Tonight our little league play-off game suffered a rain-out. After a full day of pleasant weather and blue sky, rain showed up at dinner time.  It’s not the first time in my life that rain showed up at game time and then checked out after the game was cancelled.

 

So the question I once knew the technical answer to popped up into my mind again.  Why does it rain at the dinner hour, what causes rain to finally burst down upon us between the hours of 4 pm and 7 pm?  There is a reason.   Well there are scientific theories.  It has to do with air pressure.

 

Some rain is caused by high air pressure; some rain is caused by low air pressure.  It’s like you can’t win.  One of them is going to cause the clouds to dump on you.   In short you need three ingredients for rain:

 

1.      Moisture

2.      Unstable Air

3.      Lift

 

These three elements come together at dinner for a reason.  I’ll get to that next.

 

Convection Rain from Low Air Pressure – the evening rain

Warm ground + low pressure = rain

 

These are the short showers that show up, ruin your game and are out of here right after everyone has agreed the games are cancelled and have driven off home; and yes the sun comes out wouldn’t ya know it!

 

Why it happens is simple and unavoidable.  The sun takes the whole day to warm the surface of the earth.  That warmth of the earth warms the air.  That warm air rises up to the clouds and meets the cold air.  Bang, the rain dumps on us.  Yes, it takes all day but by 4:00 pm that warm air has to go somewhere and it goes up... if there is a cloud in the sky you can bet it is holding moisture and that cloud is a bunch of cold air!  The warm air bangs into the cold air and that “unstable” mix of air is what causes the moisture to come rolling down on us.   

 

So now you know.  You pretty much can count on rain at the dinner hour.

 

So if you play softball, baseball, soccer or just about any sport that is played out of doors and relies on a pleasant dry day, this is your bane.  If you can tie together that moisture, unstable air and lift are going to be in play the morning of  your event, you can brace yourself for the worst.