U.S. climate outlook for November 2024
Despite another warmer-than-normal month over most of the Unites States, the big story during October was the extremely dry conditions observed almost coast to coast. With the exceptions of peninsular Florida, which Hurricane Milton pummeled with upwards of 6 inches of rain in a single day, the extreme Pacific Northwest, and small parts of the Southwest, the remainder of the contiguous U.S. generally received less than 50% of normal precipitation, with some parts of the eastern U.S. receiving virtually no rainfall during the month.
Although records haven’t been finalized, October 2024 is likely to be one of the driest months ever recorded for the country. Not surprisingly, the very dry month resulted in a large increase in drought coverage. Will dryness continue over much of the nation during November? And despite fall featuring generally warmer-than-average months thus far, will winter get off to an early start with some colder-than-normal temperatures? Read ahead to find out what NOAA’s Climate Prediction Center (CPC) predicts for November.
On October 31, CPC released its updated monthly climate outlooks for temperature, precipitation, and drought across the United States for November 2024. The temperature outlook favors well above average temperatures across the central and eastern parts of the nation, as well as in northern Alaska. The precipitation outlook favors well above average precipitation in the Pacific Northwest, across parts of the central U.S., and in southern Alaska, with below-average precipitation only favored right along the East Coast from North Carolina to Maine and in extreme southern Louisiana.
If you decide to keep reading (and I hope you do), I’ll provide more specific information about the outlooks and what they are based on, discuss the changes in drought during October, and present the drought outlook for November. Finally, my ever-present reminder: the colors on the temperature and precipitation outlook maps provide information about the most likely outcome, but other outcomes are also possible, just less likely. More details about interpreting the outlooks can be found here.
The updated outlooks were produced considering the Week 1 forecast from the Weather Prediction Center (WPC), and CPC’s own 6-10 day, Week-2, and Week 3-4 outlooks. Other tools that forecasters examined this month included longer-range forecast models such as the Global Ensemble Forecast System (GEFS), the Climate Forecast System (CFSv2), and the European Ensemble Forecast System (ECMWF) as well as products derived from these models. Although La Niña has yet to officially arrive, expectations that it will soon played a small role in the November outlooks. The Madden-Julian Oscillation (MJO) has remained active, but its typical impacts on the U.S. (cool conditions in the East) are out of phase with model guidance later in the month (which predicts above-average temperatures), so the main impact from the MJO was to moderate the model-based probabilities.
Outlook favors above-average temperatures in the Eastern and Central U.S.
The November temperature outlook favors well above average temperatures across all of the central and eastern parts of the nation and in northern Alaska. (Well above average means “in the warmest third of all Novembers in the recent climate record.”) No parts of the Lower 48 states are favored to have a colder-than-average month, although temperatures in southern Alaska are slightly favored to be below average, and with equal chance odds (1/3 chance each of below-, near-, and above-average) found in the western part of the country.
The greatest odds for a warmer-than-average November are found in the eastern parts of the nation, with probabilities exceeding 50%. These probabilities might have been even higher, as official outlooks during all periods (WPC’s Week-1, and CPC’s Week-2 and Week 3-4) favor above-average temperatures. However, the MJO would favor cooler solutions in the longer term for this region, injecting some uncertainty into the longer-range outlook. Likewise, the equal chance forecast in the West is somewhat dependent on typical impacts in that area when the MJO is "upstream" in the Pacific. Those favor average to above-average temperatures, while the official longer-range outlooks have a slight tilt in the odds toward below-average temperatures, continuing expectations for below-average temperatures expected during the beginning of the month. Across Alaska, trends favor above-average temperatures along the northern coast, while La Niña favors cooler-than-average temperatures along the southern Alaskan mainland and panhandle. However, November looks to begin above average in southern Alaska, so probabilities for below-normal temperatures for the month are quite modest.
Precipitation outlook tilts wet in the middle of the nation
The precipitation outlook for November favors above-average rainfall across parts of the central U.S., in the Pacific Northwest, and in southern Alaska. The highest odds extend from the Southern Plains to the Great Lakes (greater than 50%), where forecasts for the first week of the month predict 2-5 inches of rain. Early month activity and the developing La Niña favor above-normal precipitation across the Pacific Northwest and southern portions of Alaska, including the Alaskan Panhandle.
Below-average rainfall is only slightly favored along parts of the Eastern Seaboard and in extreme southern Louisiana. A dry start to the month along the East Coast, combined with Week-2 and Week 3-4 outlooks of near or below-average precipitation is enough to favor below-average precipitation from North Carolina to Maine. However, probabilities are low with uncertainty high, as the Madden-Julian Oscillation would favor troughing (jet stream shifted south of normal) across the middle of the nation, potentially bringing moisture northward and eastward during the middle and latter parts of the month.
U.S. Drought area shows significant increase during October
After one of the driest months the United States has ever seen, it should come as no surprise that the amount of drought across the contiguous United States significantly increased during October. Drought coverage increased about 20% during the month, with around 54% of the nation experiencing some level of drought at the end of the month. In addition, just over 87% of the nation is now at least abnormally dry, the largest coverage ever in the history of the U. S. Drought Monitor dating back to 2000. Although the percent of the country in the two most intense categories (D3-D4, representing extreme and exceptional drought) more than doubled to 6.5%, that amount is still fairly low when compared to the amount of the country currently in drought.
Regionally, drought degradation was quite prevalent across most of the country with only a very few small regions seeing just a one-class improvement. The largest negative changes were on the order of 2-3 classes, mainly in the middle of the country, although there was some 2-class degradation along parts of the East Coast. Out West, drought changes were almost entirely one class, as rainfall deficits were more modest, as October is not normally a particularly wet month.
Drought outlook predicts improvement in the center of the country, persistence or development in the East
With above-average precipitation favored throughout the middle of the nation, drought improvement with some drought removal is predicted from Texas northward to the Great Lakes. However, improvement was limited only to those areas where the heaviest rainfall is forecast during early November. Broad-scale drought persistence is expected for most of the West. Improvement, at least in the Pacific Northwest, becomes more likely beyond the end of November, as indicated in the seasonal drought outlook valid through the end of January. Based on precipitation deficits dating back to September, declining soil moisture, and continued dry weather through at least the first part of November, drought persistence and development are forecast for parts of the Southeast, Mid-Atlantic, and in the Northeast.
To read the entire discussion of the monthly climate outlooks from the Climate Prediction Center, check out their website.