This U.S. Drought Monitor (USDM) week saw improvement in drought-related conditions across areas of the West, Lower Midwest, Northeast, and the South. On the map, widespread improvements were made in drought-affected areas across Arizona as well as in other areas of the Desert Southwest including western New Mexico and southern Utah. In California, storms during the past few weeks, in addition to an overall wetter pattern in recent months, have continued to help improve conditions leading to removal of areas of drought in Southern California. Since October 1st, numerous locations in California, southern Nevada, and Arizona have received record to near-record precipitation accumulations including Santa Barbara, California (+8.2-inch departure from normal), Ontario, California (+4.11 inches), Las Vegas, Nevada (+2.08 inches), and Flagstaff, Arizona (+5.71 inches). In the Pacific Northwest, drier-than-normal conditions have prevailed (past 30-days) across areas of the region including central and eastern Oregon, southern Idaho, and southwestern Montana. Moreover, snowpack conditions across the Pacific Northwest continued to lag behind normal levels. In the Lower Midwest (Missouri) and areas of the South (Texas), widespread improvements were made in response to rainfall events during the past week. In areas of the Upper Midwest (Michigan, Wisconsin), exceptionally dry conditions have prevailed during the past 60-day period with numerous locations observing record to near-record dryness. In the Southeast, warm and dry conditions continued leading to expansion and intensification of drought conditions in the Florida Panhandle, southern Alabama, and southern Georgia. In the Northeast, recent rains led to reduction of areas of drought in West Virginia, while isolated areas of New England saw minor improvements.
In terms of reservoir storage in areas of the West, California’s reservoirs continue to be at or above historical averages for the date (November 24), with the state’s two largest reservoirs (Lake Shasta and Lake Oroville) at 110% and 100% of their averages, respectively. In the Southwest, Lake Powell is currently 29% full and Lake Mead is 32% full, with the total Colorado River system contents at 37% of capacity on November 23 (compared to 42% of capacity at the same time last year), according to the U.S. Bureau of Reclamation. In Arizona, the Salt River Project is reporting that the Salt River system reservoirs are 54% full, the Verde River system is 68% full, and the total reservoir system is 56% full (compared to 73% full a year ago). In New Mexico, the state’s largest reservoir, Elephant Butte, along the Rio Grande River is currently 5% full (12% of average). In the Pacific Northwest, Washington’s Franklin D. Roosevelt Lake is 94% full (105% of average for the date), Idaho’s American Falls Reservoir on the Snake River is 25% full (64% of average), and Hungry Horse Reservoir in northwestern Montana is 88% full (107% of average).
Northeast
On this week’s map, improvements were made in areas of Maine, New Hampshire, Massachusetts, New York, West Virginia, and Maryland. In New England, improvements were made in response to beneficial precipitation during the past 30-to-60 day period as well as improving groundwater conditions. In the southern tier of the region, rainfall during the past 7-day period (ranging from 1 to 2+ inches) boosted streamflow activity and soil moisture levels leading to a reduction of areas of drought in the eastern portion of West Virginia. In New Jersey, drought intensified in isolated areas (southern and northwestern) where areas of Severe Drought (D2) expanded on the map. For the past 90-day period, precipitation deficits across New Jersey ranged from 2 to 6+ inches. Moreover, the U.S. Geological Survey (USGS) is reporting below-normal streamflow levels (< 10th percentile) at numerous gages across the state. In terms of snowpack conditions, the National Weather Service National Operational Hydrologic Remote Sensing Center (NWS NOHRSC) is reporting that the Northeast region is currently 42.5% covered by snow (area) with an average depth of 1.4 inches and a maximum depth of 25.5 inches. For the week, average temperatures were below normal across most of the region with the greatest departures (4 to 8 degrees F) observed in areas of New York, Vermont, New Hampshire, Massachusetts, Rhode Island, and Connecticut.
Southeast
During the past week, conditions were generally dry with some isolated areas, including eastern North Carolina, and northern portions of Alabama and Georgia, receiving light rainfall accumulations (< 1 inch). On the map, drought-related conditions degraded in Florida, Alabama, Georgia, and South Carolina. In the Florida Panhandle, southwestern Georgia, and southeastern Alabama, a combination of factors including short-term precipitation deficits (past 30 to 120 days), and exceptionally low streamflows and soil moisture levels led to expansion and intensification of drought. In South Florida, areas of Moderate Drought (D1) expanded in response to precipitation shortfalls during the past 30-to-60-day period. In terms of average temperatures for the week, the greatest anomalies (10 to 15+ degrees F) were observed in northern portions of Alabama and Georgia, and western North Carolina.
South
Across much of the region, generally dry conditions prevailed this week, especially in the far southern and western portions of the region, with little or no precipitation observed. In contrast, light to moderate rainfall (2 to 4+ inches) was observed along a swath extending from central Texas to southwestern Arkansas. The beneficial rainfall led to one-category improvements in areas of Moderate (D1) to Extreme Drought (D3) with most of the improvements focused on areas of central and northeastern Texas. Elsewhere, minor improvements were made on the map in southeastern Oklahoma, southwestern Arkansas, and northern Mississippi. In Louisiana, short-term precipitation deficits (past 90-day period) and declining soil moisture levels led to expansion of areas of Moderate Drought (D1) and Severe Drought (D2). For the week, average temperatures were well above normal across the region with anomalies ranging from 4 to 16 degrees F above normal. Looking at reservoir conditions in Texas, Water for Texas (November 25) was reporting statewide reservoirs at 74% full, with many reservoirs in the eastern part of the state in very good condition, while numerous reservoirs in the western portion of the state were experiencing continued below-normal levels.
Midwest
On this week’s map, improvements were made in the southern extent of the region in Missouri in response to widespread rainfall (1 to 2.5 inches) across the state. Elsewhere in the region, some minor improvements were made in southern Illinois, central Indiana, and northwestern Michigan. For the week, average temperatures were above normal across the western and southern extent of the region, with anomalies ranging from 5 to 15 degrees F above normal and the greatest departures observed in western Minnesota and southern Missouri. Temperatures were cooler in the eastern half of the region ranging from 5 degrees F above normal to 5 degrees below normal (central and northern Michigan, eastern Ohio). Using the Southeast Regional Climate Center’s Climate Perspectives tool, the past two months have been very dry across much of the region, with record to near-record dryness observed in the following locations: Duluth, Minnesota (-4.52 inch departure); Madison, Wisconsin (-3.57 inches); Green Bay, Wisconsin (-2.58 inches); Detroit, Michigan (-3.75 inches); and St. Louis, Missouri (-4.3 inches).
High Plains
On this week’s map, only minor changes were made in the region, including changes in eastern Kansas, Nebraska, and southwestern South Dakota. For the week, precipitation across the region was generally light and primarily restricted to eastern and central portions of Kansas as well as in eastern and central South Dakota. In terms of average temperatures, warmer-than-normal temperatures (5 to 15+ degrees F above normal) were observed across the region with the greatest anomalies observed in the Dakotas. According to NWS NOHRSC, the current regional snowpack spatial extent is limited to areas of central and northern North Dakota.
West
Out West, recent storms have delivered much-needed precipitation to drought-affected areas of California, central and southern Nevada, southern Utah, Arizona, southern Colorado, and western New Mexico. On this week’s map, widespread improvements were made in Arizona, across the southern-third of California, and in isolated areas of Nevada, Utah, Colorado, and New Mexico. Moreover, the recent storm activity in the southern extent of the region has boosted snowpack conditions in the southern and central Sierra Nevada, Spring Mountains (southern Nevada), San Francisco Peaks (northern Arizona), Mogollon Rim (central Arizona), ranges of southwestern Utah, and Nacimiento Mountains (northern New Mexico). Elsewhere, snowpack conditions were poor across most of the Intermountain West and Pacific Northwest. In other parts of the region, some minor degradations were made on the map in northern Colorado and north-central Montana.
Caribbean
In Puerto Rico, some minor expansion of areas of Abnormally Dry (D0) were made in the central portion of the island in response to short-term dryness (past 30-day period), low streamflows, reduced soil moisture, and drying vegetation.
This week, short-term abnormal dryness continued on St. Croix and developed on St. Thomas and St. John. Rainfall observations on St Croix recorded in the CoCoRaHs network varied from 0.38 to 0.93. A well-level monitoring site from the U.S. Geological Survey showed depth to water continuing to slowly increase. Depth to water also increased at well-level monitoring sites on St. Thomas and St. John, while short-term rainfall deficits increased on both islands. Rainfall observations on St. Thomas ranged from 0.25 to 0.31 inches. On St. John, CoCoRaHs observations ranged from 0.21 to 0.25 inches, while the observer at Windswept Beach reported 0.45 inches of rain.
Pacific
On this week’s map, no changes were made in the Alaska.
On this week’s map, no changes were made in the Hawaiian Islands.
American Samoa remained free of drought or abnormal dryness this week. At Toa Ridge, 3.31 inches of rain fell, while 4.64 inches fell at Siufaga Ridge. At least 4.08 inches of rain fell in Pago Pago this week, continuing a series of wet weeks there.
Palau remained free of drought or abnormal dryness this week, though only 1.15 inches of rain had fallen through five days this week. Given each of the prior three weeks saw over 2 inches of rain, conditions should still be close to normal in Palau.
Short-term abnormal dryness developed on Saipan, where 0.23 inches of rain were reported this week. This marked the third consecutive week with less than 1 inch of rain, which was preceded by below-normal (though still sufficient) rainfall in October. On Tinian, 0.53 inches of rain were reported, marking the second week in a row with less than an inch of rainfall, though abnormal dryness has not quite developed there. On Guam, 0.88 inches of rain this week marked the second consecutive week with just under 1 inch of rain, though abnormal dryness has not yet developed. On Rota, 1.09 inches of rain fell, and conditions remained normal there.
On Yap, 4.27 inches of rain fell, and conditions remained normal there. No Drought Monitor depiction was made for Ulithi, as data there are missing. On Woleai, conditions remained free of drought or abnormal dryness with 3.09 inches of rain this week. No Drought Monitor depiction was made for Fananu due to missing data there. Chuuk remained free of drought or abnormal dryness, as at least 7.06 inches of rain fell there this week. Lukunor remained free of drought or abnormal dryness after receiving at least 4.12 inches of rain this week. Nukuoro remained free of drought or abnormal dryness this week after 2.66 inches of rain fell there. Conditions on Kapingamarangi improved from severe to moderate short-term drought after 4.86 inches of rain fell there this week, marking the third week out of the last four with at least 2” of rain. Pohnpei remained free of drought or abnormal dryness and received 3.72 inches of rain this week. No Drought Monitor depiction was made on Pingelap this week due to recent missing data. Kosrae remained free of drought or abnormal dryness this week, where 4.65 inches of rain continued a wet spell dating back several months.
No Drought Monitor depiction was made for Kwajalein due to recent missing data. Ailinglaplap remained free of drought or abnormal dryness this week, though 1.83 inches of rain this week marked the second week in a row with less than 2 inches. Jaluit remained free of drought or abnormal dryness this week and received 2.29 inches of rain. After 1.6 inches of rain last week, the monthly rainfall total on Utirik was at 2.26 inches, and short-term abnormal dryness developed. Wotje remained free of drought or abnormal dryness with 0.69 inches of rain last week, bringing the monthly total there to 5.75 inches. Mili remained free of drought or abnormal dryness with 0.93 inches of rain last week, bringing the monthly rainfall total to over 10 inches. Majuro remained free of drought or abnormal dryness this week and received 3.96 inches of rain.
Looking Ahead
The NWS Weather Prediction Center 7-Day Quantitative Precipitation Forecast (QPF) calls for moderate precipitation accumulations ranging from 2 to 4+ inches (liquid) across areas of the South and areas of the Southeast. Likewise, a significant winter storm is expected to impact the Upper Midwest and Great Lakes regions. In the West, dry conditions are expected to prevail across California and the Great Basin, while some lighter accumulations are expected across the Intermountain West. In the Pacific Northwest, moderate accumulations are expected across western Washington and some lesser accumulations across areas of the Northern Rockies of Idaho and northwestern Montana. The Climate Prediction Center 6-to-10-day Outlook calls for a moderate-to-high probability of below-normal temperatures across the eastern half of the West, Plains, South, Midwest, and Northeast. Above-normal temperatures are expected across the Southeast and along the Pacific Coast from Northern California to Washington. In terms of precipitation, there is a low-to-moderate probability of above-normal precipitation across most of the conterminous U.S. except for northern California and western Oregon where below-normal precipitation is favored.
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