When Winter’s Away, Gulf Storms Play: Severe Weather This Weekend

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My Inbox is filling with chatter and I’m not surprised. It looks like a strong low pressure system will be taking shape in the Gulf of Mexico threatening to bring (additional) flooding rains to southeastern Texas then move to the Mid-Atlantic states by Sunday. It has the attention of all the ImpactWeather forecasters within arm’s reach of a keyboard.

Any weather system will grab the attention of the forecasters at ImpactWeather. It’s our job, after all. But the big ones grab everybody’s attention. There was a time when all of the employees of ImpactWeather were meteorologists. That’s not the case any more — from admin services to IT to sales, we’ve hired specialists whose primary focus is not making a daily forecast. But many of our forecasters have moved into non-operational meteorology positions and when those folks get excited about a weather system it’s time to really pay attention. Such is the case today.

By Friday, the stationary frontal system in the northern Gulf is just begging for a low pressure system to form upon it. Click for larger image. Image: ImpactWeather StormWatch Team

This anticipated Gulf of Mexico low pressure system is complex, as the features it will form upon are not yet in place. Adding to the complexity is the fact that the most reliable computer models are not in agreement as to the strength, timing and direction of the low. Here’s what we know: A low pressure center in Colorado today moves to the Great Lakes by Thursday. Trailing off the low, a cold front that will push off the Texas Coast late tomorrow. That cold front languishes in the Gulf on Thursday — putting into place the ingredients for the formation of the infamous West Gulf Low. What happens after that is where things get a bit murky. First, will the low form? If so, where? If it forms, how strong will it get and where will it go?

By later on Friday the low is formed and by Saturday, the low is bringing heavy rain to Southeast Texas. Click for larger image. Image: ImpactWeather StormWatch Team

One of the known error traits of the GFS computer model that we follow, among others, is that it will form a low too far out into the Gulf of Mexico. That means the low could form much closer to the Texas coast. Already saturated due to previous and frequent rains, the grounds of Southeast Texas are now likely to quickly flood with additional rain — and it looks like a lot of rain may fall when this low develops. (For more on the “former” drought of Southeast Texas, these previous YourWeatherBlog articles tell the story of just how dry it was: here and here.) But it’s not just Southeast Texas. As the low gathers strength at the end of the week, the entire upper Gulf coast from Tampa to Houston is at risk of significant rainfall.

"Uncertainty #1." This is the European model (ECMWF). By midday Sunday it has developed a significant low pressure system and moved it to the coast of the Mid-Atlantic States. Click for larger image.

Low pressure systems thrive on the contrast between cold/warm and dry/moist. A cold low pressure system over the relative warmth of the Gulf of Mexico with access to the copious moisture of the Gulf and positioned on the edge of a cool, dry high pressure system to the north will not just fade quietly away. And this one is expected to fight its way to the Mid-Atlantic by Sunday and Monday. However, as mentioned, there remains a great deal of uncertainty about what exactly this low will do.

"Uncertainty #2." This is the GFS model for the same time period, midday Sunday. Where's the low off the Mid-Atlantic Coast? This is why so many excellent forecasters are bald — they've pulled all their hair out over the years wrestling with situations like this! Click for larger image.

For now we’ll focus on the low while it forms in the Gulf of Mexico — and what looks like a significant rainfall event for southeastern Texas beginning early Friday morning (so significant that, when combined with the rainfall of the past few weeks, some are suggesting the drought in this part of the country will be over).

As for winter, where is it? Lots of folks are wondering that very question (YourWeatherBlog asked it, too), but the answer is that although winter may not have slammed the Lower 48 with a record-breaking storm (or two), there have been little “outbreaks” of winter here and there, most evident across the northern tier states. Certainly the Great Lakes have had their lake-effect snows, most of the ski resorts in the Rocky Mountains have finally had some good snowfall by now and even the Plains have had snow. However, as we head into the mid- and later parts of next week, it’s beginning to look like we may see the beginnings of a significant winter storm system — residents of the Plains and Upper Mississippi River Valley take note. Then for the last week of February and first few days of March it would appear the cold Canadian air (not Arctic air) will mix with an active storm track and create what may turn out to be a major winter snow storm for the western U.S., or perhaps more specifically, the Rocky Mountains and the Plains. Winter may not exactly be on vacation right now, but in the coming weeks it looks like we’ll be reminded that February can really deliver a winter storm.


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