Heavy precipitation affected large parts of the Nation last week, with heavy snow in the central Rockies bringing some relief to the dry areas there. The broadest area of heavy precipitation stretched from the Middle Atlantic States southwestward into the Lower Mississippi Valley and the Southeast. At least 2 inches fell from the Ohio River to near the Gulf and southern Atlantic Coasts, with 7 to 10 inches measured across the much of the interior Southeast. On the other side of the 48 states, heavy precipitation covered parts of the Northwest. Near the coast in Washington and northern Oregon, most locations recorded at least 4 inches of precipitation, with isolated amounts to 10 inches in higher elevations. Just to the east, along the Cascade Range from central Oregon northward, a broad swath received at least 5 inches of precipitation, and most of a strip through central Washington reported 10 to locally 15 inches. Well inland, in the central and northern Rockies, precipitation was largely elevation-dependent,. The more elevated regions observed 2 to 5 inches, with lesser amounts in adjacent areas of lower elevation. Heavier amounts more broadly covered central Idaho and adjacent areas in Washington and Oregon, with totals of 4 to locally 8 inches common. It was another week of above-normal temperatures in the East and part of the interior Northwest, while subnormal readings were recorded in the central Rockies where the heavy snowfall dominated the week. Temperatures were 10 to 15 degrees F warmer than normal in the east-central States and part of the interior Southeast, and most sites east of the Mississippi River were at least 4 degrees F above normal. Many locations across the Country averaged 2 to as much as 5 degrees F above normal since mid-November 2019, especially east of the Mississippi River and the interior Rockies and Far West.
Between 1.5 and 3.0 inches of rain fell on D0 area on the Delmarva Peninsula, wiping out the abnormal dryness that had been there, and leaving the Northeast free from any Drought Monitor designation. The last 60 days brought somewhat below normal precipitation to several areas across northern Pennsylvania, New York, and New England, but given the time of year and lack of observed impacts, D0 does not seem warranted at this time.
The heaviest precipitation fell away from the Gulf and Atlantic Coasts, but relatively moderate amounts were sufficient to remove the D0 area along the Carolinas Coast, though some mild moisture deficits remain in a few spots. Farther south, moderate to heavy rains eliminated D0 in both southern Georgia and southwestern Alabama, as well as the western sides of the D0 and D1 areas along the Florida Panhandle, where streamflows increased. East of the Apalachicola River, dryness and drought remained in eastern sections of the Florida Panhandle. The area of moderate drought recorded 5 to 8 inches below normal rainfall in the last 3 months. In addition, abnormal dryness was expanded into much of the northern Florida Peninsula where the last 30 days brought only 0.5 to 1.0 inch of rain (among the driest 5 percent of historic occurrences there).
Abundant rainfall eliminated D0 in relatively small parts of southeastern Louisiana and southernmost Mississippi, but most areas of dryness along the central Gulf Coast missed the bulk of the precipitation, keeping most of the D0 area unchanged. Farther west, moderate to heavy precipitation (1 to locally 4 inches) eliminated almost all dryness across western Louisiana and southwestern Arkansas, and induced improvement across the D0 to D2 conditions in eastern Texas as well. In addition, moderate rains in north-central Texas as well as the Red River Valley removed D0 from those regions, but left moderate drought largely intact across southwestern Oklahoma. But farther south, most areas of dryness and drought across central and southern Texas received little if any precipitation, prompting areas of drought intensification and expansion. Severe drought now covers large portions of central and southwestern Texas, and the D3 along parts of the Rio Grande Valley expanded into neighboring counties. Over the last 90 days, precipitation deficits reached 5 to 7 inches across interior eastern Texas, and less than 25 percent of normal has fallen around the areas of extreme drought in southwestern Texas.
Heavy precipitation (over 2 inches) was restricted to the Ohio Valley, with most of the region recording a few tenths of an inch, if any. Still, longer-term surplus moisture covers most of the region, and no areas of abnormal dryness or drought have been identified.
Most of the region saw little to no precipitation this past week, leaving the Drought Monitor unchanged in south-central Kansas, and prompting some limited expansion of the D0 to D2 conditions in western Kansas and eastern Colorado. Farther west, most lowland areas received only light precipitation, but heavy snows blanketed the higher elevations from central Colorado into western Wyoming. Snowpack is now near to above normal for this time of year in western Wyoming, and considerably above normal from central Wyoming southward through most of the higher elevations in central Colorado. This prompted removal of the D0 area that had covered southwestern Wyoming. More limited improvement was noted in the D0 and D1 areas in central and western Colorado, where dryness is more entrenched.
Moderate to heavy precipitation in the Northwest and parts of the northern Intermountain West boosted snowpack enough improve drought designations in parts of the region. In Idaho, D0 was retracted to cover only the central part of the state, with some D1 remaining across the interior where snowpack remained unfavorably low (10th to 20th percentile historically for this time of year). A bit of abnormal dryness was also pulled out south-central New Mexico and northwestern Utah, but an unremarkable week kept dry conditions essentially unchanged across the rest of the Four Corners States outside Colorado. Across Nevada and California, however, dryness and drought intensification prevailed. On the 60-day time scale, markedly low precipitation totals (among the driest 5 percent of historical occurrences) covered most of a swath across central sections of California and Nevada, and 30-day amounts were less remarkable but still significantly below normal across most of the 2 states, outside the far northern and southern tiers. Since mid-December, less than half or normal precipitation has fallen from central and southern Nevada westward across most of California, with less than 25 percent of normal observed in the southern Sierra Nevada and adjacent central valleys. Central and southern sections of coastal California accumulated 3 to 8 inches less precipitation than normal during this period while deficits of 5 to 12 inches piled up in the Sierra Nevada. Precipitation summed over the past 6 months is notably below normal over most of both states. In particular, central and southern parts of the Sierra Nevada accumulated a deficit of 9 to locally near 20 inches of precipitation (about half of normal), and snowpack is less than 60 percent of normal for the date in the central and southern Sierra Nevada. The confluence of all these factors led to the introduction of moderate drought in the central and southern Sierra Nevada, and the adjacent central valleys. The state had been drought free since the first few days of December. Farther east, D0 was broadly expanded to cover part of northeastern California and a broad swath across much of interior Nevada. The last 6 months brought less than half of normal precipitation to this region, but with lower normals than farther west, accumulated deficits were less dramatic (generally 3 to locally 6 inches).
Alaska, Hawaii, and Puerto Rico
Moderate to heavy rain erased the southern tier of the dry region analyzed last week, but most sites received considerably less, keeping D0 intact farther north.. 60-day rainfall is at most 75 percent of normal in the abnormally dry area
The drought areas in Maui and the Big Island reported substantial rainfall this past week, but impacts have not tangibly improved at this time, so the depiction remains unchanged from last week
Generally light precipitation fell on the dry areas in Alaska, keeping the D0 area unchanged.
This week in American Samoa, over 8 inches of rain was recorded, which continued the recent wet and drought-free conditions.
Recent dryness on Palau gave way to over two inches of rain this week. Despite the wet week, short-term moderate drought continues here.
No changes were made to the U.S. Drought Monitor depiction in the Federated States of Micronesia this week. On Yap, only 0.13 inches of rain fell this week (with two days of missing data), and an overall dry trend since Christmas resumed after 3.88 inches of rain fell last week. Therefore, short-term abnormal dryness continued there. Only 0.17 inches of rain fell in Ulithi this week, but given the 9.24 inches of rain that fell in January, abnormal dryness has not developed. On Woleai, 1.82 inches of rain fell, a welcome change after only 0.12 inches last week, but still below the weekly minimum, and short-term abnormal dryness continued there. No data was available for Fananu this week, so no drought monitor category was assigned there. This week was drier on Chuuk, with only 0.35 inches of rain falling (with one day’s worth of data missing). Given the wet conditions in January and particularly December, though, no abnormal dryness or drought is taking place there. Only 0.07 inches of rain fell on Lukunor this week (with one day missing), so short-term abnormal dryness continued there. No rain fell on Nukuoro this week, marking the second consecutive week in which less than two inches of rain fell. However, 17.63 inches of rain fell in January, so the dry last couple weeks have not degraded conditions to abnormal dryness. This week on Kapingamarangi, 1.05 inches of rain fell, marking the eighth week out of the last nine during which less than two inches of rain fell, and short-term abnormal dryness continued there. Only 0.56 inches of rain fell this week on Pohnpei, but since conditions were wet the last few weeks, abnormal dryness has not developed. Only 0.3 inches of rain fell this week on Pingelap, though over three inches of rain fell each of the previous two weeks, so drought-free conditions continued there. On Kosrae, 0.38 inches of rain were recorded this week, with three days of data missing, and drought-free conditions continued.
Short-term drought or abnormal dryness continued on Saipan, Rota, and Guam this week. Only 0.12 inches of rain fell on Saipan, after only 2.8, 1.2 and 1.16 inches fell during November, December, and January, respectively, and abnormal dryness degraded to short-term moderate drought there. On Rota, after only 0.39 inches of rain fell this week, short-term dryness continued. On Guam, short-term dryness continued after 0.11 inches of rain fell.
No changes were made to the U.S. Drought Monitor depiction in the Republic of the Marshall Islands this week. Short-term moderate drought continued on Kwajalein, where only 0.17 inches of rain fell this week. Short-term abnormal dryness continued on Ailinglapalap this week, where no rain was recorded this week (with one day’s data missing). On Jaluit, short-term abnormal dryness persisted, as only 0.02 inches of rain were measured (with one day of missing data). On Utirik, 0.47 inches of rain fell, with 2 days missing from the record this week, and short-term moderate drought continued. On Wotje, no rain was recorded (with one day missing) this week, and short-term abnormal dryness continued. Short-term abnormal dryness continued this week on Majuro, where only 0.07 inches of rain was recorded (with two days missing). No rain was recorded on Mili this week (with one day of missing data), but due to a very wet October-January period, abnormal dryness has not developed there.
No changes were made to the U.S. Drought Monitor depiction in the U.S. Virgin Islands this week. Groundwater has been making a slight recovery on St. Croix over the last month and a half, though moderate long-term drought continues there due to 6-12 month rainfall deficits. Neutral or wet conditions at most precipitation time scales continued on St. Thomas and St. John this week.
During the next 5 days (February 13 to 17), the pattern is expected to be similar to last week, but with less extreme precipitation amounts. Still, over an inch is expected in a swath from southeast Louisiana to the upper Ohio River Valley, with a stripe of 1.5 to 2.5 inches expected from e