Weather Around The World: Activity In Both Hemispheres


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Precipitation forecast for the next week: no rain for drought-stricken west; thunderstorms in the Mississippi Valley. Forecast courtesy of NOAA

Precipitation forecast for the next week: no rain for drought-stricken west; thunderstorms in the Mississippi Valley. Forecast courtesy of NOAA

Spring has finally arrived, and it is unlikely we will see the alphabetical finale of named winter storms (Eat your heart out, Zephyr).

Good riddance to winter in the U.S. – but be careful what you wish for.

Tornadoes, Hail, And Severe Thunderstorms

Last week’s severe weather outbreak associated with Winter Storm Yona gave winter-weary midwesterners a taste of what could come next.

As the sun gets higher in the sky, daytime heating creates instability, which can lead to thunderstorms. In addition, conditions in the lee of the Rocky Mountains are ideal for conditional instability, a state in which the atmosphere is on the verge of widespread turbulence.

When warm, humid air from the Gulf of Mexico meets the dry flow aloft east of the mountains, a passing front can set off violent weather.

Tornadoes were reported Monday in Missouri, Alabama, and North Carolina. Parts of Alabama also saw minor flooding as rain exceeded six inches. Tornado season peaks in May.

Fire Danger Increases

The rising sun doesn’t only heat the land — it also dries it out. Fire danger is already high in Texas, California, and Nevada. The persistent ridge in the jet stream that has caused the drought in California is now  well established over the west coast, and summer is normally a time of little rain in that area. If there’s a glimmer of good news, it’s the developing El Niño, which can lead to a flow called the pineapple express — wet weather systems moving northeastward from Hawaii.

Weather Across The Pond: What Will Follow The Warm Winter in Europe?

Temperatures over the globe have to balance, and the cold winter in the U.S. was offset by warmth in Europe. London has had a remarkable spell of above normal temperatures: since November 27, only five days have been below normal. Londoners might wish to exchange a few degrees of temperature for a reduction in rainfall (January was the wettest winter month ever recorded); and they may get that wish. Forecasts indicate a major change in the weather pattern to colder than normal starting in mid-April.

Weather Down Under: Tropical Cyclone Ita In The Solomon Sea

While searchers use Perth in western Australia as their staging area to scour the Indian Ocean for the missing Malaysian airliner, there’s trouble brewing on the other side of the continent.

Tropical Cyclone Ita (hurricanes are called tropical cyclones in the southern hemisphere) is currently skirting the coast of Papua New Guinea after causing 23 deaths in the Solomon Islands. Recently upgraded to a category three storm with winds over 115 miles per hour, Ita is forecast to increase to a category four storm with winds over 135 miles per hour as it approaches the northern coast of Australia on Friday.

Atlantic Hurricane Season Starts June 1

Tropical storm season is on the wane in the southern hemisphere, but Ita is a reminder that the Atlantic hurricane season is approaching. Some experts believe activity will be below normal because of a developing El Niño. But even though El Niños can depress hurricane activity somewhat, the cheering should be saved for the end of the season.

The last major El Niño year, 1998, featured 14 named storms in the Atlantic Basin, seven of which struck the United States… one as a category three major hurricane.

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