Severe Weather Outbreak Beaver has departed, and the weather stateside has returned to seasonally hot in the desert and southern plains, cool along the Pacific coast and the northeast, with hit and miss showers and thunderstorms almost everywhere.
Fire danger is a concern, with the greatest threat having moved from California to much of the interior west and southern plains. And there is still the possibility of a tornado between the Rockies and the Appalachians.
But the big weather news this week is in Europe, specifically parts of old Yugoslavia — Bosnia and Serbia — where flooding is the worst on record.
Flooding In Serbia And Bosnia: How Much Rainfall Did They Get?
Much of eastern Europe, far from any major source of moisture, is fairly dry, especially in the winter. This winter was unusually rainy, and that set the stage for the recent flooding.
After twice the normal amount of rain had fallen from January through April, and three times normal in April alone, the deluge of six inches in three days last week was more than waterways and drainage systems could handle. Rivers crested at the highest levels ever recorded and whole towns were swamped.
What Caused the European Floods?
The jet stream normally flows from west to east, carrying waves with it. These waves are responsible for high and low pressure systems. Occasionally — more frequently recently — something stops up the works: A ridge can amplify into an omega-shaped configuration (an omega block); a trough can cut off and become an isolated vortex. Both of these phenomena can bring the normal movement of weather to a standstill.
For several weeks, the atmosphere has been in turmoil at jet stream level. Several cutoff lows and omega blocks have created persistent weather in places around the globe. Severe Weather Outbreaks Aardvark (three weeks ago) and Beaver (last week) caused extensive damage and some loss of life in the United States. Each lasted for several days.
Last week’s deluge in Serbia and surroundings was caused by a cutoff low that wouldn’t move. Rain fell for three days and the flooding ensued.
Is The Rain Over in Bosnia and Serbia?
Yes, the rain is over — for now. Summer is the rainy season, though that’s a comparative statement, but for the next week, the weather will be cooperative for cleanup efforts. These include not only rescuing people and rebuilding, but also the recovery of land mines planted during the wars of the 1990s which have been displaced by over 3,000 landslides.
Fish Kill In Marina Del Rey, California
Hundreds of thousands of dead fish, mostly anchovies, were found floating in Marina Del Rey on Sunday. The cause? Some are blaming it on the weather. As the temperature of water rises, its capacity to hold dissolved oxygen falls. It is likely that the full moon spring tides (exceedingly high and low tides) also played a part.
When the tide went out, there was less water, and thus less oxygen. The result: the abnormally warm water and low tide left insufficient oxygen for the volume of fish. Oxygen-depleting algae, which thrive on fertilizer runoff, may also have had a role in this and other fish kills.
Tropical Activity In The Eastern Pacific
The 2014 tropical weather season kicked off a couple of weeks ago with the system named Invest 90-E, which brought mudslides to Mexico and beneficial rain to Texas. A new disturbance, imaginatively named Invest 91-E, is located several hundred miles from the Mexican coast. This system has no future, as conditions for development will become hostile by tomorrow and movement will be west over colder water.
The eastern Pacific hurricane season ‘officially’ began on May 15; the Atlantic hurricane season begins on June 1. The tropical cyclone season runs all year in the western Pacific, and there have already been four tropical storms and a typhoon since January first.
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