As we leave July and head into August, let’s take a look at rainfall so far this summer season across the lower 48 states. The graphic below shows the percentage of total rainfall as compared to 30 year normal values over the past two months.
Any green, blue or purple colors indicate above normal precipitation. Light yellow represents areas receiving 90 percent of normal precipitation. Areas highlighted by brighter yellow, orange or red indicate areas that have received below normal amounts of precipitation.
It is easy to see from a quick glance at the map that most of the country from the east slopes of the Rocky Mountains to the Midwest and east has received adequate precipitation over the past two months. Conversely, the far west and Great Basin states have suffered through a dry past 60 days. The worst of the dryness has been hitting California, the Pacific Northwest and Great Basin. There has been a very nice increase in precipitation across some portions of the Southern Plains and Rockies (New Mexico and portions of Texas). Many areas of the central plains have also received very good precipitation over the past two months (especially Nebraska, Kansas, Oklahoma and South Dakota).
Close to normal or above normal precipitation has also occurred in the Corn Belt and Midwest.
The outlook for August continues to show that many of the same trends will continue (cooler and wet from the Rockies and points east and dry and warmer in the far west).
In the longer term there is hope for the far west. The latest long range models continue to suggest increased precipitation chances for the far west as we head into the fall season. The chart below shows enhanced precipitation chances in the far west and southwest in September, October and November (light green) as a weak to moderate El Nino develops.