It’s definitely summer.
If you couldn’t tell from the angle of the sun, the hurricanes in the eastern Pacific Ocean, or the Indian monsoon, you would know by the temperature in Columbia, South Carolina: a hundred and one yesterday; 103 expected today.
This week there are heat waves, hurricanes, wild animals, and more.
Let’s go Around The World.
Flooded Eastern Texas Braces For More Rain
May was the rainiest month ever in parts of Texas and Oklahoma. The culprit was weather pattern Government, with an upper level trough over New Mexico and a surface flow of humid air from the Gulf of Mexico. The combination was enough to produce a biblical deluge as the system, like the government, wouldn’t move.
The current situation is a little different, weather-pattern-wise, but the result is the same. This time the perpetrator is a weak tropical storm, recently given the name Bill, which will move northwest from the Gulf of Mexico into Texas today.
The moisture has the same source, but the lifting mechanism, which squeezes the moisture out of the atmosphere, is different. Winds spiraling into the tropical storm are forced to rise; rising air cools; cooler air cannot hold as much moisture as warmer air, so some of the moisture condenses and falls as rain.
The rain will be heavy along the coast this time, but plenty of rain will fall in the southern and central plains where a weak trough in the jet stream, a remnant of Government, will enhance the lifting.
Since the ground is still saturated from the May deluge, less rain will be required to produce flooding. And since this system is also slow-moving, the rain could last for several days. Some areas could pick up over five inches.
To complicate matters, moisture from eastern Pacific Hurricane Carlos could find its way to the plains by the weekend.
Weather Pattern Changes
Weather Pattern Government, which was characterized by a deep trough in the west and a complementary ridge in the east, has given way to a zonal (west-to-east) flow.
Meteorologists recognize three main types of weather pattern over the United States: Cellular blocking (Government was this type); High-latitude zonal (the pattern we have now); and low-latitude zonal (a pattern normally only seen in the winter).
Our high-latitude zonal flow has a jet stream with only shallow undulations. Since it is located in the northern tier of the US and southern Canada, the southern states are under very weak winds at all levels. With the sun high in the sky and no relief from the north, the temperatures in the southern half of the US are soaring from coast to coast. The only relief will be where clouds and rain restrict the rising temperature.
Monsoon Brings Relief To All Of India
Cooling monsoon clouds, wind, and rain now cover virtually all of India, following the killer May heat wave. In the north, which feels relief last, yesterday’s high temperature in Delhi was ninety degrees.
This was the first day on which the temperature did not reach at least 95 degrees since April 17. Though El Niño years are correlated with a weak monsoon, this year’s monsoon is about average so far.
El Niño Strengthens, Now Expected To Last Through The Winter
Decoded Science named El Niño Eggplant last fall and has consistently been more aggressive than NOAA in forecasting its strength.
Now virtually all forecasters agree that this is a significant event that will probably last until next spring. It will be the first strong El Niño since 2010, and is already affecting conditions, the Indian monsoon notwithstanding, worldwide.
Still A Long Way From Peak, Hurricane And Typhoon Season Ramps Up
El Niño years normally are accompanied by below average tropical activity in the Atlantic and above average activity in the Pacific. In the Atlantic, where the season is supposed to start June 1, we had a hurricane off the east coast in May and now a second storm, Bill, in the Gulf of Mexico. Not all El Niño years produce below-normal Atlantic activity.
There have already been three Super-Typhoons (winds over 150 miles per hour) in the western Pacific, where the water is warm enough for the ‘official’ season to run all year.
In the eastern Pacific, where the season begins May 15, there have been three named storms, including one that made landfall in Baja California last week, and Hurricane Carlos which is now affecting the west coast north of Acapulco.
El Niño years are not only correlated with above-average numbers of storms in the eastern Pacific, but also an increase in the number that make Mexican landfall.
October is an especially dangerous month, as the jet stream migrates south and steers storms towards the coast.
Lions And Tigers And Bears. Oh My!
Unusual weather can happen on any scale and have many different results. We’ve heard of ‘the dog days of summer,’ but hippopotamuses roaming the streets is a bit much.
On Saturday, a single thunderstorm that stalled over a mountain in Georgia (the country) caused a massive flood on the Vere River, normally a small stream, killing at least twelve people, and destroying the enclosures of a zoo. Many of the animals are still on the loose in Georgia’s capital city of Tbilisi.
By all available accounts, this was just a single thunderstorm that stalled for a few hours in an unfortunate place. Other nearby rivers did not flood. Still, it’s not the first flood in the region — not even the first time the zoo was inundated.
Sluggish Summer Weather Pattern In Place For Much Of The US
The high-latitude zonal jet stream pattern will confine cooler air to the northern states for at least a couple of weeks. How hot is it where you are?
Decoding Science. One article at a time.