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An update for this article is available HERE.
Gonzalo has been undergoing phases of strengthening and then of disorganization since yesterday. Yesterday evening the satellite imagery showed some signs of weakness while the night and his DMax allowed him to regain strength and resume the path of strengthening with an intensity of 55 kts, close to the hurricane stadium.
The last images of this morning show again a circulation around the heart largely disturbed by the ingestion of dry air and the last microwave passes show a deficient organization whereas a few hours before an eye seemed to be forming with a semicircle clearly visible.
This is the problem with compact systems. They can change organization extremely quickly and are generally more exposed to dry air. However, this one has been resisting for 48 hours and it surprises all forecasters by its resistance to this situation.
Situation
Storm Gonzalo remains very compact with deep convection which has spread quite a bit over the past 2 hours. Its position at 9:10 UTC was 47N by 19W with a slow motion again at 270 km / h to the west (997 °). The pressure is estimated at XNUMX hPa and intensity at 55 kts with much stronger gusts.
Intensity
Gonzalo is currently in a delicate phase. Its deep convection has spread a little as it comes in closer and closer contact with the dry air and the internal circulation is more and more difficult to see on satellite imagery. Already last night he had experienced a period of disorganization but he had recovered well that night and continued to strengthen.
This day will be crucial for its development. If it manages to reorganize itself to refocus its convection, it will be necessary to expect that the south of the arc will be impacted by a compact but tough system. If he doesn't manage to reorganize quickly, his debuff could be very fast and marked.
Forecasting models are still so divided and circumspect in forecasting its intensity. It goes from small storm to hurricane Cat. 2, or even 3… in short, it's an incredible mess. It is extremely rare to find in this uncertainty 48 hours after the classification in cyclone. The nhc meanwhile, he tries to position himself on a sort of average between all these forecasts. In any case, the level of confidence in these forecasts (including that of the nhc) remains extremely weak and if you are on the south of the arc you have to take this into account.
Path
Regarding the trajectory forecast, things are much simpler. A high pressure ridge to its north is driving it westward, slowly for now and little faster from tomorrow.
The deviations that can be seen in the forecast at the arc level (and even more afterwards) are mainly related to the uncertainty of intensity. A slightly more intense cyclone may move up a little further north against the high pressures. In this area also the nhc is in a middle position compared to the consensus of the models.
I remind once again that these forecasts have a significant margin of error at 72 hours (over 100km) and that we must therefore remain cautious in the areas bordering the planned passage. And a Cat1 hurricane on Saint Lucia can have consequences on the south of Martinique!
Environmental
Gonzalo is always in an extremely contrasting environment. He is currently in an area where the water temperature is 29 ° and there is no or very little shear above him. At the same time he has to deal with a pocket of dry air and sand which is increasingly nearer. The result for the moment is that he gets stronger in spurts, leaving everyone in suspense.
Conclusion
Gonzalo maintains himself in the position of an extremely difficult cyclone to pinpoint and anticipate. 48 hours ago no model nor the nhc Was not considering a possible classification in Hurricane and we are almost there. It is therefore important to be very vigilant about its evolution today.
We can now determine 3 main risk areas:
- South of the arc (between Trinidad and Saint Lucia) where the risk is important for the passage of a hurricane.
- Center of the arc (mainly Martinique) where the risk is medium and above all linked to the fact of being north of the system, therefore potentially exposed to strong winds.
- Northern half of the arc where the risk is low to zero.
Despite that, I can only advise everyone to stay informed and on their guard, regardless of their location. A cyclone is by nature unstable and a compact like Gonzalo always difficult to predict, even at 48H / 72H.
To follow the evolution in real time of this weather system, it's here: Tropical Storm Gonzalo
Image credits; Tropical tidbits, NHC / Noaa, UW-CIMSS
