Indian Summer Expected With Big Changes to Follow

As I write this blog post, the “Super Moon” is in the sky and we’ve got super weather to enjoy it.  Aside from a few clouds, the viewing should be spectacular for this unusually bright orb above. The reason we have a “Super Moon” is because the moon’s orbit is elliptical. When its closest point to the earth (its perigee) corresponds to a full moon, we get the “Super Moon” title. This will be the largest and brightest in nearly 70 years!

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                Our unusually large moon ushers in an unusually warm stretch of weather for mid-November. Despite having a light freeze over parts of Green Country this morning (shown above), tonight and subsequent ones ahead this week have no threat of freezing conditions.  That’s because another ridge of high pressure in the upper levels of the atmosphere will build overhead through midweek, allowing for clear skies and daytime temperatures to soar to near-record levels by Wednesday and Thursday.  We’re not alone in this warm spell. Most of the United States is experiencing a lack of cold air, which is starkly apparent in the lack of snow cover. Only 0.3% of the Lower 48 is covered in snow at this time, and that includes the Rocky Mountains.  Compare that to two years ago on this date, and you can see how parts of the country can be in the throes of winter already.

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                Even in one of the warmest falls on record, upper 70s for highs and lows in the 50s just can’t be sustained very long by this point in the year. There’s simply too much cold air building in the northern Hemisphere. A strong storm system moving ashore on the West Coast this week will put our Indian Summer to an end. While the cold front won’t arrive until early Friday, the effects of this system will be felt by midweek. Strong southerly winds will be induced by this system. Initially, it won’t bring back much moisture, but allow the unseasonable warmth to build. That combination of warmth, dryness and strong winds means we’ve got fire danger on our hands.  From Wednesday through Friday, avoid any burning outdoors as flames could quickly spread out of control, especially as lots of our vegetation is going dormant.

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                Our late-week storm system will be missing one main component for heavy-duty storms in its passage: moisture. While some moisture returns from the Gulf, it may be too little too late for parts of the state. Green Country stands the best chance of seeing showers and a few storms late Thursday night into Friday midday with slightly more atmospheric moisture on hand. However, the fast-moving nature of the system won’t allow for much rain to fall before dry, cold winds kick the storms east of us. It’ll be a narrow wind of time for those rain chances early Friday.

                This system will do what most of our previous cold front have not done well: bring us cold, Canadian air.  While it will modify on its southward journey, the weekend ahead will be cooler than normal with our first widespread freeze likely Sunday morning. Tulsa’s first freeze will likely end up being about 18 days past our average first freeze date. If the winds later this week don’t strip our trees of most of their leaves, this freeze will bring more coloring to our foliage, which has been running a few weeks behind this season.

                While next weekend will bring the coldest air of the season thus far, it doesn’t look like it’ll hang around for long. The jet stream pattern during Thanksgiving week will be fairly zonal with the west-to-east winds aloft holding back a cold air intrusion from the high latitudes. In other words, there’s little to cause a major cold snap.  Instead, we might have a few storm systems to glide through Oklahoma. It may bring a wetter than normal pattern that week, but warmer than normal temperatures appear likely to return through the holiday. Even if it’s rainy at times, it sure beats an early winter storm during the busiest travel week of the year!

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                Be sure to follow me on Twitter: @GroganontheGO and on my Facebook page for more weather updates!