Map released Nov. 6, 2020 | Data valid Nov. 3, 2020
This week’s drought summary: Hurricane Zeta made landfall near Cocodrie in southeastern Louisiana during the late afternoon on Wednesday, Oct. 28, as a Category 2 hurricane with sustained winds estimate at 110 mph. With a fast northeastern track that took it off the mid-Atlantic Coast in about 24 hours, the rapid pace limited rainfall totals along its track to between two and four inches, with locally heavier amounts in southern Mississippi and Alabama of up to eight inches. Unfortunately, the fast pace delayed the weakening of Zeta’s winds, and widespread wind damage and power outages occurred along Zeta’s path, even into the mid-Atlantic. In addition, as the period started, an upper-air low over the southern Rockies slowly tracked eastward, becoming infused with tropical moisture from Zeta and the Gulf of Mexico. It dumped 1.5 to 3.5 inches of precipitation, locally to five inches, from the western Oklahoma and northern Texas Panhandles eastward across northern Oklahoma and southern Kansas, southern Missouri and northern Arkansas, and into the Ohio and Tennessee Valleys.
Although the precipitation was beneficial to the winter wheat crop and pastures, some of the precipitation fell in the form of snow and freezing rain in West Texas, Oklahoma, and Kansas, causing damage. Once the upper-air low and Zeta cleared the East Coast, much drier and colder air rushed into the Northeast and Southeast, with light snow accumulating across parts of western New England and upstate New York.
Elsewhere, little or no precipitation occurred in the Far West, Southwest, Rockies, southern and northern Plains, and upper Midwest. Subnormal weekly temperatures enveloped the Midwest, Southern and Central Plains, and Northeast, while the West, Rockies, and Southeast experienced near to above-normal readings. Welcome showers fell across most of Puerto Rico while drought expanded across portions of Hawaii’s Big Island.
South: As the week started, the upper-air low over the southern Rockies tapped Gulf moisture, bringing welcome and beneficial precipitation (1.5-5 inches) to the south-central Plains. Unfortunately, the demarcation of the haves versus have-nots was sharp, with southern Kansas, the northern half and far eastern Oklahoma, and the Panhandles of Oklahoma and Texas coming out favorably. Accordingly, the copious precipitation resulted in one and two category improvements, particularly in northwestern Oklahoma where three to five inches fell, including some light amounts the previous week.
Western Texas, much of it in D3-D4, did receive some light precipitation (0.25-1 inch), but could have used a lot more, and improvements were minimal. In contrast, little or no precipitation fell on the southern half of Texas for the second consecutive week, resulting in additional degradation. October is normally one of the wetter months in south-central Texas, so with many locations measuring less than 25% of normal the past 30 days, short-term deficits have rapidly accumulated. USGS 7-day average stream flows have also picked up on the dryness, with many gauges in the much below category (less than tenth percentile).
Looking ahead: During the next five days (Nov. 5-9), a change in the upper-air pattern should bring unsettled weather (cold and wet) to the West, including moderate to heavy totals (one two three inches) to the Cascades, Sierra Nevada, and Rockies, according to WPC’s five-day QPF. Light rain is expected in the upper Midwest, while moisture from the remnants (or reformation) of Hurricane Eta (currently in Central America) will soak southern Florida. The rest of the contiguous U.S. should be mostly dry. Temperatures during the next five days will average above normal for much of the Nation (from the Rockies eastward), while cooler weather envelops the Far West.
The Climate Prediction Center’s 6-10 day outlook (Nov. 10-14) favors above-normal precipitation across Alaska, the Northwest, Midwest, and East Coast. Subnormal precipitation was limited to the northern Plains, with equal chances elsewhere. Odds for subnormal temperatures are quite likely across the West, Rockies, and High Plains, while above-normal readings are strongly favored in the eastern third of the Nation.