Blog Post #2: Air Currents and Jet Streams

As mentioned in Post #1, Limon receives rain year round. Even in the 'dry' months the area receives over 5" of rain on average.

Rainfall amounts with temperature. Found here: http://www.world-climates.com/city-climate-limon-costa-rica-north-america/ 

Rainfall amounts in Limon have mostly to due with convection.

Diagram showing how convection causes clouds and rainstorms.                                                                                          Found here: http://www.weatherquestions.com/How_do_clouds_form.htm

Costa Rica is surrounded by water on two sides. Since the air over land warms faster than the air over water, the air over Limon rises. The dew point in Limon is relatively high, usually staying within 10 degrees of the temperature, so the rising parcel quickly forms clouds and rain showers. 

Limon sits at 9 degrees north latitude, so it is only indirectly effected by the changes brought during winter in the northern hemisphere. 

Digital image showing the major air masses. This was taken in Spring or Fall. When it is winter in the northern hemisphere, the polar air mass moves farther south, pushing the warmer air masses south as well.                                                        Found here: http://www.weatherquestions.com/What_is_an_air_mass.htm

Winter in the northern hemisphere brings the rainy season. November through January see a rise in average rainfall. This is because the continental polar air mass shifts southward causing the maritime tropical air mass to also shift south. As it does, warm moist air moves across the gulf bringing heavier rains during these months.

The rest of the year is drier except for the huge spike in July. This spike has a lot to do with the movement of the International Convergence Zone (ITCZ)

ITCZ Movement Year Round. The ITCZ is a low pressure zone that promotes heavy rainfall across different areas as it moves north and south of the equator.                                                                                                                                   
(Found at http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Stages_of_Hurricane_Dev/ITCZ/ITCZ.html

As the ITCZ moves north it moves directly over Costa Rica in July, bringing heavy rainfall with it, thus there is a spike in the normal drier months, especially July.