The weekend passage of a cold front delivered limited relief from the 13+-month drought to portions of the East. The heaviest rainfall, in excess of 2 inches, occurred from central and eastern Pennsylvania into New Jersey and southeastern New York. As much as 6 inches was reported in parts of New Jersey. Locally heavy amounts were also observed in the eastern Carolinas. Nevertheless, pastures remain at least 60% in very poor to poor condition as of August 15, according to USDA's National Agricultural Statistics Service (NASS), in Connecticut, Delaware, Kentucky, Maine, Maryland, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Virginia, and West Virginia. While the Eastern rains dampened dry topsoils and eased the wildfire threat, much more rain is needed to significantly dent the region's long-term drought. From Texas to the southern Atlantic Coast, meanwhile, a third consecutive week of hot, mostly dry weather further depleted topsoil moisture and severely stressed livestock, pastures, and immature summer crops. The cold front finally reached the South at mid-month, helping to lower temperatures slightly but failing to provide significant rainfall except along the southern Atlantic Coast. Farther west, cooler weather and scattered showers aided fire containment efforts in the Great Basin, where more than 1 million acres (nearly 1,625 square miles) burned between August 5-15, according to the National Interagency Coordination Center (NICC). Beneficial showers were also noted in the northern High Plains and the Northwest, while seasonal rains further eased long-term moisture deficits in the Southwest.

Palmer (long-term) Drought Index
Crop (short-term) Moisture Index
Long-Range Outlooks from the Climate Prediction Center (to be updated August 19, 1999)

The Mid-Atlantic, Northeast, and upper Ohio Valley: A cold front crossed the region on August 14, preceded and accompanied by widespread, beneficial showers. Two to locally as much as 6 inches of rain fell across parts of the northern Mid-Atlantic region, especially from central Pennsylvania to New Jersey. According to the U.S. Geological Survey (USGS), Mid-Atlantic streamflow reached a minimum prior to the front's passage on August 12, when 27% of the 220 gauging stations reported record-low flows, and another 37% had flows in the lowest 10% of historical observations for the date. By August 16, only 28% of the gauges had flows in the lowest one-tenth of historical observations for the date. Similarly, streamflow in the Ohio River Basin improved slightly, from 31% in the lowest one-tenth of all observations for the date on August 12 to 19% on August 16. Prior to the arrival of the late-week rainfall, cool air made its strongest push in recent weeks into the Northeast. In Washington, D.C., an 18-day streak (July 22 - August 8) with highs at or above 90 degrees F -- the city's longest such streak since 1988 -- ended with a high of 84 degrees F on August 9. Agriculturally, the northern Mid-Atlantic region continued to be hardest hit by the drought. Pastures were rated 100% very poor to poor in New Jersey, followed by 92% in Connecticut and 90% in Pennsylvania. Pennsylvania corn remained in the most dismal condition of the 17 major corn-producing states, with 65% of the crop rated very poor to poor. Outlook: During the next 5 days, much cooler air will overspread the region. In addition, widespread rainfall will reach the upper Ohio Valley on August 19 and the Mid-Atlantic and Northeastern States a day later. Rainfall is forecast to range from 0.50 to 2.00 inches across the region during the 5-day period. Unfortunately, relief from the extreme dryness is expected to be short-term, as near- to below-normal rainfall, accompanied by hot weather, is forecast to return during the 6- to 10-day (August 24-28) period.

The South: Extreme heat gripped the region into the weekend, when a cold front's passage provided some relief in the Southeast. In North Carolina, Raleigh-Durham (RDU) noted four daily-record highs during the week of August 8-14, including maxima of 101 degrees F on the 8th and 11th. So far this year, RDU has set or tied 23 daily-record highs. In addition, RDU's 12 days of triple-digit heat has easily surpassed the airport's previous record of 8 days, set in 1952. Farther south, six daily-record highs were set or tied during the week in Augusta, Georgia, including maxima of 103 degrees F on the 12th and 13th. Little Rock, Arkansas, recorded a high of 105 degrees F on August 11, its highest temperature since an all-time-record high of 110 degrees F on July 31, 1986. As slightly cooler air trailed the front across the South on Sunday, August 15, highs reached 87 degrees F in RDU, and 89 degrees F in Little Rock. For Little Rock, it represented the first day since July 14 that the high temperature failed to reach the 90-degree mark. Little Rock's most recent longer such streak occurred just last year, during the Southern drought of 1998 (33 consecutive days), and its longest such streak on record occurred in 1980 (57 consecutive days). As of August 16, USGS streamflow data indicated that 46% of the South Atlantic-Gulf Basin gauges were reporting flows in the lowest one-tenth of observations for the date, down from a peak of 54% on August 8. Significant late-week and weekend rainfall (in excess of 2 inches) was confined to scattered locations in the eastern Carolinas. Earlier in the week, some locally heavy rainfall also occurred from the lower Mississippi Valley eastward into Florida and extreme southern Georgia. The heat wave did not break at week's end across the South-Central U.S., where Dallas-Ft. Worth (DFW), Texas recorded its 19th consecutive day of 100-degree heat on Sunday, August 15. DFW first experienced triple-digit heat this year on July 23, but has failed the reach the plateau only twice since. Just last year, DFW noted 29 consecutive days (July 6 - August 3) with highs at or above 100 degrees F, second only to a 42-day such streak in 1980. August 15 also represented DFW's 36th consecutive day without measurable rainfall. Rainfall has also been very scarce for the past 5 weeks in a broad swath from northeastern Texas northeastward to the Ozark Plateau, including portions of eastern Oklahoma, northwestern Louisiana, Arkansas, and southwestern Missouri. Nationally, cotton rated 48% good to excellent and 20% very poor to poor on August 15, according to NASS, a change from 60% good to excellent and 12% very poor to poor on July 25. As of August 15, cotton rated 35% very poor to poor in both Georgia and South Carolina, and 31% very poor to poor in Tennessee. Among the 19 major soybean-producing states, the percentage of the crop in very poor to poor condition was highest in Georgia (51%), followed by South Carolina (47%), Tennessee (41%), and Alabama (40%). Outlook: Unfavorably dry weather will continue across north-central Texas, despite a gradual return to normal temperatures during the next 10 days. Elsewhere in the region, occasional rain and cooler weather will provide varying degrees of relief from recent extreme heat and dryness. In particular, locally heavy rainfall (1 to locally more than 3 inches) is forecast to develop along the Atlantic and Gulf Coasts during the next 5 days. A cool, wetter-than-normal pattern is forecast to expand across the Southeast from August 24-28. In addition, the 6- to 10-day outlook calls for above-normal rainfall across southern Texas.

The central Plains, mid-Mississippi Valley, and eastern Corn Belt: Heat also crept into the central Plains and the mid-Mississippi Valley last week, but remained just south of the primary Corn Belt, where extreme highs generally ranged from 80 to 95 degrees F. Despite the favorably cool Midwestern weather and late-week showers, soil moisture remained deficient across most of the southeastern Corn Belt. Little significant rain fell during the week south of a line from southern Nebraska to central Indiana. Corn and soybean conditions stabilized across the Midwest, following a month of declines. Among the Midwestern states, the percentage of the crop in very poor to poor condition was highest in Missouri (33%), Indiana (28%), and Ohio (27%). In southern Missouri, Joplin's high of 104 degrees F on August 12, was its highest reading since a high of 108 degrees F on July 30, 1986. A day earlier, Wichita, Kansas, recorded 106 degrees F, its highest temperature since June 20, 1998. As alluded to in an earlier paragraph, mid-July to mid-August rainfall was less than 25% of normal in many areas from the southeastern Plains to the Tennessee and mid-Mississippi Valleys. In the Tennessee Valley, 33% of USGS's 37 gauges were reporting streamflow in the lowest 10% of observations for August 16, up from none as recently as July 26. Outlook: During the next 10 days, sporadic showers will provide near- to below-normal rainfall across the region, accompanied by near- to above-normal temperatures. As a result, additional topsoil drying is likely in some areas, especially in the mid-Mississippi Valley.

The Southwest, Great Basin, Intermountain West, and interior Northwest: For the week ending August 14, temperatures averaged 3 to 10 degrees F below normal in California and the Great Basin. Scattered showers accompanied the cool weather in many areas, including northern California, helping to curb the wildfire threat. Despite the late-week improvement, wildfires burned more than 1 million acres (nearly 1,625 square miles) in the Great Basin between August 5 and 15. As a result the nation's year-to-date wildfire acreage through mid-August reached 3.85 million acres (more than 6,000 square miles), 173% of the 10-year average. More than three-quarters of the acreage has burned in the three regions: the western Great Basin (34% of the total), Alaska (27%, mostly during July), and the Southern (17%, mostly during the spring). On August 11 in Idaho, measurable rain (0.26 inch) fell in Boise for the first time since 0.03 inch fell on June 15, ending a 56-day dry spell. Boise's longest dry spell on record spanned 109 days from May 30 to September 15, 1919. Farther east, Great Falls, Montana, collected 1.03 inches of rain on August 11, the heaviest one-day rainfall there since 1.88 inches accumulated on May 30, 1998. Similarly, Cut Bank, Montana, netted 1.79 inches on the 11th, its greatest single-day sum since 2.09 inches fell on June 6, 1995. Despite the showers, pastures remained 54% very poor to poor in Washington and 32% very poor to poor in Oregon. Meanwhile, seasonal showers returned to the Southwest on August 14, following a brief lull in activity. Since early July, frequent monsoon showers have significantly dented long-term moisture deficits in the Southwest. Outlook: Very hot, dry weather is forecast to develop across California and the Northwest. In the latter region, the heat and dryness will partially offset the beneficial effects of recent rainfall. In addition, the conditions will increase the threat of wildfire activity. Agriculturally, the hot, dry weather will spur the development of cotton and other summer crops in California, and favor small grain harvesting in the Northwest. Meanwhile in the Southwest, monsoon showers during the next 10 days will further reduce long-term moisture deficits.
Author: USDM