Weather Blog: September 2021 outlook

Weather Blog

A look at the September 2021 temperature and precipitation outlooks for NW Arkansas and the River Valley.

September is finally here and marks the start of the fall season and the transition to winter. Here is a look at how the overall pattern is shaping up across the Lower 48 and Northwest Arkansas for the 9th month of the year.

Temperature Outlook

The Climate Prediction Center’s forecast shows an overall warmer pattern for September across the Pacific Coast states and western Rockies. Southern Florida and New England are also slightly favored to see above-average temperatures overall for the month.

The forecasted weather pattern in Central Gulf Coast and Lower Mississippi River Valley leans more towards a slightly cooler than average September.

The rest of the Lower 48, including Northwest Arkansas and the River Valley region, are in the neutral zone. This means there is an equal chance for September to be above average or below average overall in these areas.

Precipitation Outlook

The Climate Prediction Center’s forecast for precipitation in September favors above-average rainfall in the Northeast and Mid-Atlantic, however, the remnants of Hurricane Ida greatly influenced this output. The pattern is expected to favor above-average rainfall in the Gulf Coast region and the southern Rockies.

Drier than average conditions are expected overall for September in the Pacific Northwest. The Central Plains and upper Great Lakes region have an equal chance of either below-average precipitation or above-average rainfall throughout September.

Northwest Arkansas and the River Valley region are included in the neutral zone, signaling the pattern favors neither a wet nor dry September this year.

September Preview

Northwest Arkansas

We definitely cool off in September! Fayetteville’s average high temperature throughout the month will fall from the mid-80s into the upper-70s while overnight temperatures drop from the low-60s to the low-50s.

We also lose 1 hour and 5 minutes of daylight throughout the month. Our sunrises will occur after 7 A.M. by the end of the month. Northwest Arkansas’s sunsets will occur just after 7 P.M. by September 30, 43-minutes earlier compared to the start of September.

In the precipitation department, we typically see about 4.26″ of rain in September at Drake Field in Fayetteville.

River Valley

The River Valley’s average high will drop below 90°F in September, and be in the low-80s by the end of the month. Overnight lows will fall from the upper-60s to the upper-50s.

Our sunrises in the River Valley will do a 180-degree flip to the other side of 7 AM, going from 6:50 AM to 7:12 AM by the end of September. The sunset will move up by 42 minutes throughout the month, occurring just after 7 PM on September 30th. Overall, the River Valley will lose 1 hour and 4 minutes of daylight this month.

Northwest Arkansas typically sees a little more rain compared to the River Valley. Overall, Fort Smith Regional Airport picks up just over 4-inches of rain in September.

Keep in mind, this is an overall look at the pattern for September 2021. The daily/weekly variations in the forecast may not follow the outlooks exactly. Be sure to stay up to date with your Weather Authority team on all the forecast details on-air, online, and on social media!

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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