It’s a busy week in the weather world: El Niño in the Pacific, tropical cyclones in the Indian and Pacific Oceans, warm weather in Europe, new atmospheric CO2 record imminent, flooding in Kentucky, and hazardous surf for spring breakers in Florida. Let’s go Around The World.
What El Niño? Oh, THAT El Niño
Three months ago, Decoded Science named El Niño Eggplant. Last week NOAA got around to recognizing that there is an El Niño.
It’s not that they didn’t notice; the conditions didn’t quite satisfy their definition. As near as this reporter can tell, they still don’t. But let’s not quibble; there’s been an El Niño for several months. It has already affected the weather and probably will continue to do so at least until summer.
The first noticeable effect of El Niño Eggplant was the heavy rain in southern California in November — the heaviest in two years. Since then there has been another round of rainfall — in record amounts — in early February.
Hurricane forecasters are struggling to determine whether El Niño Eggplant will last long enough to subdue hurricane activity in the Atlantic Ocean this year.
Last winter’s weather pattern has returned to Europe. A split in the jet stream has produced warm temperatures in northern Europe, near normal in southern Europe, and cool weather in northern Africa and the Middle East. Here are a few highlights:
- London‘s daytime high temperature has been above average every day since February 15.
- Edinburgh reached 50 the last five days. (thru Monday).
- Berlin was 62 on sunday — 21 degrees above average. All of Germany has been above average for over a month.
- Since a cold spell at the end of January, Moscow has been continuously above average, reaching 50 on Monday for the first time since October.
- Temperatures in Rome and Athens have been close to average the last month.
- Temperatures in Libya, Egypt, Turkey, and Israel have been below normal for about a month.
Ohio River Floods Louisville From Snowmelt
Last week’s record snow in Kentucky stopped traffic for days. Now residents have to deal with the aftermath — melting snow leading to rising rivers.
When it rains, the water disburses efficiently as it hits the ground. But snow piles up; if it all melts at once, flooding is more serious than if the same amount of water fell as rain. Much of the snow melted yesterday and flowed into the Ohio River, which flooded parts of Louisville. The river is expected to crest around noon today, as rain exacerbates the flooding.
Rip Currents In Ft. Lauderdale For Spring Break
College students are descending on south Florida for the annual ritual of blowing off steam. Some of that takes place in the surf, and this week surf’s up. Surfers appreciate the four-foot breakers, but there’s a danger in the roiled waters — riptide.
Riptides, or rip currents, are not very mysterious. When the wind blows towards the beach — this is what makes the surfing waves — the water has to go somewhere, basically back where it came from, out to sea.
So while the surface water piles up on the shore, a reverse flow underneath returns the water to the deep. Turbulence or a change in the bottom contour can bring the seaward flowing water to the surface in narrow bands — rip currents.
Rip currents can be powerful enough to thwart the attempts of even the strongest swimmer to return to shore. Luckily, we’re dealing with a conservation principle here: The ocean is staying where it is, so the flows towards and away from the shore must balance. The conventional wisdom is to swim parallel to shore and soon you’ll reach a place where the current is more favorable. Or if you have more time, just ride it out to sea a short distance until it peters out and swim back to shore at an angle.
Cyclones In The Indian And Pacific Oceans
A minor cyclone named Haliba will lose strength as it heads away from Madagascar and into the southern Indian Ocean.
A more important cyclone, Pam, is gathering steam in the Pacific Ocean north of New Zealand. Pam’s winds will top out at 140 miles per hour, which would make it the equivalent of a category four hurricane.
Pam will transition to an extra-tropical cyclone as it passes several hundred miles northeast of New Zealand.
Tropical cyclones affect New Zealand about once each year. Cyclone Bola struck New Zealand the second week of March in 1988 and did extensive damage. Bola, a western south Pacific storm, should not be confused with north Indian Ocean Cyclone Bhola, which made landfall in Bangladesh in 1988.
Carbon Dioxide Goes Higher And Higher
Here’s a prediction that’s not hard to make: The atmospheric carbon dioxide reading on Mount Mona Loa in Hawaii will set an all-time high when it reaches its seasonal maximum in May.
2015 marks the first year in which the reading exceeded 400 parts per million in the month of February. At over 401 ppm, the CO2 level is almost up to last year’s record set in May. There’s not much doubt we’ll beat the record weekly reading of 402.7 by April — possibly before the end of March.
The pre-industrial CO2 level was 280 ppm.
The Struggle In The Pacific Goes On
Last winter, the sea surface temperatures (SST) in the Gulf of Alaska contributed to a displacement of the polar vortex which dominated the weather over the United States. This winter, the warm water pool has been challenged by an El Niño, which tends to create a jet stream pattern with wet weather on the west coast and warm weather over much of the US.
At the beginning of February, El Niño was ascendant, causing the aforementioned record rains in California. Since then the Alaskan SST anomaly fought back, producing a bitterly cold spell in the eastern States.
Things are changing again. The jet stream is flattening and the eastern US is warming rapidly as Eggplant flexes its muscles. Current forecasts indicate that by the end of next week, the ridge will return to the west coast and the polar vortex will again descend on the midwest and New England. Boston will probably get the two inches of snow it needs to break its all-time winter snowfall record in about ten days.
Heading Into Spring
A dramatic warmup will overspread most of the US this week. Signs of spring will sprout everywhere. What are the signs where you live?
Decoding Science. One article at a time.