By:
Jeff Masters and Bob Henson
, 4:04PM,GMT on September 5,2016
The two-week marathon that gave us a string of names and a landfalling hurricane--Invest 99L, Tropical Depression 9, Tropical Storm Hermine, Hurricane Hermine, and Post-Tropical Cyclone Hermine--rolls
onward, with no immediate end on tap. Hermine remains a strong
post-tropical cyclone, with data from an Air Force Hurricane Hunter
flight on Monday morning supporting peak surface winds of 70 mph as of
the 11 am EDT advisory from the National Hurricane Center.
Located about 230 miles southeast of Montauk, NY, on the eastern tip of Long Island, Hermine is now moving northwest at about 6 mph. Hermine has gotten close enough to the Mid-Atlantic and Northeast shorelines to produce rough surf and riptides, but stayed enough out to keep weather impacts minimal thus far. The maximum storm surge observed on the U.S. coast late Monday morning was 1.6 feet in Chatham, Massachusetts. Showers and thunderstorms far north of Hermine’s center have been gradually shifting toward the west since Sunday, and it will be a windy, showery Labor Day on parts of Cape Cod, Long Island, and nearby islands. Tropical storm warnings remain in effect from eastern Long Island and eastern Connecticut to the south shore of Cape Cod in Massachusetts, with coastal flood advisories along the Mid-Atlantic coast of New Jersey, Delaware, and Virginia, as well as parts of Chesapeake Bay.
Figure 1. Infrared satellite image of Hermine as of 1337Z (9:37 am EDT) Monday, September 5, 2016. The brightest colors correspond to the coldest (highest) cloud tops, although few of these clouds were producing rainfall over New England except for southeast Massachusetts. Image credit: NASA/MSFC Earth Science Office.
Hermine’s brush with Long Island and Cape Cod
For days, computer models had suggested that Hermine would be re-intensifying on Monday and perhaps regaining some tropical characteristics. It now appears that process has been torpedoed by a timing problem. On Sunday, Hermine was located near the north edge of the Gulf Stream, where it had access to 26-28°C waters (at least 2°C above average). The idea was that Hermine would take advantage of that oceanic warmth while an upper-level low to its west would give Hermine a dynamical boost and pull it closer to the U.S. coast. However, the upper low’s influence was delayed, in part because Hermine moved so far east over the weekend. Now Hermine is approaching waters cooler than 26°C, too cool to support much in the way of tropical redevelopment.
Computer models now agree on weakening Hermine gradually over the next couple of days, but residents of coastal New York and southern New England would be smart to keep an eye on it. The 00Z Monday runs of the GFS, European, and UKMET models--our three best track models--keep Hermine moving to the northwest or even west-northwest, bringing it by Tuesday within 200 miles of New York City and only about 100-150 miles south or southeast of Montauk. The models then start to move Hermine east-northeast on Wednesday at varying speeds, taking it just south of Cape Cod. If nothing else, Hermine’s approach will keep surf high and rip current dangerous, especially along beaches east and north of New York City and along the New Jersey coast. There is a chance of tropical-storm-force winds (sustained winds of 39 mph or more) and bursts of heavy rain on eastern Long Island and over far southeast Massachusetts. Storm surge will be less than previously feared, but some minor coastal flooding remains possible, and beach erosion may mount over the next several days. For the latest on local impacts, check the local statements compiled on the NHC website.
Figure 2. Visible satellite image of Invest 92L at 1500Z (11:00 am EDT) Monday, September 5, 2016. Image credit: CIMSS/SSEC/University of Wisconsin-Madison.
Little change to 92L
Satellite images on Monday morning showed that the moderate level of heavy thunderstorm activity associated with a large tropical wave passing through the Lesser Antilles Islands (Invest 92L) had changed little since Sunday. 92L brought winds near tropical storm-force to the Lesser Antilles on Sunday night, according to data from the ASCAT satellite. No rotation of the storm’s echoes was apparent on Martinique radar, though. The wave is fighting a large amount of dry air, which is keeping heavy thunderstorm activity relatively sparse.
A strong and persistent ridge of high pressure should keep 92L on a west to west-northwest path, and the system will be near Jamaica by Wednesday and approach the western tip of Cuba and Mexico’s Yucatan Peninsula by Thursday night. If 92L does develop, it probably won’t last long. The 8 am EDT Monday SHIPS model forecast for 92L showed light to moderate wind shear of 5 - 15 knots through through Tuesday, rising to the high range, 20 - 25 knots, for the latter part of the week. The latest 0Z Monday operational runs of our three top models for forecasting tropical cyclone genesis--the GFS, European and UKMET models--did not show development of the system over the next five days. Almost all of the ensemble members of the 0Z Monday runs of the GFS and European model that did develop 92L showed the storm being destroyed by high wind shear and dry air before reaching Jamaica on Wednesday. In their 8 am EDT Monday Tropical Weather Outlook, NHC dropped their 2-day and 5-day development odds to 10% and 20%, respectively.
New African tropical wave may develop late this week
A tropical wave expected to leave the coast of Africa on Tuesday could develop into a tropical depression by next weekend, a few hundred miles west-southwest of the Cabo Verde Islands, predicted the 00Z Monday runs of the UKMET and European models. The Sahara Desert dust and dry air machine will be moderately active during the week, and development of this new tropical wave will likely be hindered by dry air. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave this future system 2-day and 5-day development odds of 0% and 20%, respectively. The long-range models are showing a west-northwesterly track for this storm into the Central Atlantic to a location where few storms ever become a threat to the Lesser Antilles Islands.
Figure 3. Latest satellite image for Tropical Storm Newton.
Hurricane warnings for Tropical Storm Newton along Mexico’s Baja California Peninsula
A hurricane warning is up for the southern tip of Mexico’s Baja California Peninsula, including Cabo San Lucas, as a strengthening Tropical Storm Newton heads north-northwest at 12 mph. Newton formed in Mexico’s Pacific waters about 200 miles southwest of Puerto Vallarta late Sunday night, and is already bringing very heavy rains and gusty winds to southwestern Mexico, as seen on satellite loops. The Hurricane Hunters are scheduled to investigate Newton on Monday afternoon.
Newton’s top winds had increased to 60 mph as of the 11 am EDT advisory from NHC, and an eye was beginning to appear on satellite imagery. There is potential for Newton to strengthen quite a bit more before its expected landfall on southern Baja California late Tuesday. The 12Z Monday output from the SHIPS statistical model shows a high potential for rapid intensification, with a 40% chance of Newton’s top winds increasing by at least 40 knots (46 mph) in 24 hours. That would make Newton a Category 2 storm by landfall. None of the 06Z Monday computer model runs show that amount of intensification, and it’s possible that dynamical factors not included in the SHIPS model will keep Newton from its full potential.
Newton’s north-northwest motion should take it off the Baja California peninsula and over the very warm waters of the Gulf of California by Wednesday, which could allow to be at or near tropical storm intensity as it approaches Arizona late Wednesday. Ahead of Newton’s large circulation, moisture will surge through the Gulf of California into the U.S. Southwest on Tuesday and Wednesday, fueling showers and thunderstorms. Heavier rains may develop late Wednesday into Thursday, especially over southeast Arizona, as the core of Newton moves inland. Newton’s moisture could also enhance thunderstorms over the southern and central Great Plains late this week.
We’ll be back with our next update on Tuesday. To our readers in the U.S. and Canada, Happy Labor Day!
Jeff Masters and Bob Henson
Figure 4 WU depiction of official forecast for Tropical Storm Newton as of 11 am EDT Monday, September 6.
Located about 230 miles southeast of Montauk, NY, on the eastern tip of Long Island, Hermine is now moving northwest at about 6 mph. Hermine has gotten close enough to the Mid-Atlantic and Northeast shorelines to produce rough surf and riptides, but stayed enough out to keep weather impacts minimal thus far. The maximum storm surge observed on the U.S. coast late Monday morning was 1.6 feet in Chatham, Massachusetts. Showers and thunderstorms far north of Hermine’s center have been gradually shifting toward the west since Sunday, and it will be a windy, showery Labor Day on parts of Cape Cod, Long Island, and nearby islands. Tropical storm warnings remain in effect from eastern Long Island and eastern Connecticut to the south shore of Cape Cod in Massachusetts, with coastal flood advisories along the Mid-Atlantic coast of New Jersey, Delaware, and Virginia, as well as parts of Chesapeake Bay.
Figure 1. Infrared satellite image of Hermine as of 1337Z (9:37 am EDT) Monday, September 5, 2016. The brightest colors correspond to the coldest (highest) cloud tops, although few of these clouds were producing rainfall over New England except for southeast Massachusetts. Image credit: NASA/MSFC Earth Science Office.
Hermine’s brush with Long Island and Cape Cod
For days, computer models had suggested that Hermine would be re-intensifying on Monday and perhaps regaining some tropical characteristics. It now appears that process has been torpedoed by a timing problem. On Sunday, Hermine was located near the north edge of the Gulf Stream, where it had access to 26-28°C waters (at least 2°C above average). The idea was that Hermine would take advantage of that oceanic warmth while an upper-level low to its west would give Hermine a dynamical boost and pull it closer to the U.S. coast. However, the upper low’s influence was delayed, in part because Hermine moved so far east over the weekend. Now Hermine is approaching waters cooler than 26°C, too cool to support much in the way of tropical redevelopment.
Computer models now agree on weakening Hermine gradually over the next couple of days, but residents of coastal New York and southern New England would be smart to keep an eye on it. The 00Z Monday runs of the GFS, European, and UKMET models--our three best track models--keep Hermine moving to the northwest or even west-northwest, bringing it by Tuesday within 200 miles of New York City and only about 100-150 miles south or southeast of Montauk. The models then start to move Hermine east-northeast on Wednesday at varying speeds, taking it just south of Cape Cod. If nothing else, Hermine’s approach will keep surf high and rip current dangerous, especially along beaches east and north of New York City and along the New Jersey coast. There is a chance of tropical-storm-force winds (sustained winds of 39 mph or more) and bursts of heavy rain on eastern Long Island and over far southeast Massachusetts. Storm surge will be less than previously feared, but some minor coastal flooding remains possible, and beach erosion may mount over the next several days. For the latest on local impacts, check the local statements compiled on the NHC website.
Figure 2. Visible satellite image of Invest 92L at 1500Z (11:00 am EDT) Monday, September 5, 2016. Image credit: CIMSS/SSEC/University of Wisconsin-Madison.
Little change to 92L
Satellite images on Monday morning showed that the moderate level of heavy thunderstorm activity associated with a large tropical wave passing through the Lesser Antilles Islands (Invest 92L) had changed little since Sunday. 92L brought winds near tropical storm-force to the Lesser Antilles on Sunday night, according to data from the ASCAT satellite. No rotation of the storm’s echoes was apparent on Martinique radar, though. The wave is fighting a large amount of dry air, which is keeping heavy thunderstorm activity relatively sparse.
A strong and persistent ridge of high pressure should keep 92L on a west to west-northwest path, and the system will be near Jamaica by Wednesday and approach the western tip of Cuba and Mexico’s Yucatan Peninsula by Thursday night. If 92L does develop, it probably won’t last long. The 8 am EDT Monday SHIPS model forecast for 92L showed light to moderate wind shear of 5 - 15 knots through through Tuesday, rising to the high range, 20 - 25 knots, for the latter part of the week. The latest 0Z Monday operational runs of our three top models for forecasting tropical cyclone genesis--the GFS, European and UKMET models--did not show development of the system over the next five days. Almost all of the ensemble members of the 0Z Monday runs of the GFS and European model that did develop 92L showed the storm being destroyed by high wind shear and dry air before reaching Jamaica on Wednesday. In their 8 am EDT Monday Tropical Weather Outlook, NHC dropped their 2-day and 5-day development odds to 10% and 20%, respectively.
New African tropical wave may develop late this week
A tropical wave expected to leave the coast of Africa on Tuesday could develop into a tropical depression by next weekend, a few hundred miles west-southwest of the Cabo Verde Islands, predicted the 00Z Monday runs of the UKMET and European models. The Sahara Desert dust and dry air machine will be moderately active during the week, and development of this new tropical wave will likely be hindered by dry air. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave this future system 2-day and 5-day development odds of 0% and 20%, respectively. The long-range models are showing a west-northwesterly track for this storm into the Central Atlantic to a location where few storms ever become a threat to the Lesser Antilles Islands.
Figure 3. Latest satellite image for Tropical Storm Newton.
Hurricane warnings for Tropical Storm Newton along Mexico’s Baja California Peninsula
A hurricane warning is up for the southern tip of Mexico’s Baja California Peninsula, including Cabo San Lucas, as a strengthening Tropical Storm Newton heads north-northwest at 12 mph. Newton formed in Mexico’s Pacific waters about 200 miles southwest of Puerto Vallarta late Sunday night, and is already bringing very heavy rains and gusty winds to southwestern Mexico, as seen on satellite loops. The Hurricane Hunters are scheduled to investigate Newton on Monday afternoon.
Newton’s top winds had increased to 60 mph as of the 11 am EDT advisory from NHC, and an eye was beginning to appear on satellite imagery. There is potential for Newton to strengthen quite a bit more before its expected landfall on southern Baja California late Tuesday. The 12Z Monday output from the SHIPS statistical model shows a high potential for rapid intensification, with a 40% chance of Newton’s top winds increasing by at least 40 knots (46 mph) in 24 hours. That would make Newton a Category 2 storm by landfall. None of the 06Z Monday computer model runs show that amount of intensification, and it’s possible that dynamical factors not included in the SHIPS model will keep Newton from its full potential.
Newton’s north-northwest motion should take it off the Baja California peninsula and over the very warm waters of the Gulf of California by Wednesday, which could allow to be at or near tropical storm intensity as it approaches Arizona late Wednesday. Ahead of Newton’s large circulation, moisture will surge through the Gulf of California into the U.S. Southwest on Tuesday and Wednesday, fueling showers and thunderstorms. Heavier rains may develop late Wednesday into Thursday, especially over southeast Arizona, as the core of Newton moves inland. Newton’s moisture could also enhance thunderstorms over the southern and central Great Plains late this week.
We’ll be back with our next update on Tuesday. To our readers in the U.S. and Canada, Happy Labor Day!
Jeff Masters and Bob Henson
Figure 4 WU depiction of official forecast for Tropical Storm Newton as of 11 am EDT Monday, September 6.
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