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After some morning showers and isolated thunderstorms (dotting the radar as I write this), the winds of winter will howl anew, pushing in much colder air from the Arctic. This won't happen all at once, and today will do its best to hold in the 50s or even 60s, but by tonight we'll be back to the 30s and upslope-triggered snowflakes will fly, especially west of Roanoke. The best chance of significant accumulation will be in the higher elevations from Quinwood up to Snowshoe in West Virginia and also in the tallest part of the Smokies along the North Carolina-Tennessee border. The ground will be warm and the snow fleeting most other places, but some of the highest elevations and west-facing slopes west of Interstate 81 might get a little white, and also the high areas around Mount Rogers.

The more widespread issue will be the potential for a regionwide freeze by Wednesday morning. We're still ahead of our typical last-freeze date, but some of you have gardens or sensitive plants outside, so take precautions.

Latest advisories from the National Weather Service

A squall line is pushing through states to our west, ahead of the strong cold front set to arrive Monday morning. A severe thunderstorm watch is in in effect for some counties of far Southwest Virginia and much of the western half of West Virginia. This squall line will eventually work into our region after midnight, but will likely weaken quite a bit. Still, a rumble of thunder and a gust of wind might occur with some brief heavy rain showers overnight.

Monday will be a blustery day as the cold air begins to settle in, leading to much colder temperatures and a chance of snow showers overnight Monday into Tuesday. A widespread freeze is likely by Wednesday morning.

Here is another one of these Hydrometeorological Prediction Center maps projecting heavy snowfall risk that you might have thought you wouldn't see again until at least November. But the northwest winds that develop behind a strong low tightening near the Great Lakes early next week are likely to fire up the upslope snow machine for an encore performance, and in parts of West Virginia and the far southwest part of Virginia, that snow might even pile up a few inches. The blue represents a slight risk of 4-plus inches Monday evening through Tuesday evening. The green spot in far northwest North Carolina signifies a moderate risk. Don't be surprised to see some vigorous snow showers by Tuesday morning in the New River Valley and possibly a few flurries even into the Roanoke Valley. Again, this is not a terribly unusual setup for early April, and it's not necessarily the last.

Between now and then, we have another sunny day in the 70s on Sunday and then some showers and possibly thunderstorms late Sunday night into Monday, before the cold front pushes through. This doesn't look like a repeat of the 1-2 inch rains that occurred last week, but perhaps enough to keep up our steady pace of rain that is continuing to make progress against our long-term dryness.

First, just a note about extremes with the storm system approaching us. Yes, Texas is a huge state, but the contrast across it today was stunning. While the Panhandle region was experiencing a blizzard with temperatures in the teens, Harlingen in south Texas set a record high for the date of 101 degrees. Summer and winter a few hundred miles apart. Not surprisingly, there was angry spring weather in the middle, including hail, high winds and tornadoes.

We've had three or four disturbances (I've honestly lost count) bring us a series of rounds of rain since Wednesday. On Saturday, the core system will finally affect us, as a strong low pressure system heads northeast from Texas toward the Great Lakes and drags a strong cold front into the area (strong in the sense of wind dynamics ... it's a Pacific front, so not extremely cold stuff for our region). This low will pull more Gulf of Mexico moisture than we've seen yet into our region, and we could see some heavy rain, with the Hydrometeorological Prediction Center projecting 1.5 to  2 inches of rain over much of Southwest Virginia through Sunday evening (the rain should actually end Sunday morning).

We may even hear a few rumbles of thunder on Saturday afternoon and evening. The Storm Prediction Center continues to have us at the edge of the slight risk zone for severe weather on Saturday, but it appears that the cool air wedge east of the mountains will limit severe weather in our immediate area. Without surface heating, it will be hard to build the updrafts into cooler air aloft necessary for large and powerful thunderstorms. However, because of the extreme wind energy involved in this storm, a few severe wind gusts cannot be ruled out with a few of the stronger storms in our region. It will mostly be a heavy rain event here, with a more serious severe weather threat from the Deep South into the Carolinas.

Some showers are possible during the day Friday, but we will be between disturbances. Meanwhile, a powerful low pressure system will be cranking up to our west, bringing a dangerous threat of severe weather to the lower Mississippi River Valley and heavy snow to the Texas/Oklahoma Panhandle region (the linked map is for 4-plus inch threat, but local forecasts there are calling for 1-2 feet with drifts of 10-20 feet on 55 mph winds). Moisture will again begin to surge into our area Friday night, and by Saturday, with the strong low passing just to our west and dragging through a strong cold front, there could even be a threat of the season's first strong to severe thunderstorms.

Storm Prediction Center

National Weather Service-Blacksburg

I don't often link to articles on the major weather Web sites, but this blog entry on AccuWeather.com is just too much on the money, specifically pointing out Roanoke's recent-years snow drought and noting that the Eastern snow drought is really part of an overall year-round precipitation drought -- a familiar theme of mine.

Thanks to reader Douglas Rutz for pointing this out to me.

The next several days will feature a highly active weather pattern, not just for Virginia, but across much of the central and eastern United States. The last couple of days brought severe weather to the central U.S. and a blizzard to the northern Plains, where record flooding is also occurring from both precipitation, snow melt and ice jams. Severe weather again developed in Texas today, resulting from the same disturbance that will bring our second round of rain on Thursday. A strong upper-level low pressure system will trigger severe weather in the lower Mississippi River Valley (think Arkansas, Louisiana, Mississippi) over the next couple of days, and also a large snowstorm over the southern Plains, particularly the Oklahoma and Texas panhandles. The powerhouse surface low triggered by this diving disturbance will move northeast and drag a vigorous cold front eastward, which will spread possibly heavy rain our way late Friday and through the weekend, and Saturday could even bring severe thunderstorms into Southwest Virginia (though the chances will be much better south and east of us).

On top of all this, after a brief hiatus early next week, another strong low pressure system moving from the Plains to the Great Lakes may affect the weather over much of the central and eastern U.S. about the middle of next week.

It's almost too much weather to keep up with. The good news is that several very dry areas from the Southern Plains to the Southeast to the Appalachians are getting moisture ... maybe a bit too much in some places. (Tonight's rain potential map from the Hydrometeorological Prediction Center is projecting widespread amounts over 2 inches in our area over the next 5 days). But there will also likely be some weather misery too, ranging from floods to tornadoes to car-burying snowdrifts. In our region, despite the long-term dryness preceding it, there is at least some risk of flooding problems by the weekend if some of the heavier rain bands and stronger thunderstorms move through our area.

It's 50 degrees in Roanoke at 4 p.m., but the dew point is 6 degrees. And there lies the issue tonight as we teeter on the edge between a significant snowfall and a cold rain. As moisture continues to stream into the area, precipitation will begin to fall into the very dry air near the surface. The resulting evaporational cooling ... heat being taken out of the air, used to evaporate the moisture ... will cause temperatures to drop throughout the atmosphere. Eventually, the precipitation will reach the surface. If it is below freezing all the way from cloud to very near the ground, snow will fall. Sleet and freezing rain are also possible in pockets, but it is likely that either rain or snow will dominate a given area for a few hours early Friday. The Hydrometoeorlogical Prediction Center is highlighting most of Southwest Virginia, including both the Roanoke and New River valleys, for a slight risk of 4-plus inches of snow tonight and early Friday. That is probably the upper end of what could happen if precipitation falls heavily enough and temperatures cool fast enough. The National Weather Service in Blacksburg is favoring light accumulating snow in counties just north of Roanoke and Blacksburg ... including Botetourt, Alleghany and Rockbridge ... and has issued a winter weather advisory for those counties. Meanwhile, the weather service is calling for mainly a rain-dominated wintry mix in the Roanoke Valley, with more snow in the New River Valley, but minor accumulations of an inch or two.

A factor working against accumulation is the warm state of the ground from several recent days of sunshine, including days near or above 80 degrees. I've seen plenty of cases where snow falls heavily enough to overcome that, but it can be a limiting factor, especially with lighter snow. A factor working for accumulation is the timing of the precipitation in the morning hours. Even though the sun is behind the clouds, its radiation is absorbed by the surface later in the day, and that degree or two is sometimes very critical in whether it snows or not, and how much accumulates.

It's another winter weather cliffhanger as the season stubbornly refuses to give way to spring, even after a small taste of summer. We may not know much about how this one plays out until it starts happening overnight. I don't expect this to be a widespread hazard, but heavier bands of snow could make some areas slick quickly. For those who get snow, it will probably just be a pretty coating on what, in some cases, are already budded trees.

There  is a narrow window of borderline opportunity for possible snow in Southwest Virginia late Thursday night and early Friday. It all depends on the mix of moisture from the Gulf of Mexico and the depth of cold air following an Arctic cold front. The window, give or take a few hours, is from about midnight Thursday to noon Friday, when moisture overrunning a dome of cold air a the surface could trigger snow, sleet, freezing rain or plain ol' cold rain. More likely, most places will get some mixture of two or more of those precipitation types.

Any snow that falls should be very wet and slushy, with any accumulations primarily on grassy surfaces and exposed objects that don't hold the many days of 70- and even 80-degree heat in. A period of heavy snow might spread the accumulation around more by cooling the air and surface a little more and by falling faster than it can melt for a short period of time, but it looks most of the precipitation will be light to moderate. The higher in elevation you are, the better chance you have at seeing a few inches. Most folks will see an inch or less.

While slightly milder air will overcome the cold enough over the weekend to get us back to all rain, some forecast models depict a possible storm system in the Monday-Wednesday timeframe next week that could again bring some snow to the area. Let's take things one system at a time! It gets harder and harder to snow with each passing day, but it's still possible if the right pieces line up in the sky.

It may be hard to believe with Wednesday's highs near 70, but snow is back in the forecast as soon as Friday. A cold front moving through Wednesday night will return chilly air to the region, with Thursday's highs possibly not topping 50 and Friday's highs struggling to crack 40. Meanwhile, some Gulf of Mexico moisture will overrun that new cold air at the surface Thursday night and Friday, and, especially overnight into the morning hours, it may be cold enough for some snow. Don't expect anything like last time ... this looks pretty weak and temperatures will even be more marginal than before ... but some wet snowflakes may plop down. The overrunning Gulf of Mexico air will gradually warm things over the weekend just enough to get us out of snow-making temperatures, so any snow threat will probably be brief and probably wont' accumulate much.

There could be another shot of snow showers late Tuesday into Wednesday with a new cold front. That one doesn't look like too much either, from this distance.