Cincy ForecastDaily Weather Updates and Analysis

Intro/Overview
With the start of meteorological winter only a month away, it is time to take an in-depth look at what we should expect to see across the Ohio Valley! To start things off, let’s review what the trends have been over the last several months, as they are very useful to examine when long-range forecasting. For a good part of 2009 (stemming back to last winter), the Ohio Valley has been cooler than normal overall, even with a few above normal periods thrown in from time to time. Going hand-in-hand with the cooler than average temperatures has been above normal rainfall. It was actually quite something to go through the summer/fall months with repeated rounds of rain/t-storms during what we would consider our dry season. So let’s see…a cool spring/summer/fall overall (with July being the COLDEST ON RECORD for many locations across the country, including the tri-state) along with abnormally wet conditions. With such a persistent pattern, it would make a lot of sense that our winter will reflect it as well. While a stormy/cool spring/summer doesn’t always guarentee the same for the winter, it surely needs to be considered…

Solar Minimum
Being that weather/climate’s biggest controller is the sun, it’d only make sense to make this my starting point! Around the new millenium, the sun began showing signs of quieting down. Since then, we have really seen a significant drop in the amount of sunspots/solar activity, which correlates nicely with the decreasing global temperatures (even significantly in many areas around the globe). The current solar minimum has actually been rated one of the lowest on record, which really goes to show that we need to keep the sun on our minds when forecasting. Subtle changes in the sun don’t always translate to “the ground” in very noticeable ways, but when you have these impressive minimums (or vice-versa), the effects really begin to show their faces (i.e. record cold, decreasing global temperatures, etc). While it is being overlooked by some forecasters (as well as the driving force behind the AGW movement), the weak sun DEFINATELY needs to be taken into account when making forecasts for the upcoming winter.

El Nino
Beginning in early 2009, we really began to see the prospects of an El Nino event coming together. SSTs across the equitorial Pacific began to slowly rise, and as of today, we have offically passed the moderate El Nino threshold. I expect this to be about as “strong” as this phase will get, though I expect it to increase a bit more before beginning to fall over the next couple of months. For the US, a typical El Nino event is depicted by an active southern storm track and cooler than average temperatures across the southern states. That is what we TYPICALLY witness with El Nino events. However, when taking into account the weak sun, adjustments to what is TYPICALLY seen need to be made. I definately beleive that we will have a very active southern storm track. However, what will make this ENSO event different is the amount of colder than average temps. This time around, I don’t expect it to be confined to the southern regions, but rather encompass much of the country. Mark my words…this winter will go down in the record books for many locations across the country for the amount of cold air witnessed.

NAO
When long-range forecasting, teleconnections are very useful to observe and track. The NAO (North Atlantic Oscillation) is one of the bigger players in our weather patterns across the Ohio Valley/NE. When negative, we typically see a large amount of “troughiness” across the east, leading to cooler than normal temperatures. Currently, the NAO is around neutral, but is expected to become positive for the beginning of November (before tanking to negative levels shortly thereafter). Overall, I expect the NAO to show a dominance of neutral/positive values for the first part of winter, before becoming negative for the remainder (correlating with the expected fading of El Nino).

PDO
Like the NAO, the PDO (Pacific Decadal Oscillation) is another teleconnection with a strong control over the USA’s weather. The biggest indicator of what phase the PDO is in would be the SSTs just off the West Coast. In a negative phase, they cool rather significantly, and vice-versa with a positive phase. Currently, the PDO is negative, albeit currently rising towards more of a neutral level. El Nino is a big player in the level of the PDO, which is why it’s currently negative. Because of the warm SSTs over the Central/Western Pacific, the PDO needs to be negative in order to maintain balance. Consequently, a negative PDO leads to troughing over the west and ridging over the east/western atl ocean (which we have begun to see more of in recent weeks, though not very persistent). However, once El Nino begins to fade (especially during the second half of the winter), the PDO will become positve and the NAO will enter what will likely be a long phase of negative values. Once that occurs, I really think we will have a lot of fun around here (though I still expect some wintry action before that).

Snow/Ice Cover (setting the stage)
Even after looking at the ENSO pattern, solar activity, and various teleconnections, it is also very important to examine the snow/ice cover trends. Coverage of both snow and ice is fairly substantial to our north, with many areas being ahead of schedule. A solid snow/ice cover to our north allows the cold air to really collect/build up. We are in that stage of the game right now. The amount of cold air building to our north is very impressive, and will no doubt be tapped into repeatedly over the upcoming winter months.

Putting It All Together
Now is the time to put all of the data and trends together. I am forecasting a cooler than average winter across the Ohio Valley, along with above normal snowfall. The Cincinnati area typically receives just over 20″ of snow each winter, but I’m expecting a good 25-35″ this time around, with the highest totals falling to our north/northwest. Temps will be cooler than average overall, though I still expect a few periods of “milder” air (though not enough to offset the dominance of cold).