Japan Prepares for Usagi

Guest blogger Margie Kieper


Wednesday afternoon update (yet again): From the Atlantic TWO: "AN AIR FORCE RECONNAISSANCE PLANE INVESTIGATING THE AREA OF LOW PRESSURE AND A TROPICAL WAVE NEAR THE WINDWARD ISLANDS THIS AFTERNOON WAS NOT ABLE TO FIND A CLOSED CIRCULATION." And that is that -- for now. Tonight -- we'll Usagi (it sounds like it could be a verb!).


Wednesday afternoon update #2: There appears to be a broad low with no closed circulation on the latest recon obs for 99L -- which is back on the NRL web site (sigh). Winds are light and variable, and no westerly winds at all on the leg from the SW in to the center. Let's pretend we're in the cockpit of that flight, flying back and forth... Plaintive voice on the radio back to NHC: "Nothing here -- can we go home now?" :)

Will update on this in the evening.

Usagi is steadily weakening. This is what I didn't understand from the Monday and Tuesday forecasts -- how strengthening could be forecast for an area of ocean where the heat content drops off rapidly. Usagi will still be a significant typhoon when landfalling in Japan, but not the Cat 4 that it was earlier.

They did it again in the forecast discussion for TS Erick..."A WEAKENING BLOB OF DEEP CONVECTION." Sigh (again).

Here's a link to the UK forum that will be updating "Typhoon Hunter's" Usagi experience (gotta love those names, huh). Here's a link to Japan's radar.


Wednesday afternoon update: Initial recon obs for the disturbance just about to enter the eastern Caribbean appear to show support for a closed circulation at 1000 ft (HD OB 14 and 15 showed WSWly winds), with very light winds and a lowest pressure reading so far of 1002 mb. If a closed circulation is found, this disturbance will probably be labeled a tropical depression. Most recent water vapor imagery shows a moister environment in the eastern Caribbean, but convection is still disorganized.

The latest forecast from JTWC for Usagi shows it decreasing to 95 kt intensity just prior to making landfall in Japan. A microwave image from this morning shows the change in organization, with what appears to be an open eyewall to the southeast.




We'll hopefully be hearing some reports from "Typhoon Hunter," who headed for Japan a couple of days ago to intercept Usagi.

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During the day in the West Pacific, Usagi maintained a classic presentation on visual satellite imagery:




But at this same time, on microwave, the outer bands of convection took on a ring-like appearance, outside of the eyewall convection:




This convective pattern has since shifted, with strong convection remaining in the eyewall and the eye temperature remaining warm. JTWC has backed off intensifying in the forecast, and has maintained the 120 kt intensity, but still forecasts Usagi to hit southern Japan at the eastern tip of Kyushu with a maximum intensity of 115 kt, and JMA forecasting 80 kt (10-min wind).

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***Horrors!*** I'm shocked -- shocked, I tell you. NHC has used the word "blob" in a forecast discussion on TS Erick: "...WITH THE CENTER OF CIRCULATION LOCATED NEAR THE EASTERN EDGE OF AN AMORPHOUS BLOB OF DEEP CONVECTION."

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There continues to be no closed surface circulation associated with the area of disturbed weather approaching the eastern Caribbean, and invest 99L, which is now a tropical wave with some associated convection, and was dropped around 12Z this morning. The mid-morning Tropical Weather Outlook seems to want to keep it alive, however, even while noting, "ENVIRONMENTAL CONDITIONS DO NOT APPEAR ESPECIALLY FAVORABLE FOR DEVELOPMENT," so perhaps it will make a reappearance later today. Barbados weather obs, which can be followed here, will tell the story (pressure is currently rising).

More importantly, the TWO notes the disturbed weather in the GOM on the tail of the front that moved off the East Coast yesterday.

More updates in mid-afternoon.

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For Jeff�s early August hurricane outlook, which came out Sunday, link here.