Tropical Update

It has been a while since our last update. Since then, the Western Pacific has remained relatively quiet with a few rain-bearing disturbances that moved through the Philippines. However, we are seeing an uptick in activity as two developing tropical waves has been spotted in the Pacific. First one is Invest 93W which was last spotted approximately 100km NW of Palau or about 900km east of Mindanao and Invest 94W located approximately 840km southeast of Guam.

IR Image from NRLMRY

Invest 93W currently has a LOW rating by the JTWC. An ASCAT pass earlier today reveals 15 to 30kph winds near a weakly-defined low level circulation center. Conditions are marginally favorable for development with weak to moderate wind shear, and normal SSTs. The outflow, however, is somewhat suppressed by a feature called an upper level low (ULL). Computer models are not showing development for this system either but we'll continue to monitor it. As 93W moves slowly northwestward, it could eventually bring rain showers to parts of Eastern Philippines next week.

Invest 94W, on the other hand, seems to have a better chance of development down the road. High SSTs, weak-moderate wind shear, and good outflow should help the system consolidate further over the next 24 hours. In fact, JTWC has upgraded 94W's chances to Medium due to the said factors. Computer models, too, are showing some development out of this system. GFS seems to be the most aggressive among the models and is showing a potential tropical storm in the next 3 to 5 days. No matter what happens next week, all signs point on a recurvature, or at least a more poleward path. While it isn't forecast to impact the Philippines, 94W could move near Guam and the Marianas Islands as early as Monday bringing the threat of thunderstorms and widespread rain showers.

Due to the presence of these systems, we'll have another update tomorrow afternoon (earlier if one of them develops).
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Issued (0630 UTC) 230pm PhT 051912