Eye on the Tropics

Red skies are a sailor’s delight… except when a slow-moving tropical storm is near

ORLANDO, Fla. — You’ve heard the saying “red sky at night sailors delight; red sky in the morning sailors take warning.” This is a variation from other similar stories and bible quotes, but we’ve found scientific validity to this, of course, with a couple of caveats.

Many saw the beautiful sunsets on Sunday evening as we had tropical storm Isaías near our east coast.

After tropical storms, we usually get to experience gorgeous sunsets. The fact is that after a hurricane or a tropical storm, good weather days often follow and that’s where the saying takes validity, scientifically.

Weather systems, overall, move from west to east in mid-latitudes. So when a storm is exiting and stable weather is entering from the west and the sun is setting the effect illuminates the leaving clouds with tones of orange, yellow and red. The reddish tones are courtesy of aerosols and suspended dust particles in the atmosphere and also the light scattering through them that are maximized in the lowest levels of the atmosphere. If we add the high pressure the reddish tones become extra radiant and that’s when the first part of the saying becomes valid: red sky at night, sailor’s delight.

Alternatively, if there are red skies in the morning, that’s because the sun, at sunrise, is illuminating clouds of an incoming storm system. So, red skies in the morning, sailors take warning.

With Isaías we did have beautiful sunsets across much of Florida on Sunday. The system was to our east and there is a high-pressure system centered over the Gulf of Mexico. Lots of dry air over the Peninsula helped Isaías weaken as it was pushed offshore.

Read more: Hurricane Season 2020: How are they named? Who names them? Why? When? Why they retire names?

We will not have completely stable weather, because of local weather and some left over effects of Isaías, but overall, the weather is improving.

As far as for the sailor’s delight, it won’t happen right away. There is still plenty of wave action, strong winds and a high rip risk for swimmers. Conditions are expected to gradually improve.


Small craft advisory is in effect for our east Central Florida coast through much of this afternoon. Seas could still reach 8 feet and isolated storms are possible. By Tuesday the seas will return 3 to 4 feet and the winds will be from the south between 5 and 10 knots.

Isolated storms will sweep from west to east across parts of Central Florida this afternoon, courtesy of Tropical Storm Isaías. It will be a hot day with temperatures around 103 degrees.

On Tuesday expect higher chances for scattered storms, and more tropical moisture arriving from the Gulf of Mexico and Bay of Campeche for the latter part of the week with rain and storm activity.

Latest satellite image: Isaías

Forecast Track


¡Esta nota en español! Resumen de los trópicos: ¿Qué está pasando? ¿A dónde van? ¿Que se espera?

Read more: Hurricane Season 2020: How are they named? Who names them? Why? When? Why they retire names?