GRAHAM COUNTY – The Gila Valley received a light dusting of rain overnight, but, with the forecast calling for only a slight chance of storms for the rest of the week, it looks like it is unlikely to rain on the Pioneer Days’ parade.
According to the University of Arizona Meteorological Network’s Safford Station, the area saw .19 of an inch of rain Tuesday, bringing the yearly total to 4.05 inches. The station is located half a mile southeast of the intersection of Lone Star Road and Montierth Road.
While the yearly total is less than the 4.69 inches the area had last year at the same time, it is still on par to see more precipitation this year on average than the area has had annually during its last 20 years of drought. Last year’s total precipitation of 13.71 inches was the most ever recorded at the UA’s station near Safford in its 28-year history.
This year’s rain total was boosted by above-normal winter storms attributed to an El Nino season, which experts predicted could lessen the monsoon season’s rainfall. However, the Gila Valley historically has had more of its rain in the latter half of the summer monsoon season, with storms coming in late July through August.
According to weather expert Rachelle Oblack, a monsoon is a seasonal shift in wind direction and pressure distribution that causes a change in precipitation. As surface temperature rises, the air above it expands and an area of low pressure develops. Since the ocean remains at a lower temperature than the land, the air above the ocean retains a higher pressure. That causes winds to flow from the ocean inland, bringing along the precipitation along the way.
In Arizona, precipitation-bearing winds from the Pacific Ocean build clouds as the summer heat increases throughout the day before unleashing its torrent as afternoon thunderstorms.
However, with the National Weather Service forecasting just a 20-percent chance of thunderstorms each day through Sunday and high temperatures in the low 100s, the area is unlikely to see any significant precipitation this week.