Pacific coast of Mexico preps for a one-two punch from Max and Lidia

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Two named storms in less than 48 hours will slam into Mexico’s Pacific coastline early this week – one of them likely to be a strengthening hurricane – making for an unusual double-barreled threat. Yet another tropical cyclone will make landfall in the Pacific during the same period – this one expected to strike the U.S. Northern Mariana Islands as an intensifying typhoon.

First to make landfall will be Tropical Storm Max, which developed late Sunday off the coast of Guerro state west of Acapulco. As of 11 a.m. EDT Monday, Max was packing top sustained winds of 60 mph and was located about 50 miles south-southeast of Zihuatanejo, Mexico, moving north-northeast at 5 mph, with a central pressure of 996 millibars. On its current trajectory, Max will make landfall Monday afternoon or evening just east of Zihuatanejo as a strong tropical storm, possibly becoming a Category 1 hurricane just before landfall. Max’s compact area of strong winds will affect a sparsely populated section of coastal Mexico. However, the storm’s envelope of moisture will push upslope against the rugged terrain of Guerro state, especially just inland from roughly Acapulco to Làzaro Cardenas. Totals of four to eight inches of rain – and locally more than a foot – will raise a serious threat of flash flooding and mudslides.

#Max is intensifying markedly as it is nearing landfall and could be near hurricane strength. A MW pass from a few hours ago sampled a small inner-core and recent IR/VIS loops show that a formative eye has appeared – NHC’s estimate of 60KT might be conservative.

— KeviShader (@KeviShader) October 9, 2023

Farther to the northwest, the much larger Tropical Storm Lidia is expected to vault to hurricane strength as it accelerates toward the coastlines of Jalisco, Nayarit, and Sinaloa states. Lidia is expected to make landfall late Tuesday near or just north of Puerto Vallarta, which could put that heavily populated area on the more dangerous right-hand side of the storm and push storm surge into the Bay of Banderas, where the city lies.

As of 11 a.m. EDT Monday, Lidia had top sustained winds of 65 mph with a central pressure of 992 mb. Lidia was located about 400 miles west-southwest of Las Islas Marias, heading northeast at about 6 mph. A Hurricane Warning extended from Playa Perula to Escuinapa, including the Puerto Vallarta area. A Hurricane Hunter flight was en route to investigate Lidia late Monday morning.

Lidia forecast map
Figure 1. Tracks of ensemble model output from the European, GFS, and UKMET model runs for Lidia from 0Z Monday, October 9. The operational GFS model (green line) has consistently brought Lidia to the coast about 12 hours faster than the Euro (red) and UKMET (dark blue), so there remains some uncertainty in the timing of landfall. The thick black line shows the average track of all three ensembles. (Image credit: Tomer Burg)

The new HAFS intensity model has projected for days that Lidia could rapidly intensify during its final day of approach to the coastline. This still appears possible, as Lidia will be crossing very warm seas at or above 30 degrees Celsius (86 degrees Fahrenheit) in an environment of decreasing wind shear and high moisture (a midlevel relative humidity of 60-65%). As of Monday morning, the SHIPS rapid intensification index gave a 45% chance of Lidia’s peak winds increasing by 30 knots (35 mph) in 24 hours, which is the official threshold for rapid intensification. The National Hurricane Center predicts that Lidia will make landfall as a Category 2 storm.

As with Max, heavy rains of four to eight inches and localized amounts topping 12 inches can be expected across the coastal areas and higher elevations just inland near Lidia’s path, likely triggering flash floods and mudslides. Lidia could also bring a substantial storm surge near and just south of its eventual landfall location. Moisture from Lidia may also help spawn heavy rains along the U.S. Gulf Coast (see below).

Tropical Storm Bolaven headed for the Northern Mariana Islands

Typhoon warning flags are flying for Tinian and Saipan islands in the U.S. Northern Mariana Islands with a Tropical Storm Warning up for the islands of Guam and Rota as Typhoon Bolaven heads northwest toward an expected landfall Tuesday night local time (Tuesday morning U.S. EDT). Guam radar on Monday showed the outer bands of Bolaven were already affecting the islands, which were under a Flash Flood Watch.

At 12Z Monday (8 a.m. EDT, 10 p.m. local time in Guam), Bolaven had top sustained one-minute average winds of 65 mph and was headed northwest at 14 mph, according to the Joint Typhoon Warning Center. The Japan Meteorological Agency rated Bolven as having a central pressure of 980 mb and 70 mph winds (10-minute average, which is normally substantially lower than the 1-minute average). The Joint Typhoon Warning Center predicted that Bolaven would rapidly intensify into a typhoon within 12 hours, a Category 2 storm as it passed Tinian Island Tuesday night local time (Tuesday morning U.S. EDT), becoming a powerful super typhoon with 150-mph winds on Thursday. No land areas lie in Bolaven’s path after it passes through the Northern Mariana Islands and recurves to the north and northeast.

The National Weather Service on Guam was predicting that Bolaven could bring the islands eight to 14 inches of rain, with isolated amounts of up to 20 inches. Waves of 16-22 feet were predicted near Tinian and Saipan for Tuesday night local time, with possible typhoon-strength winds on both islands.

Bolaven the second named storm to affect the Northern Marianas in 2023

Bolaven will be the second named storm to affect the Northern Mariana Islands this year. On May 24, Typhoon Mawar passed just north of Guam as a Category 4-equivalent typhoon, becoming the strongest storm to affect the island since Typhoon Pongsona in 2002. According to insurance broker Aon, Mawar killed two and did $250 million in damage to the Northern Mariana Islands, mostly to Guam. But the storm could have been much worse: An eyewall replacement cycle briefly weakened Mawar as it approached Guam, and it became an ultrapowerful Category 5 super typhoon with 185-mph winds the next day.

From tropical storm to category-5 equivalent intensity: 6 days of Typhoon Mawar via Himawari-9 IR imagery.

According to JTWC, #Mawar‘s estimated peak wind speed of 160 kt (185 mph) has been achieved by only 13 other typhoons since 1979.

— Dr. Kim Wood (@DrKimWood) May 26, 2023

Scenes from around Tumon Bay, #Guam the day after #typhoon #mawar – lots of tree damage, power and water out, hum of generators everywhere, immediate shoreline battered by surge and some cars shunted around by wind

— James Reynolds (@EarthUncutTV) May 25, 2023

One more Cabo Verde system to watch

The Atlantic Cabo Verde hurricane season, in which tropical waves stream off Africa near the Cabo Verde Islands and develop in the tropical Atlantic’s main development region, is close to an end. However, there is one more African wave expected to develop, which was located several hundred miles south of the Cabo Verde Islands on Monday afternoon. This wave, designated Invest 92L by the National Hurricane Center, was headed west-northwest to northwest toward the remote central Atlantic. This wave has considerable support for development from the models and is likely to form into a tropical depression this week. In its Tropical Weather Outlook issued at 8 a.m. EDT Monday, the National Hurricane Center gave 92L two-day and seven-day odds of development of 60% and 80%, respectively. This system is likely to recurve into the open central Atlantic and not be a threat to any land areas except perhaps the Azores Islands. The next name on the Atlantic list is Sean.

map of rainfall forecast for the United States
Figure 2. Predicted three-day precipitation amounts ending at 8 a.m. EDT Thursday, October 12, 2023. A tropical disturbance in the Bay of Campeche is expected to help bring heavy rains of two to four inches to portions of the Gulf Coast. (Image credit: NOAA)

Disturbance in the Bay of Campeche likely to feed into heavy U.S. Gulf Coast rains

As the Cabo Verde season winds down in October, attention in the Atlantic turns toward the southern Gulf of Mexico and especially the Caribbean, which in some years continue to churn out storms into November. This autumn, we have two powerful competing factors at work: sea surface temperatures that are still unusually warm for the season (one to two degrees Celsius or two to four degrees Fahrenheit above average throughout the region) juxtaposed with a tendency for increased wind shear because of a potent El Niño event now underway.

The area in the Bay of Campeche noted in the NHC outlook seems like it will turn into a hybrid frontal low, without any notable tropical development. Upper westerlies across the Gulf will make any sort of tropical development tough.

— Andy Hazelton (@AndyHazelton) October 9, 2023

An area of disturbed weather has formed in the Gulf of Mexico’s Bay of Campeche, near the coast of Mexico. This disturbance is expected to move slowly north to north-northwest toward Texas through Tuesday, then recurve to the northeast on Wednesday as it gets absorbed into a frontal zone. This disturbance does have a modest amount of support for development by the European and GFS model ensemble forecasts and is likely to help bring heavy rains of two to four inches to the northern Gulf Coast Tuesday through Thursday. Moisture from Tropical Storm Lidia in the eastern Pacific may also feed into these rains, as seen in Figure 2 above. In its Tropical Weather Outlook issued at 8 a.m. EDT Monday, the National Hurricane Center gave the disturbance two-day and seven-day odds of development of 20%.

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