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Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.Karl Joins Julia in the Atlantic; Another Major Typhoon to Clip Taiwan
It was a busy early Friday morning for tropical cyclones in the Atlantic, with three storms active at the same time--Ian, Julia and Karl. Late Friday morning, we were down to two named storms, though, thanks to the demise of Tropical Storm Ian in the central Atlantic. Of our two remaining storms, the closer one to land was Tropical Storm Julia, which continued to spin a few hundred miles off the coast of South Carolina. Satellite images on Friday morning showed that Julia continued to struggle with high wind shear, with the low-level center of the storm exposed to view, and the heaviest thunderstorms all to the east of the center. Radar loops from Wilmington, North Carolina showed that Julia’s rains were well offshore. The top winds observed at any offshore buoys on Friday morning were 29 mph, gusting to 36 mph, at buoy 41002, 225 nm south of Cape Hatteras, North Carolina, at 7:50 am EDT. Storm surge levels along the Southeast U.S. coast at 10:30 am EDT Friday were 1.0’ or less.
Figure 1. Latest satellite image of Julia.
Forecast for Julia
Julia is embedded in an atmosphere with very dry air (45 - 50% relative humidity at mid-levels of the atmosphere) and wind shear is expected to stay high, 20 - 35 knots, through Sunday. These conditions should cause the storm to gradually weaken as it meanders off the coast of South Carolina in an atmosphere with weak steering currents. Two of our top models, the GFS and European, predict that high wind shear and dry air should combine to bring about Julia’s demise by Sunday. However, the UKMET model disagrees, predicting that Julia will survive the hostile conditions this weekend, and re-intensify into a strong tropical storm early next week when the wind shear finally relents. The UKMET model keeps Julia wandering off the coast of South Carolina/North Carolina until at least Thursday.
Figure 2. MODIS image of Karl on Friday morning, September 16, 2016. Image credit: NASA.
Tropical Storm Karl continues west with little change
Tropical Storm Karl formed Thursday evening in the waters of the eastern tropical Atlantic, and was headed west at 13 mph towards the Lesser Antilles Islands late Friday morning. Steering currents will likely take Karl far enough to the west-northwest by early next week to keep the storm well clear of the Lesser Antilles Islands, but a potential long-range threat to North America or Bermuda cannot be ruled out at this time. Satellite images on Friday morning showed that Karl was well-organized, with a large circulation and plenty of low-level spiral bands, but the center was nearly completely exposed to view due to high wind shear of 20 - 25 knots, with the storm’s heavy thunderstorms limited to the northeast side of the center. Karl has marginal conditions for development, with relative humidity at mid-levels of the atmosphere near 60% and sea surface temperatures (SSTs) near 27°C (81°F). By Sunday, SSTs will increase to 28°C and wind shear is expected to drop to the low range--less than 10 knots. These conditions favor strengthening. However, the atmosphere surrounding Karl will get drier this weekend, which should slow development.
The track forecast for Karl for the next five days is fairly straightforward, with the steering currents expected to take the storm west, then slightly south of due west, then west-northwest. Karl should clear the northern Lesser Antilles Islands by several hundred miles at the time of its closest approach on Wednesday. As usual, the picture gets pretty murky more than five days into the future. The most probable track painted by the models for Karl a week or more into the future is for the storm to get caught in the steering flow of a strong trough of low pressure passing to its north late next week. This would result in a recurving path for Karl to the north and then northeast, with the storm missing the U.S. East Coast. This is the prediction from about 80% of the 50 members of the 00Z Friday run of the European ensemble forecast, and all 20 members of the 00Z Friday GFS ensemble forecast. In this situation, Bermuda and the Maritime Provinces of Canada might still be at risk from a direct hit, though. The other possibility is that the trough passing to the north of Karl late next week will not be able to capture the storm, and a ridge of high pressure will build in over Karl, forcing it the west or northwest, potentially bringing Karl to a landfall along the U.S. East Coast about ten days from now.
Another African tropical wave may develop early next week
The 00Z Friday runs of our three reliable models for predicting tropical cyclone genesis--the GFS, European, and UKMET models--had one of them, the UKMET model, predict that a new tropical wave expected to come off the coast of Africa on Friday night to develop into a tropical depression early next week. This storm is expected to take a track more to the west-northwest than Karl, and does not appear to be a long-range threat to the Lesser Antilles Islands or North America. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 20% and 50%, respectively. By the middle of next week, this storm will encounter a region more hostile for development, with drier air, higher wind shear and cooler SSTs.
Tropical Storm Ian becomes post-tropical
Tropical Storm Ian made the transition to a powerful extratropical storm with 65 mph winds in the central Atlantic on Friday morning. Ex-Ian will pass close to Iceland on Saturday, potentially bringing sustained winds of 40 - 45 mph to the coast.
Figure 3. Enhanced infrared image from Japan’s Himiwari-8 satellite of Typhoon Malakas at 1430Z (10:30 am EDT) Friday, September 16, 2016.
Category 3 Malakas will brush Taiwan en route to Japan
Just as Super Typhoon Meranti narrowly avoided a direct landfall on the southern tip of Taiwan, it appears that Typhoon Malakas may do the same on the island’s northeast corner, though it will be a very close call. As of 12Z (8:00 am EDT) Friday, the Joint Typhoon Warning Center placed Malakas about 300 miles southeast of Taipei, Taiwan, moving northwest at about 14 mph. Malakas has strengthened to Category 3 strength, with top winds now 125 mph and a pinhole eye evident on satellite imagery. JTWC predicts that Malakas will reach Category 4 strength by Saturday local time.
Malakas is in the midst of a classic tropical cyclone recurvature, so its path will gradually arc rightward, hopefully just in time for its center to miss Taiwan on Saturday. The GFS, European, and UKMET track models all bring Malakas within about 50-75 miles of Taiwan’s northeast corner, perhaps close enough to bring heavy rain and tropical-storm-force winds to the Taipei area. The typhoon’s stronger east side would likely remain offshore, although it could still impact Japan’s Yaeyama Islands. After it recurves, Malakas will be sweeping to the northeast toward Japan’s main island, Honshu. The 00Z Friday runs of the GFS and European models take Malakas directly over Honshu on Tuesday, as depicted in the JTWC outlook below, while the UKMET model solution is slower and a bit further north. Malakas could arrive as a Category 1 typhoon, merging with the remnants of Meranti and bringing torrential rain that could easily top 10” in some locations (see Figure 5 below).
Figure 4. WU depiction of track forecast for Typhoon Malakas from the Joint Typhoon Warning Center as of 8:00 am EDT Friday, September 16.
Figure 5. Accumulated precipitation across eastern Asia from the 06Z Friday run of the GFS model shows the combined effects of Typhoon Malakas and the remnants of Super Typhoon Meranti. Rainfall is shown in millimeters (100 mm = 3.94”). Image credit: tropicaltidbits.com.
East Pacific: So long, Orlene
After surging to hurricane intensity for a second time on Thursday, Tropical Storm Orlene is now on its last legs. Orlene has been enveloped by very dry air (only 20-25% relative humidity at midlevels), which has more than counteracted any potential boost from light wind shear and marginally warm sea-surface temperatures. By Friday morning, Orlene’s tiny core of showers and thunderstorms had almost completely dissipated. As it drifts westward, Orlene will likely be a remnant low by Sunday, perhaps even sooner.
Invest 93E may threaten the Baja Peninsula next week
A new tropical system, Invest 93E, is taking shape a few hundred miles southwest of Acapulco. Thunderstorms remain disorganized within a broad area of low pressure, but 93E will be nourished by a moist atmosphere (RH of 70-80%) and warm SSTs (28-29°C), with only light to moderate wind shear to contend with (10-20 knots). In its tropical outlook issued at 8:00 am EDT Friday, NHC gives 93E a 70% chance of developing into at least a tropical depression by Sunday and a 90% chance by Wednesday. The 00Z and 06Z Friday runs of the GFS model fail to develop 93E, but the European and UKMET models produce a moderately strong tropical storm that parallels the Mexican coast for several days, then potentially arcs toward Baja California and the Southwest U.S. early next week.
We’ll be back with a new post this afternoon on the 2016 Arctic sea ice minimum just reached this week.
Jeff Masters and Bob Henson
Figure 1. Latest satellite image of Julia.
Forecast for Julia
Julia is embedded in an atmosphere with very dry air (45 - 50% relative humidity at mid-levels of the atmosphere) and wind shear is expected to stay high, 20 - 35 knots, through Sunday. These conditions should cause the storm to gradually weaken as it meanders off the coast of South Carolina in an atmosphere with weak steering currents. Two of our top models, the GFS and European, predict that high wind shear and dry air should combine to bring about Julia’s demise by Sunday. However, the UKMET model disagrees, predicting that Julia will survive the hostile conditions this weekend, and re-intensify into a strong tropical storm early next week when the wind shear finally relents. The UKMET model keeps Julia wandering off the coast of South Carolina/North Carolina until at least Thursday.
Figure 2. MODIS image of Karl on Friday morning, September 16, 2016. Image credit: NASA.
Tropical Storm Karl continues west with little change
Tropical Storm Karl formed Thursday evening in the waters of the eastern tropical Atlantic, and was headed west at 13 mph towards the Lesser Antilles Islands late Friday morning. Steering currents will likely take Karl far enough to the west-northwest by early next week to keep the storm well clear of the Lesser Antilles Islands, but a potential long-range threat to North America or Bermuda cannot be ruled out at this time. Satellite images on Friday morning showed that Karl was well-organized, with a large circulation and plenty of low-level spiral bands, but the center was nearly completely exposed to view due to high wind shear of 20 - 25 knots, with the storm’s heavy thunderstorms limited to the northeast side of the center. Karl has marginal conditions for development, with relative humidity at mid-levels of the atmosphere near 60% and sea surface temperatures (SSTs) near 27°C (81°F). By Sunday, SSTs will increase to 28°C and wind shear is expected to drop to the low range--less than 10 knots. These conditions favor strengthening. However, the atmosphere surrounding Karl will get drier this weekend, which should slow development.
The track forecast for Karl for the next five days is fairly straightforward, with the steering currents expected to take the storm west, then slightly south of due west, then west-northwest. Karl should clear the northern Lesser Antilles Islands by several hundred miles at the time of its closest approach on Wednesday. As usual, the picture gets pretty murky more than five days into the future. The most probable track painted by the models for Karl a week or more into the future is for the storm to get caught in the steering flow of a strong trough of low pressure passing to its north late next week. This would result in a recurving path for Karl to the north and then northeast, with the storm missing the U.S. East Coast. This is the prediction from about 80% of the 50 members of the 00Z Friday run of the European ensemble forecast, and all 20 members of the 00Z Friday GFS ensemble forecast. In this situation, Bermuda and the Maritime Provinces of Canada might still be at risk from a direct hit, though. The other possibility is that the trough passing to the north of Karl late next week will not be able to capture the storm, and a ridge of high pressure will build in over Karl, forcing it the west or northwest, potentially bringing Karl to a landfall along the U.S. East Coast about ten days from now.
Another African tropical wave may develop early next week
The 00Z Friday runs of our three reliable models for predicting tropical cyclone genesis--the GFS, European, and UKMET models--had one of them, the UKMET model, predict that a new tropical wave expected to come off the coast of Africa on Friday night to develop into a tropical depression early next week. This storm is expected to take a track more to the west-northwest than Karl, and does not appear to be a long-range threat to the Lesser Antilles Islands or North America. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 20% and 50%, respectively. By the middle of next week, this storm will encounter a region more hostile for development, with drier air, higher wind shear and cooler SSTs.
Tropical Storm Ian becomes post-tropical
Tropical Storm Ian made the transition to a powerful extratropical storm with 65 mph winds in the central Atlantic on Friday morning. Ex-Ian will pass close to Iceland on Saturday, potentially bringing sustained winds of 40 - 45 mph to the coast.
Figure 3. Enhanced infrared image from Japan’s Himiwari-8 satellite of Typhoon Malakas at 1430Z (10:30 am EDT) Friday, September 16, 2016.
Category 3 Malakas will brush Taiwan en route to Japan
Just as Super Typhoon Meranti narrowly avoided a direct landfall on the southern tip of Taiwan, it appears that Typhoon Malakas may do the same on the island’s northeast corner, though it will be a very close call. As of 12Z (8:00 am EDT) Friday, the Joint Typhoon Warning Center placed Malakas about 300 miles southeast of Taipei, Taiwan, moving northwest at about 14 mph. Malakas has strengthened to Category 3 strength, with top winds now 125 mph and a pinhole eye evident on satellite imagery. JTWC predicts that Malakas will reach Category 4 strength by Saturday local time.
Malakas is in the midst of a classic tropical cyclone recurvature, so its path will gradually arc rightward, hopefully just in time for its center to miss Taiwan on Saturday. The GFS, European, and UKMET track models all bring Malakas within about 50-75 miles of Taiwan’s northeast corner, perhaps close enough to bring heavy rain and tropical-storm-force winds to the Taipei area. The typhoon’s stronger east side would likely remain offshore, although it could still impact Japan’s Yaeyama Islands. After it recurves, Malakas will be sweeping to the northeast toward Japan’s main island, Honshu. The 00Z Friday runs of the GFS and European models take Malakas directly over Honshu on Tuesday, as depicted in the JTWC outlook below, while the UKMET model solution is slower and a bit further north. Malakas could arrive as a Category 1 typhoon, merging with the remnants of Meranti and bringing torrential rain that could easily top 10” in some locations (see Figure 5 below).
Figure 4. WU depiction of track forecast for Typhoon Malakas from the Joint Typhoon Warning Center as of 8:00 am EDT Friday, September 16.
Figure 5. Accumulated precipitation across eastern Asia from the 06Z Friday run of the GFS model shows the combined effects of Typhoon Malakas and the remnants of Super Typhoon Meranti. Rainfall is shown in millimeters (100 mm = 3.94”). Image credit: tropicaltidbits.com.
East Pacific: So long, Orlene
After surging to hurricane intensity for a second time on Thursday, Tropical Storm Orlene is now on its last legs. Orlene has been enveloped by very dry air (only 20-25% relative humidity at midlevels), which has more than counteracted any potential boost from light wind shear and marginally warm sea-surface temperatures. By Friday morning, Orlene’s tiny core of showers and thunderstorms had almost completely dissipated. As it drifts westward, Orlene will likely be a remnant low by Sunday, perhaps even sooner.
Invest 93E may threaten the Baja Peninsula next week
A new tropical system, Invest 93E, is taking shape a few hundred miles southwest of Acapulco. Thunderstorms remain disorganized within a broad area of low pressure, but 93E will be nourished by a moist atmosphere (RH of 70-80%) and warm SSTs (28-29°C), with only light to moderate wind shear to contend with (10-20 knots). In its tropical outlook issued at 8:00 am EDT Friday, NHC gives 93E a 70% chance of developing into at least a tropical depression by Sunday and a 90% chance by Wednesday. The 00Z and 06Z Friday runs of the GFS model fail to develop 93E, but the European and UKMET models produce a moderately strong tropical storm that parallels the Mexican coast for several days, then potentially arcs toward Baja California and the Southwest U.S. early next week.
We’ll be back with a new post this afternoon on the 2016 Arctic sea ice minimum just reached this week.
Jeff Masters and Bob Henson
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.