Drought Monitor 3 May - Continuous Level 3 & 4 Drought Now Reaches From S. Arizona To Arkansas

National Drought Summary -- May 3, 2011

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilized include the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14 Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast web page used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

Southeast: While an historic tornado outbreak and areas of flooding rainfall slammed areas to the northwest and north, the areas of dryness and drought from Alabama eastward to the central and southern Atlantic coast generally received only light rainfall, maintaining or worsening conditions. Only parts of central Georgia, northern Florida, and southeasternmost Florida recorded over an inch of rain, improving D1 to D0 in a small part of central Georgia. Elsewhere, moderate drought was extended from the central Carolinas eastward to the Atlantic coast, and deteriorating short-term conditions led to the expansion of abnormal dryness and the introduction of an area of moderate drought in southeastern Virginia. Elsewhere, the status quo was maintained. Some areas along and near the northeastern Gulf coast have received 12 to 20 inches less than normal rainfall over the past 6 months, and deficits of 6 to 12 inches affect many areas farther northeast thru the southern Atlantic coast into southeastern Virginia.

Plains and Lower Mississippi Valley: Heavy rainfall from last week’s historic storm system impinged on the northern tier of the dry areas from eastern Oklahoma through northern Alabama, with significant precipitation extending as far south as northern Louisiana and northeastern Texas. As a result, dryness and drought classifications improved by 1 to locally 2 categories throughout this region. The areas of dryness and drought that recorded the most rainfall extended from southeasternmost Oklahoma through most of central and southern Arkansas and across northern Mississippi, where totals exceeded 5 inches in many areas. Parts of the adjacent areas farther south and southwestward through north-central Texas reported numerous amounts in the 2 to 5 inch range. Many of these areas also saw drought improvement into the D0 to D2 range, although D3 was maintained through northern Louisiana and adjacent areas where dry conditions have been observed for a considerably longer period of time. Other areas declining into D3 or D4 included relatively small swaths of central and northwestern Texas, and part of east-central New Mexico. Finally, a dry week and increasing short-term moisture deficits prompted expansion of D0 and D1.

The remaining areas along the central Gulf coast westward through most of Texas and eastern New Mexico, and northward through the central Plains, reported only light precipitation, if any. As a result, dryness and drought either persisted or intensified. Of note, a large area from western Texas into southeastern New Mexico deteriorated into the most severe D4 category. Most of this region has only received about 10 percent of normal precipitation over the last six months. In addition, D4 was introduced in parts of the Oklahoma Panhandle and adjacent areas where again 6-month totals were only about 10% of normal amounts. Other areas declining into D3 or D4 included relatively small swaths of central and northwestern Texas, and part of east-central New Mexico. Finally, a dry week and increasing short-term moisture deficits prompted expansion of D0 and D1 from central Kansas northward through central Nebraska.

Much farther north, recent precipitation eliminated the moderate drought that had covered parts of the northern Great Lakes region and northeasternmost Minnesota, but was insufficient to affect the extent of abnormally dry conditions.

Rockies and Southwest: Only scattered light precipitation fell on the region, maintaining or worsening dryness and drought classifications in the region. D2 and D3 conditions expanded in the northeast quarter of New Mexico and the southeast quarter of Arizona due to slowly declining surface moisture conditions.

Hawaii, Alaska, and Puerto Rico: Another week of moderate to heavy precipitation in the former D0 areas of Puerto Rico eliminated abnormal dryness throughout the Commonwealth.

Although precipitation has recently been observed across southern Alaska, continuing deficits on 90-day to 1-year time scales led to the expansion of D0 throughout southern coastal regions of the state, including the Panhandle. In contrast, a re-assessment of conditions farther north led to the removal of abnormal dryness across the northern tier of the former D0 region.

One to locally over three inches of rain fell along the southeastern tier of the Big Island, but lesser amounts fell on other areas of dryness and drought. What rain fell was not enough to change the classifications of dryness and drought that persist over the southeastern half of the state.

Looking Ahead: During May 5 – 9, 2011, light to locally moderate rain is forecast across North Carolina and Virginia, the Gulf coasts of Texas and Louisiana, through parts of Kansas and Nebraska, and across the northern Great Lakes region. None or very little is anticipated through the remaining areas of dryness and drought in the contiguous 48 states.

The outlook for May 10 – 14, 2011 brings enhanced chances for above-normal precipitation through the dry areas in Arkansas and across the northern Great Lakes, but in most areas of dryness and drought in the continental 49 states, near or below normal precipitation is favored.

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