Summer is far from over for the Western United States.
Labor Day is fast approaching, yet the atmosphere seems to be resisting the advance of the calendar.
In most areas of the West, temperatures have again been running hotter than normal during each month of the summer.
Many of us think about early September as marking the beginning of cool morning temperatures, shorter days, and the gradual transition toward fall weather. This year, however, the transition may come a little later than anticipated in certain areas.
For people hoping to escape the summer heat, relief may take a little longer to arrive.
Stronger ridging patterns anchor persistent summer warmth
El Niño conditions are continuing to become stronger across the equatorial Pacific according to NOAA’s forecast discussion. Forecasters indicate that these conditions will begin to exert a larger influence on weather patterns.
That influence is expected to increase as the Northern Hemisphere advances further into fall.
Additionally, NOAA’s forecast discussion includes favorable ridging over western North America.
Atmospheric patterns characterized by ridging typically contribute to warmer-than-average temperatures due to sinking air and generally stable atmospheric conditions.
NOAA’s week 3-4 temperature outlook indicates above-average temperatures across much of the western United States. Elevated probabilities for unusual warmth also extend into parts of Alaska.
Individual weather systems will continue to pass through the region.
However, most forecasters feel that the prevailing pattern will continue to produce above-average temperatures.
Late-August and early-September windows capture the anomaly
The timing of this unusual warmth is becoming apparent.
NOAA’s Week 3-4 Outlook covers the period from Aug. 29 through Sept. 11.
During this period, above-average temperatures are predicted across much of the western United States.
The forecast discusses expected ridging over western North America as being responsible for continued warmth in the region.
Forecasts continue to show increased chances for above-average temperatures across large sections of the western U.S. during this late-summer and early-fall period. The latest outlook from NOAA’s Climate Prediction Center supports that pattern.
NOAA outlooks point to a delayed seasonal transition
September 1 marks the beginning of meteorological autumn. However, large-scale atmospheric patterns often have a greater influence on temperatures than the date shown on a calendar.
New outlooks continue to favor above-average temperatures across a large portion of the western United States.
Those warmer-than-normal conditions are expected to persist as August transitions into September. The forecast signal remains strongest across much of the western U.S. this period.
Current forecasts indicate that many western communities can anticipate higher-than-normal temperatures during the first weeks of September. While record-breaking heat is not expected, western communities should still prepare for unseasonably warm conditions.
For many people in the western United States, cooler fall weather may take longer to arrive.
Contrasting temperature trends emerge across Alaska and the Great Lakes
At the same time, NOAA indicates a reduced confidence level regarding temperature anomalies outside of the western U.S. A very small area surrounding the Great Lakes is one of the few places where below-average temperatures are predicted.
Above–normal temperatures are favored across much of Alaska as anticipated southerly flow continues to influence the region.
Forecasters also favor warmer-than-normal conditions along parts of the southern tier of the United States.
The highest confidence levels appear along parts of the Gulf Coast, where convection should be less frequent than normal at this time of year. The calendar may say autumn has arrived.
Conditions across much of the West could continue to feel much more like late summer.
As more forecast information becomes available, weather patterns can continue to develop. NOAA’s forecast continues to favor unusual warmth across much of the West into early September.
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