 10-15 years, and it varies by who's on duty at the NHC. I've spoken with Dr. Neil Frank about this. Much of what is classified now as a TD/TS wouldn't have cut it when he was director.

As for its current intensity, I'd say that there is considerable doubt that this is a TS. Convection is weak, Dvorak down to 1.5 at 18Z, down from 2.0 at 12Z. A mid-level rotation is not confirmation of a TS. Earlier ASCAT showing a possible 35kt northerly wind SOUTH of the center is not confirmation of a TS. I don't think Kirk has much of a future.

[Emmett_Brown]

The 12Z GFS shows less shear around the islands after 160 hours. Kirk gets to the islands around 138 hours when shear is still strong, and GFS weakens Kirk. But if the shear starts to slacken a little earlier, then he might have a window to sneak into the E Caribbean. Some of this shear also depends on the structure of Kirks' own upper level anti cyclone and how fast he moves. Conditions are definitely marginal at best, but a low riding Kirk may stay in tact.

[Emmett_Brown]

So where did the NHC find ASCAT data confirming "an area of 30-35 kt winds northwest of the center"? Hmm...

https://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/221436.shtml

I've noticed that the NHC has become quite generous with TC classification since 2005. Does anyone know why?

Edit: the NHC does have higher-resolution satellite-derived data than are available to us outsiders...

I'm not sure what they are looking at. I can assure you that we have the same data as the NHC, by the way. Dvorak down to 1.5 as of 18Z. The only thing the NHC has that we don't is the Florida State superensemble.

Classification criteria have changed quite a bit in the past 10-15 years, and it varies by who's on duty at the NHC. I've spoken with Dr. Neil Frank about this. Much of what is classified now as a TD/TS wouldn't have cut it when he was director.

Ah, the old days... they just don't make 'em like they used to!

[Hammy]

I went back and checked the ASCAT and ScatSat imagery for Kirk (valid about 1100Z today) and cannot see anything but 25kt winds. Dvorak then was 2.0. I don't think Kirk qualifies as a TS. 12Z EC & GFS dissipate it near the eastern Caribbean, if not sooner.

http://wxman57.com/images/ASCAT-Kirk.JPG
http://wxman57.com/images/ScatSat-Kirk.JPG

So where did the NHC find ASCAT data confirming "an area of 30-35 kt winds northwest of the center"? Hmm...

https://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/221436.shtml

I've noticed that the NHC has become quite generous with TC classification since 2005. Does anyone know why?

Edit: the NHC does have higher-resolution satellite-derived data than are available to us outsiders...

It's there.

[wxman57]

Ah, the old days... they just don't make 'em like they used to!

At the NTWC this past April, I was seated at a table with former NHC directors Max Mayfield, Bill Read, and Dr. Frank. Storms are definitely handled differently now.

[Emmett_Brown]

Ah, the old days... they just don't make 'em like they used to!

At the NTWC this past April, I was seated at a table with former NHC directors Max Mayfield, Bill Read, and Dr. Frank. Storms are definitely handled differently now.

Cool that you got to hang out with those guys. Frankly, I think a lot of this is because the average Monday morning QB public hobbyist (like me) has access to a lot of sophisticated products. The NHC has to face a lot of criticism if they don't pull the trigger and upgrade a storm the minute a circulation is evident on a microwave pass. It must be difficult to manage in the face of the flood of info and pseudo expert commentary.

[chaser1]

Looking at the data, i'd have to lean toward's Wxman57's perspective on NHC possibly having jumped the gun. That's not to suggest that a slow increase in overall development won't occur but I just think it got tagged "Kirk" at a diurnal max point. I can't help but notice a very large big-time low level surge flying toward Kirk from the ENE. I can potentially see this being counterproductive with regard to the developing systems' still fragile low level circulation. As broad as Kirk is, it's not as if a strong vertical core such as a strong storm or hurricane has had the time to develop quite yet. Undercutting strong unidirectional inflow could still potentially disrupt the newly developed cyclonic surface feature. I think I would've waited for a bit more Ascat supported data or at least for a few more hours time to see co-located convection in relation to the COC.

[chaser1]

Hammy, I saw those ASCAT plots you posted but boy....., even if there are one or two wind barbs actually showing 35 Kt's. that's a pretty minimal showing for data when you consider it being the solo one pass and without any additional corroborating data. I generally stand on the side of "call it as you see it" but there's something to be said for continuity too. Zero argument on it's being upgraded to a T.D. but I don't see where 6-12 hours of additional observation would've hurt prior to NHC's early upgrade to T.S. It's not as if T.S. conditions were going to threaten those in the islands to the north. This coming from someone who believed 97L should have been earlier upgraded (even if it were the size of a large waterspout lol). At least with that feature, I thought a very small tight core feature was discernible and a continuous feature that persisted for well more then a day.

[Hammy]

Hammy, I saw those ASCAT plots you posted but boy....., even if there are one or two wind barbs actually showing 35 Kt's. that's a pretty minimal showing for data when you consider it being the solo one pass and without any additional corroborating data. I generally stand on the side of "call it as you see it" but there's something to be said for continuity too. Zero argument on it's being upgraded to a T.D. but I don't see where 6-12 hours of additional observation would've hurt prior to NHC's early upgrade to T.S. It's not as if T.S. conditions were going to threaten those in the islands to the north. This coming from someone who believed 97L should have been earlier upgraded (even if it were the size of a large waterspout lol). At least with that feature, I thought a very small tight core feature was discernible and a continuous feature that persisted for well more then a day.

I would say the call was good here especially since weaker side of the circulation was caught, but agree there is some inconsistency with when it's applied. Personally I'd like to see an across the board standard of going with the highest available measurement (unless the strongest wind is outright missed) in all cases when using ASCAT.