During the final week of April, the southern Great Plains along with the Lower Mississippi Valley also received widespread precipitation with amounts exceeding 2 inches across southeastern Colorado, northern and eastern Oklahoma, and northeastern Texas.
Late April was mostly dry across the Central to Northern Great Plains and Middle Mississippi Valley. Little to no precipitation was observed throughout the West where a significant warmup at the end of April resulted in rapid snowmelt, runoff, and flooding along streams and rivers. In contrast to these above-normal temperatures, cooler-than-normal temperatures occurred across the Great Plains, Corn Belt, and much of the East from April 25 to May 1.
Balancing longer term SPIs and recent widespread rainfall (1 to 3.5 inches), a 1-category improvement was made to parts of Oklahoma and Texas. Improvements were also made to parts of central Texas along with the Texas Gulf Coast after more than 1.5 inches of rainfall this past week. CPC’s leaky bucket soil moisture and 90 to 120-day SPI supported a slight expansion of moderate (D1) to severe (D2) drought in west-central Texas.
Based on soil moisture considerations and impact reports (very dry pastures), extreme (D3) drought was increased in coverage across the Texas Panhandle. The addition of abnormal dryness (D0) in east-central Tennessee was based on increasing 30-day deficits, SPEI, soil moisture, and 28-day average streamflows
Based on increasing 30 to 60-day precipitation deficits, 30 to 60-day SPIs, and CPC’s leaky bucket soil moisture, abnormal dryness (D0) and moderate drought (D1) was expanded across Iowa, Illinois, western Indiana, and Missouri. A swath of short-term severe drought (D2) was introduced to central Missouri where 60-day precipitation deficits exceed 4 inches and have support from soil moisture indicators for D2 intensity.
Rainfall of 1.5 to 2 inches, or more, during the past week along with SPI at various time scales and soil moisture supported a 1 to 2-category improvement to southeastern Colorado. For similar reasons, a 1-category improvement was made to southwestern Kansas.
However, 12-month SPI still supports D3-D4 across much of western and central KS. Wichita has only received 0.72 inches of precipitation from March 1 to April 30, which made it the 2nd driest March and April on record and the driest since 1936. Based on the NDMC’s short and long-term objective blends and CPC’s leaky bucket soil moisture, D1-D3 expansion was warranted for northern Kansas and south-central Nebraska. D3 was increased westward across west-central Nebraska following a very dry April.
North Platte tied the driest April on record. Degradations were also made to southeastern Kansas based on 60 to 120-day SPEI. Abnormal dryness (D0) coverage increased in northeastern Wyoming based on recent dryness and declining soil moisture. A small improvement was made to the southwest corner of South Dakota, based on a local report that was consistent with VegDri and objective drought blends.
30 to 60-day SPI along with soil moisture indicators support an expansion of abnormal dryness (D0) and moderate drought (D1) across southeastern Montana. 30 to 90-day SPIs, recent warmth, and soil moisture led to a 1-category degradation in northwestern Montana.
