(By Steve Gregory - Substituting for Dr. Masters who is on Vacation.)
Figure 1: NEXSAT image showing both Rammasun and newly formed T.S. Matmo just a couple hours before Rammasun made landfall.
Super Typhoon Rammasun has made landfall on the Luichow Peninsula just north of Hainan most likely as a low end CAT 4 Typhoon. (Officially, JTWC has carried it as a borderline CAT 5). Haikou
on the north coast of Hainan, about 50NM SSE of the storm center, reported a sustained wind of 68Kts with gusts to 88Kts (100mph) as the storm passed just to their north, and a minimum pressure of 955mb. Winds continue to gust to tropical storm strength as of the writing of this report.
Rammasun intensified rapidly during the past 12-18 hrs as a strong outflow channel developed equatorward of the storm, and wind shear decreased to about 15kts. With an east-west ridge line just north of the storm, Rammasun should develop a more westward track during the next few hours and is expected to make its final landfall in northern Vietnam by around 03Z Saturday.
Figure 2: One final WV image clearly showing Rammasun’s eye and very large circulation field.UP NEXT: MATMO
Since yesterday, TD 10W has become slightly better organized and is now being carried as Tropical Storm Matmo. The slowly developing cyclone is about 235 NM north of Koror, Palau, and is drifting WNW at about 3-5 kts. Dvorak estimates and imagery loops suggest Matmo remains a borderline storm, but the marginally conducive environment is expected to become more favorable for intensification during the next 72 hours as the storm begins to track northwestward at a somewhat faster forward motion.
All of the specialized hurricane forecast models are in generally good agreement that Matmo will intensify to CAT 2 as it approaches Taiwan by the middle of next week. A couple models are calling for a much stronger storm – though these appear to be outliers at this point (as are some of the Japanese models that show a more northerly track towards Japan). It is worth noting that after 6 model runs forecasting only minor development, the GFS has come back into excellent agreement with the Hurricane models in forecasting a vigorous cyclone, tracking it towards northern Taiwan.
Figure 3: The above product depicts satellite derived winds, with strong outflow channels to the south of Rammasun. However, only a weak outflow exists to the northwest of MATMO, and poor outflow in all other quadrants around the cyclone..
Figure 4: The 06Z HWRF model run shows a somewhat more eastward track projection for Matmo compared to the GFS, but other models (not shown) show a track closer to that of the GFS.
Figure 5: Interpreting the Intensity forecast models is somewhat more problematic – with the typically more reliable models calling for Matmo to eventually become a CAT 1 or CAT 2, but a couple models are calling for a far more intense storm. Considering the EURO and GFS global model solutions, I tend to believe a low end CAT 2 to be the most likely outcome.
Figure 6: The official JTWC forecast calls for Matmo to be a CAT 2 Typhoon as it approaches northern Taiwan on Wednesday.TROPICAL STORM WALI
An unusual (but certainly not rare) Tropical Depression formed yesterday in the central Pacific, about 1,100 NM ESE of the Hawaiian Islands. By early today, better organization of the small cyclone prompted NOAA forecasters to officially designate the system Tropical Storm ‘Wali with 40Mph winds. The storm is currently located about 950 NM ESE of Hilo.
The storm is moving slowly W-NW, and while it may intensify a bit more, cooler SST’s and most notably, stronger wind shear and drier air should significantly weaken the system prior to it reaching the Big Island on Tuesday.
Figure 7: Enhanced IR imagery of Tropical Storm WALI. It’s relatively deep convection and symmetrical signature prompted NOAA forecasters to upgrade the storm early today, but the storm remains quite small and is heading towards a more hostile environment.
Figure 8: Wali is currently located in a relatively low wind shear environment, but a deep TROF NW of the Hawaiian Islands is generating strong, southwesterly wind shear over the eastern Islands and will impact Wali as it heads towards the Big Island in a couple days.
Figure 9: Official Track forecast for WaliTROPICAL ATLANTIC
The Tropical Atlantic remains fairly quiet – but continues to trend towards a more seasonal pattern as wind shear continues to ease off, and more distinctly, the environment has continued to 'moisten' up.
The Tropical Wave that first emerged off the African coast early yesterday has moved westward, loosing most of its deep convection. However, the wave has brought a strong moisture surge to the eastern Atlantic, though the warm Saharan air has stifled convection.
The more significant wave approaching the Windward Islands and is bringing showers and some heavier convection to the Islands, which will continue westward over the weekend. While wind shear as fallen off considerably compared to last week, it remains relatively high across the southern CARIB, especially in the SW CARIB, and this fact alone will prevent the Tropical wave near the Windward Islands from developing.
While none of the global models are forecasting any cyclone development during the next 10-14 days, the environment is expected to become a bit more conducive to cyclone formation during the last week of the month.
Figure 10: Todays 'big picture' shows the wave bringing significant rainfall to the Windward Islands, with the eastern Atlantic wave representing the leading edge of a significant moisture surge. (While not clearly shown, another large wave over west Africa should reach the coast by tomorrow.
Figure 11: The above enhanced water vapor image highlights the moisture surge over the eastern Atlantic that has accompanied the large tropical wave that came off the coast early yesterday.
Figure 12: The wide view water vapor imagery shows the continuing ‘moistening’ across the Tropical Atlantic Basin – a dramatic change compared to the first 10 days of July.
Figure 13: Wind shear continues to decline across the basin, but remains relatively strong across the southern CARIB which will inhibit any development of the wave near the Windward islands.
Next update will be Saturday afternoon.