Thursday, July 10, 2014

The US Drought Monitor

The Monitor says: During the past 7-days, heavy rain (greater than 2 inches) fell in parts of the Northeast, eastern North Carolina, the Florida peninsula, the Great Lakes region, northern and central portions of the Mississippi Valley, and parts of the southern Great Plains and Southwest. An unusually strong cold front for early July moved across the eastern contiguous U.S. early in the period, approaching the Atlantic Seaboard as a Category-2 hurricane (Arthur) was moving across the Outer Banks of North Carolina. As the hurricane accelerated to the northeast, it gradually became incorporated into the larger-scale cold front and associated low pressure system, resulting in heavy rains across portions of the Northeast. Meanwhile, the onset of the Southwest summer monsoon across Arizona and New Mexico brought moderate precipitation (0.5-2.0 inches) to portions of the Four Corners region.

...The Southwest and California: The initial moisture surges of the summer monsoon commenced on schedule across Arizona and New Mexico this past week. River Forecast Center rain gauge data depicts a few widely scattered 2-3 inch rainfall amounts, but much of Arizona and New Mexico reported moderate amounts of precipitation (0.5-2.0 inches). In northwest New Mexico, which missed out on the significant rainfall this past week, extreme drought (D3) was expanded eastward across all of San Juan County, and continuing across the western one-third of Rio Arriba County. In south-central Colorado, a one-category downgrade was made, based on very dry short-term SPI’s (less than -1.5), and on VIC soil moisture model considerations. In southeast Colorado (western Kiowa County), conditions are still deplorable with little vegetation on the ground, and there is also the occasional dust storm kicking up. In Otero County, where better moisture conditions exist, a one-category improvement was made to the depiction. In Baca County, a one-category improvement was rendered based on June-early July precipitation, SPI values near and slightly above zero, and reports that the wheat harvest is looking better than it has in this county for several years. No other modifications were made throughout the Southwest or California. As an important side note, according to the Federal Bureau of Reclamation, southern Nevada’s Lake Mead is expected to fall this week to its lowest level since 1937, when the manmade lake (the largest reservoir in the United States) was first being filled.....

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