Sunday was the longest day of 2015 in the northern hemisphere. Today isn’t much shorter, but as the summer goes on the shortening will become more noticeable.
Since the season lags the length of day in most places, the hottest days are yet to come, usually in July, sometimes in August.
Temperatures are soaring in the southern United States right now, thanks to weather pattern Hotzilla, but there’s also a cold temperature record to report in the lower 48.
Flooding was an issue as Tropical Storm Bill kept his identity from the Gulf Coast to the east coast and dumped a deluge in his path, while the Indian monsoon doused Mumbai.
And to spice things up this week, one tropical cyclone formed in the South China Sea and is about to bring heavy rain to Vietnam, while another is developing in the Indian Ocean.
Let’s go Around The World.
Floods Ravage Mumbai
India is one place that violates the general rule that the highest temperatures come after the solstice. The whole country suffered a horrible heat wave in the last ten days of May that claimed over 2,000 lives. The days before the arrival of the monsoon are always the hottest. This year the monsoon was a little late in Mumbai, so its hottest days were in early June.
Moderated by winds off the Arabian Sea, the temperature in Mumbai never reached the century mark this year, but the high temperatures were above 90 every day in May, and averaged about three degrees above normal for the month.
The cooling precipitation finally started mid-month, with temperatures retreating to the 80s. But last Friday was too much of a good thing. While the temperature topped out at 82 degrees, tropical deluges flooded much of the city.
Monsoon rains are not spread around evenly. Since the air is saturated with tropical moisture, any slight disturbance that provides just a little lift can release torrents of rain. Parts of Assam province in the northeast part of the country have also been flooded.
Tropical Storm Bill Drops Rain Where It’s Not Needed
Tropical Storm Bill swept ashore last week near Houston and continued on a path over the already saturated ground of northeast Texas and southeast Oklahoma. The storm retained tropical characteristics and produced flash flooding into the midwest and eventually the mid-Atlantic states.
Decoded Science has sometimes criticized the Weather Channel and NOAA for their practices with regard to dangerous weather, but this time both deserve kudos.
The weather Channel continued to call the rain warnings tropical and in fact kept an on-screen graphic saying ‘tropical downpours’ until the system left the building.
The National Hurricane Center passed jurisdiction of the storm on to the Weather Prediction Center, but they continued to call it tropical depression Bill.
It is important to convey weather information so that it is understood by laymen looking for guidance. The word ‘tropical’ gets everyone’s attention when it’s connected with wind or rain.
Weather Pattern Hotzilla Sets Records
Last week, Decoded Science announced that weather pattern Hotzilla had replaced Weather Pattern Government. Government was a blocking pattern that featured a deep low pressure center over the western US and a high pressure center called an omega block in the east. The result was a system that didn’t move (like the government) and brought record-setting rain to Texas and Oklahoma.
Hotzilla is entirely different. The straight west-to-east jet stream over far northern US and southern Canada is called high latitude zonal. The cold air is bottled up north of the jet stream and the south has become very hot. Here are just a few of the daily records set Sunday:
- Provo, Utah, 101
- Eureka, Nevada, 95
- Augusta, Georgia, 101
- Alamosa, Colorado, 92
- North Charleston, South Carolina, 98
- Charlotte, North Carolina, 100
- Daytona Beach, Florida 96
The heat was pervasive from coast to coast.
High Latitude Zonal Jet Stream Pattern Hotzilla’s Cold Side
The jet stream associated with Hotzilla is quite strong, and a temperature gradient (change of temperature with distance) is normally in the shadow of the jet stream. Cold air is pretty much confined to Canada, but with even the shallow waves rippling along Hotzilla’s axis, colder air has been able to penetrate the far north. On Sunday, the temperature at Watertown, NY reached a new record low of 40 degrees.
Tropical Cyclones On The Other Side Of The World
After the excitement of Tropical Storm Bill, US citizens can breathe easy this week, as no tropical development is likely for several days at least. The eastern Pacific is quiet also.
In the eastern Pacific, Tropical Storm Kujira formed in the South China Sea late last week. The storm crossed China’s Hainan Island last night with winds of 50 miles per hour. It is now about to reach northern Vietnam, where it will drop substantial rains as it heads northwest into Asia.
In the Arabian Sea, a potential cyclone is gathering strength off Mumbai. Most forecasts have the cyclone intensifying and making landfall near Mumbai during the week, possibly exacerbating flooding in the already soggy city.
Weather Pattern Hotzilla Will Be Replaced Next Week
The high latitude zonal flow of Weather Pattern Hotzilla is forecast to give way to a more wavy pattern. Whether the new pattern will develop a block like Government is still uncertain. But some cooler air will infiltrate south to the Carolinas next weekend or early the following week.
Upstream factors are sending conflicting messages about what weather pattern will dominate this summer. El Niño Eggplant is pushing while the warm water in the Gulf of Alaska is pulling. The US could have a topsy-turvy summer, with patterns changing often.
Summer is starting out hot in much of the United States. What do you see where you live?