Weather Blog

Heat wave over, what's next?

Heat wave over, what's next?

Now that temperatures are back to quasi-normal around here, people are already thinking about the next step. We've had quite a few e-mails asking how the autumns and winters shaped up after the last time we had such an extended heat wave: 1977.  In the 19 days between July 30 and Aug. 17 that year, the average high temperature was 88.3 degrees.

This year, for the 18 days between July 15th and Aug. 2 (our recent hot stretch) the average high was 86.0 degrees.

On the other hand, in 1977, the following 19 days after the heat wave broke, the average high was just 69.3 with 11 of the 19 days rainy. In fact, it went on to become the third wettest August, just based on the 18th-31st alone.

The short term forecast seems to indicate we're going to try and at least follow the trend. The next seven days are featuring a few days with rain and temperatures in the upper 60s to low-mid 70s.

Beyond this week, the medium range forecasts indicate more of the same.

Here are two 6-10 day forecasts trends from the National Climate Prediction Center:

Temperature: http://www.cpc.noaa.gov/products/predictions/610day/610temp.new.gif
Rainfall: http://www.cpc.noaa.gov/products/predictions/610day/610prcp.new.gif

These maps indicate our big heat wave is moving east, about to bake the Midwest for a while with an extended hot and dry period.  But actual forecast models show it won't be all that unusual of a heat wave, might not even last that long, and that actually the far upper Midwest might remain cool. But Midwest heat periods usually translate to cool and rainy here, and the forecast map agrees.

Beyond that? Not much change. Here is the 8-14 day forecast:

Temperature: http://www.cpc.noaa.gov/products/predictions/814day/814temp.new.gif
Rainfall: http://www.cpc.noaa.gov/products/predictions/814day/814prcp.new.gif

What about fall and winter?

This is really not the best way to forecast, because just because you follow one trend doesn't mean you'll follow the script for months on end. (For example, the summer after the winter of 1949-1950 was a little cooler than normal -- certainly not the case after our frigid winter).

But since many people are asking...

September, October and November 1977 also ended up cooler than normal, although not significantly so. December was a touch warmer than usual, while January and February 1978 was warmer.

Rainfall was pretty much average over the course of the winter.

As far as this upcoming fall and winter goes, climate prediction models show equal chances for above or below normal temperatures, but above normal chances for a drier winter, which would be in step with the budding El Nino.

If you're interested in these long range forecasts, bookmark these next two links, which show the predicted 90 day forecasts for the next several months:

Temperature: http://www.cpc.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/t.gif
Rainfall: http://www.cpc.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/p.gif

In the meantime, enjoy the cool, rainy weather for a change :)