Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 3:20 PM GMT on July 14, 2014
The Philippines Islands are bracing for the impact of Typhoon Rammasun, the islands' first typhoon since the devastating strike by Category 5 Super Typhoon Haiyan in November 2013. Haiyan was the deadliest and most expensive natural disaster in Philippines history. Fortunately, Rammasun is much weaker--a mere Category 1 storm. Top winds were 85 mph (1-minute average from the Joint Typhoon Warning Center), and the central pressure was 975 mb (as rated by the Japan Meteorological Agency) at 8 am EDT on Monday morning--a far cry from the incredible 195 mph sustained winds and central pressure of 895 mb of Haiyan at its peak. Rammasun is intensifying, though. Satellite loops on Monday morning showed a steady increase in the intensity and areal coverage of the typhoon's heavy thunderstorms. With wind shear a light 5 - 10 knots and Sea Surface Temperatures a very warm 30°C, further intensification is likely until landfall occurs. Philippines radar showed the outer spiral bands of Rammasun were already affecting Samar Island, where Haiyan initially made landfall. The core of Rammasun will pass north of Samar Island and strike the main Philippines island of Luzon, with the center passing very near the capital of Manila early Wednesday (local time). The main concern will be flash flooding and mudslides over Luzon and Samar, but wind damage also has the potential to be considerable, since the typhoon is passing over the most heavily populated part of Luzon.
After crossing Luzon, Rammasun will have the opportunity to re-strengthen over the South China Sea before making a second landfall in China near Hainan Island on Friday. Our two top track models, the GFS and European, predict a landfall in China between 03 - 12 UTC on Friday.
Figure 1. Rainfall rate of Typhoon Rammasun as estimated by a microwave sounding instrument on NOAA's F-18 polar orbiting satellite at 6:44 am EDT Monday July 14, 2014. Rainfall rates in excess of 1"/hour (orange colors) were indicated in the northern eyewall of the typhoon. Image credit: Navy Research Lab, Monterey.
Extreme heat in Western Canada, unusual coolness in Midwest U.S.
The remnants of Super Typhoon Neoguri, which pushed northeastwards into Alaska after the storm hit Japan last week, set in motion a chain-reaction set of events that has dramatically altered the path of the jet stream and affected weather patterns across the entire Northern Hemisphere. Neoguri caused an acceleration of the North Pacific jet stream, which amplified a trough low pressure over Alaska, causing a ripple effect in the jet stream over western North America, where a strong ridge of high pressure developed. The ridge helped push temperatures as high as 106°F (41.1°C) in British Columbia on Sunday. A compensating strong trough of low pressure formed over the Midwest U.S., and that trough is now pumping cool, polar air southwards into the Upper Midwest. The high temperature in Minneapolis on Monday is predicted to be in the low 60s, about 15°F below average. This jet stream pattern is similar to the nasty "Polar Vortex" pattern that set up during the winter of 2014 over North America, but calling it the polar vortex in this case is not technically correct.
Figure 2. Forecast for the departure of surface temperature from average for 5 pm EDT July 14, 2014, as predicted by the GFS model at 00 UTC July 14, 2014. A strong trough of low pressure is predicted to bring high temperatures much below average over portions of Minnesota and Wisconsin, while much above average temperatures are predicted over much of British Columbia and Alberta, Canada. Data/image obtained using Climate Reanalyzer™ (http://cci-reanalyzer.org), Climate Change Institute, University of Maine, Orono, Maine.
Quiet in the Atlantic
None of the reliable models for predicting genesis of Atlantic tropical cyclones is predicting development over the next five days, and there are no threat areas to discuss. The tropical Atlantic is dominated by dry air and high wind shear, and SSTs are 0.2°C below average in the Hurricane Main Development region between the coast of Africa and Central America, between 10°N - 20°N. If we get another tropical storm this month, the most likely area for formation would be off the Southeast U.S. coast or in the Gulf of Mexico.
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