2021 Summer Forecast from Weather Works

2021 Summer Forecast

Inside This Outlook

Recapping Summer 2020 2

2021 Summer Forecast 2

Monthly Forecast 3-4 Breakdown

Outlook Insights 4 2021 Summer Forecast Recapping the Summer of 2020 The summer of and Maryland see- 2020 was the ing their second tenth consecu- warmest overall. tive warmer than average summer It was a fairly dry across the Low- summer nation- er 48, coming in ally, coming in as as the 4th warm- the 33rd driest est out of the summer on re- last 126 seasons. Cooler Warmer Drier Wetter cord. Precipitation The most anom- lacked the most alous heat was Summer 2020 Temperature (left) and Precipitation (right) Ranks. NCEI/NOAA. in the Southwest across the Four and the Plains. It Corners, Upper Midwest, Great Lakes, Northeast, and was also rather dry across the southern Great Lakes and Mid-Atlantic. More seasonable conditions were found upper Ohio Valley, as well as into much of New England. towards the lower Mississippi Valley. Massachusetts, However, the lower Ohio Valley and Mid-Atlantic were a bit Rhode Island, and Connecticut recorded their warm- wetter, partially fueled by tropical impacts from Fay and est summer on record, with New Jersey, Delaware, Isaias. Summer 2021 Forecast Overview

Will 2021 bring us an 11th consecutive warmer than av- Another somewhat dry summer appears likely across erage summer for the U.S? Based on our forecast, it the nation, though much of that dry weather is ex- is quite likely. The hottest weather is expected to be pected to be focused out west. With many areas al- focused across the West, and like last summer, we do ready in a drought in the western U.S., another worse expect a pool of closer to average temperatures near than normal fire season is distinctly possible this the Mississippi and Ohio Valleys. Along the East Coast, summer and fall. It will be wetter across much of the there may be one or two big heat waves, and similar eastern U.S., though the Upper Midwest and northern to last summer, we expect the mild nights and lack New England are also at risk to occasionally turn dry. of cool downs to drive the above normal values. Into The upcoming sections provide more details to our the Midwest and Ohio Valley, June may be the hottest temperature and rainfall forecasts for each month month relative to normal, with more seasonable tem- this summer. peratures for the rest of the summer.

Page 2 www.weatherworksinc.com 2021 Summer Forecast Temperature Outlook June 2021 Forecast • A warm June is expected across most of the coun- try, though the warmth is expected to be most pro- nounced in the western U.S., especially later in the month.

• Much of the eastern U.S. will likely be warmer than normal, with the first half of the month favored to see the most anomalous heat. A few cold fronts likely bring briefly cooler weather in late June, especially across New England.

• The central U.S. likely trends hotter through the month, with periods of slightly cooler weather early on across the Plains. Precipitation Outlook • Dry conditions are expected across most of the western United States, with particularly dry weather in parts of the northern Rockies, worsening through the month.

• Parts of Florida and perhaps northern New England may also be a bit dry at times.

• Active weather is likely from the Mississippi Valley on east into the Ohio Valley and the northern Mid-Atlantic. This may include some severe weather, especially when fronts interact with the unseasonable warmth towards the East Coast.

July 2021 Forecast Temperature Outlook • Overall, July will be another very warm month across the Low- er 48, with the worst of the heat from the Plains and Upper Midwest, through the Rockies, and towards the West Coast.

• A trend to more “typical” temperatures is expected across the Ohio Valley, Southeast, and even the southern Mid-Atlantic, though humidity levels likely remain uncomfortable.

• New England is expected to remain warm and rather humid, along with nights that don’t cool off much.

• The more seasonable temperatures will likely be accompanied Precipitation Outlook by a wetter pattern from the Ohio Valley and Appalachians into the northern Mid-Atlantic and southern New England. Tropical development will need to be monitored for increased rainfall.

• The western and central U.S. will generally be on the dry side again in July, with the least amount of rainfall across the Pa- cific Northwest, northern Rockies, and northern Plains.

• Signs do point to the monsoon ramping up across the Four Corners, which may bring some needed rainfall to the region.

Page 3 www.weatherworksinc.com 2021 Summer Forecast Temperature Outlook August 2021 Forecast • The trend of overall warmth continues, with the heat focused out west.

• The pool of “cooler” weather likely shifts west towards the Mis- sissippi River in August.

• Signs point to both heat and humidity ramping up along the East Coast. The pattern may not favor big heat waves, but it looks persistently warm and humid with mild nights.

Precipitation Outlook • Unfortunately, the Pacific Northwest and northern Rockies are unlikely to see much drought relief, with dry weather across the Plains as well. The monsoon may try to provide some relief to the Southwest U.S.

• Parts of New England and perhaps the northern Great Lakes look to trend somewhat drier for the month.

• Frequent rainfall is expected from the Ohio Valley into the Southeast and Mid-Atlantic. As we near the peak of hurricane season, the risk for tropical moisture getting drawn into the Gulf Coast, Southeast, and perhaps Mid-Atlantic will increase. Outlook Insights Drought Concerns La Niña Weakens In summer, the large-scale weather pattern still helps to drive temperature and rainfall trends, but it has a weaker influence than in winter. This means that other, more localized factors can have a greater affect on the weather. In summer, dry conditions tend to promote continued hotter, drier weather. Much of the western U.S. is in a deep drought, and this is an area that will likely remain hot and dry this summer. We’ll watch areas such as the Great Lakes and the Northeast, as some areas have recently trended drier.

El Niño forecast plumes, courtesy of the ECMWF. Summers that occur during a La Niña (cooler waters across the tropical Pacific) tend to favor hotter, somewhat drier summers across the U.S., while those that occur during an El Niño (warmer waters in the tropical Pacific) tend to be cooler and wetter. The La Niña that was in place since last year is weaken- ing. However, there are no signs of strong El Niño development yet, which means there will be either little Current Drought Monitor. Via USDA/NDMC/NOAA. influence or perhaps some lingering La Niña effects.

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