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Sudden Storm, Lingering Storm: Hurricane Newton Hits Baja, Hermine Still Spinning

By: Jeff Masters 4:30 PM GMT on September 06, 2016

Hurricane Newton is battering Mexico’s Baja Peninsula after whipping into existence on Sunday and intensifying with frightening speed. Newton became a tropical depression on Sunday afternoon in the waters a few hundred miles south-southeast of the tip of Mexico’s Baja Peninsula, and rapidly grew into a hurricane in just 24 hours. Just 36 hours after the first advisory on the new tropical depression was issued, Newton was battering the southern tip of Baja with sustained winds of 90 mph, with the eye of the storm passing directly over the resort town of Cabo San Lucas. On Tuesday morning, an automated station at an altitude of 735 feet in Cabo San Lucas recorded sustained winds of 79 mph, gusting to 116 mph, between 2:10 - 2:20 EDT. An automated station along the central spine of the Baja Peninsula at Sierra La Laguna at an elevation of 6,394 feet recorded sustained winds of 73 mph, gusting to 136 mph, at 3:20 am EDT Tuesday. Newton’s sudden explosion into a landfalling hurricane didn’t give much time for evacuations and preparations, but the Mexican civil defense system for hurricanes is one of the best in the world, and I am hopeful that they got everyone to safety in time. Since reliable record keeping of intensification rates of Atlantic hurricanes began in 1970 (when regular satellite coverage became available), the fastest an Atlantic storm has gone from its first appearance as a tropical depression to hurricane strength is 18 hours, in the case of Hurricane Humberto of 2007. There were seven storms that accomplished the feat in 24 hours. I haven’t studied the statistics on this matter for the Eastern Pacific.


Figure 1. MODIS visible satellite image of Hurricane Newton on Monday, September 5, 2016, at 2:45 pm EDT. At the time, Newton was about to become a Category 1 storm with 75 mph winds. Image credit: NASA.

Forecast for Newton
Newton will finish traversing the southern portion of the Baja Peninsula by Tuesday afternoon, then emerge over the warm waters of the Gulf of California for 6 - 12 hours before making a final landfall on the coast of northwestern Mexico early Wednesday morning. Due to the narrowness of the Gulf of California and the high mountains on either side, plus an increase in wind shear, Newton will continue to weaken until its final landfall on Wednesday morning. Heavy rains will be the main threat from Newton over the next two days, with up to 18” expected in Baja. A significant pulse of moisture will surge into southeastern Arizona and southern New Mexico on Wednesday afternoon through Thursday, bringing widespread heavy rains of 1 - 3” and the risk of flash floods. A Flash Flood Watch is posted for portions of southeast Arizona, southern New Mexico, and southwest Texas.


Figure 2. Winds of 65 mph churn the ocean in this view taken inside of Hermine by an Air Force hurricane hunter aircraft on September 5, 2016. Image credit: LM TSgt Banks.

Hermine gradually winding down
Post-Tropical Cyclone Hermine is gradually spinning down as it meanders over the cool waters just over 100 miles southeast of Long Island, per the 11 am NHC advisory.  New York, where a Tropical Storm Warning continues. Data from an Air Force Hurricane Hunter flight early Tuesday morning and recent buoy observations suggested Hermine’s top sustained surface winds had decreased to 60 mph by late morning Thursday. Hermine is close enough to the Mid-Atlantic and Northeast shorelines to produce rough surf, rip currents and a storm surge of 1 - 2 feet, but has dropped very little rainfall over the past day. The maximum storm surge observed on the U.S. coast late Tuesday morning was 2.0 feet in Atlantic City, New Jersey. Wind gusts from Hermine on Long Island on Tuesday morning included 37 mph at Farmingdale, 37 mph at Shirley, 37 mph at JFK Airport, and 32 mph at La Guardia Airport. At the Montauk Point Lighthouse, on the eastern tip of Long Island, sustained winds of 58 mph and gusts to 64 mph were reported at 12:20 am EDT Tuesday.


Figure 3.Visible VIIRS image of Hermine as of 1755Z (1:55 pm EDT) Monday, September 5, 2016. Image credit: NASA.

Forecast for Hermine
Hermine is now over waters cooler than 26°C—too cool to support tropical redevelopment. Furthermore, the storm is no longer receiving energy from atmospheric dynamics (from contrasts between warm moist air and cool dense air.) Without either source of energy to sustain it, Hermine will gradually spin down until it dissipates. Dissipation is predicted to occur by Thursday afternoon by both the European model and the GFS model. 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 before dissipation occurs. Storm surge will be less than two feet, but some minor coastal flooding and beach erosion will occur. For the latest on local impacts, check the local statements compiled on the NHC website.

92L little threat to develop
Satellite images on Tuesday morning showed that a tropical wave (Invest 92L) was bringing heavy rains to Hispaniola. The activity was much weaker and less organized than on Monday. A strong and persistent ridge of high pressure should keep 92L on a west to west-northwest path, and the system will bring some heavy rains to Jamaica and eastern Cuba on Wednesday and western Cuba on Thursday. Development is being arrested by dry air, and the 2 am EDT Tuesday SHIPS model forecast for 92L showed increasing dry air and wind shear for the latter part of the week, which should keep any development from occurring. The latest 0Z Tuesday 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. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC dropped their 2-day and 5-day development odds to 0% and 10%, 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 Tuesday runs of the UKMET, GFS 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 Tuesday Tropical Weather Outlook, NHC gave this future system 2-day and 5-day development odds of 10% and 60%, 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 or North America.

Jeff Masters



Video 1. Heavy rain and high winds sweep across Nantucket Island on Monday, September 5, 2016. Image credit: Blair Perkins, @xplorenantucket.

Hurricane

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