Wednesday, November 14th 2012, 2:35 pm
After our recent roller-coaster ride with temperatures, our pattern has leveled out - literally, in fact. We went from a deeply meridional flow (fancy talk for large troughs and ridges in the jet stream) to very zonal, west-to-east flow. In this latter pattern, we don't see any significant storm systems with weak waves of energy passing through the region every couple of days. What does that mean for us?
Deep troughs and strong ridges allow for extreme temperature distribution. As with this past system, a very cold air mass spilled down behind the cold front in association with the deep trough aloft in the jet stream. Ahead of it and before the front moved in, we were unseasonably warm. In the wake of that cold front and subsequent cool-down, the zonal flow has allowed temperatures to moderate to near-seasonal norms. That would be highs in the lower 60s and lows near 40 for mid-November. Without any storm systems of consequence, our weather stays nearly the same. Moisture return is minimal due to weak winds from the south.
The only change I see is a slightly stronger kink in that jet stream arriving by early next week. Stronger southerly winds may bring back enough moisture in time for some scattered showers for a day or two. Due to its more southerly origins, this storm system will not bring much cooler air behind it. In fact, as we head into the big travel week for Thanksgiving, temperatures will be on the rise as that zonal flow breaks down and a ridge of high pressure with warmer temperatures builds into the western 2/3s of the country.
While the holiday weekend lies just beyond our forecast range, we can see the general trend for warmer conditions. The Climate Prediction Center shows in the map above that we will not only be warmer, but likely, drier than normal over the Thanksgiving holiday timeframe. That bodes well for travel in this region of the country, but not well for our drought. It may be the end of the month before we see another strong storm system plow through the region. Thus, don't count on significant precipitation and more winter-like days for some time.
As with everything we forecast, the pattern is subject to change. At least, for now, I can provide some good news for folks planning to travel to see loved ones for Thanksgiving. The northeast may be the only trouble spot with a potential Nor'easter next week. Even that, however, is not a certainty at this point.
I'll keep you updated on Twitter: @GroganontheGO and on my Facebook page!
November 14th, 2012
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