This week was defined by a significant precipitation divide, highlighted by a major deluge across parts of the South and Gulf Coast. Persistent storm systems funneled heavy moisture into Louisiana, Mississippi, and Alabama, where total rainfall reached 4 to 6 inches—and in some coastal pockets even higher—representing departures of 3 to 5 inches above seasonal norms. While an active frontal corridor brought a secondary band of moderate rain (1 to 3 inches) from Texas through the Ohio Valley and into the Northeast, the Western U.S. remained exceptionally dry, with most areas west of the Rockies receiving less than 0.1 inch of rain. This lack of moisture, paired with blustery winds, triggered extreme fire danger across the Upper Mississippi Valley, though the period concluded with a pattern shift as a significant Pacific low-pressure system finally moved onshore to deliver moisture to the Northwest.
Temperature patterns showed an equally sharp geographical split, with unseasonable warmth gripping the West and parts of the South while a late-spring chill lingered over the North. In the Southwest and South Texas, summer-like heat took a firm hold as Rio Grande Village, Texas, hit a national high of 105°F and Death Valley consistently reached the triple digits; overall, the Western U.S. averaged 5 to 15°F above normal. Conversely, a significant cool-down settled over the Northern Plains and Upper Midwest, where the Dakotas and Minnesota experienced temperatures 5 to 15°F below seasonal averages. This thermal contrast was further sharpened by winter-like conditions in high-elevation regions of the West, where stations in Utah recorded lows as cold as 10°F, even as record-challenging warmth began to expand across the Pacific Northwest and the Southern Border states.
The Northeast region experienced a pronounced late-spring chill coupled with a sharp geographical divide in precipitation. Average temperatures ranged from 39°F–48°F in northern portions of the region to 60°F–66°F in parts of Maryland and Delaware. Temperatures were below normal across nearly the entire region, with the most significant cold anomalies concentrated in New York and Pennsylvania; in these areas, departures reached 6°F to over 10°F below average. Precipitation patterns were equally divergent, featuring a surplus in the north and west but deficits in the south. Heavy moisture was concentrated in Western New York, Northwestern Pennsylvania, and much of Maine, where precipitation amounts ranged from 0.45 to 1.8 inches above normal. Moderate (D1) to severe (D2) drought, along with abnormal dryness (D0) were improved in Maine. Conversely, rainfall totals were below-normal across southern portions of the region, with precipitation deficits generally falling between 0.45 and 1.35 inches below normal. Severe (D2) drought was expanded in northern Massachusetts, Delaware, and southern portions of Pennsylvania, New Jersey and West Virginia, while moderate (D1) drought was expanded in Massachusetts, Rhode Island, Connecticut and southern Pennsylvania this week.
Southeast
Much of the Southeast experienced below-normal temperatures this week, where temperatures were 5°F to 10°F below normal. Florida, Georgia, and parts of Alabama and South Carolina were the exception, where averages were in the 80s—up to 10 degrees above normal. Exceptional precipitation totals (1.5 to 3.0 inches) were recorded across much of Alabama, and portions of Georgia and the Florida Panhandle. Localized accumulations in these areas reached 4 to over 7 inches, representing significant departures of 3 to 6 inches above normal. Weekly rainfall totals of 1.5 to 3.0 inches extended from southern Appalachian region to south-central North Carolina. Exceptional (D4) drought was removed from south-central North Carolina and northeast Georgia, and improved in the Florida Panhandle. Extreme (D3) drought improved across parts of northern Florida, Alabama, Georgia, and the Carolinas. Rainfall totals were below normal from northern portions of North Carolina, Virginia, and much of the Florida Peninsula, observing deficits of 0.5 to 1.5 inches. Extreme (D3) drought was expanded in central and southern portions of Virginia and slightly into a northern pocket of North Carolina, while moderate (D1) drought to extreme (D3) drought were expanded in southeast Florida.
South
The Southern region experienced a stark contrast in both precipitation and temperature during the week, defined by torrential Gulf Coast rains and a significant late-spring chill across the interior. Precipitation was most intense across the central Gulf Coast, particularly in Louisiana and southern Mississippi, where weekly totals reached 7 to over 9 inches. These amounts represent exceptional departures of 6 to 7.5 inches above normal. Moderate (D1) to Exceptional (D4) drought was reduced in southern and eastern portions of Texas, and in parts of Louisiana, Mississippi, and southern Tennessee. Abnormal dryness (D0) was improved in parts of Texas and southern Louisiana. Conversely, drier conditions prevailed in West Texas, Oklahoma, and much of the Tennessee Valley, where precipitation was generally 1.5 to 3 inches below average. Exceptional (D4) was introduced in southwest Oklahoma and from the Texas Panhandle into northwest Oklahoma, and expanded in parts of Arkansas and northern Mississippi. Extreme (D3) expanded in northern portions of Texas and western Oklahoma. Heat persisted in southern Texas, where average temperatures reached the 80s and 90s, representing departures of up to 5°F above normal. However, a powerful cold anomaly gripped the northern, eastern, and central portions of the region. In these areas, temperatures were broadly 5 to 10°F below normal for the week.
Midwest
The Midwest region experienced a widespread late-spring chill and a stark contrast in moisture levels between the north and south. Temperatures were broadly below average across the entire region, with the vast majority of the Midwest observing departures of 5 to 10°F below normal. Average temperatures ranged from a cool 30–40°F along the northern border of Minnesota and Wisconsin to the more seasonable 60–70°F in the southern reaches of Missouri and Kentucky. Precipitation was notably sparse across the northern half of the region, including Minnesota, Wisconsin, Iowa, and Michigan, where totals remained under 0.1 inches, resulting in departures of 0.5 to 1.5 inches below normal. In contrast, the southern tier—particularly across parts of Kentucky, southern Missouri, and the Ohio Valley—saw more active weather with precipitation totals ranging from 1.5 to over 3 inches, leading to surpluses of 0.5 to 1.5 inches and resulting in the reduction of severe (D2) and extreme (D3) drought in western parts of Kentucky. However, moderate (D1) to extreme (D3) drought was expanded in portions of central and eastern Kentucky, where rainfall amounts were below normal. Abnormal dryness (D0) was also expanded in parts of Minnesota, western Iowa, southern Missouri, and in pockets of Indiana and Ohio.
High Plains
Anomalous warmth dominated most of the High Plains this week, while precipitation was defined by a significant east-west gradient. The eastern portions of the region, remained under a persistent late-spring chill with average temperatures falling 4°F to 10°F below seasonal norms. This area was also exceptionally dry, receiving less than 0.05 inches of rain, which resulted in precipitation deficits of 0.6 to 1.2 inches. Persistent dryness resulted in the expansion of exceptional (D4) drought in Nebraska, while and moderate (D1) to extreme (D3) drought were expanded in northeastern Wyoming, South Dakota, Nebraska, and Kansas. In contrast, the western High Plains across Wyoming, much of Colorado, and western portions of South Dakota and Nebraska, experienced unseasonable warmth, with departures ranging from 2°F to 6°F above normal. This warmth was accompanied by an active moisture corridor through the southern High Plains; while northern and eastern reaches were dry, portions of Colorado and adjacent areas of Wyoming and Kansas recorded 0.7 to 1.6 inches of precipitation, ranging from 0.3 to 0.9 inches above normal. This above-normal precipitation resulted in the removal of exceptional (D4) and reduction of extreme (D3) drought in Wyoming, and improvements to severe (D2) to exceptional (D4) drought in Colorado and severe (D2) to extreme (D3) drought in western Kansas.
The West was characterized by unseasonable warmth and widespread dryness across the Pacific Coast and Great Basin, contrasted by cooler, more active conditions in the Rocky Mountains this week. The eastern portion of the region—specifically eastern portions of Montana, Utah, and New Mexico—remained notably cooler, with departures ranging 3°F to 6°F below normal. However, most of the region, particularly in parts of Oregon, California, and Nevada, experienced significant temperature departures of 6°F to over 12°F above normal, with actual average readings in the Desert Southwest reaching the 80s and 90s. This heat was paired with minimal moisture, as coastal and interior basin states recorded less than 0.1 inches of rain, resulting in precipitation deficits of 0.6 to 1.5 inches below seasonal averages. Exceptional (D4) drought was expanded in southern Idaho, while extreme (D3) drought was introduced in Oregon and expanded in Montana, Idaho, and Nevada this week. Severe (D2) and moderate (D1) drought were expanded in Oregon, Idaho, and Montana. Severe (D2) drought was also introduced in northern Washington and expanded in northern Nevada. Conditions deteriorated over parts of southwest Washington and northwest Oregon resulting in the expansion of abnormal dryness (D0) in these areas. Conversely, localized moisture resulted in the moderate (D1) to severe (D2) drought and abnormal dryness (D0) improvements in southern Arizona, while improvements to moderate (D1) drought occurred in parts of western Nevada.
Conditions were dry over Puerto Rico this week. Below-normal rainfall amounts, along with stressed vegetation, low soil moisture, and depleting groundwater and lake levels, resulted in the introduction of abnormal dryness in southern parts of the island.
The rainfall situation for the U.S. Virgin Islands from May 6 to May 12, 2026, was characterized by a dry, stable weather pattern, with total rainfall significantly below seasonal averages. Although isolated showers did occur, they were mainly a result of shallow moisture moving rapidly within the trade winds.
This week, St. Croix experienced light rainfall, with totals reported in descending order. VI-SC-20 (Frederiksted 1.7 ESE) received the highest amount at 0.78 inches, followed by VI-SC-30 (Christiansted 1.7 SW) with 0.34 inches and VI-SC-35 (Frederiksted 1.3 ENE) measuring 0.19 inches. VI-SC-10 (Christiansted 1.6 E) recorded 0.16 inches, while VI-SC-23 (Christiansted 6.5 W) received 0.08 inches. Finally, VI-SC-34 (Frederiksted 1.9 NE) reported the lowest amount of 0.07 inches. These measurements reflect the light rains experienced across the island. The Standardized Precipitation Index (SPI) value for East Hill over the past month was -0.85, indicating short-term abnormally dry conditions. Similarly, the SPI values for Christiansted Hamilton at 1, 3, and 6 months were -0.72, -0.82, and -2.67, respectively, indicating drought conditions in the western parts of St. Croix. As of May 12, 2026, the water level at Adventure 28 Well in St. Croix, USVI, was 21.01 feet, which is an increase from the previous week. This level is also higher than the level on the same date last year (May 14, 2025), when it was 14.85 feet, further indicating that St. Croix is experiencing abnormally dry conditions.
Cyril E. King Airport in St. Thomas recorded 0.06 inches of rainfall this week. As of May 7, 2026, the one-month Standardized Precipitation Index (SPI) at the airport was -0.95, indicating drier-than-normal conditions. Additionally, the rainfall total for VI-ST-15 (Charlotte Amalie West, 1.3 N) was 0.15 inches. The depth to the water level below the land surface at the Grade School 3 well in St. Thomas has continued to increase since April 20, 2026. On May 12, 2026, the depth was measured at 8.32 feet, which contributes to the island being in an abnormally dry condition.
Similarly, St. John experienced low rainfall this week, with only 0.29 inches recorded at VI-SJ-3 (Windswept Beach) and just 0.23 inches at VI-SJ-5 (Cruz Bay 1.6 E). Additionally, the water level at the Susannaberg DPW 3 well (St. John, USVI) was measured at 13.84 feet below the land surface on May 12. This represents a significant increase from last year, when the water level was 8.92 feet below land surface on the same date in 2025. These indicate that St. John is currently experiencing abnormally dry conditions.
Pacific
Temperatures were broadly below normal across Alaska this week, while parts of the east-central interior and Panhandle observed above-normal temperatures. Precipitation varied across the state this week, with below-normal precipitation falling over northern and western parts of the state. Precipitation was above normal over central and south-central Alaska, resulting in the reduction of abnormal dryness (D0) in these areas.
No changes were made in Hawaii this week.
Rainfall across the Marshall Islands was moderate to heavy this week. Southern atolls like Majuro benefited from proximity to the near-equatorial trough, reporting 2.9 inches this week. Northern atolls remained seasonally dry, but Jaluit, Utirik, and Wotje reported 1.06, 0.61, and 0.34 inches, respectively, to remain drought-free. Kwajalein and Ailinglapalap reported heavy rainfall: 5.71 and 4.7 inches this week, respectively. The current synoptic environment features east-northeast trade winds and weak low-level convergence, resulting in localized heavy showers in the south; for example, Milli recorded 3.12 inches of rain.
This week, the Federated States of Micronesia (FSM) experienced some of the highest precipitation totals in the region, driven by an active monsoon-like flow and a series of tropical disturbances moving westward. The central and eastern states—Chuuk, Pohnpei, and Kosrae—reported significant rainfall. Specifically, Chuuk received 2.95 inches, Kosrae recorded 7.29 inches, and Pohnpei had 5.57 inches of rain (with 2 days of data missing). Yap improved from abnormally dry conditions to drought-free status, receiving 5.42 inches of rainfall. Woleai reported 5.96 inches. Kapingamarangi, on the other hand, reported 0.31 (with 2 days of data missing); however, it remains drought-free due to earlier wet conditions, having recorded 2.46 inches in one day last week (on May 1, 2026). In contrast, Ulithi received only 1.95 this week, remaining abnormally dry. Lukunor and Nukuoro reported 0.59 and 0.62, respectively, with two days missing. However, both islands remain drought-free due to the recent wet conditions.
The surface trough remained nearly stationary near the American Samoa islands until May 8, before drifting south. This trough provided most of the week's moisture before drier trade-wind air returned over the weekend. Pago Pago reported 0.79 inches of rain, although two days of data are missing. Meanwhile, Siufaga Ridge and Toa Ridge recorded 2.31 and 0.61 inches of rain this week, respectively, keeping the islands drought-free.
This week, the Koror area experienced significant rainfall, totaling 4.55 inches. The week began with mostly dry conditions as Palau transitioned into ENSO-neutral conditions, continuing through May 11. However, on May 12, a heavy, localized rainfall event occurred, with 2.76 inches falling in Koror. This event was influenced by a southward pulse of the Intertropical Convergence Zone (ITCZ) and shifting tropical moisture. Additionally, WSO Palau Airai reported 2.4 inches of rain for the week. In April, Koror received only 2.53 inches of rainfall, far below the normal 9.1 inches, marking the lowest total in 75 years of recorded data. Although there has been a surge in heavy rain by the end of this week, the overall atmospheric conditions are still influenced by the suppression of the Madden-Julian Oscillation (MJO) over the Western Pacific. This suppression is leading to an abnormally dry pattern as the islands get ready for a possible El Niño shift in the coming months.
This week, the Mariana Islands have seen rainfall primarily influenced by moderate easterly trade winds and weak surface troughs, marking the early effects of a developing El Niño. Rota recorded 1.3 inches of rain this week, to remain drought-free. Meanwhile, Guam and Saipan reported 0.82 inches and 0.55 inches, respectively, keeping both islands free from drought this week.
Looking Ahead
Over the next five days (May 12–16, 2026), weather patterns across the United States will feature a stark contrast between record-challenging heat in the West and unsettled, cooler conditions in the East. A building atmospheric ridge will maintain well-above-normal temperatures across the western U.S., with several high-temperature records likely to be tied or broken as this warmth spreads into the central Plains by mid-week. Conversely, the eastern half of the country can expect near to below-normal temperatures as a series of frontal systems bring frequent rounds of showers and thunderstorms from the Midwest to the Atlantic Coast. Meanwhile, an incoming Pacific low-pressure system is forecast to deliver light to moderate precipitation to the Pacific Northwest and northern Rockies, while gusty winds may accompany the passage of these weather systems across the Rockies and Great Plains.
Further out, the Climate Prediction Center’s 6–10 day outlook (valid May 17–21, 2026) favors above-normal temperatures across Hawaii and most of the contiguous U.S., with the most intense heat probability concentrated in the Southeast. Areas along the northern border and southern parts of Alaska are favored to be cooler-than-average during this period. Probabilities for above-normal precipitation are increased across Hawaii and the vast majority of the lower 48 states and Alaska. In contrast, below-normal precipitation is favored across the West Coast, particularly over northern California, and in parts of the East Coast, from the Mid-Atlantic to the Carolinas.
No comments:
Post a Comment