Atlantic ‘Wakes-Up’ / Typhoon Matmo Heads For Taiwan

ATLANTIC ‘WAKES-UP’ / TYPHOON MATMO HEADS FOR TAIWAN


(By Steve Gregory - Substituting for Dr. Masters who is on Vacation.)

Morning VIS imagery shows a well defined low level closed circulation has formed about 1,200 NM east of the CARIB near 11.6N / 42.6W and is westbound (280ᵒ) at 20Kts – and is now being carried by NHC as INVEST 92L.



Fig 1: A relatively small but well-defined Low level circulation has formed within a small area of weak convection.

Convection remains fairly weak, but does exist just to the SE of the center of rotation, and high level wind analysis from CIMSS does NOT show significant outflow. That said, wind shear is believed to be quite low (est. under 10Kts)




Fig 2: With limited derived values for high level winds associated with INVEST 92L, there is currently little evidence of significant outflow associated with the tropical Low. (More data should become available if/when convection deepens.)



Fig 3: Likewise, what wind data is available in the vicinity of the Low, wind shear is likely quite low (under 10 Kts) and this should enable INVEST 92L to slowly intensify once deeper convection is able to develop.

Global models still have not resolved this system, but after manual initialization by NHC, Early Track and Intensity model forecasts call for the system to become a Depression today and possibly reach Tropical Storm intensity during the next 48-72 hours once the system moves over waters that are warm enough to support storm formation.



Fig 4: Early 12Z model runs show a W/WNW track, with the system reaching the Northeast CARIB Friday.




Fig 5: Early 12Z model runs (primarily based on CLIMO and limited dynamical / statistical forecasts) show the system becoming a Tropical storm, and POSSIBLY a minimal CAT 1 by the time it reaches the NE CARIB. Confidence is Low for this forecast.

ASSUMING this developing cyclone manages to become a Tropical storm or Hurricane near the eastern CARIB, extended global model forecasts depict a weakening of the sub-tropical ridge north of the system by then, and an approaching large-scale long wave TROF in the eastern US suggests the system will eventually turn northward away from the US mainland. However, this assumes that the system does in fact reach the northern CARIB as currently forecast by the early model runs. That said, should the cyclone stay on a more westerly track into the central CARIB AND manage to find a low shear environment this weekend - track / intensity forecasts beyond then become quite problematic. And, of course, the developing system could simply turn northward prior to reaching the CARIB and would simply head out sea by the weekend.


CAT 1 MATMO HEADING FOR TAIWAN


Typhoon MATMO is located about 485 NM South of Okinawa, Japan, heading NNW at 15 Kts. With Dvorak T numbers near 5.0 and the JAM estimating a central pressure near 970mb, MATMO’s Max sustained winds are estimated near 75Kts.



Fig 6: A tightly 'wound up' and small-to-average size storm is depicted in the last VIS image of MATMO.




Fig 7: Deep convection is especially prominent in this color enhanced IR image.

Overall, recent Imagery depicts a bit more symmetrical storm signature with strong, deep convection (with typical diurnal variation) - especially in the southern semi-circle. As anticipated, wind shear has fall off to near 15 Kts, with a continuing decline to near 10 Kts expected during the next 12 hours. This has allowed for a much improved outflow to develop, with moderate to strong outflow channels noted pole-ward and equator-ward, with MAX speeds near 50 Kts.



Fig 8: Wind shear has decreased since yesterday and should promote intensification during the next 24 hrs.



Fig 9: Strong Outflow channels are clearly seen to the north and south of the cyclone's center.

With this overall improvement in outflow – and a projected track over quite warm SST’s – MATMO should reach CAT 2 intensity within 12-18 hrs, and may approach CAT 3 intensity in 24-36 hrs.

There has been virtually no change in the forecast track for MATMO for the past 2 days, with both the GFS and specialized hurricane track models showing the storm center passing across the northern Taiwan east coast WED around 06Z,

With the approach of an upper air TROF over eastern China, wind shear should then increase as the storm continues NNW towards the SE China coast. Combined with cooler SST’s and interaction with the mountainous terrain of Taiwan (and additional interaction with the China mainland) MATMO should approach the SE coast of China around 06Z THU as a minimal CAT 1, or strong Tropical Storm. At this time, there is minimal risk that MATMO will be stronger than a CAT 3 when it reaches Taiwan.



Fig 10: The official Track forecast from JTWC (above) is in excellent agreement with all track forecast models, and now, the track and intensity forecast from the JMA.


I will have another update on the ATLANTIC INVEST late this afternoon.

Steve Gregory