Tropical Storm Guchol Update #5

Tropical Storm Guchol strengthens slightly as it moves north of Yap. The storm was last located approximately 140km northeast of Yap Island. Maximum sustained winds have increased to 75kph with gusts reaching up to 100kph. TS Guchol is currently moving to the west northwest at a speed of 20kph.

Tropical Storm Warning remains in effect for Fais, Ulithi, and Yap Island. Stormy conditions will continue for these areas throughout tonight. Yap Airport already reporting continuous light to moderate rains, winds of up to 40kph, and continuous decrease in atmospheric pressure. Since Guchol will be passing to the north of the island, we expect winds of below tropical-storm force although occasional gusts of 60 to even 80kph is possible tonight. Rains of up to 100mm are possible as well. Furthermore, rough seas will continue tonight and for the next 2 days. Rains and gusty winds should slowly taper off later tomorrow.

IR Image from NRLMRY

Infra-red image continues to show slow improvements with Guchol. Although convective activity isn't well organized, poleward outflow has improved allowing the storm to intensify slightly today. Banding is also improving with the circulation center becoming more organized. The turn to the west northwest in the past 3 hours, as well as an apparent increase in forward speed, are signs of the effects of the subtropical ridge.While we're still unsure about the long-term track of Guchol, the recent turn in movement is a good sign for Luzon.

Tropical Storm Guchol will continue moving west northwestward and is forecast to enter the Philippine Area of Responsibility by Thursday evening; PAGASA will assign the local name 'Butchoy'. Wind shear should weaken across the Philippine Sea, and with warm sea temperatures, TS Guchol should intensify at a faster pace. Barring any sudden weakening, we expect Guchol to become a typhoon by as early as Friday morning.

Forecast Track (NOT OFFICIAL!)

Medium to long-range forecasts continue to have differences among the computer models. However, latest solutions are becoming more and more closely packed signifying a better handling from these computers. Furthermore, the latest consensus show the track away from Luzon and into the Yaeyama and Miyako Islands in Japan. With that said, we have made very little changes with our forecast track. The only difference would be the peak intensity which we have raised to Category 2 by Sunday. Nevertheless, keep in mind that Luzon, Taiwan, and Okinawa are still inside the forecast cone so continued monitoring from these places is encouraged. For the Philippines, in particular, the approaching storm is not forecast to bring direct stormy impacts. However, Guchol will still likely enhance SW Monsoon by this weekend so expect scattered rain showers for Luzon and Visayas.

We'll have another update tomorrow.
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Issued (09 UTC) 5pm PhT 061312