Norbert Drenching Baja; 90L Moving Through Cape Verde Islands

Hurricane Norbert continues to chug parallel and just offshore from the coast of Mexico's Baja Peninsula, bringing heavy rain and tropical storm-force winds to the coast. Sustained winds as Cabo San Lucas on the southern tip of the Baja Peninsula peaked at 32 mph at 7:43 pm Thursday evening before the airport shut for the night, and the airport recorded 7.4 inches (188 mm) of rain in a 24-hour period ending Friday morning. Satellite loops on Friday morning showed that Category 1 Norbert had no eye but some very intense eyewall thunderstorms with cold cloud tops. Norbert should be able to take advantage of warm SSTs, a moist atmosphere, and moderate wind shear and maintain Category 1 hurricane strength through Saturday morning. By Saturday evening, Norbert will encounter ocean temperatures below 26°C (79 °F), and drier air, which should induce a steady weakening trend. The models all show the core of the hurricane remaining just offshore as it moves northwest parallel to the Baja Peninsula, so heavy rains of 3 - 6" causing flash flooding will be the primary threat from Norbert to Baja. The counter-clockwise flow of air around the hurricane is pulling moisture from the remnants of Tropical Storm Dolly and from the tropical Eastern Pacific northwards into Northern Mexico and the Southwest U.S., and this moisture will be capable of causing flooding rains this weekend in those regions. The heaviest rains in the Southwest U.S. are expected to occur in Southeast New Mexico, where amounts in excess of 3" may fall, due to the assistance of a cold front not related to Hurricane Norbert.

Wunderground member webcamstraveldot has a webcam in Cabo San Lucas that is showing some impressive rough surf today.


Figure 1. MODIS true-color image of Hurricane Norbert near the tip of Mexico's Baja Peninsula at 4:25 pm EDT September 4, 2014. At the time, Norbert had top sustained winds of 90 mph. Image credit: NASA.


Figure 2. Predicted seven-day precipitation amounts for the period ending on Friday, September 12 show a large area of 3+ inches are expected over Southeast New Mexico, thanks to the flow of moist air northwards caused by Hurricane Norbert's circulation and the influence of a weekend cold front. Image credit: NOAA/HPC.

Tropical wave 90L
A tropical wave (90L) is bringing strong winds and heavy rain showers to the Cape Verde Islands off the coast of Africa on Friday as the wave moves west at about 15 mph. Satellite images show 90L has plenty of spin, but little heavy thunderstorm activity. Conditions are marginal for development, with moderate wind shear of 10 - 20 knots, marginal Sea Surface Temperatures of 27°C (81°F), and dry air to the north. One of our three reliable computer models for predicting tropical storm formation (the GFS) shows development of 90L over the next five days. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave the system 2-day and 5-day odd of development odds of 20% and 30%, respectively. The long-range Friday morning runs of the GFS and European ensemble models favored the storm taking a more west-northwesterly track into the open ocean next week, with a low threat to the Lesser Antilles Islands. The Atlantic is expected to be dominated by dry, sinking air next week, due to the phase of the Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days, so I expect that 90L will struggle to develop. The 2 am EDT Friday run of the SHIPS model showed 90L encountering increasingly dry air over the next five days in the face of moderate wind shear--conditions hostile for development.

Following on the heels of 90L will be a new tropical wave that is expected to push off the coast of Africa on Monday, bringing heavy rain showers and gusty winds to the Cape Verde Islands on Monday on Tuesday. Two of our three reliable computer models for predicting tropical storm formation (the GFS and UKMET) show development of the new wave by Wednesday. The new wave will see similar conditions to 90L, and will struggle with dry air and moderate wind shear.


Figure 3. The "Weather Report From 2050" video from the Japan Broadcasting Corporation imagines a future weather report for Japan with record heat waves and a Super Typhoon.

Weather Reports From 2050
If humanity’s current "business as usual" approach to emissions of heat-trapping gases like carbon dioxide continues, the average temperature of the Earth’s lower atmosphere could rise more than 4°C (7.2°F) by the end of the 21st century. But what does a global average temperature rise really mean? How would we experience it on a daily basis? To find out what could lie in store, the World Meteorological Organization (WMO) invited television weather presenters from around the world to imagine a “weather report from the year 2050.” Each day between now and the convening of the key 2014 climate summit in New York City the week of September 21, 2014--when the leaders of the world will assemble to lay out the road map to the crucial December 2015 climate negotiations in Paris--the WMO will release a new "Weather Report From 2050" on their website. Yesterday's video from the Japan Broadcasting Corporation imagined a future for Japan with record heat waves killing 6,500 people annually, the delay of fall colors in Kyoto until Christmas, the destruction of Okinawa's coral reefs due to increasing ocean acidity and temperature, and an increase in the numbers of Category 4 and 5 Super Typhoons hitting Japan. The Weather Channel's "Weather Report From 2050" video will be released on September 10. It's not to be missed!

Jeff Masters