Weather Around The World, 7/5/16: Summer Heat; Killer Flood; Tropics Getting Active


Home / Weather Around The World, 7/5/16: Summer Heat; Killer Flood; Tropics Getting Active

The Strawberry Moon was eclipsed in 2010 — but it was not on the equinox. Photo credit: Jared Alcher

In June, the highest sun of the year in the northern hemisphere brought a severe heat wave to the American southwest.

Slow-moving thunderstorms caused flooding in West Virginia.

And the fourth Atlantic named tropical storm formed on the earliest date ever.

There was also news about pancakes.

So what’s in store for July? Let’s go Around The World.

Northern Hemisphere’s Longest Day Of The Year Coincides With Full Moon

The summer solstice might have passed unnoticed this year but for the fanfare around the fact that it occurred on the same day as the Strawberry Full Moon. The June full moon is concurrent with strawberry harvest in some places. But it only occurs on the solstice, on average, once every 29 years. We are in a veritable drought of Strawberry Solstice Moons, the last one having occurred in 1967, while the next one will be in 2062.

In non-leap years, the time of the summer solstice advances about six hours from the previous year. This year’s Solstice was at 6:34 p.m. Eastern Daylight Savings Time (the local time in New York) on June 20. Next year’s summer solstice will occur on the 21st at 24 minutes after midnight.

Considering that the time of solstice is advancing six hours per year, you may wonder why the solstice doesn’t pirouette right into July and beyond; and in the days before the rotation of the earth and its revolution around the sun were well understood, calendars did get seriously misaligned with the seasons.

Now, of course,, we compensate for this yearly advance, which is caused by the extra quarter of a day in each earthly year (365-1/4), by adding a day every fourth year. That extra day puts the solstice back just about to where it was four years earlier.

In the Northern Hemisphere, The Strawberry Moon may appear unusually low in its arc across the southern sky. Since the moon circles the earth very close to the ecliptic (the plane of the earth’s path around the sun), the June full moon is where the sun is in December — at its lowest arc in the northern hemisphere. Winter full moons are correspondingly high in the sky, following the sun’s summer path.

Killer Flood In West Virginia

A cluster of heavy thunderstorms sat over western West Virginia for most of the day on June 23. Analysis courtesy of NOAA.

A slow-moving cluster of thunderstorms delivered nearly ten inches of rain to parts of West Virginia on June 23.  The previous June daily rainfall record was less than two inches. Twenty-three people died in the ensuing flood.

Though there is no quantitative study that shows that incidents of flood-producing rains are more common these days, that is certainly the perception from news reports. One explanation could be that there are simply more people in the way of floods.

But there is also a suspicion that the excessive rains have something to do with climate change. A warming atmosphere can hold more water vapor — more water vapor, more potential rain. Furthermore, weather systems seem to be moving more sluggishly. A whole day of rain can produce a flood where a few hours of rain will not.

Welcome Monsoon Arrives Eight Days Late To India

The satellite view for July 2 shows copious monsoon rain over India. Image courtesy of NOAA.

Last year’s Indian monsoon dropped only 86% of normal rainfall, consistent with the historical data for El Niño years.

This year’s monsoon arrived eight days late and June rainfall was 11% below normal, but with El Niño gone, rainfall is now at normal or greater intensity, and Indian meteorologists expect normal to above normal precipitation for the important July planting period.

The cooling rain and clouds also bring relief from searing heat.

US Also Has A Monsoon

Though it doesn’t produce the copious rains of the Indian monsoon (1,000 inches per year in extreme cases), the American monsoon provides some relief from the solsticial heat of June in the desert southwest.

Some moisture works its way from the Gulf of Mexico to the deserts of Arizona. In the past week rain arrived in desert locations that had seen temperatures climb to near-record levels in the hundred and teens. The high temperature in Phoenix on June 30 and July 1 was below 100 degrees with clouds and showers.

Water Temperatures Suggest Northern Hemisphere Could Have An Active Tropical Cyclone Season

Water temperatures in the northern hemisphere tropical and sub-tropical oceans are mostly above normal. Analysis courtesy of NOAA.

Atlantic Ocean

The Atlantic recorded its D-named storm, Danielle, earlier than any other season’s. This record comes with several asterisks.

  • The A storm, Alex, occurred in early January and was really a remnant of the 2015 season.
  • The C and D storms were bare-minimum tropical storms which might have gone unnoticed in the days before enhanced data from satellites, buoys, and ship observations.

The Atlantic is currently quiet. However, the strongest storms normally form near Africa in August or September. A tongue of cold water which moved south from the anti-blob (cold pool) farther north has largely dissipated. The water in the major-hurricane breeding ground near the Cape Verde Islands is now warmer than normal.

Eastern Pacific Ocean

The Pacific Ocean has been unusually quiet this year; the only named storm during the first six months was Hurricane Pali in the central Pacific in January. But now things are heating up. Agatha formed southwest of the southern tip of Baja California on July 2, and Blas is not far behind. Agatha is too far west to strengthen to hurricane force and will dissipate over the colder water to the north and west. Blas has time to reach hurricane strength — possibly even major hurricane strength — over the warmer water closer to Mexico before it too winds down as it moves in the general direction of Hawaii.

Western Pacific Ocean

At 2 a.m. EDT on July 5, Typhoon Nepartak had winds of 100 miles per hour and was headed for Taiwan and China. Forecast courtesy of US Navy.

The typhoon season runs all year in the western Pacific, so the absence of storms through June leaves Decoded Science wondering if this was the calm before a busy summer storm season.

And sure enough, here comes Typhoon Nepartak. The latest forecast has Nepartak, which now has winds of 100 miles per hour, reaching Super Typhoon intensity (150 miles per hour) before passing over the northern tip of Taiwan. By the time the storm reaches the coast of China near Shanghai, it is expected to have diminished below hurricane intensity.

The northern hemisphere tropical cyclone season

Water temperatures are relatively elevated over virtually the entire tropical and sub-tropical northern hemisphere: Indian Ocean; Pacific Ocean east and west; and Atlantic Ocean. As the water heats up further during July and August, so will the tropical cyclone activity.

Pancake Lovers Breathe Easy

What could be more important than the weather? Food, of course. And food is often dependent on the weather.

Decoded Science reported in February that unusually warm weather had started the maple sap running at an unprecedentedly early date. Maple syrup producers worried that the sap would dry up and affect the natural harvest. In fact, the harvest ran below normal for much of the season.

Now comes word that cool weather late in the season has boosted the crop to near normal, and prices will remain stable.

As Decoded Science always notes, statistics are slippery as eels. Some of the production can be attributed to increased effort. The number of taps increased fivefold in the last 15 years. Nevertheless, the result is that the price of maple syrup is stable at $50 per gallon, — pancake lovers rejoice!

July Shaping Up To Be Hot

Last summer’s weather pattern featured a branch of the jet stream across the southern US, keeping temperatures moderate. This year a La Niña pattern with the jet stream further north has been dominant for the start of summer. While the northern states have normal summer temperatures, the southern states are sweltering. There is no indication as of this time that this pattern will break before August.

What’s it like where you are?

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