Mike Grogan Weather Blog: Rain In The Forecast After Christmas

We’ve just made it through the longest night of the year on this first full day of winter, which also happens to be the coldest we’ll see in quite a while. Temperatures that dip below freezing are normally routine by this point in the season, but the lack of Arctic air is still making it a rarity.  The coldest temperature of the season has been 25° from last week. Technically, we haven’t even had a “killing” freeze in Tulsa (24°) and we’ll likely break the record here for the latest first occurrence of the season currently at December 28th.  El Niño continues to be the biggest driver behind this.

El Niño is also driving an active storm pattern for us this Christmas week.  It drives moisture-laden storm systems along a conveyer belt from the Pacific Ocean thanks to the strong jet stream.  The first system races into Oklahoma tonight. Significant moisture return will occur for just a short window ahead of this system so the chance of rain and even storms is low. However, the strong dynamics of this storm could lead to an overnight severe thunderstorm threat over southeastern Oklahoma as the first map shows. Large hail and high winds would be the main threats between midnight and sunrise on Wednesday.  The rest of the area may see a fast-paced shower late tonight.

WARN Interactive Radar

This system won’t pull down much cold air so the mild trend carries on. After two windy days, Christmas Eve will feature cool, but relatively calm conditions with 40s during the evening hours. Christmas Day will see a return to south winds, bringing temperatures into the 60s by afternoon. Our record warmest Christmas Day in Tulsa had a high of 73° in 1922. While we may not be sing Mele Kalikimaka as on a “bright Hawaiian Christmas day,” we can still get away with short-sleeved shirts that afternoon. I personally would not mind a little time outdoors that day without wearing a big coat!

 We’ll need to add a rain coat to the wardrobe by the weekend as a very strong cut-off low pressure system approaches the area. An almost unprecedented amount of moisture will surge back into Oklahoma starting Christmas night and provide a rare non-snow-melting induced flood potential here in the winter season. As much as half a foot of rain may fall across parts of our area Saturday into early Monday (see attached map). Flash flooding and river flooding both seem like distinct possibilities, especially given the relatively short span between heavy rain events. Depending on exactly where a frontal boundary sets up, it’ll either by quite mild and soggy or raw and wet. It’s still too early to tell how much cold air settles into the area, but there’s a fairly high confidence at this point that most of the wintry weather will be to our west.  This is great news for our part of the state as the amount of moisture and slow-moving nature of this system could bring record snowfall or ice.  Northwestern Oklahoma and the Panhandle regions may have quite the winter storm on their hands, however. It would be worth now making a Plan B if you have travel plans that way after Christmas.

Once again, this weekend storm is not locked in place so we can’t entirely rule out severe weather or even a little wintry mix sneaking into the area at the end, but the main concern will be flooding at this point. Without a doubt, 2015 will go out as one of the wettest years on record for eastern Oklahoma.

For those wanting a White Christmas, you may have to travel to the Rockies or northern Plains to find snow. While we don’t see snow often on Christmas, places that expect it in the northeast U.S. will also likely be left with a barren ground. This unseasonable fetch of warm weather pushes all the way to northern Michigan, Ontario and northern New England, depriving these locations of snow as well.

If you’re sticking closer to Green Country, enjoy the mild weather and pay attention to the weekend if you’ve got travel plans. I’ll keep you updated on Twitter: @GroganontheGO and on my Facebook page! Have a Merry Christmas and Happy New Year and thanks to all the loyal viewers of my blog!