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Even on vacation more than 8.000 km from Martinique I endure all day long this bullshit storm that hits social networks. Everyone says and shares anything about this disturbance which threatens the Antilles. It would be laughable if it weren't so important! So I say it again: stop sharing anything you find on theInvest 92L. Share as long as you want the newsletters of nhc … But nothing else, including my posts! it is necessary that a little calm returns on the subject.
Okay, now that I've made my shitting-preventing-sharing-quiet, let's talk about 92L… which is a bit reluctant to transform into Isaias.
Unlike Gonzalo who was a small system with high organizational variability that moved slowly, 92L is a huge disturbance that moves rather quickly. This specificity makes its organizational changes, upward or downward, very slow. Unlike a small system, its size allows it to better withstand the surrounding dry air by relocating its convection to a more humid area and having a much greater capacity to humidify the atmosphere, but in reality, this does not is not really what's going on.
Moreover, for more than 48 hours, even if its organization is a little better, with in particular the appearance of concentric convective bands, we remain with a system which has difficulty creating a constant internal circulation and especially a permanent convection. The presence of very dry air to its north and on its trajectory certainly had something to do with it and contrary to what was anticipated, it was moving at the same speed as 92L which made the conditions not much more favorable. But she is in a fairly humid "bubble" of air which protects her a little. During this time she is traveling at nearly 30 km / h. With this speed, time is in our favor and the longer it takes to organize itself, the lower the risk of an intense system on the arc. But if the convection were to develop rapidly, the risk of rapid strengthening could not be excluded. It should play out tonight.
Since 36 hours we have noticed a very clear tendency in numerical models to weaken the intensity of the forecast. The GFS for example, went from a system at 970hPa on north arc to one of 1007 hPa rather north of Angilla. The same goes for anyone who was on an aggressive forecast. Alone of HWRF (tracking model) and the Navgem which has not offered enormous confidence since its inception, continue to envision a hurricane on the West Indies.
If we look at the intensity forecast, this trend is very clear. 36 hours ago a majority of models provided for a rapid classification in Category 1 or 2, or even 3 for some. Now no one sees anything more intense than a storm and a majority even envisions a “small” storm (in terms of intensity). Hence the interest of avoiding sharing long-term forecast charts if they are not “appraised”.
THEECMWF extension, which is the first model to have identified this disturbance last week, has been extremely stable in its forecast for a few days, namely a large disturbance passing over the northern half of the arc with a strong wind to its north (50 kts) but no organization and no vortex. In general, I always trust a stable model more in its forecast than in those who change their mind with each run… and the past has often shown that this was indeed a sign of confidence in the forecast. But as always, we are talking about specific atmospheric phenomena of which unpredictability is one of the major characteristics!
Finally, Météo France models, particularly sharp for these conditions, remain on a forecast slammed on that of theECMWF extension (as most often) with gusts of 50 kts on a good part of the West Indies but a large system planned.
It is still quite possible that a storm will appear in the next few hours. If this is the case, given its size and inertia, great care should be taken because it could develop very violent gusts and heavy rainfalls. But the risk of a violent system in the West Indian region, even if it cannot be completely concealed, is considerably reduced.
When we look on the one hand at the real situation and the exits of models and on the other the collective paranoia that has developed on the subject… we just have the impression of not talking about the same thing!
To follow the live quantified evolution of Invest 92L is HERE.
Image credits; Tropical tidbits, NHC / Noaa, UW-CIMSS
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