Sunday, June 9, 2013

Tropical Storm Yagi (Dante) Update #5

Issued (02 UTC) 10am PhT 061013

Tropical Storm Yagi (Dante) was last located approximately 730km southeast of Okinawa. Maximum sustained winds remain at 75kph with gusts of up to 95kph. TS Yagi is moving northeastward at 15kph.

IR Image from NRLMRY

Yagi's intensity remains unchanged despite the well-defined circulation center that looks almost like an eye. The reason for the weak intensity is the fact that convective activity hasn't really been all that strong in the past 24 hours. We haven't seen really cold cloud tops especially near the storm's center. Furthermore, dry air and subsidence to the northwest continue to impede development in that quadrant of the storm.

While we aren't seeing the continued intensification that we have forecast in the past two days, we still expect Yagi to remain a Tropical Storm (maybe even intensify a little bit more) as it heads northward. It will start to move into unfavorable area beginning Tuesday with increasing vertical wind shear and decreasing sea surface temperatures.

There has been some change with the track forecast as well. Most computer models are now showing a re-curving that will take Yagi just south of Japan and then make a u-turn so it won't make landfall. However, the two agencies: JMA and JTWC, are showing two different forecasts as of this moment. The former agency is showing a track towards the island of Shikoku whereas the JTWC is following the model consensus and is showing a u-turn track showing Yagi moving towards Japan but will re-curve at the very last moment to avoid a direct landfall.

The track differences all hinge on the strength and orientation of the sub-tropical ridge anchored in the Northern Pacific. Obviously, there are two camps with the forecast track right now. For now, we are taking the middle solution and forecast Yagi to still move into Japan, perhaps near the Kii Peninsula, on Wednesday before weakening significantly. Please do note that there is low confidence in the forecast track and we will have to keep monitoring this storm and the sub-tropical ridge very closely over the next 24 hours.

We'll have another update later tonight.

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