USA NATIONAL FORECAST
Pattern Change Could Bring Severe Storms, Heavy Rain and Snowstorm to Central and Western States; Fall Heat Will Hang On in East
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Pattern Change Could Bring Severe Storms to Central and Western States
A weather pattern change the first weekend in October could bring a snowstorm to parts of the western states, severe weather to the central states and continued above-average warmth to the East.
At a Glance
- The jet stream will divide temperatures in the Lower 48 late this week and into the weekend.
- A snowstorm is possible in the Rockies and High Plains.
- Severe storms and heavy rain could accompany the storm system in the central states.
A weather pattern change during the first weekend in October could bring a snowstorm to parts of the western states, severe weather to the central states and continued above-average warmth to the East.
The jet stream, a ribbon of strong winds above the Earth's surface, will take a sharp plunge southward across the West this weekend while riding well to the north over the eastern states. Much of the week ahead will feature this weather pattern, as well, but in a less amplified manner than what is expected over the weekend.
When such an exaggerated north-to-south-oriented jet stream pattern takes shape during the fall, it typically results in a dichotomy of weather conditions across the United States.
Temperatures are usually split between colder-than-average and warmer-than-average. In this case, above-average high temperatures are forecast late this week and into the weekend from the Southeast into the Ohio Valley and mid-Atlantic.
Fresh off one of its warmest Septembers on record, the Southeast will continue to see unfall-like temperatures as highs rise into the mid- to upper 80s late this week and into the weekend.
Forecast Highs
(The contour shows where temperatures on Saturday will be above average (yellow, orange) and below average (blue).)
From the Rockies to the northern Plains and upper Midwest, an initial shot of chilly air will drop temperatures below early-October averages Wednesday and Thursday. Another charge of cold air will then quickly move in this weekend across the West and Plains as the previously mentioned jet stream takes a deeper dive south.
Highs in the 30s, 40s and lower 50s will be common from the Rockies into the northern Plains and upper Midwest during this time.
Less certain than the temperature forecast is the timing and locations affected by a potential trifecta of threats that could materialize:
- Snow: A significant early-season snowstorm is not out of the question from the northern and central Rockies to the High Plains Sunday into early next week. This could be preceded by an initial round of snow from the northern Rockies to North Dakota Thursday into Friday.
- Thunderstorms: Strong to severe thunderstorms could take aim at the nation's midsection later this weekend and into early next week. When a powerful plunge of the jet stream dives into the Rockies and there is warm, moist air to tap into over the Plains, it typically leads to the development of numerous showers and thunderstorms. Depending on how those ingredients come together, severe thunderstorms with damaging winds, hail and even tornadoes would be possible.
- Excessive Rain: Repetitive downpours could affect portions of the Plains and Midwest late this week through early next week. Too much rain over the same area could eventually lead to flooding.
Sunday's Weather Forecast
(A developing storm system could bring severe storms and heavy rain to the central states as a snowstorm takes aim at the Rockies and northern Plains.)
It's too far out in time for specifics on the magnitude of those potential threats, but we'll provide updates on weather.com throughout the week ahead.
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