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Weird Olaf Dies; Huge Tides Swamp SE U.S.; Indonesia Ties All-Time Heat Record

By: Jeff Masters and Bob Henson 3:33 PM GMT on October 27, 2015

The weird and remarkable Northern Hemisphere tropical cyclone season of 2015 is on the wane, and we don't have any active systems anywhere on the planet to discuss today. On Tuesday morning, Tropical Storm Olaf met oblivion over the cool 25°C waters between Hawaii and California, ending a long run as a most unusual tropical cyclone. Back on October 19, Olaf set a record for becoming the most southerly major hurricane ever observed in the Eastern Pacific, at 9.9°N latitude. And on Monday night, Olaf performed another rare feat--crossing from the Central Pacific into Eastern Pacific. Moving from southwest to northeast, Olaf crossed the magic line of 140°W, which marks the boundary between the two ocean areas. The Central Pacific Hurricane Center (CPHC) in Hawaii stopped issuing advisories on the storm, and the National Hurricane Center (NHC) in Miami resumed issuing them. This was the second time Olaf had crossed 140°W--Olaf passed from the Eastern Pacific into the Central Pacific on October 20, causing a reverse hand-off of responsibility, from NHC to CPHC. Olaf is the only named storm ever to require a double hand-off of advisory issuing responsibility between the two hurricane centers. The only other storm to cross from the Central Pacific in the Eastern Pacific was an unnamed 1975 storm. Earlier this month, Tropical Storm Oho almost did so, becoming post-tropical just 50 miles before crossing 140°W from southwest to northeast. Since 1949, no late season (October or later) system has formed south of Hawaii and moved to the northeast; we know two storms this year that have done that, Oho and Olaf. This year's unusual activity in both the Eastern Pacific and Central Pacific has been due to unusually low wind shear and record-warm ocean temperatures caused by a strong El Niño event combined with the long-term global rise in temperatures underway.


Figure 1. MODIS image of Tropical Storm Olaf as seen from NASA's Aqua satellite on Monday afternoon, October 26, 2015, as the storm was about to cross 140°W from the Central Pacific into the Eastern Pacific. At the time, Olaf had top sustained winds of 60 mph. Image credit: NASA.

Earth's next tropical cyclone: an Arabian Sea storm?
In the Arabian Sea, Invest 94A is growing more organized, and is likely to become a named storm later this week as it heads westwards towards Oman and Yemen, according to recent runs of the GFS and European models.

The Atlantic and the Eastern Pacific are quiet, with none of our reliable models for predicting tropical cyclone genesis showing anything developing over the next five days. I'm not expecting any more named storms to form in the Atlantic this year, but I expect we'll get 1 - 2 more named storms in the Eastern Pacific and 2 - 4 more storms in the Northwest Pacific.


Figure 2. Predictions of the surface wind field of Invest 94A on Monday, November 2, 2015, from the 00Z Tuesday, October 27, 2015 runs of the GFS and European (ECMWF) models. Image constructed from our wundermap by TWC's Stu Ostro.

Indonesia ties all-time national heat record
Along with life-threatening amounts of smoke from agricultural burning during a very strong El Niño, Indonesians are dealing with extreme heat. On Tuesday, the airport station at Semarang, Indonesia, soared to a high of 39.5°C (103.1°F). This ties the national record for the hottest temperature ever observed in Indonesia, set in Cirebon Jatiwangi in 2006. These data come from international weather records researcher Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. As documented in our October 21, 2015 post, there were fourteen nations or territories that had set or tied all-time heat records this year as of October 21. Indonesia brings that tally to sixteen, since Meteo France announced a new all-time high temperature record for French Guiana was set on October 22, 2015, when the mercury hit 37.8°C (100°F) at Saint Laurent du Moroni.

As El Niño-related drought intensifies its chokehold on the region, Indonesia’s pall of smoke and haze is only getting worse, and the effects are accumulating. Six Indonesian provinces have declared states of emergency, and since July more than 500,000 acute respiratory infections have been reported. Despite the health catastrophe, there is no national ban on agricultural fires. A spokesperson for Indonesia’s meteorological agency, Sutopo Puro Nugroho, said: “This is a crime against humanity of extraordinary proportions…But now is not the time to point fingers but to focus on how we can deal with this quickly.” As we noted earlier this month, the fires are Earth’s most expensive weather-related disaster of 2015. The Indonesian government now estimates that the total costs to the government are at least $30 billion (US dollars).


Figure 3. Motorists ride on a road as thick haze from forest fires shrouds the city in Palangkaraya, Central Borneo, Indonesia, on Tuesday, October 27, 2015. The haze has blanketed parts of western Indonesia for about two months and affected neighboring countries like Singapore, Malaysia and Thailand. Image credit: Associated Press.


Figure 4. An Indonesian soldier puts out a fire in Kampar in the Indonesian province of Riau on September 18, 2015. Image credit: Adek Berry/AFP/Getty Images.

Highest tides in decades sweep into Charleston, Savannah
A predicted high tide came in substantially stronger than expected this morning across much of the southeast U.S., especially along the South Carolina and Georgia coasts. Near Savannah, the Fort Pulaski station reported a tide of 10.43 feet above mean lower low water (MLLW). Even including hurricanes, this is the third highest tide at Fort Pulaski since records began in 1935, beaten only by 10.47’ on August 11, 1940 and 10.87’ on October 15, 1947 (thank to Nick Wiltgen at The Weather Channel for these records). At Charleston, the high tide of 8.68’ this morning was the highest in 26 years, beaten by 8.84’ (January 1, 1987), 10.27’ (August 11, 1940), and 12.56’ during Hurricane Hugo (September 21, 1989). Motorists in the Charleston area were asked to avoid traveling onto the peninsula this morning, with many roads blocked by accidents and/or high water.


Figure 5. Tidal records for October 24-27, 2015, at Fort Pulaski, Georgia, just southeast of Savannah. Image credit: NOAA Advanced Hydrologic Prediction Service.

It doesn’t take a hurricane to produce historically high tides. In this case, the high water is the result of strong coastal flow from the northeast (which pushed water onshore due to the Ekman transport effect) combined with a perigean spring tide. The latter occurs when the moon is at the closest point to Earth in its monthly orbit (perigean tide) and also happens to be either new or full (spring tide). Increasing sea levels as a result of human-produced climate change, combined with land subsidence in some areas, are making such events progressively worse. A NOAA primer on perigean spring tides notes: “In some instances, perigean spring tides have coincided with a shift in offshore ocean circulation patterns and large scale shifts in wind that have resulted in unexpected coastal flooding. It is expected that occurrences of minor 'nuisance flooding' at the times of perigean spring tides will increase even more as sea level rises relative to the land.” In September, NOAA predicted that atmospheric patterns related to El Niño will tend to drive more water into the coastline this autumn and winter, possibly leading to record amounts of nuisance flooding, especially along the mid-Atlantic coast.

Jeff Masters (tropical); Bob Henson (Indonesia, Southeast tides]



Hurricane Flood Heat Sea level rise

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