Tropical Update

Invest 90W weakened yesterday but seems to have bounced back overnight--owing to the diurnal maximum we have mentioned in our update yesterday. Nevertheless, the TCFA issued by JTWC has been cancelled and the system's rating has been downgraded to MEDIUM. Invest 90W was last located approximately 520km west southwest of Chuuk or about 900km south southeast of Guam.

IR Image from NOAA

The system has regained some of its structure overnight with banding reforming and convection reappearing. However, a slight weakening can be observed during the past 6 hours. All these cycles are typical of thunderstorms and developing disturbances in the tropics. We expect another burst of convection to occur tonight and into tomorrow. Wind shear has weakened in the area (5-10 knots) and sea surface temperatures remain very conducive for further development. While computer models have backed down from their forecast from a couple of days ago, we are still seeing some hints from the latest outputs regarding a potential development in the next 2 to 3 days. Certainly, JTWC still feels 90W has a chance and so they are keeping that MEDIUM rating on it.

We'll keep watching this system and will have another update tomorrow.
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Issued (0830 UTC) 430pm PhT 061012