Illustration from the US National Weather Service
10 Jul 2023

Millions under flood warning in July 2023 - while 1/3 of US population under heat advisory


The three hottest days ever recorded for the planet occured last week, according to Copernicus. In the UK, it was 0,9C hotter than the previous record in 1940. In the US, 120 millions have been under heat advisory.

Texas and part of the south-west of the US are affected by heatwave, and according to the BBC, and at one point, more than 120 million Americans ( more than one in three of the total population) were under some form of heat advisory, based on statements by the US National Weather Service. 

Since the weekend, millions of people in the north-eastern US are under flood warnings as of Monday morning.

Two people have died in the intense floods, and as of Sunday evening, around 12,000 homes were reportedly without electricity in New York state. More than 1,000 flights to New York airports were cancelled.

Intense thunderstorms are expected to bring even more dangerous conditions in coming days. The National Weather Service (NWS) said in an alert that Vermont and north-eastern New York were the areas most at risk for more severe weather in coming days. 

Extreme heat is also forecasted for Arizona, which according to the National Weather Service could be "rivalling some of the worst heat waves this area has ever seen". 


Three hottest days ever measured for the planet

The average world temperature hit 16.89C (62,4F) on Monday 3 July and exceeded 17C (62,6F) for the first time on 4 July, with an average global temperature of 17.04C / 62,7F.

Preliminary numbers are suggesting the heat record was broken for the third day in a row on 5 July when temperatures reached 17.05C.

The North Atlantic Ocean is reportedly experiencing the highest surface water temperatures ever recorded. Around the coasts of the UK,  some areas have allegedly experienced temperatures approaching 5C above what you would normally expect for this time of year.

The US National Oceanic and Atmospheric Administration (NOAA) has labelled the warm North Atlantic Ocean water  a "Category 4 heatwave" - designation is rarely used outside of the tropics.


 El Niño returns

According to the World Meteorological Organization, the global weather pattern El Niño has returned for the first time in seven years. This is thought to bring about extreme weather events and high temperatures.

The United Nations agency made a declaration on Tuesday July 4, that the weather pattern was likely to return.  after months of forecasting.  

"The onset of El Niño will greatly increase the likelihood of breaking temperature records and triggering more extreme heat in many parts of the world and in the ocean," WMO Secretary General Prof. Petteri Taalas said in a statement.

El Niño is a natural phenomenon, however, according to Prof.Taalas, this is the first time the weather pattern is occuring in combination with a peak of temperatures caused by human activities.  


Uncertain how El Niño will affect hurricane season

The change in  wind patterns which are caused by the  El Niño and La Niña  have a strong influence on hurricane activity in the Atlantic.

According to the CBC, the U.S. National Oceanic and Atmospheric Administration (NOAA) is projecting 12 to 17 named storms, of which five to nine of which will become hurricanes. They released their Atlantic hurricane outlook for the upcoming 2023 season on Thursday July 6. 

NOAA is forecasting a modest 40 per cent chance of a normal year - but also a 30 percent chance of both an above-normal and below-normal season. 


Graphics Credit: Illustration from the US National Weather Service