Warmer Temperatures Arrive for the First of November - What's Behind the Warm Up

It may be good news for some.  For others, you may just be ready for the cold and snow.  But if you're looking for that during the month of November, you may just be out of luck.

Let's first start with the temperature outlook for November.  This comes from the Climate Prediction Center and was produced earlier in October.  If this outlook holds true, the Northern Plains and Midwest would have a higher likelihood for above average temperatures.  Now, does this mean 70's all the time?  No.  Because the average high during the month drops through the 50's and 40's, but temperatures would still be warmer.

And it looks like the first few days of the month will not disappoint.  Following a chilly Thursday afternoon, highs after Halloween will climb to the 60's for Sunday, November 1st, and then into the 70's for the 2nd through the 4th.  Looking into the extended forecast shows a few dips here and there, but no prolonged period of cold.  At least within the first couple of weeks of November.

Why are we going to see this type of pattern change?  Well, we have to look at what's going on in other parts of the world.  Everything across the globe is connected in weather.  Patterns in Asia affect what happens in the U.S.  It's like the Chaos Theory - a butterfly flaps its wings in Africa and a tornado forms in Oklahoma.  Everything in weather is connected.  So to understand why our temperatures will warm next week, we have to look out west...to the Pacific.  The Pacific hurricane season has been fairly active, but we're now in a period of suppressed activity.  This ultimately has an impact on our jet stream pattern.

We all know what El Niño and La Niña are, but what about other atmospheric patterns. One in particular is the Pacific/North American pattern.  According to the Climate Prediction Center, the Pacific/North American teleconnection pattern is one of the most prominent modes of low-frequency variability in the Northern Hemisphere extratropics.  This pattern has a positive and negative phase, and is in reference to heights in the mid-levels of the atmosphere.  Even though this pattern is something that naturally occurs, it is also influenced by ENSO (El Niño Southern Oscillation).  The positive phase of the PNA pattern is often associated with El Niño, while the negative phase is more so associated with La Niña.  What's happening out west is the PNA pattern has turned slightly negative.  This means mid-level heights will be rising in the Gulf of Alaska producing a ridge of high pressure.  This in turn causes the jet stream to buckle down the west coast, while forcing warm air into the middle and eastern part of the country.  Interesting, considering we're supposed to be entering into a strong El Niño pattern.

Even more interesting is that during past strong El Niño events, November has typically ended up below average!  During the '97/98 winter, when we had the strongest El Niño on record - the month of November was almost 7 degrees below average for Rockford.  During the '82/83 El Niño, November was nearly 2 degrees below average.  Opposite of what's expected this November.  So it's almost as if we've entered into more of a La Niña pattern.  Now, looking at the data we're pretty confident that's not going to happen as Pacific waters near the Equator remain very warm.  But it's interesting to take note and remind us that there is no 'typical' pattern when we are talking about weather.