77ºF

Tropical Tracker: Saharan dust could bring vibrant sunrises, sunsets to Central Florida

Dust helps limit tropical activity while it's around

SUn coming up on June 25, 2019 with Saharan Dust in the atmosphere.
SUn coming up on June 25, 2019 with Saharan Dust in the atmosphere.

ORLANDO, Fla. – After the Atlantic hurricane season got off to a hot start, things have quieted down dramatically.

Cristobal became the earliest third-named storm on record in the Atlantic before making landfall in Louisiana on June 7.

June is typically a quiet month, with only 6% percent of storms developing in the month.

A quiet stretch

Since Cristobal’s landfall, wind shear has dominated the tropical Atlantic, helping to keep tropical development down.

Tropical systems need a relatively calm environment to thrive. The growing thunderstorms want to be able to grow straight up, think of a skyscraper.

This is the opposite of strong thunderstorms on land. The wind shear helps the storm grow diagonally as well, think the Leaning tower of Pisa. This separates the updraft and downdraft allowing the storm to breathe.

Vibrant sunrises and sunsets coming

Look for the more vibrant than normal sunrises and sunsets starting Tuesday June 23 and becoming more vibrant through the end of the week and into the weekend (June 27,28)

Heading into next week, another tropical limiting factor will be around: dry air.

Almost every year around this time, dust from the Sahara Desert in Africa gets lofted into the atmosphere and makes its long trip across the Atlantic. Sometimes, the dust ends up all the way in the United States!

Satellite imagery on 6/18 shows a cloud of dust moving toward the Caribbean. It's not uncommon for dust of the Sahara Desert to be transported across the Atlantic. Sometimes it makes its way to the United States.
Satellite imagery on 6/18 shows a cloud of dust moving toward the Caribbean. It's not uncommon for dust of the Sahara Desert to be transported across the Atlantic. Sometimes it makes its way to the United States.

Over the last week, satellites have picked up on a large cloud of dust hovering over the Eastern Atlantic.

As of Saturday, some of the dry, dusty air has entered the Eastern Caribbean, en route to the United States.

By early next week, the highest concentration of dust looks to head toward Texas and the North Gulf Coast. Some of that dust will spread over the Sunshine State, enhancing our sunrises and sunsets. Later in the week, toward the weekend of June 27,28, higher concentrations of dust will be in our atmosphere. further enhancing the sunrises/sunsets.

Project Saharan Dust Saturday June 27th. Light dust will arrive Tuesday/Wednesday (23/24) with higher concentrations of dust arriving Friday into next weekend. (June 27/28) Look for vibrant sunrises/sunsets during these times.
Project Saharan Dust Saturday June 27th. Light dust will arrive Tuesday/Wednesday (23/24) with higher concentrations of dust arriving Friday into next weekend. (June 27/28) Look for vibrant sunrises/sunsets during these times.

When the sun is low on the horizon in the morning and evening, the sun’s rays have to travel through more of the Earth’s atmosphere. The light scatters more, producing beautiful red, orange and pink colors in the sky.

When small dust particles are introduced, more scattering takes places enhances the already vibrant colors. Here’s an example of a sunrise with Saharan Dust in our sky from last year.

Be sure to pay attention to air quality as sensitive groups could have some issues with extra dust in our atmosphere.

ENSO Update

If you follow the tropics, get to know ENSO.

You may be more familiar with El-Nino and La-Nina, but ENSO, or El-Nino Southern Oscillation, is the blanket that encompasses El-Nino, the warm phase of ENSO and La-Nina, the cool phase.

The phase of ENSO plays a pretty big role when it comes to tropical systems in the Atlantic Basin.

El-Nino tends to suppress tropical development with higher wind shear and sinking air over the Atlantic. La-Nina tends to enhance development by promoting rising motion, favors thunderstorm development, and a much calmer atmosphere.

Just last month, the IRI and Climate Prediction Center favored ENSO neutral conditions, neither El-Nino or La-Nina, through the peak of hurricane season, August, September and October (ASO). The early June update increased the probabilities that La-Nina could be around for the peak of hurricane season. Just about 50/50 with ENSO neutral.

The chances La-Nina are around for the peak of hurricane season (ASO) has increased since the mid-May update. La-Nina tends to enhance the hurricane season. El-Nino helps to suppress. The blue bar represents La-Nina.
The chances La-Nina are around for the peak of hurricane season (ASO) has increased since the mid-May update. La-Nina tends to enhance the hurricane season. El-Nino helps to suppress. The blue bar represents La-Nina.

The percentage that El-Nino could develop by the peak also dropped dramatically, only a 6% chance. The much above average forecasts from NOAA and others were based on the lack of El-Nino, but if La-Nina were to develop, that could enhance things further.

Through the end of June

At least for the next week, increased wind shear and Saharan Dust should keep the tropics mainly quiet. Indications are as we move through the last week of June, conditions could become favorable for development in the Western Gulf of Mexico.

This computer forecast highlights upward motion. The United States is on the right side of the graphic. Orange represents sinking air not favorable for tropical development. Green represents rising air more favorable for tropical development.
This computer forecast highlights upward motion. The United States is on the right side of the graphic. Orange represents sinking air not favorable for tropical development. Green represents rising air more favorable for tropical development.

The green represents upward motion, something needed for thunderstorm development. This does not guarantee storm development as other factors are in play, but hints at the most favorable locations for a storm. The second picture represents June 23.

Every Thursday, we’ll provide an overall update as to what is currently happening in the tropics and what the next week to two weeks could bring.

Of course, if and when development becomes likely, individual attention will be given to those disturbances.


About the Author: