Two typhoons (NW Pacific Ocean) 9 September 2021

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As previously described, it has been a relatively benign season to date for the Typhoon season across the North West Pacific Ocean.

However, it is identified that oceanic waters have now been heated to as much as 30C and 31C east of the Philippines and South East of Taiwan over recent weeks and there has been little storm activity to feed off this warmth. The ocean east of the Philippines have absorbed much energy and surface waters have warmed by at least 2C over the past 3 weeks.

Two storm systems have developed within the region with one named Conson and the other named Chanthu.

Tropical Storm Conson - Philippines

This storm has passed over the Philippines travelling in a north west direction. Once the storm clears Luzon Island, the storm is forecast to strengthen into a Category 1 typhoon on the Saffir Simpson Scale with peak wind gusts to 65 to 70 knots (120 to 130 km/h) at the core. Landfall is forecast to be either Hainan Island or if it misses this island, the storm will make landfall over North East Vietnam bringing gales and flooding rains.

This storm is the weaker of the two storms.

Typhoon Chanthu

A second storm further east of the Philippines has rapidly intensified from a tropical storm to a Category 4 typhoon in the space of 24 hours. This remarkable development shows how much energy there is available within the region to support the development of such a strong storm in such a short period of time.

Tuesday evening, this was named as a tropical storm but by Wednesday evening, the storm had reached Category 4 on the Saffir Simpson Scale and there is potential for further development given how the oceanic waters have been heated compared to what existed just three weeks ago.

Peak wind gusts at the core have already reached 120 knots or more than 220 km/h but the CIMSS model is forecasting further intensification with peak wind gusts to 135 knots (Upwards of 250 km/h). The storm will threaten the North East coastline of Luzon Island of the Philippines and its core may even approach the coastline. The storm may also approach or brush the South East coastline of Taiwan in coming days.

Should the storm miss both land masses as suggested, then the storm will make landfall in South East China as a weaker system (Category 2) but still result in damaging winds and flooding rains.

This is by far the strongest storm this season for this part of the Pacific Ocean.

Should the storm make landfall as a Category 4 system in either Luzon Island or Taiwan, then it will have a major impact to either country.

This storm is being monitored closely. Not shown on the models 8/9/2021, there is the distinct possibility that the storm will further develop into a Category 5 system given its location, the abundance of warm waters to feed it (30C to 31C) and the recent lack of storm activity in the region to help cool the oceanic waters.

The image from JTWC SATOPS shows Typhoon Chanthu as having a very tiny but distinct eye that is surrounded by a ring of tightly packed cumulonimbus clouds. It’s intensity is obvious given how compact it is.

The images of both storms are derived from:-

NASA Worldview - 7/9/2021.
CIMSS - 7 and 8 September 2021.
JTWC SATOPS (Operated by Japan) - 8/9/2021.

Addendum 9/9/2021 - A Category 5 storm

This storm has become a Category 5 system on the Saffir Simpson Scale with peak wind gusts to 140 knots (260 km/h) at the core and concern now is that an updated CIMSS model suggests that the storm will brush the NE coast of Luzon Island then turn more to the north west and make landfall as a slightly weaker Category 4 storm over south east Taiwan which is populated.

This is one storm that looks set to have a dramatic impact upon landfall in coming days.

Tropical Storm 16 Now named Omais – 21 August 2021

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One week ago, Tropical Depression 16 which was located east of the Philippines was expected to strengthen into a significant storm and a typhoon that would have threatened either the Philippines or Taiwan.

However, the storm broke apart which was not expected to occur. The storm reformed a second time over the past 24 hours as a moderate to strong tropical storm. The storm has now been named Omais.

Given its current location, the storm is only now expected to approach typhoon strength but not exceed such thresholds. The maximum peak winds are now only expected to reach 50 knots or 93 km/h at its core before weakening as it moves further away from the tropics (CIMSS 21/8/2021).

Landfall is now not expected.

So far this season, the area where the storm is located has been relatively benign and there have not been any intense storms to note. This is unusual given that the north west Pacific Ocean is regarded as the most productive regions globally for the development of typhoons. Most years intense storms usually occur within the region. Sea level temperatures are still around the 30 to 31C just east of the Philippines but cooler waters prevail further offshore (29C) which may be contributing to a quieter typhoon season.

This area will continue to be watched for such storms in coming months.

Tropical Storm Grace / Hurricane Grace – Gulf of Mexico – 17 – 22 August 2021

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During Tuesday 17 August 2021, a tropical storm formed south east of Haiti and was named Tropical Storm Grace. The storm impacted southern Haiti including the area that was recently hit by the earthquake. The rains from the storm has compounded the issues and recovery effort within the earthquake impact zone with flooding and landslides occurring as the storm passed by.

The storm passed back out to sea and continued to travel west. During Wednesday and Thursday 18 and 19 August 2021, the storm intensified further to a category 1 Hurricane under the Saffir Simpson Scale and as it approached the Yucatan Peninsula of Mexico, the storm remained small but compact and without an eye. However, the storm sustained peak wind gusts to 70 knots (130 km/h) at its core.

At the time of writing, the storm had crossed over the central part of the Yucatan Peninsular before crossing back out to sea as a tropical storm below hurricane strength.

Forecast models from CIMSS now show the storm approaching the east coast of Mexico and making landfall over Veracruz State as a small compact storm with peak wind gusts to 75 knots (139 km/h) at the core. It appears that landfall will occur in the vicinity of a town called Papantla De Olarte. The storm is expected to weaken rapidly upon final landfall.

Despite passing over waters of 30C to 31C, the development of the storm has been restricted due to the storm passing too close to land masses. One feature is that the storm would have made two coastal landfall crossings of Mexico during its lifespan.

To date, the hurricane season in this part of the world has been relatively benign and there have been no major storms to date this season within the Gulf of Mexico.

Hurricane Grace will likely cause coastal gales and flooding at landfall but its impact will be localized because the storm is small and compact in size.

Addendum

Hurricane Grace has made landfall as expected as per the forecast Friday / Saturday 20 and 21 August 2021. The only matter to note at landfall is that the storm has briefly intensified further to a low range Category 2 system on the Saffir Simpson Scale with peak wind gusts to 90 knots (167 km/h at the core. The storm is now expected to weaken following its landfall.

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