It was already expected largely thanks to El Nino, but it appears that our December 2015 is off to a warm start. That warm start is going to get even warmer. Average temps this time of year are 44 degrees (high) and 27 degrees (low) and we could be 10-20 degrees above average over the next few days.
After a small weather system gave us a wet start Monday, we are going to start today off on a dry note. A few clouds will remain in place all day but highs in the lower 50s are expected. The temperature will be slow to fall tonight thanks to a south breeze and continued partial cloud cover. Lows will dip into the lower 40s.
A weak trough of low pressure will slide through the Ohio Valley on Wednesday. This rather benign weather maker will do nothing more than bring a few passing midday showers and one day of slightly cooler weather. Scattered light showers will be possible between 8 a.m. and 5 p.m. but it will not rain all day. Temperatures will be limited to the upper 40s as a result of the clouds and showers.
We return to warmth on Thursday afternoon after a morning low in the upper 30s. Highs will climb into the middle 50s under partly cloudy skies. One more very weak and moisture starved system will slide by Thursday night but nothing more than a sprinkle is anticipated.
A much larger weather system will take shape across the Plains this weekend. On the leading edge, a warm front will develop and move into Ohio on Friday. This will lead to overcast skies and a few light showers. It will be quite mild again with highs in the upper 50s. Overall, the weather will not be too bad besides a few passing light showers mainly late in the day.
Most of these passing showers will move north on Saturday with the warm front besides just one or two spotty ones. Temperatures will get yet another shot in the arm as deep southerly flow pumps even warmer air into the Ohio Valley. Highs on Saturday will push above 60 degrees, some 15-18 degrees above average. Partly to mostly cloudy skies will prevail as the southerly flow continues to stream moisture into the area.
We may push the middle 60s on Sunday even with continued mostly cloudy skies. A strong cold front will surge east on Sunday night attached to a powerful low pressure system moving into the Great Lakes. This will bring rain and gusty winds well after dark Sunday night into early Monday morning. We will see a “cool down” back to average temps (40s) on Monday.
Long Range Outlook
A very active Pacific jet stream (possibly influenced by El Nino) will continue to batter the west coast over the next couple weeks. This results in an average trough position in the jet stream over the west coast and promotes ridging over the eastern U.S. The sensible weather result is mild air streaming west to east (rather than cold air from the north). As stronger bundles of energy roll east, stronger areas of low pressure will develop, like this weekend for example. These lows can pull down some cooler air behind them temporarily, but a return to the large scale pattern is likely shortly afterward.
After a week of above average temperatures through Sunday, one of these brief cool downs to near or slightly below average appears possible at the start of next week. This will be followed by a return to warmer weather fairly quickly. Another shot of cooler air is possible between the 18th and 21st. Unfortunately there are no signs yet of snowfall before Christmas. In fact, the beginning of Christmas week could be rather mild. But this is still fairly far out…So stay tuned!