HOUSTON (KIAH) — Goodbye, summer. Hello, fall! Meteorological fall, that is. NOAA’s Climate Prediction Center thinks most of the U.S. is likely to experience warmer-than-normal temperatures over the course of September, October and November. The rain outlook isn’t quite as clear, but favors drier-than-normal for a large area.
Meteorological fall vs. calendar fall: You may be saying, “wait, doesn’t fall officially start on September 22nd this year?” On the calendar, and in terms of Earth’s position to the sun, yes, the autumn equinox isn’t for three more weeks. But for weather and climate record-keeping purposes, the seasons are divided neatly into groups of three months. So, “meteorological fall” consists of September, October and November.
Back to the forecast, NOAA’s Climate Prediction Center weighs several factors into their long-range outlooks. One of those is the ongoing La Niña pattern. La Niña means the sea surface temperatures of the Pacific Ocean near the equator are cooler than normal, which impacts global weather patterns in a specific way.
For the U.S., the temperature outlook is a little more straightforward than the precipitation outlook. Some of the most populated areas, along the coasts for example, fall in the “equal chances” category. This doesn’t mean these areas will see near normal precipitation. It means these areas see an equal chance of above normal, below normal or near normal precipitation. Essentially, there is no clear indicator to make a confident forecast one way or another.
What about the outlook specifically for September? For temperatures, we see a large area leaning towards warmer than normal (mainly west), but we also see a large area in the vague “equal chances” range.
September’s precipitation outlook is even more tricky. Again, a large area falls in the “equal chances” forecast zone. Of course, in September, the wild card for the Gulf Coast states is the arrival of a tropical system. As of this writing on August 31st, a landfalling named storm is not expected within at least the next five days.