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Severe Thunderstorms Threaten Buenos Aires, Montevideo on Wednesday

Written by Meteo Expert Josef Lukas

There is a significant risk of severe thunderstorms across Argentina and Uruguay on Wednesday. Damaging winds, large hail, and flash flooding are all possible. Additionally, frequent cloud-to-cloud and cloud-to-ground lightning is expected.

Chances for severe weather on Wednesday

The Details:

A cold front will push northward across Argentina on Wednesday and run into a hot and unstable air mass across central South America. Moisture from the Atlantic Ocean will get drawn toward the cold front and help ignite heavy, severe thunderstorms.

The severe weather setup on Wednesday

The major metropolitan areas of Buenos Aires and Montevideo have the greatest severe risk potential Wednesday afternoon and evening. Damaging winds in excess of 80 kph and large hail of 2-4 cm in diameter are possible.

Another concern with these storms is the potential for flash flooding. Rainfall amounts of 25-75 mm are expected within the thunderstorm threat area over a short period of time, leading to areas of flooding.

The severe weather risk will shift northward through Argentina and Uruguay Wednesday night.

Cooler and drier air will move into Buenos Aires and surrounding areas later Wednesday night and during the day Thursday.

Keni Acquires Severe Tropical Cyclone Status; Batters Fiji

Written by Meteo Expert Josef Lukas

Cyclone Keni strengthened into a severe tropical cyclone on Tuesday. Keni is expected to batter Fiji with heavy rain, damaging winds and coastal flooding Tuesday into Tuesday night.

In anticipation of the storm, the Fiji National Disaster Management Office briefed government officials and tweeted out a statement saying they are prepared for the cyclone.

Cyclone Impacts

Keni is expected to drop between 50-100 mm of rain on the northwest side of Fiji’s largest island, Viti Levu. The southeast side of Viti Levu will see less rain because of downsloping winds from the mountains in the middle of the island.

Winds of 80-100 kph are expected across Viti Levu, particularly across the southern part of the island which will be closer to the central of the cyclone.

The good news for Fiji is that Keni will be a quick moving cyclone. On Wednesday, some sunshine will return to the area as Keni marches southeast away from the country.

 

Keni is the seventh named cyclone of the South Pacific cyclone season, which runs from November 1st to April 30th each year.

Large Hail, Gusty Winds, and Tornadoes Rake the South on Friday!

Written by Team Morecast

 

Severe storms rumbled across portions of the Mid-South on Friday, producing high winds, large hail, and a few tornadoes as well (see radar animation and storm reports above). Here is some vivid video evidence of the large hail, received via Twitter.

 

 

In the end, the SPC (Storm Prediction Center) counted 145 total severe weather reports, including 92 hail, 43 wind, and 10 tornado. The largest hail reports came from the suburbs on the north side of the Dallas-Ft. Worth metro area (see above), up to three inches in diameter. Fortunately the pattern calms down in the next few days with no significant chances for severe storms in the foreseeable future.

Atlantic Hurricane Season 2018 Looks Closer to Normal After Hectic 2017

Written by Team Morecast

 

The 2017 hurricane season in the Atlantic basin was one of the most active and destructive on record (see graphic below). In terms of ACE (Accumulated Cyclone Energy, a measure of the total destructive power of all the cyclones in the season), it was the seventh-most active season on record. Hurricane Harvey became the costliest Atlantic hurricane ever after wrecking the Houston, Texas metro area in late August. Hurricane Irma, the strongest hurricane ever observed outside of the Gulf of Mexico and Caribbean, raked the northern Caribbean and southeast U.S. in early September. Just a few weeks later, Hurricane Maria (lead image, courtesy of astronaut Paolo Nespoli and NASA) devastated Puerto Rico, causing widespread destruction from which the island is still recovering.

 

 

The energetic 2017 season can mostly be blamed on a favorable orientation of the ENSO (El Nino Southern Oscillation) weather pattern. Specifically, it was in the negative phase (La Nina), typically favorable for tropical cyclone development in the Atlantic basin. Sea surface temperatures were also running above normal over the Atlantic, providing fuel for cyclone development.

 

 

The La Nina that developed in Fall 2017 has persisted through the winter, but there are indications that it will swing back towards neutral (see graphic above), or perhaps even rise into the positive (El Nino) phase, albeit weakly positive. El Nino is typically not as favorable for hurricane development in the Atlantic due to increased upper level winds which tend to disrupt hurricane organization. However, even less-active-than-normal seasons in the past have provided devastating landfalls. Hurricanes Hugo in 1989 and Andrew in 1992 both occurred in otherwise quiet seasons. Sea surface temperatures over the Atlantic basin are also expected to remain near to above normal. And seasonal forecasts can change – in 2017, early predictions of a developing El Nino and a quiet hurricane season proved wildly optimistic. The bottom line is that even if 2018 turns out to be a quieter tropical season than 2017, coastal residents shouldn’t be caught unawares when a major hurricane looms.