Also, all of these areas are affected by at least one tropical system almost every year.įigure D.
This is due in part to heavy rainfall produced by summer thunderstorms. June through August is a wet period for all states in the region. There is more precipitation in March and less in October and November for every state in the region. Florida has the starkest contrast with summer monthly totals 4-5 inches higher than winter amounts and Virginia has the lowest with about an inch of precipitation variation between months. The remaining four states, NC, VA, FL, and SC, have wet summers, June through September. Georgia and Alabama have wet summers, June through August, and also wetter than average winters, December through March. Though all six states are in the same region, their yearly precipitation patterns are not the same. Average Number of days with measurable precipitation in the southeast US. This is probably due to heavy rains produced by moisture coming from the Gulf of Mexico to its south.įigure C. This means that, on average, rain that falls here is heavier than the other states in the region per event. Even though Figure B it is entirely blue, meaning it has a high annual precipitation total, Figure C shows it as light green with spots of yellow, meaning it has relatively few days with measurable precipitation compared to other areas. If you look at Alabama, you’ll notice something interesting. Annual average precipitation in the southeast US from 1961-1990.įigure C is an image of the average number of days per year measurable precipitation falls in an area. The average annual precipitation for these states ranges from 43 inches in Virginia to 54 inches in Florida.įigure B. Figure B is a zoomed-in image of the Southeast. The Southeast has the second highest annual precipitation average of any region in the country after the northwest coast. This is why observers carefully melt the snow to get an exact measure of water content. A ratio of 10-to-1 for snow to rain is often used to estimate the water equivalent of snow (so that a 10 inch snow would equal a 1-inch rainfall) but in actuality a heavy wet snow can have a snow to water ratio of 5:1 and a very light fluffy snow in frigid weather can be more like 15:1. The values include the water equivalent of snowfall which contributes to the total precipitation an area receives each year. Annual average precipitation for the US from 1961-1990.įigure A shows the average precipitation totals for the contiguous US. Values cited in the text are calculated from precipitation averages during the years of 1895-2009 that are supplied by the SERCC.įigure A. Maps are included here for precipitation averages from the years 1961-1990 that were produced by the National Climatic Data Center. For the purposes of the information provided below, those are the states that will be discussed. The Southeast Regional Climate Center (SERCC) includes Virginia, Florida, Georgia, North Carolina, Alabama, and South Carolina as states included in the "Southeast". I should already be familiar with: Precipitation Types, Lifting Mechanisms By understanding patterns of precipitation, areas prone to flooding can be better equipped during time of need. Why do I care? Precipitation types and patterns influence the vegetation that is supported in certain areas and what types of crops can be grown. The Southeast gets an average of around 50 inches of precipitation each year, including some frozen precipitation in all areas except most of Florida and southern Georgia. The Southeast (as defined here) includes NC, SC, AL, GA, FL, and VA.