Archive | August 9, 2013

Potential typhoon threat for Luzon on Monday

Good evening–tonight we’re tracking the developments of Tropical Depression Labuyo about 705 km northwest of Palau as it tracks toward the west-northwest at 10 kt.  There is a lot of variance in the initial intensity.  While JMA officially reports the cyclone at 30 kt, along with PAGASA, Dvorak analyses are all over the place.  JMA’s Final Dvorak T-Number was T1.5, which matches their initial 09Z intensity.  However, the National Weather Services placed the initial intensity at T3.0, which would yield about 45 kt using the US 1-minute average method.  My personal analysis tends to suggest a cyclone of tropical storm-strength, which is backed up by an 0309Z OSCAT pass which indicated 40 kt winds in convection northeast of the center.  Since 03Z, convection has dramatically consolidated around the center with “white” banding appearing now on the Dvorak Infrared enhancement, suggesting colder cloud tops or stronger thunderstorms.

Near-term forecast keeps Labuyo moving west-northwest along the southern/southwestern edge of the subtropical ridge… and this forward motion should continue through the weekend and into early next week.  Based on the latest track guidance, this would be Cagayan, Isabela, and Aurora provinces in the Philippines under the gun for landfall.  Intensity is rather tricky.  With the wide variance in initial intensity, that will play a huge role in the day 2/3 intensity.  However, most major agencies are suggesting at least minimum typhoon strength prior to landfall, with JTWC indicating at least 80 kt.  In additional to strong winds, heavy rains will also play a factor as GFS is suggesting 100-150 mm with isolated amounts up to 230 mm through Monday afternoon.

Once JMA officially upgrades this depression to a tropical storm, it will be named Utor (oo-TORE), which is a Marshallese word for “squall line.”

More detailed analysis in the video below:

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