WunderBlog Archive » Category 6™
Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.Julia More Annoyance Than Threat for U.S.; Keep an Eye on TD 12 in Eastern Atlantic
After the surprise emergence of Tropical Storm Julia on Tuesday evening while the center was located over land in northeastern Florida, the storm appears determined to stick around through the weekend and annoy coastal South Carolina and North Carolina with days of intermittent rain showers. Satellite images on Thursday morning showed the classic appearance of a storm struggling with high wind shear, with the low-level center of Julia, now a tropical depression, exposed to view, and the heaviest thunderstorms all to the east of the center. Radar loops from Wilmington, North Carolina showed Julia’s heaviest rains were mostly well offshore, with only one modest band affecting coastal North Carolina. The top winds observed at any offshore buoys on Thursday morning were 27 mph, gusting to 36 mph, at buoy 41004, 47 miles southeast of Charleston, South Carolina, at 7:50 am EDT. Storm surge levels along the Southeast U.S. coast at 9:30 am EDT Thursday were 0.7’ or less.
Figure 1. Latest satellite image of Julia.
Figure 2. Latest radar-estimated rainfall accumulation image for Julia.
Forecast for Julia
Julia is more annoyance than threat, with the storm likely to dump only another 1 - 2” of rain along the immediate coast over the next two days. Wind shear is expected to stay high, 20 - 30 knots, through Sunday, which should prevent any significant intensification as the storm meanders off the coast of South Carolina in an atmosphere with weak steering currents. Our top two models, the GFS and European model, predict that high wind shear and dry air should combine to bring about Julia’s demise by Sunday.
Figure 3. Latest satellite image of TD 12.
Tropical Depression 12 continues west with little change
Tropical Depression Twelve brought heavy rain showers and gusty winds to the Cabo Verde Islands on Wednesday, and is now pulling away from the islands as it heads west at 16 mph. Satellite images on Thursday morning showed that TD 12 was well-organized, with a large circulation and plenty of low-level spiral bands, but the center was completed exposed to view due to high wind shear of 20 - 25 knots, with most of the storm’s heavy thunderstorms far from the center. TD 12 is embedded in a moist atmosphere and has warm SSTs near 27 - 27.5°C (81°F) under it, and may be able to develop into Tropical Storm Karl this weekend, when the shear is expected to drop to the moderate range, 10 - 20 knots. However, the atmosphere surrounding TD 12 will get drier this weekend, which should interfere with development—or possibly dissipate the storm by five days from now, as predicted by the operational GFS model and 17 of its 20 ensemble member forecasts. While most of the 50 members of the European model ensemble show TD 12 eventually recurving out to sea without affecting any land areas, 6 out of 50 of the forecasts show the storm hitting the U.S. East Coast 10+ days from now, so it is too early to assume that TD 12 will be a “fish” storm.
Another African tropical wave may develop next week
The 0Z Thursday runs of our three reliable models for predicting tropical cyclone genesis—the GFS, European, and UKMET models—agreed that a new tropical wave expected to come off the coast of Africa on Friday will develop into a tropical depression early next week. This storm is expected to take a track more to the west-northwest than TD 12, and is less likely to be a long-range threat to the Lesser Antilles Islands or North America. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 0% and 50%, respectively.
Tropical Storm Ian in the central Atlantic: not long to live
Tropical Storm Ian was accelerating to the northeast in the central Atlantic late Thursday morning, and doesn’t have long to live. On Friday, Ian will become entangled with a cold front and an upper level low pressure system, and will transition to an extratropical storm without ever reaching hurricane status. Ian is not a threat to any land areas.
Invest 93E off the Pacific coast of Mexico may threaten the Baja Peninsula next week
In the Eastern Pacific, an area of low pressure a few hundred miles southwest of Acapulco, Mexico (Invest 93E) has grown more organized, and is a threat to develop into a tropical depression this weekend. Two of our top three models for predicting hurricane genesis, the UKMET and European models, predicted in their 0Z Thursday runs that 93E would develop into a tropical storm which would hit Mexico’s Baja Peninsula on Monday or Tuesday. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 30% and 80%, respectively.
Storm with subtropical characteristics affecting France and Spain
An extratropical storm (called “Stephanie” by the Free University of Berlin) is in the Bay of Biscay off the west coast of France, and has acquired some subtropical characteristics as it lingers over waters near 23°C (73°F). For more info on this storm, see comment 312 by WU member barbamz in the previous blog post. This storm is expected to move inland near the France/Spain border by Friday morning, spreading heavy rains and gusty winds.
Bob Henson will be back with a new post this afternoon on the typhoon activity in the Western Pacific, along with a a detailed look at a new study finding that landfalling typhoons have increased in intensity in recent decades.
Jeff Masters
Figure 1. Latest satellite image of Julia.
Figure 2. Latest radar-estimated rainfall accumulation image for Julia.
Forecast for Julia
Julia is more annoyance than threat, with the storm likely to dump only another 1 - 2” of rain along the immediate coast over the next two days. Wind shear is expected to stay high, 20 - 30 knots, through Sunday, which should prevent any significant intensification as the storm meanders off the coast of South Carolina in an atmosphere with weak steering currents. Our top two models, the GFS and European model, predict that high wind shear and dry air should combine to bring about Julia’s demise by Sunday.
Figure 3. Latest satellite image of TD 12.
Tropical Depression 12 continues west with little change
Tropical Depression Twelve brought heavy rain showers and gusty winds to the Cabo Verde Islands on Wednesday, and is now pulling away from the islands as it heads west at 16 mph. Satellite images on Thursday morning showed that TD 12 was well-organized, with a large circulation and plenty of low-level spiral bands, but the center was completed exposed to view due to high wind shear of 20 - 25 knots, with most of the storm’s heavy thunderstorms far from the center. TD 12 is embedded in a moist atmosphere and has warm SSTs near 27 - 27.5°C (81°F) under it, and may be able to develop into Tropical Storm Karl this weekend, when the shear is expected to drop to the moderate range, 10 - 20 knots. However, the atmosphere surrounding TD 12 will get drier this weekend, which should interfere with development—or possibly dissipate the storm by five days from now, as predicted by the operational GFS model and 17 of its 20 ensemble member forecasts. While most of the 50 members of the European model ensemble show TD 12 eventually recurving out to sea without affecting any land areas, 6 out of 50 of the forecasts show the storm hitting the U.S. East Coast 10+ days from now, so it is too early to assume that TD 12 will be a “fish” storm.
Another African tropical wave may develop next week
The 0Z Thursday runs of our three reliable models for predicting tropical cyclone genesis—the GFS, European, and UKMET models—agreed that a new tropical wave expected to come off the coast of Africa on Friday will develop into a tropical depression early next week. This storm is expected to take a track more to the west-northwest than TD 12, and is less likely to be a long-range threat to the Lesser Antilles Islands or North America. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 0% and 50%, respectively.
Tropical Storm Ian in the central Atlantic: not long to live
Tropical Storm Ian was accelerating to the northeast in the central Atlantic late Thursday morning, and doesn’t have long to live. On Friday, Ian will become entangled with a cold front and an upper level low pressure system, and will transition to an extratropical storm without ever reaching hurricane status. Ian is not a threat to any land areas.
Invest 93E off the Pacific coast of Mexico may threaten the Baja Peninsula next week
In the Eastern Pacific, an area of low pressure a few hundred miles southwest of Acapulco, Mexico (Invest 93E) has grown more organized, and is a threat to develop into a tropical depression this weekend. Two of our top three models for predicting hurricane genesis, the UKMET and European models, predicted in their 0Z Thursday runs that 93E would develop into a tropical storm which would hit Mexico’s Baja Peninsula on Monday or Tuesday. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 30% and 80%, respectively.
Storm with subtropical characteristics affecting France and Spain
An extratropical storm (called “Stephanie” by the Free University of Berlin) is in the Bay of Biscay off the west coast of France, and has acquired some subtropical characteristics as it lingers over waters near 23°C (73°F). For more info on this storm, see comment 312 by WU member barbamz in the previous blog post. This storm is expected to move inland near the France/Spain border by Friday morning, spreading heavy rains and gusty winds.
Bob Henson will be back with a new post this afternoon on the typhoon activity in the Western Pacific, along with a a detailed look at a new study finding that landfalling typhoons have increased in intensity in recent decades.
Jeff Masters
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.