40/70 Benchmark

I have just about the same correlation as you do.

Tropical Storm Helene Poised Inundate Florida Gulf Coast as Hurricane Late Thursday Night Devastating Surge Likely for Florida "Big Bend" Region The Situation: As of 11AM EDT, newly formed Tropical Storm Helene is located near latitude 19.5 degrees North and longitude 84.3 degrees West and moving towards the Northwest at 12mph. Maximum sustained winds are near 45mph with the minimum central pressure approximately 1000mb. Track Forecast: Although the track forecast for Helen is fairly fluid and complex, it is relatively high confidence. The system is currently being steered to the northwest between an upper level low to its west-southwest and one to its northeast in the general vicinity of southern Florida. There is fairly strong agreement that once Helene reaches the Yucatan channel and in the general vicinity of the northeast tip to the Yucatan peninsula, it will begin to veer to the north around the western periphery of the upper level Low over Florida. The system will then eventually accelerate to the north northeast or northeast, as it becomes influenced by the southwest flow aloft in advance of an approaching trough over the south central US. Guidance is in remarkably good agreement on the aforementioned scenario relative to this timeframe. While there maybe come subtle changes that could have drastic impacts for the areas affected between now and landfall, the larger-scale interaction with the approaching trough from a synoptic track standpoint is fairly easy to diagnose. It is how the interaction with this trough modulates Helene's intensity that is the primary challenge from a meteorological standpoint, but from a societal standpoint, this point is moot. Intensity Forecast: Currently Tropical Storm Helene is just beginning to become better organized and develop a nascent central core. This is likely in response to the system beginning to exit the area of greatest wind shear in association with the upper level low near the Yucatan and convection should begin to slowly encompass more of the center of circulation over the next 24-36 hours. This process of steady, albeit deliberately paced organization should continue until the system potentially interacts with the northeast tip of the Yucatan tomorrow night. Limited interaction is anticipated at this time, however, it could be enough to halt or even reverse the current intensification for a period of time. The degree of interaction with and the amount of time spent over the Yucatan is the first crucial variable at play with respect to the intensity forecast because if it were to spend several hours plus over this area, then the core could be severely disrupted, which would result in a dramatically weaker storm. Assuming that is not the case, and folks should be preparing as such, the system then veers to the northeast and accelerates over some of the warmest and deepest waters that the entire Atlantic basin has to offer courtesy of the "loop current". The system's increasing forward speed would act to limit any self destruction by way of the upwelling of cooler waters once it becomes appreciably potent, anyway, however a track over the loop current will. make the next to impossible. Wind shear is rapidly decreasingly over the southern Gulf at this time. In fact, poleward ventilation of Helene may be enhanced as a result of the approaching trough's initial interaction with the system in addition to what is obviously likely to be a very moist airmass in the mid levels of the atmosphere. Thus needless to a say conditions may be essentially ideal for a period of rapid intensification over the central Gulf of Mexico during the day on Thursday. The main limiting factor with respect to maximum sustained wind speed achieved may be the sheer size of Helene, as larger systems tend be more stable and less prone to wild fluctuations in strength. Thus even under very favorable conditions, it may take a considerable amount of time for Helene's circulation to constrict. The system's large size coupled with the notion that there is a finite amount of time before environmental conditions potentially begin to grow more hostile once again by later Thursday warrants the use of caution with respect to maximum intensity. Depending on the precise speed and direction of movement, increasing wind shear in association with the incoming trough that caused the system to turn to the northeast and initially enhance outflow may begin to have a detrimental impact on the overall health of the storm by tilting the system's structure. Helene will also most likely begin to have drier air work into the circulation by Thursday evening, would could also act to weaken the system somewhat on approach to the coast. Drier air should definitely have began to be entrained into the core prior to landfall late Thursday night of very early in the predawn hours of Friday. But the final variable with respect to Helen's precise interaction with with the trough that will play a crucial role in the modulation of intensity will be how much diffluence (spreading of wind vectors) remains up until landfall. It is possible that this can offset negative factors, such as wind shear, and to a lesser extent dry air. However, it is much easier to offset wind shear with the evacuation of air aloft then it is dry air being entrained into the core, as that has a highly deleterious impact on tropical cyclones. FIRST CALL: **Cautionary Note**: It was mentioned that the Helen's ultimate landfall intensity, albeit immensely challenging due to the multitude of factors at play with respect to its interaction with the trough, is a "moot" for those directly impacted. This is because due to the large size, fast movement on final approach landfall and high likelihood of appreciable intensity all but ensuring a devastating storm surge, which will be the primary impact. The difference between a 100 mph and 130 mph landfall will be relatively trivial and primarily a point of contention for those in meteorological circles. Surge on the east side of Apalachee Bay, FL is likely to reach 15', regardless. Final Call be Issued on Thursday-

First Call....last look on Thursday. https://easternmassweather.blogspot.com/2024/09/tropical-storm-helene-poised-inundate.html

Given the sheer size...surge will be lethal, but max winds may not ramp up as quickly as some pine for.

Ah good 'ole Rog'...always playing it close to the vest-

Looks to me like it has a window of nearly ideal conditions on Thursday.

I think we see slow, steady intensification for the next 36-48 hours.

I think there is about a 12 hour window for potential RI during the day on Thursday, after the core is well established and its over the loop current before some drier air begins getting entrained the final few hours prior to LF....probably from about 00z Thursday and onward.

I was just noticing that...about 25% of the ensembles do, as well...a few GEFS members do, too.

I love using 700-500RH....often reveals subtle red flags in guidance that are not always reflected well im raw intensity output....kind of a akin to clown maps dropping a 20" snowgasm only to notice razor thin warm layers and/or drier air at 700-800mb.

I wonder if ultimately all this delay does is act to pushback any ERC until near landfall, if at all.

You should do an outlook this year.

https://easternmassweather.blogspot.com/2024/09/consensus-aligning-with-expectations.html

Just fiishing up an in depth update on La Nina and first glimpse at potential winter compisites...shoud publish tonight. My thoughts on La Nina have not changed at all. I never bought that La Nada fake out.

Yea, the obstinance is absolutey reprehensible (and repulsive)...that is a different matter altogether.

I don't understand dismissing a met because he has busted horribly in the past...if you are going to strictly adhere to that, then you aren't going to be left with anyone to follow.

I'm just talking about the deviation from the west PAC forcing and the influence on sensible weather. That said, I don't see wall-to-wall juggernaut PV, either.

I think something like 20-21 and 21-22 is attainable.

I'm sure it won't be thst cold due to the west Pac warm pool in conjunction with overall CC, but it should be better than last year. Hopefully we get some amplified MC MJO acitivty in October per Bluewave to confirm my suspicion of some periods of disconnect from that wretched west Pac warmth.

I will say that it doesn't matter as much with a weaker La Nina....2008 was a weaket Modoki La Nina with a -PDO and very favorable north Pac....not a horrible analog. The cool ENSO walker cell will not be completley overwhelming like it was two years ago.

The reason for the variation is due to both the differences in placement of each el nino in terms of max anomalies relative to the entire Pacific basin...the ongoinf huge west pac warn pool is related to why none of those seasons had had nearly as deep a -PDO. Pretty clear that 1972 was by far the best march of the 3 in hindsight. I got that wrong and have learned a great deal from it.

I'm not sure what he is smoking with the east-based la Nina claim...its been rapidly shiftng for awhile now.

Its a great ONI analog...the best IMO.

I did well with 2016-2017, 2017-2018, 2020-2021 and 2021-2022.