This Week's Drought Summary (8/30)
Frontal systems brought thunderstorms and some heavy rainfall to parts of the Plains, the Midwest, and the South. While rainfall was enough to reduce or alleviate drought conditions in some places, such as Arkansas, northern Missouri, Kansas, Wisconsin, and Michigan, it wasn’t enough in other areas, such as southwestern Missouri and Idaho, as deficits and impacts remain. This past week saw temperatures slightly below average across much of the nation, with areas of eastern Montana and western North Dakota 4-8 degrees F cooler than normal, which helped to slow, but not halt, drought development. Conversely, parts of the Southwest, Texas, and areas along the eastern northern tier of the U.S. were well above their average temperatures. In Texas, notably, the widespread heat exacerbated evolving and ongoing drought.
Very few changes were made to the depictions in the Northeast this week. Recent wet conditions have relieved shorter-term dryness in most places except for the areas that were already experiencing abnormal dryness (D0) and moderate drought (D1), which generally remained unchanged. The area of D0 in southeastern Massachusetts was reduced, reflecting normal local stream flows and groundwater levels. No changes were made this week to the depictions in the rest f the Northeast.
Abnormally dry (D0) conditions along the central North Carolina/South Carolina border expanded southward into the central part of South Carolina, where the region has received limited amounts of rainfall over the short and long term, including less than 1 inch over the past couple of weeks. As noted by a local hydrologist, “while the dry weather has been good for harvesting crops, such as corn, it is starting to impact other crops such as grasses. Stream flows are also down in this portion of the state, especially along the Lynches River Basin.” In northern Alabama, some broad areas received no rainfall and continued to dry, albeit with cooler-than-average temperatures which helped to moderate the summer impacts. Stream flows were below average from Sumter and Pickens through northern Tuscaloosa to Jefferson Counties. As such, a few areas of D0 were expanded in central and northern parts of the state, while a lone pocket in Elmore County improved to normal in the southeast, as did western Baldwin County in the southwestern corner. No changes were made this week to the depictions in Virginia, Georgia, and Florida.
Lack of precipitation led to more short-term deficits and thus more widespread abnormal dryness (D0) across northern Mississippi into southwestern Tennessee. To the west, Arkansas saw widespread improvements continue this week due to recent record rainfall and continuing precipitation. The only part of the state that continued to see drought conditions is in the southwest corner, which has missed out on most of the precipitation. Neighboring northwest Louisiana actually saw moderate (D1), severe (D2), and extreme (D3) drought conditions expand a bit. Eastern Louisiana has seen comparatively more rainfall, and D1 conditions improved some near the southwestern Mississippi border. Oklahoma also saw improvements, including the southwest where exceptional drought (D4) improved to D3 and in the northeast, although the area of severe drought did expand a bit into Washington County. As noted in an impact report from a local producer, “over the last 180 days, which is not only the entire growing season but also is the base for cool and warm season forage, we have been considerably below normal in precipitation.That lack of precipitation has impacted us in several ways including the failing of crops, the decline in hay production by nearly half and the reduction in our normal daily weight gain in our cattle due to the lack and decline of forage”. In Texas, with the exception of the northern Panhandle, it was hot and dry, with temperatures climbing into the upper 90s and 100s (F) in many places. In southern Texas, McAllen broke temperature records throughout the week, reaching highs of 104 to 106 degrees F each day. This area has received only about 3% of its typical rainfall over the past couple of months. The Gulf Coast has had almost no rain since a major rainfall event in mid-June. Overall, abnormal dryness and drought conditions remained steady or degraded across most of the state. Perhaps most notably, D3 pockets expanded in several areas.
Drought conditions in Missouri improved quite a lot this week, particularly in the north and northeast where there were widespread heavy rains. One small region around Knox and Lewis Counties saw a 2-category improvement where rainfall was particularly heavy (4-6 inches or more). Most of central and southern Arkansas remained status quo as effects linger here, although extreme drought (D3) regions did improve to severe (D2). Abnormally dry (D0) and moderate drought (D1) conditions were reduced in regions across northern Minnesota, central Wisconsin and central Michigan where a series of heavy rainfall events reduced or eradicated dryness in parts of these states. In the area encompassing La Crosse to Adams Counties in Wisconsin, 6 to 11 inches of rain fell in a 12-hour period. Wetsby, in Vernon County, recorded a (preliminary) 9.98 inches from 8 PM Monday night through 7 AM Tuesday morning, marking its record highest 1-day rainfall total, breaking the previous record of 7.17 inches on August 18-19, 2007. Additionally, a record flood wave moved down the Kickapoo River. The flood wave was so high that it knocked out at least three river gauges. In this region, dryness and drought conditions have been completely eradicated. To the southeast, the D0 footprint shrank in northern Indiana where the area received more than twice its normal rainfall over the past week. Unfortunately, northern Ohio mostly missed out on the precipitation and a new region of D0 was introduced in the northeastern corner of the state. There are reports that trees in that area are dropping leaves early due to water stress. No changes were made this week to the depictions in Iowa, Illinois, and Kentucky.
Conditions along parts of the northern tier of the U.S. bordering Canada continue to deteriorate. This week the remaining area of normal conditions from northwestern North Dakota into northeastern Montana (see West for more information about Montana) was degraded to abnormally dry (D0). The area has missed out on all the rains from the last few storms.and the soil has been very dry, dating back to the previous year’s drought. In Kansas, conditions improved enough to contract D0 in the central and south central part of the state eastward. In east central Kansas, some areas of moderate (D1), severe (D2), and extreme (D3) drought also improved. However, there are still longer-term deficits and impacts remaining in the state. In eastern Colorado, D3 was improved to D2 in Crowley County and northern Otero County, where there were a few isolated thunderstorms in the area over the past week. D2 improved to D1 in southeast Las Animas County and western Baca County, where up to 2 inches of rain fell. Eastern Baca and Prowers Counties also received up to 2 inches of rain, allowing for improvement from D1 to D0. No changes were made this week to the depictions in South Dakota, Nebraska, and Wyoming.
Similar to North Dakota, some areas across the northern tier of Montana continued to deteriorate. The area of abnormally dry conditions (D0) was expanded eastward to connect with the dry area in North Dakota. Also along the northern tier, the two severe drought (D2) areas expanded slightly westward. However, improvements were made in southern Beaverhead, Madison, Gallatin, and Park counties in the southwest where precipitation has been more abundant. Conditions there are now considered normal. Drought continues to plague Oregon and grow worse in areas. This week the area of D2 expanded through most of the southern part of the state. In Utah, D2 improved to moderate drought (D1) across eastern Washington County and western Kane and Garfield Counties. This area has received its typical moisture since the beginning of July. No changes were made this week to the depictions in Washington, California, Nevada, Arizona, and New Mexico. Additionally, no changes were made to the depiction in Idaho, but, as an aside, some precipitation did provide enough relief to Boise to make the region smoke free for the first time in a couple of weeks. Conditions still remain dry.
Alaska, Hawaii, and Puerto Rico
Hurricane Lane dumped a tremendous amount of record-breaking rainfall over parts, but not all, of Hawaii this past week, and not necessarily in agriculturally-related drought areas. As such, several areas of abnormally dry (D0) conditions improved to normal. Over Kaua’i, the small area of abnormally dry (D0) conditions improved to normal as it did on Lanai and Kaho’olawe. Over Maui, where windward rainfall was excessive in some areas, the D0 area was reduced toward the southwest. Notably, the area of severe drought (D2) in west Maui is consistent with the large brush fire that went out of control when Lane approached. No changes were made here. Over the Big Island, the 40-50 inch and higher rainfall totals fell mainly in the existing drought-free areas. The area of D0 was scaled back in the west and most was removed on the east side. Local experts continue to monitor the islands to assess how the rainfall impacts pasture conditions. No changes were made to the depictions in Alaska or Puerto Rico this week.
Over the week beginning Tuesday August 28, the Midwestern states are expected receive the highest precipitation, including northern Missouri, which as been plagued by extreme (D3) and exceptional (D4) drought conditions. Temperatures are forecast to reach the 90s (F), and even the 100s in places, across most of the central and southern tier of the U.S.. The Northeast will begin with temperatures in the 90s, but is forecast to cool into the 70s and 80s by the end of the Labor Day weekend. Daytime highs in the 70s and 80s are also forecast across much of the northern tier. Southern Florida and the central Appalachians are forecast to receive up to 3 inches of rainfall, while most of the West and the High Plains are expecting a quarter of an inch or less, with no rain forecast for much of the region. Looking further ahead at NOAA’s Climate Prediction Center (CPC) 6-10 day Outlook (September 2-6), the probability of dry conditions is highest in the Northwest from southern Alaska into Oregon, northern Idaho, and western Montana., while wet conditions are most likely across the Midwest, Mid-Atlantic, and Northeast. During this period, below-average temperatures may be seen over the much of the forecasted wet areas -- upper Northwest into Alaska -- while above-average temperatures are forecast for most of the contiguous U.S., especially the eastern half. Looking two weeks out (September 4-10), the likelihood of above-average temperatures is highest in central to southern California and in the eastern third of the contiguous U.S. The probability of below-average temperatures is highest across most of Alaska and Montana. The probability of above-average precipitation is highest over a swath of the central U.S. stretching northeast from New Mexico to eastern North Dakota, Minnesota, and western Wisconsin, with the highest probability of dryness now expected across Washington, Oregon, and Idaho.