As the proverb states, April showers bring May flowers. This old saying has captivated the likes of children and adults for countless generations. Since the month of April is nearly two weeks old, the potential of seeing these April showers continues to grow. During a spring afternoon, have you ever been outside with the sun shining on your back, but then a cloud quickly develops without little notice. You then hear a tap-tap on the ground and a pitter-patter elsewhere. Before long, these sounds become more numerous until you are fully engulfed in a quick spell of rainfall. As fast as this rainfall began is as fast as it eventually left. This, my friends, shows the character of Mother Nature in the emergence of the April shower.
April showers signify more then a poetic choice of words that rhyme with May flowers. Their task does not only produce water for our ground, but they also represent a turning point for the climate in the Mount Washington Valley. The month of April is a transition month in much of North America for temperatures and precipitation. Throughout the United States, the dynamic activity of winter decreases while steady frontal rains also become less prominent. These atmospheric activities become replaced with the April rain shower. It is important to note that April showers can produce precipitation in the form of snow. While this is true, the main key to the April shower is its suddenness of precipitation that falls from a single convective cloud. These showers are generally not associated with low-pressure systems that contain a dominant shield of precipitation.
Winter's grip is still prominent in the upper level regions of the atmosphere throughout much of April. To the contrary, the surface of the Valley is usually bare of snow and likely to be very moist during the same period of time. This allows the sun's growing heat to evaporate moisture from the soil and also aids to significantly warm the air adjacent to the earth's surface. The clash of warm and cold air in the atmosphere forces bubbles of moist air to rise rapidly until they eventually reach condensation. When conditions are prime, the bubbles will grow into large cumulus clouds that usually first appear as small raindrops that are ascending in the air.
The growth of the raindrop depends upon the strength of the updraft in the atmosphere. Eventually, the updraft will collapse due to there being a lack in sufficient amounts of warm air. The liquid droplets may also become too heavy for the updraft to support. In either case, the updraft's collapse is usually sudden, which forces an onset of rain to fall upon the earth. Updrafts are also formed when moist air is forced over a physical barrier, such as the mountains of our region. Once the air reaches condensation and the liquid water collects in the clouds, the supporting updrafts of air are cut as the clouds move over a mountain's summit. The air then descends as a new band of April showers develop.