This Week's Drought Summary (10/8)
Temperatures for the week were below normal over much of the Plains, Midwest, South, Southeast and Mid-Atlantic, with departures of 5-10 degrees below normal for many locations. The West continued to be warm with temperatures near normal to slightly above through the Rocky Mountains and 5-10 degrees above normal over the West Coast. Temperatures in New England were also slightly above normal, with the greatest departures in Maine. Below-normal precipitation dominated almost the entire country. Precipitation amounts were greatest over the eastern seaboard, with the Northeast recording the most rain. Almost no precipitation was recorded in the western two-thirds of the country. In the next several days, eyes will be on Hurricane Delta and where it will make landfall along the Gulf Coast. Current projections are taking the storm ashore in Louisiana.
The greatest rains fell from northern Virginia into central Pennsylvania and portions of New England. Coastal areas did not fare as well and conditions continued to dry out there. Temperatures ranged from 6-8 degrees above normal in Maine to 2-4 degrees below normal in western Pennsylvania. Where the greatest rains fell, abnormally dry conditions were improved over eastern New York, southern Vermont and into extreme western Massachusetts and Connecticut. Extreme drought continued to spread into more of southern New Hampshire, eastern Massachusetts and Connecticut. A new area of extreme drought was also introduced in western Maine, as even with the recent precipitation, indicators were still the driest in this region. Abnormally dry and moderate drought conditions were expanded over northern and western New York, eastern and western areas of Pennsylvania and into northern West Virginia.
Cooler than normal temperatures dominated the region this week with departures of 6-9 degrees below normal. Most areas were dry this week, but coupled with the cooler temperatures, development of dryness or drought conditions was minimal. In the short term of the last 60 days or so, there are pockets of dryness developing, and abnormally dry conditions were expanded in southeast Georgia and also western Alabama this week. The impact of Hurricane Delta will need to be watched going forward to determine how quickly other areas could develop into the abnormally dry status.
A mix of precipitation over the eastern portions of the region and into Michigan but dry over much of the rest of the area was the theme for this week. Temperatures were well below normal in the region, with most areas 6-8 degrees below normal for the week. Abnormally dry and moderate drought conditions were expanded this week in portions of Ohio, Indiana and southern Illinois. Portions of northern Illinois were reevaluated based on recent precipitation, and some improvements were made to the moderate drought and abnormally dry conditions based on the short-term precipitation. Areas of southwestern Missouri continue to dry out and a new area of extreme drought was added this week while areas of moderate and severe drought also expanded. Northwest Iowa also saw degradation this week as severe drought was expanded and a new pocket of extreme drought was introduced. Abnormally dry and moderate drought conditions were also expanded over southeast and northeast Minnesota, northwest Minnesota, and portions of western Wisconsin.
Cooler than normal temperatures dominated the eastern half of the region with departures of up to 6-8 degrees below normal while the western half was warmer than normal with departures of 4-6 degrees above normal. Precipitation was almost none existent in the region for the week, with only a few areas of light showers in portions of South Dakota and Nebraska. Moderate drought and abnormally dry conditions were expanded in portions of eastern North Dakota. In eastern, southwest and central Nebraska, severe drought expanded along with some expansion of moderate drought. Moderate, severe, and extreme drought also expanded in western Nebraska as the entire state continues to dry out. In South Dakota, moderate drought was expanded in the northwest while severe drought was expanded in the southeast. A new area of extreme drought was also introduced in southeast South Dakota. Extreme drought was introduced in far southwest South Dakota while moderate drought also expanded to the east. In northeast Wyoming, moderate drought expanded while severe drought expanded slightly in the southeast. Eastern Colorado had a large expansion of extreme drought conditions while severe drought expanded in the northeast.
Although most of the region received no precipitation during the week, cooler temperatures helped to reduce the amount of drought expansion this week as temperatures were generally 3-6 degrees below normal. Abnormally dry conditions and moderate drought were expanded over northern Oklahoma this week while extreme drought expanded over the southwest portions of the state. Abnormally dry conditions expanded over portions of southern Louisiana and eastern Mississippi while moderate drought and abnormally dry conditions expanded over northwest Arkansas. Texas continued to see conditions deteriorate over the panhandle and areas of the south Texas Plains and into the Hill Country.
Hot and dry continues to be the theme of the region and also the monsoon season that was minimal at best, all of which is providing the conduit for continued deterioration in the region. Over the last 6 months, Arizona and California have had their warmest April–September period ever in 126 years, with New Mexico and Nevada the 2nd warmest. During that same 6-month period, Utah and Arizona have also had their driest period ever, with New Mexico having their 2nd and Colorado their 3rd driest. In Arizona, the new established record for statewide precipitation was greater than 2 inches drier than the previous record. During the current week, temperatures were warmest along the coast, where departures were 5-10 degrees above normal for the week. Drought intensified and expanded over southeast Montana and into northwest Wyoming where moderate, severe, and extreme drought all increased in coverage. A new area of moderate drought was introduced in southwest Wyoming and into southeast Idaho. Western Colorado and eastern Utah had large expansions of exceptional drought, and this also went into northwest New Mexico. Extreme drought also expanded over north central Colorado. Western and northern New Mexico as well as northeast Arizona had severe and extreme drought expand while a new area of extreme drought was introduced in eastern portions of New Mexico. In southern Arizona, extreme and exceptional drought also expanded in coverage. In Idaho, abnormally dry conditions and moderate drought expanded over the southeast and southwest portions of the state as well as into southeast Oregon. Central and northeast Oregon also had expansion of severe and extreme drought this week.
Alaska, Hawaii, and Puerto Rico
There were no changes in Hawaii and Puerto Rico this week. In northern Alaska, areas of abnormally dry conditions were reduced in response to well above normal precipitation during September.
This week the Republic of Palau remained free of dryness and received ample rainfall with 5.49 inches at Palau’s International Airport and 4.66 inches at the COOP station for the week ending Oct. 6. September precipitation totaled 7.28 inches at the airport.
The Mariana Islands also had a wet week, remaining free of dryness, with rainfall exceeding the 1 inch weekly minimum needed. Saipan received 1.64 inches for the week and 7.46 inches for the month of September. The ASOS station received 4.97 inches for the week, while the NPS station received 3.45 inches. Rainfall in Rota was 8.42 inches for the week after receiving 17.90 inches in September. Guam received 3.57 inches for the week and 10.96 inches in September.
Most islands in the Federal States of Micronesia received more than 2 inches for the week, including Chuuk with 5.77 inches, Kosrae with 4.22 inches, Nukuoro with 5.02 inches, Pingelap with 2.59 inches, Pohnpei with 4.49 inches and Ulithi with 2.97 inches. Woleai, Yap, Lukunor and Fananu were drier, each receiving less than an inch, but received enough rain in previous weeks to remain free of dryness. Kapingamarangi remained at D3 and received just 0.43 inches for the week and only 0.86 inches for September, with 0.40 falling on Sept. 2. Three and a half of Kapingmarangi’s water reserve community tanks had been used, leaving two and a half tanks of water, enough for just over a month. Vegetation withered with most coconut trees turning yellow and containing less coconut juice in the fruits. Most other vegetation, including banana trees and taros, have turned brown, and taro patches have dried up. A relief requested was submitted by the Chief Magistrate office of Kapingamarangi to the Pohnpei State Disaster Office, requesting drinking water supplies and other food products.
Most locations in the Marshall Islands exceeded the weekly minimum of 2 inches of precipitation to meet most water needs. Ailinglaplap, Kwajalein, Majuro and Mili all received more than 2 inches and remained free of dryness. Jaluit remained in D0, having received 1.53 inches for the week. Wotje was at D2, but was improved to D1 after 4.70” fell during the week.
Locations in American Samoa remained free of dryness as Pago Pago received 3.19 inches and Toa Ridge received 2.00 inches.
Radar-based estimates of rainfall for the 7 days ending at 12z on Tuesday in the U.S. Virgin Islands indicated rainfall of at least 2 inches across nearly all of St. Thomas and St. John, while St. Croix received at least an inch on the western two-thirds of the island, while the eastern third was drier.
St. Thomas became free of abnormal dryness. Precipitation at Cyril E. King AP was 1.64 inches, or above normal. The CoCoRaHS stations reported rainfall ranging from 0.53 to 2.06 inches for the week. SPI values indicated drought-free conditions at 1 and 3 months, but abnormal dryness at 6, 9 and 12 months.
Adequate rainfall allowed St. John to emerge from abnormal dryness this week. The CoCoRaHS stations reported 1.51 to 2.24 inches. SPI values for Windswept Beach at 1 and 3 months were nearing that of abnormal dryness, but pointed toward abnormal dryness to moderate drought at 6, 9 and 12 months.
St. Croix went from D0 to drought-free this week as rainfall at Henry Rohlsen AP amounted to 1.10 inches, which was about normal. The CoCoRaHS stations reported rainfall ranging from 0.81 to 2.74 inches. SPI values for the airport were drought-free at 1 and 3 months, but indicated near abnormal dryness to moderate drought at 6, 9 and 12 months.
Over the next 5-7 days, it is anticipated that precipitation chances will be greatest in the East and Southeast, with the greatest precipitation associated with Hurricane Delta. A more active pattern over the Pacific Northwest will likely bring precipitation into that area and into the northern Rocky Mountains. Areas of the northern Plains are also anticipating less than an inch of precipitation. Temperatures will be above normal for almost the entire country, with portions of the Plains having departures of up to 12 degrees above normal.
The 6-10 day outlooks show the greatest probabilities to record above-normal temperatures are along both the West and East coasts as well as the Northeast, with below-normal chances of above-normal temperatures in Alaska. The precipitation outlook has above-normal chances of below-normal precipitation over the western half of the United States and above-normal chances of above-normal precipitation over much of the South, Midwest, and Mid-Atlantic and into the Northeast.