This week's drought picture featured a mixed bag of conditions with worsening drought in the lower Mississippi valley and the lower Great Lakes region. Meanwhile, prolific rainfall continued in parts of the Southwest, South, and Southeast, leading to significant drought improvement across southern and western Texas and parts of the Southern Appalachian region. Additional drought improvement was found over the western Great Lakes in Minnesota and Wisconsin and parts of the Upper Peninsula of Michigan. Despite little rainfall in the Four Corners region of the Southwest, additional improvements were made as a result of substantial rainfalls over the last several weeks, leading to tremendous flooding in some places and rapidly-filling reservoirs.
In the Northeastern U.S., substantial rainfall occurred along a frontal boundary from the Middle Atlantic states up to coastal New England, leading to several inches of rain in Southeastern New England as well as Down-East Maine. These areas experienced one-category improvements in drought over Southeastern Massachusetts and Maine's Central to Eastern Coastal region. Meanwhile, the combination of generally above average temperatures and well below normal rainfall led to the introduction of moderate drought across Western New York State into far northeastern Ohio. Abnormally dry conditions also expanded into North-Central and Northeast Pennsylvania into Central New York due to lack of autumn rainfall.
Southeast
The Southeastern United States also experienced a mixed bag of drought improvements and degradations. An intense corridor of rain fell from far Northern Georgia into Western North Carolina leading to one and two-category drought improvements and in some cases, removing drought entirely. Up to eight or more inches of rain fell in far Northern Georgia leading to flash flood emergencies and substantial flooding along the Toccoa and Ocoee Rivers.
Conditions deteriorated in the Eastern Carolinas as the rain that did fall was inadequate to make a dent in the current severe to extreme drought conditions, especially in Central and Eastern North Carolina. Slight drought improvements occurred across parts of North Florida and Central Alabama, although warmer than normal and dry conditions led to the introduction of moderate drought near Mobile, Alabama.
South
The drought pattern continued to be quite polarized across the Southern States, with exceptional drought worsening across Arkansas, Louisiana, Mississippi, Southeastern Oklahoma, and Eastern Texas. According to the National Centers for Environmental Information, 20 to 30 inches of rainfall is required over the span of 3 months to end the exceptional drought in these states. In stark contrast, substantial rains fell in Southern and Western Texas resulting in one and two categorical reductions in drought intensity, especially over South Texas where up to 9 inches of rain fell. Significant drought relief occurred across much of Western and Central Tennessee where several inches of rain fell in some places this past week helping to reduce the extreme drought to some extent.
Midwest
The story of substantial variability in dry and wet weather patterns continued to rear its head across the Midwestern states. Drought improvement occurred across much of Kentucky into Southern Indiana and Southern Ohio, as well as most of Minnesota, Northwestern Wisconsin, and parts of the Upper Peninsula of Michigan adjacent to Lake Superior. Several inches of rain fell in these areas helping to put a big dent into Minnesota's long-term drought, however dry signals still occur with long-term, multi-year rainfall deficits still impacting Eastern Minnesota and Northwestern Wisconsin. In between these rainy systems, intensifying dry and drought conditions were found from Illinois to the southern half of Lower Michigan. Rainfall was inadequate this past week to improve drought across most of Southern Missouri.
High Plains
The High Plains States were the least active in terms of drought category changes this past week as little precipitation fell. With evaporation rates reduced this time of year, any worsening drought moves at a much slower pace. Only spotty drought improvements from rainfall occurred in Eastern South Dakota into Northeastern Nebraska, and Southwestern Kansas.
Despite an overall lack of substantial rainfall in the West this past week, continued drought improvements were made across many states from Southeast Montana southward to New Mexico and westward to Southern California and Nevada. Near-record soil wetness has resulted from the recent weeks of tremendous El Niño-influenced rainfall. It hasn't been all good news in the West, as some drought degradation was introduced in northern Idaho and northwestern Montana this past week.
Many reservoirs have been filling up at an exceptionally rapid pace in the Desert Southwest, making up for months of declining levels over just the last few weeks. The Navajo reservoir in Northwestern New Mexico has added over 600,000 acre-feet of water since mid-September from recent rain and flooding events, and now sits at 110% of average storage for this time of year. Lake Powell behind the Glen Canyon dam has also benefited tremendously with the addition of almost 1.4 million acre-feet of water since mid-September. However, Lake Powell is still only at 42% of average storage for this time of year.
A shift in the weather pattern has brought beneficial rain across Puerto Rico this past week, contributing to improved streamflows, reservoir levels, and groundwater levels in monitored wells, along with reduced crop stress. Thirty-day rainfall deficits have eased over the eastern half of Puerto Rico but some areas still show rainfall of only 50% of normal. Additional reduction in drought intensity therefore occurred in parts of the territory this week.
Extreme to exceptional drought (D3-D4) remains entrenched across the U.S. Virgin Islands. Even though portions of St. Croix reported moderate to heavy rainfall in some areas, but coverage was not widespread, and given the protracted nature of the drought, extreme drought (D3) was maintained there. The first 9 days of November brought a decent 1.72 inches of rain to East Hill on St. Croix, but this brought May 1-November 10 totals to just 9.06 inches, only 38 percent of normal for this period of just over 6 months, and among the driest 1.5 percent of the climatological distribution of rainfall totals for the period. November totals are lower farther to the north across St. John and St. Thomas, with amounts generally ranging from about 0.5 to 1.0 inch, with parts of the Charlotte Amalie, St. Thomas area recording as much as 1.3 inches. During May 1-November 10, Windswept Beach on St. John reported 10.83 inches of rain, which is almost 19 inches below (36 percent of) normal. This equates to a standardized precipitation index (SPI) of -2.6, or among the driest 0.5 percent of expected occurrences given the current climatology there.
Pacific
No drought modifications were made across Alaska with this U.S. Drought Monitor update.
No drought modifications were made across Hawaii with this U.S. Drought Monitor update.
Koror in Palau maintained moderate drought (D1) status this week. The first 10 days of November brought 2.33 inches of rain, which is about 59 percent of normal and on pace for a monthly total slightly lower than necessary to keep up with demand. This follows an October that brought marginally adequate rain (8.49 inches, 70 percent of normal) and an August-September that was acutely dry (6.88 inches of rain compared to a normal of about 26 inches; about 16 inches would have been needed to keep up with demand). Since August 1, a total of 17.70 inches fell on Koror, compared to a normal of over 42 inches for the period.
The Marianas reported generally surplus rainfall this year through early autumn, with periods of excessive rainfall and impacts from a few tropical cyclones. Over the past few weeks, however, conditions have dried out. November 1-10 brought a few tenths of an inch to Guam and Rota (8 to 15 percent of normal) and 1.50 inches to Saipan (about ¾ normal). This has begun to draw down surface moisture at some locations, especially on Guam, and is beginning to become evident on short-term drought indicators. The Keetch-Byram Drought Index reached a new daily record high among 60 years of data late in the week, and the Normalized Difference Vegetative Index has dropped somewhat below normal for this time of year. This supports the introduction of abnormal dryness (D0) at Guam. Other locations are not quite as dry in the short-term so no abnormal dryness was assessed elsewhere, but conditions will be closely monitored for signs of deterioration.
Across western Micronesia, abnormal dryness (D0) was maintained across Yap, Ulithi, and Woleai. November 1-10 rainfall totaled 0.11 inch at Ulithi and 0.30 inch at Woleai, which is 4 and 11 percent of normal, respectively. The current spell of subnormal rainfall dates back through October, with October 1-November 10 totals of 3.21 inches reported at Woleai (normal 12.89 inches) and 5.27 inches at Ulithi (normal 13.25 inches). Yap has been a little wetter this November, with a 10-day total of 0.92 inch reported (about 1/3 normal). Both September and October were drier than normal at Yap, but amounts were sufficient to keep up with demand.
Subnormal precipitation continued affecting the central tier of Micronesia, keeping Kapingamaringi in moderate drought (D1) and Chuuk, Lukunor, and Nukuoro in abnormal dryness (D0). Kapingamaringi reported 2.15 inches of rain for the first 10 days of November, about two-thirds normal, perpetuating a pattern of subnormal rainfall dating back to the start of August. Since August 1, Kapingamaringi recorded 14.26 inches of rain, which is less than 54 percent of normal and considerably under the 25 or so inches that would be needed to keep pace with demand during this period. Farther north, totals reported for the first 10 days of November were 0.28 inch at Chuuk (8 percent of normal), 0.83 inch at Lukunor (under 25 percent of normal), and 1.93 inches at Nukuoro (55 percent of normal). September 1-November 10 rainfall totaled 14.97 inches at Chuuk (54 percent of normal) and 12.19 inches at Lukunor (49 percent of normal). At Nukuoro, 8.44 inches have fallen since October 1 (normal 13.83 inches). Subnormal rainfall dates back to at least July at Nukuoro, which reported 36.37 inches since the beginning of that month (almost 16 inches below normal), but totals have been sufficient to keep up with demand until the past 6 to 8 weeks.
In eastern Micronesia, abnormal dryness (D0) continued affecting Kosrae, while Pohnpei remained free of any dryness or drought designation. Kosrae reported 2.56 inches during November 1-10 (about half of normal), which brought their total since October 1 to 9.78 inches, under 59 percent of normal and just below what is typically necessary to keep up with demand. Pohnpei recorded only 0.62 inch so far this November (about 12 percent of normal), but this followed 61.59 inches during the prior 3 months.
Abnormal dryness (D0) remained in place along the western tier of the Marshall Islands (Kwajalein, Ailinglapalap, and Jaluit). Rainfall totals for November 1-10 were 0.40 inch at Kwajalein (11 percent of normal), 0.57 inch at Ailinglapalap (13 percent of normal), and 0.95 inch at Jaluit (28 percent of normal). At Kwajalein and Ailinglapalap, subnormal precipitation dates back about 6 weeks. During October 1-November 10, 7.46 inches of rain fell on Ailinglapalap and 7.44 inches on Kwajalein, in both cases around 48 percent of normal and somewhat less than what is typically needed to keep pace with demand. On Jaluit, rainfall has been consistently lower than normal since July, with 26.45 inches recorded July 1-November 10. This was almost 2 feet less than (53 percent of) normal, but amounts were sufficient to keep pace with demand during August and September.
Utirik and Wojte in the northeastern Marshall Islands remained free of any dryness or drought designation. Rainfall totals for November 1-10 were somewhat below normal at both locations (1.76 inches (73 percent of normal) at Utirik and 1,75 inches (68 percent of normal) at Wotje). However, rainfall during prior months has been sufficient to keep significant moisture shortages at bay for the time being.
In the southeastern Marshall Islands, Majuro reports 2.90 inches of rain (65 percent of normal) so far this November while Mili reports 1.15 inches (36 percent of normal). Abnormal dryness (D0) was maintained at Mili this week, but increased rainfall late this past week was sufficient to keep significant dryness at bay in Majuro. After a couple weeks without rain, reports indicated that some small cisterns used for household water were running dry, but rainfall late this past week brought at least some short-term improvement, and amounts during November 1-10 were nominally sufficient to keep pace with demand. The larger reservoir on Majuro was filled to 88 percent of capacity at the end of the week.
Moderate drought remained in place across American Samoa. Pago Pago recorded only 0.44 inch of rain during November 1-10, only about 12 percent of normal. Going back to the start of October, only 2.66 inches of rain has been reported, just 1/3 of normal. September totals were above normal and sufficient to keep up with demand, but August was acutely dry, with only 2.08 inches reported (1/3 of normal). For August 1-November 10 as a whole, Pago Pago reported 15.02 inches of rain, which is more than one foot less than (54 percent of) normal.
Looking Ahead
Over the next week, a potential Nor’easter could bring substantial rainfall to interior portions of Pennsylvania, New York, and Southern New England. A series of potent weather systems should impact the West Coast from Central California up to Washington, with up to 5 inches or more of precipitation being predicted by the NOAA Weather Prediction Center through next Tuesday. Another axis of substantial rainfall is predicted from Eastern Texas into Oklahoma and Southern Kansas. The Northern Plains and the Southeast are predicted to stay mostly dry. The NOAA Climate Prediction Center depicts well above normal temperatures across much of the Plains States, with below normal temperatures in the Southeast. Precipitation is projected to be above average in the Southwestern U.S. and below average over the eastern half of the country.
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