Between South and North America, there is two extremes currently going off.

While an enhanced sub-tropical jet is providing heavy, flooding rains across parts of the US Gulf Coast region and further heavy rain is expected over Texas in the next 2 weeks, further south into the tropics and sub-tropics it’s a very different story. Abnormally strong upper ridging and dryness is forcing temps into record territory.

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Like the rains further north, this may be a consequence to the strong eastern equatorial Pacific warming as the El Nino strengthens.

The strong heating underneath the abnormally strong upper ridge may be enhanced by large quantities of Saharan dust blowing westward over the Atlantic into the Caribbean.

This was the model projection from several days back showing the strong and persistent blocking high over Central America responsible for the hot weather but I suspect the El Nino has a lot to do with why it’s so extreme compared to normal. This large scale sinking and dusty environment with dry ground also heats fast.

Check out this infrared image depicting the strong ridge (purples) over Mexico’s Yucatan vs the very wet, stormy Gulf Coast of the US with the sub-tropical jet visibly crossing Mexico direct from the warm Pacific.

Forecasted high back last week for this week were pretty accurate, seeing all-time record heat potential in the extremely dry, dusty and hot conditions covering this region.

The sustained dry spell has triggered wild fires on the Yucatan and has led to incredible sunsets over Miami and South Florida. Image via NWS Miami.

This map is small I know but if you look at the precipitation anomalies from the past 90 days it’s been wet over much of Mexico but from the Yucatan east across the Caribbean, Florida and even the Southeast US, it’s been dry.

90 days

In the last 30 days, it’s turned much wetter in the Southeast US, stayed wet in Mexico but it’s remained dry over the Yucatan across the Caribbean into South Florida and this is where the heat wave has focused.

This reason for such stronger than normal ridging and heat may be due to the presence of the enhanced sub-tropical jet passing to the north, another El Nino byproduct.

So, just how hot are we talking?

All-Time Record Highs For Merida, Mexico & Havana, Cuba

Both Merida on Mexico’s Yucatan and Havana, Cuba have reached their hottest temperatures in recorded history.

On 21 out of the first 26 days of April, Merida has seen temps hit 100F with an all-time max topping 110F on the 25th and 26th.

The intense heat even by mid summer standards not only affected Mexico and Central America but Cuba and South Florida too. Boca Raton topped 100F while Ft Lauderdale set a new April record at 96 while Miami’s 96 tied the April record.

However across the Florida Straits and into Cuba, the heat was even more impressive, not just setting monthly but all-time records in the historic capital, Havana. Here, an all-time record of 37C or 98.6F was reached while Holguin touched Cuba’s second ever highest reading of 38.7C or 101.6F.

Big Shift To Wetter

While the sub-tropical jet continues to roar across Mexico into the US, areas suffering the severe heat is now seeing welcome relief as the ridge has weakened and storms are now bringing much needed rainfall.

Sub-tropical jet will sink south in the coming days.

Look at the much wetter Caribbean over the next 10 days.

See today’s video for the discussion.

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Tags: el nino, ENSO, record heat, record rain