Kevin Myatt is The Roanoke Times' weather columnist.

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• Coldest morning of winter so far likely across much of Southwest Virginia; Tuesday precipitation looking doubtful
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Will this winter be remembered as a mild one that had a cold spell in the middle? Or will it be remembered as a cold, snowy and icy winter that started out mild?

The next two weeks will likely determine that. By Valentine's Day, the lasting legacy of this winter will be set. At least that's what I think.

Thursday is the next focus of attention. A low pressure system is expected to form in the northwest Gulf of Mexico near the Texas coast and move northeast. Its track and strength will determine the mix of precipitation, but it does appear that there will be more precipitation than there was for the slushy mix back on Jan. 21. A snow-to-sleet-to-ice storm appears to be the best bet, though the odds of mostly snow appear to be somewhat better than the last time around.

If you're a snow fan in Southwest Virginia, this winter has been like watching your team get run off the football field for half the game. Your team has been moving the ball lately, but doesn't have much on the scoreboard to show for it yet. So you're frustrated, but hopeful.

If you're a fan of winter warmth, you're frustrated because the game should have been put out of reach a long time ago. Your team was rolling, but now the momentum is with the snow misers, and you're worried they'll rally to come from behind and take the winter. You need a turnover.

With the sole exception of a mild respite Saturday, we've been in a persistently cold pattern since Jan. 17. But it's been mostly dry, as the strong shots of Arctic air have shoved the moist air flow common in El Nino winters way to the south.

Getting the moist southern branch of the jet stream and the cold northern branch of the jet stream to interact is the key to getting winter precipitation events.

Too much moist and too little cold results in mild, wet weather. Too much cold and too little moist brings cold, dry weather. We've had each of those this winter.

The Thursday system is the first sign the moist flow is alive and kicking, and may become a serious player the next 10 to 14 days as the cold pattern persists.

We'll probably have two or three more shots at wintry precipitation before the cold pattern can relent about mid-February. Arctic air is being reinforced today after the latest in a series of cold fronts moved through Tuesday evening. Meanwhile, an even larger and deeper shot of cold is likely to follow Thursday's storm this weekend. Our coldest temperatures of the season could occur if we have a snow/ice layer on the ground to accompany the cold.

We'll go into February with only a half-inch of snow officially for Roanoke, and in reality, most of that was sleet. (Sleet accumulation counts as snowfall for official records.)

Only twice since 1948 have we had less snow accumulation going into February. Only one-tenth of an inch had accumulated by the end of January in 1975-76, which ended up being our least snowy winter on record with 2.3 inches, 2.2 inches of which fell in March. Only four-tenths of an inch fell by the end of January in 1991-92, which ended with a total of 5 inches.

Historically, February is our snowiest month, averaging a little more than 7 inches since 1948, about one-half inch more than January.

The last two Februarys have provided significant snows that raised the season into double digits for snow accumulation. Last year's 5-inch snow on Feb. 13 helped get us to exactly 10 inches, while a 9-inch snow on Feb. 28 helped get us to 16 inches in 2005.

If we're going to get to double digits, or if we are to just get above the all-time record low snowfall of 2.3 inches, the storms that lift us may well have to happen before Valentine's Day. The pattern of repeated shots of Arctic air appears likely to run out of ammunition by then, and before it could recover, we could be well into spring, when Arctic air usually means mere chilly rain.

It all starts with Thursday. Keep track on the latest on the storm potential on my weather blog at blogs.roanoke.com/weatherjournal/. Thousands of you visited during the last winter storm. We'll take a look back at this storm and a look ahead in Saturday's "Weather Journal" column.