U.S. Drought Monitor Report for the Week Ending Oct. 23 (Text)
Following is the text of the weekly U.S. Drought Monitor as released by the National Drought Mitigation Center in Lincoln, Nebraska:
National Drought Summary -- October 23, 2012
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/.
Weather Summary: A slow-moving storm resulted in several days of cool, cloudy, showery weather in the Midwest, replenishing soil moisture. Rain also extended southward through the Mississippi Valley. Mostly dry weather prevailed, however, across the lower Southeast. One exception to the dry pattern was southern Florida, where locally heavy showers occurred. Farther west, mostly dry weather accompanied a warming trend across the Plains. Significant precipitation was limited to the eastern Dakotas, while the High Plains’ hard red winter wheat belt received little or no rain. As a result, soil moisture shortages continued to limit wheat emergence and development across the northwestern half of the Plains. In addition, mid- week wind gusts locally in excess of 70 mph raised dust and temporarily closed major roadways across parts of the Plains. On the southern half of the Plains, however, a combination of warmer weather and previous soil moisture improvements promoted wheat growth. Elsewhere, dry weather from southern California to the central and southern Rockies contrasted with substantial precipitation in northern California and the Northwest.
The East: Heavy rain in the northern Mid-Atlantic region brought further reductions in the coverage of abnormal dryness (D0) and moderate drought (D1). Farther south, however, little or no rainfall occurred. As a result, drought coverage began to gradually increase in the interior Southeast, including parts of Alabama and Georgia. On October 21, USDA rated topsoil moisture 49% very short to short in Georgia and 38% very short to short in South Carolina.
The Mid-South: Spotty showers provided some additional drought relief in a few areas, including parts of Missouri and western Tennessee. Meanwhile, drought coverage increased slightly in areas bypassed by rain, such as a few locations in northern and western Arkansas.
The Midwest: The second significant rainfall event in less than 2 weeks provided broad drought relief. In addition, an increasing area of the Midwest is being affected primarily by only long-term drought (L), rather than both short- and long- term drought (SL). The most recent rainfall event was heaviest in the states bordering Lake Michigan, while locally heavy showers and thunderstorms also dotted Missouri, Iowa, and the far upper Midwest (the eastern Dakotas and western Minnesota). By October 21, topsoil moisture had improved dramatically, with less than one-fifth rated very short to short in Indiana (13%) and Michigan (16%).
The Plains: From October 16-18, a low-pressure system over the Midwest generated high winds across the nation’s mid-section. On the 18th, gusts were clocked to 74 mph in Pierre, South Dakota, and 70 mph in Broken Bow, Nebraska. Two days earlier in Montana, Havre (62 mph on October 16) had noted its highest October gust since 1999. The wind raised dust, temporarily closing several major roadways--including parts of I-80 in Nebraska--and triggering several chain-reaction automobile accidents. In some of the nation’s hardest-hit drought areas, winter wheat has been very slow to emerge this fall. For example, only 13% of South Dakota’s crop had emerged by October 21, versus the 5-year average of 80%. The wheat emergence situation is only slightly better in Montana (36 vs. 67%), Nebraska (58 vs. 87%), and Colorado (66 vs. 82%). On October 21, Nebraska continued to report the nation’s worst rangeland and pasture conditions (97% very poor to poor; tied with California). Behind Nebraska were Kansas (80% very poor to poor), South Dakota (80%), Montana (77%), Oklahoma (71%), North Dakota (59%), and Texas (41%). Meanwhile, the storm that produced the high winds also brought much-needed moisture to the eastern Dakotas. On the strength of heavy rain, extreme drought (D3) was eradicated from eastern North Dakota. Some of the greatest improvements occurred in the Red River Valley of the North.
The West: The most impressive precipitation of the season overspread northern California, the Pacific Northwest, and the northern Rockies. The precipitation also helped to establish high-elevation snow packs, with 1 to 2 feet reported at some locations in the Cascades and Sierra Nevada. The heaviest rain and snow fell in drought-free areas, although precipitation chipped away at dryness and drought in a few areas. Meanwhile, dry conditions prevailed across the southern half of the West. In fact, extreme drought (D3) was expanded slightly in northern Utah based on continuing long-term precipitation deficits. On October 21, Utah’s stock water supplies were reported by USDA to be 56% very short to short. Rangeland and pasture conditions remain abysmal in much of the West, with nine of eleven states reporting more than half rated very poor to poor. On October 21, California (97% very poor to poor) matched Nebraska for the nation’s worst rangeland and pasture conditions, followed by Colorado (86%), Wyoming (86%), New Mexico (84%), Nevada (82%), Montana (77%), Utah (56%), Idaho (54%), Oregon (53%), Arizona (49%), and Washington (35%).
Hawaii, Alaska and Puerto Rico: Currently, there is no drought- -only abnormal dryness (D0)--depicted in Alaska and Puerto Rico, where no changes were introduced. Alaskan dryness is confined to the northern part of the state. Meanwhile in Hawaii, October has featured very dry conditions. At Hawaii’s major airport observation sites, October 1-23 rainfall ranged from 0.01 inch (1% of normal) at Kahului, Maui, to 2.35 inches (36%) at Hilo, on the Big Island. Moderate, severe, and extreme drought (D1, D2, and D3) covers more than half of Hawaii, with some of the driest conditions noted in leeward areas. On October 21, Hawaiian topsoil moisture was reported to be 78% very short to short, and irrigation was being used in many areas to maintain favorable crop conditions.
Looking Ahead: During the next 5 days (October 25-29), the complex interaction between Hurricane Sandy, a cold front crossing North America, and a blocking high-pressure system over the northern Atlantic Ocean will result in a high-impact weather event in the eastern U.S. Coastal highlights will include large waves and beach erosion. Inland--especially in the Northeast-- conditions developing during the weekend and persisting well into next week should include multiple days of high winds and heavy rainfall. Precipitation may eventually change to snow in parts of the Appalachians. Farther west, rainfall associated with the cold front could total 1 to 2 inches in the Midwest. Similar precipitation totals should also occur during the next 5 days in the Northwest. In contrast, dry weather will prevail from southern California to the southern Plains. Cold air will gradually engulf much of the nation, although temperatures will rebound to above-normal levels in the West by early next week.
The NWS 6- to 10-day outlook for October 30 - November 3 calls for below-normal temperatures across the eastern half of the U.S., while warmer-than-normal weather will prevail from the Pacific Coast to the High Plains. Meanwhile, near- to below- normal precipitation across the majority of the U.S. will contrast with wetter-than-normal conditions in the Northeast and Northwest.
Author: Brad Rippey, U.S. Department of Agriculture
Dryness Categories D0 ... Abnormally Dry ... used for areas showing dryness but not yet in drought, or for areas recovering from drought.
Drought Intensity Categories D1 ... Moderate Drought D2 ... Severe Drought D3 ... Extreme Drought D4 ... Exceptional Drought
Drought or Dryness Types S ... Short-Term, typically <6 months (e.g. agricultural, grasslands) L ... Long-Term, typically >6 months (e.g. hydrology, ecology)
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