Hay pocas nubes, de manera que la visibilidad mejora.

Because hay is the form Spanish uses to say that something exists / there is / there are.

• hay pocas nubes = there are few clouds
• It comes from the verb haber used impersonally.

You do not normally use estar or ser for simple existence in this kind of sentence.

• Hay pocas nubes = there are few clouds
• Las nubes están... would describe the clouds’ state or location, not just their existence.

A very useful rule:

• hay = there is / there are
• It stays the same for singular and plural:
  • hay una nube
  • hay pocas nubes

Because pocas has to agree with nubes, and nubes is:

• feminine
• plural

So the adjective/quantifier must also be feminine plural:

• poca nube = little cloud / not much cloud cover in a very specific phrasing
• pocas nubes = few clouds

Compare:

• pocos coches = few cars
• pocas nubes = few clouds

After hay, Spanish very often uses a noun without an article when introducing something that exists.

So:

• Hay pocas nubes = There are few clouds

Not:

• Hay las pocas nubes ❌

This is similar to how English says there are few clouds, not there are the few clouds, unless you mean some very specific clouds already known in the conversation.

Here, de manera que means so, therefore, or as a result.

It links the first idea to its consequence:

• Hay pocas nubes → la visibilidad mejora
• There are few clouds → visibility improves

So in this sentence, de manera que introduces the result of the first clause.

Common English equivalents here:

• so
• therefore
• which means that
• as a result

It can do more than one job depending on context.

1. Result / consequence

That is the use in your sentence:

• Hay pocas nubes, de manera que la visibilidad mejora.
• There are few clouds, so visibility improves.

2. Manner / way

It can also mean something like in such a way that.

For example:

• Lo explicó de manera que todos lo entendieron.
• He explained it in such a way that everyone understood it.

So the exact meaning depends on the sentence, but in your example it clearly expresses result.

Because this sentence is presenting a real, factual consequence, so Spanish uses the indicative:

• la visibilidad mejora

That means:

• visibility improves
• visibility is improving
• visibility gets better

If the sentence expressed purpose, intention, or something less factual, Spanish might use the subjunctive in other contexts. But here the idea is straightforward: few clouds → better visibility, so indicative is the natural choice.

Spanish often uses the definite article with abstract nouns where English might not.

So:

• la visibilidad mejora literally = the visibility improves

But in natural English we usually just say:

• visibility improves

This is very common in Spanish:

• La situación mejora.
• La temperatura baja.
• La calidad aumenta.

So the article is normal and idiomatic here.

Yes, visibilidad is feminine:

• la visibilidad

A useful pattern is that nouns ending in:

• -dad
• -tad
• -tud
• -umbre
• often -idad

are usually feminine.

Examples:

• la ciudad
• la libertad
• la actitud
• la costumbre
• la posibilidad
• la visibilidad

So once you learn the ending pattern, la visibilidad feels quite predictable.

Because the subject is la visibilidad, which is singular.

• la visibilidad mejora = visibility improves

Even though nubes is plural in the first clause, it is not the subject of mejora. The sentence has two separate clauses:

1. Hay pocas nubes
2. la visibilidad mejora

So:

• nubes belongs to the first clause
• visibilidad is the subject of the second clause

Yes. That is very natural.

Possible alternatives include:

• Hay pocas nubes, así que la visibilidad mejora.
• Hay pocas nubes, por lo que la visibilidad mejora.
• Hay pocas nubes, de modo que la visibilidad mejora.

They all express a similar idea: few clouds, so visibility improves.

De manera que is a bit more formal or written-sounding than así que, which is very common in everyday speech.

Yes, you can.

Both are possible:

• la visibilidad mejora
• mejora la visibilidad

The version in your sentence, la visibilidad mejora, is straightforward and neutral because it puts the subject first.

Spanish allows more flexibility with word order than English, so changing the order can affect rhythm or emphasis, but both are grammatical.

It is the present indicative of mejorar.

• mejoro = I improve
• mejoras = you improve
• mejora = he/she/it improves or improves
• mejoramos
• mejoráis
• mejoran

In this sentence, mejora refers to la visibilidad, so it means:

• visibility improves
• or in context, visibility is improving

Spanish often uses the present tense in places where English might choose either simple present or present progressive, depending on context.

Not exactly, though they can be similar in meaning depending on context.

• Hay pocas nubes = There are few clouds
• Está despejado = It is clear / The sky is clear

Hay pocas nubes is a more literal description of the number of clouds.

Está despejado focuses on the overall condition of the sky.

So they are related, but not identical:

• A sky with a few clouds may still be described as despejado
• But hay pocas nubes is more specific about what you can see

The comma separates the two clauses:

• Hay pocas nubes
• de manera que la visibilidad mejora

It helps show that the second part is the consequence of the first part.

In English, you would often do something similar:

• There are few clouds, so visibility improves.

So the comma is not random; it makes the structure and logic of the sentence clearer.