Cold front pushing rain into the areaPosted Feb29, 2008 at 04:36 PM
Yes, there is a much bigger show on the horizon Tuesday and Wednesday, possibly one of the most powerful low pressure systems to move near or through our regions in years. A lot remains to be seen on the details, but for now, it definitely looks more like a rain maker than anything wintry. I'll be taking a closer look at this over the weekend. An easy morning to set a record lowPosted Feb29, 2008 at 12:01 PMBlacksburg set a record low this morning and Roanoke tied a record low, but it was the easiest day of the year to do so. With Feb. 29 only showing up every 4 years, there are a lot fewer opportunites for record temperatures to be set on this date than any other date on the calendar. Blacksburg's low of 15 beat out the previous leap day record of 15 set in 1984, while Roanoke's low of 22 tied the Feb. 29 record set in 1980. Most record lows for this time of year run in the single digits for Blacksburg and in the teens for Roanoke. Quinwood, W.Va. wins again -- 15 inches of snowPosted Feb28, 2008 at 01:25 PMWithin the National Weather Service-Blacksburg office's forecast area that includes much of Southwest and Southside Virginia plus a few counties in southeast West Virginia and northwest North Carolina, Quinwood, W.Va., in western Greenbrier County is the typical winner in an upslope snow event. This time was no different coming in with 15 inches of snow from the intermittent snow showers and squalls that were squeezed out as northwest winds climbed the mountains the last couple of days. Below, in the extended entry, is a National Weather Service list recapping snowfall amounts from the snows of the last couple of days. In the Roanoke Valley, we just got a trace on a few snow showers Wednesday. Continue reading "Quinwood, W.Va. wins again -- 15 inches of snow" » A few speckles on radar kick out lots of snow for somePosted Feb27, 2008 at 05:56 PM
The snow showers and flurries will gradually dwindle overnight, and we'll be left with a cold but sunny Thursday before a gradual warmup through the weekend. A few flakes in the air today, no big deal in RoanokePosted Feb26, 2008 at 11:50 PMThe marathon upslope snow shower episode that is expected to deal up to a foot of snow in eastern West Virginia is off to a slow start tonight, but should pick up overnight and into Wednesday as strong northwest winds carry Great Lakes moisture up the western side of the mountains. On this side of the Appalachian spine, we may see a few flakes blowing through the air from time to time in the blustery breezes, but probably no significant accumulation. I wouldn't rule out a white ground in parts of the New River Valley, but even most places there should escape significant accumulation. Latest advisories and warnings from National Weather Service-Blacksburg Blustery winds will blow snowflakes in tonight and WednesdayPosted Feb26, 2008 at 12:24 AMAfter a cold front pushes through some showers today, strong northwest winds will kick in as a low pressure system develops in the Northeast. This is a familiar prescription for upslope snow showers, and this time, they will likely continue for so long that some of the higher elevation areas in eastern West Virginia could get 6 or more inches of snow. That's why winter storm watches were issued for a few counties over that way on Monday to cover the time from 6 p.m. tonight until 6 a.m. Thursday. There will be enough bleed-over from the upslope snows that some places in the New River Valley could get a dusting to an inch, and I wouldn't even be surprised to see a couple of the more vigorous snow showers amid off and on flurries in the Roanoke Valley briefly whiten the ground in a few places. Not a big snowstorm for the New River and Roanoke valleys, but enough snowflakes in the air to remind us that it's still winter. The week ahead: A roller coasterPosted Feb24, 2008 at 11:39 PMSome of you might have seen a few wet snowflakes during the evening and overnight. That was a passing weak disturbance that had marginally cold air to work with. The next couple of days will be pretty mild with temperatures in the 50s, maybe pushing 60. Rain will be moving in on Tuesday as the strong low pressure system takes shape to our west and moves into the Ohio Valley. Wednesday and Thursday will turn blustery and cold as this system moves by, dragging a cold front through, then as the low re-forms off the Atlantic coast of New England. We'll get a couple of days of wintry winds and probably quite a few snow showers, the kind that accumulate in the mountains of West Virginia but just make things seem a little more wintry over on this side of the Appalachian spine. So the temperatures will go up, then down, this week, before steadily climbing again next weekend. So now that this has piddled out, what's next?Posted Feb22, 2008 at 08:28 PM
It looks like we've dodged the icePosted Feb22, 2008 at 11:55 AMA couple of weak showers have moved through the Roanoke Valley with temperatures just above freezing, and more showers are on the way from the west, though they are diminishing somewhat in intensity and areal coverage. While we can't rule out a few icy spots on bridges and overpasses this afternoon, it would appear that we have essentially dodged this winter weather threat in most of Southwest Virginia. One late wave of rain coming -- but will it freeze?Posted Feb22, 2008 at 07:34 AMIt is now a race between the last piece of this very broken storm system, currently moving across Tennessee and Kentucky (click here for national and regional radar views), and whether surface temperatures can warm above freezing before it gets here. We will probably see some rain as that last spoke in the wheel moves through later this morning or early in the afternoon. Temperatures are well above freezing in the atmosphere above the surface level, so anything reaching the surface will almost certainly be liquid. It's just a matter of whether temperatures at ground level will be cold enough to allow any ice to build once that precipitation arrives later today. The National Weather Service in Blacksburg is hanging on to a winter weather advisory until noon just in case the last wave slaps us with a little ice. Precipitation will be tardy or absentPosted Feb21, 2008 at 08:52 PMUPDATE 12:55 a.m. Friday Feb. 22: New precipitation is firing over Arkansas, Mississippi, Alabama and Tennessee as I write this. This could move into our area later this morning, though it's still doubtful that this will be much more than a minor ice/sleet event. But it will have to be monitored in case heavier precipitation moves in while it's still below freezing. If rain arrives much later today, it could well warm above freezing. It's a very disorganized winter storm, sort of symbolic of a strange winter. 
Will precipitation keep doing the old spliteroo?Posted Feb21, 2008 at 03:23 PM
This split in precipitation we've been seeing was not entirely unexpected -- forecast models have been picking up on it for days. The question is whether or not overnight or on Friday a low moving east will drag more of the southern piece of moisture northward toward us. The two precipitation areas are connected now by a thin band near the Mississippi River -- we'll probably get that, if nothing else, and it will probably grow. But if we are going to get anything beyond an inch of snow/sleet and a thin glaze, the southern precipitation area will have to become more involved. Some of our moisture may well be getting eaten up by the thunderstorms along the Gulf of Mexico. As of now, it still looks some wintry precipitation will move into our area late tonight, probably after 10 p.m., but it's looking like a rather light event at this point unless something changes in the next several hours. The more mix we get, the less ice will build upPosted Feb21, 2008 at 09:49 AMWith the expectation that most of the area will see enough of a mix that the freezing rain portion of the event will not collect more than 1/4 inch, the National Weather Service in Blacksburg has gone the route of issuing a winter weather advisory for most counties in Southwest Virginia, including the Roanoke and New River valleys. Floyd, Carroll and Patrick counties, and a few more in northwest North Carolina, are under a winter storm watch for the possibility of getting 1/4 inch or more of ice on top of whatever snow and sleet falls to begin tonight's winter weather event. While it seems likely that wintry precipitation will occur across the area tonight, the amounts are the tricky part, especially weighing how much falls as snow/sleet and how much ends up as freezing rain, which all depends on how deep the cold air is being pushed from the north and how fast warm, moist air from the south can erode that colder air in the upper atmosphere. The local forecasters in Blacksburg, as this map shows, believe that counties along the Blue Ridge south of Roanoke have the best chance at getting more ice, owing to some southeast winds banking moisture against the eastern slopes of the mountains. But national forecasters at the Hydrometeorological Prediction Center favor areas from Roanoke northward having a better chance of getting 1/4 inch of ice or more, as this map shows. There is a question about the amount of moisture that will be available. This morning's radar shows the precipitation splitting up north and south, looking as if it might go on either side of us. I would expect that to fill in later today, as the split is primarily the result of separate pieces of energy in the northern and southern branches of the jet stream that will eventually become better aligned, though not perfectly. The moisture from the south is what is expected to spread northward, but thunderstorms down there could reduce the moisture flow. That's always an issue to watch when moisture is moving in from the Gulf. The flip side is that if fewer thunderstorms fire, we could see a surge in moisture that could push us into winter storm warning territory. My early guess: About an inch of snow/sleet on the front end in Roanoke with a quarter-inch of ice, pretty similar in New River with maybe a little more snow/sleet accumulation, just enough to get us on the edge of significant ice storm potential. I'm skeptical of any forecast or computer model that warms us above freezing before late afternoon on Friday ... the wedge of cold air from the northeast should hold tight and ice/snow accumulation will keep the air chilled near the surface at least a few hours longer than projected. Forecasting ice accretion is a slippery taskPosted Feb20, 2008 at 11:33 PMForecasters are facing a complicated storm system with a tricky forecast tonight and Friday. What seems very likely is that significant moisture will move over below-freezing air at the surface. Wintry precipitation is all but absolutely certain, and it could be quite troublesome -- at least a nuisance for travelers, but possibly a problem for trees and power lines if only a little more occurs than is forecast. That's not what we want to hear after the Feb. 10 windstorm and Feb. 1 ice storm power outages. One of the hardest things in winter forecast is projecting ice accretion. It's not as simple as saying "we're going to get a quarter-inch of rain, therefore we'll get a quarter-inch of ice." * The first complication is that much of the early precipitation may fall as snow or, especially, sleet. The more falls as snow and sleet, the less will fall as freezing rain, and therefore the less ice can accumulate. * Secondly, more of the rain will freeze if temperatures are a few degrees below freezing than will if it's very near freezing. The same level of freezing rain at 25 degrees is much more of a problem than it is at 32. * Temperatures aloft matter. If the air is very warm above the surface, the rain falling through it takes a longer to freeze at the surface than it would if it were falling through air just a few degrees above freezing. * How hard the rain falls also matters. A heavy rain may run off more and not freeze on objects as readily, whereas a steady, light to moderate rain runs off less and therefore has more of a chance to freeze on trees and power lines. Weighing all of those factors and many more as of late Wednesday night, forecasters were expecting up to two-tenths of an inch of ice on top of a layer of an inch or so of snow and sleet. That forecast could change many times today. If the National Weather Service believes there is a reasonable chance 1/4 inch or more of ice could accumulate, a winter storm watch or ice storm warning may go into effect. Expectations could change many times as the storm takes shape today. For the latest, click on the National Weather Service-Blacksburg's "Current Event" page. No watch, but a wintry mess likely on its wayPosted Feb20, 2008 at 05:18 PMThe National Weather Service in Blacksburg has, for the time being, declined to issue winter storm watches for the system headed our way Thursday night into Friday. It takes an expectation of 4 inches of snow or 1/4 inch of ice to trigger watches, and right now, the fast speed of the system may keep precipitation amounts light. Also, we may see so much mixing of snow, sleet and freezing rain that the ice won't get to 1/4 inch by itself (very little chance the snow would get to 4 inches under any circumstances -- an inch, maybe). So for now, it looks like a messy, mucky winter storm that could be a nuisance but not a particularly severe winter storm. New data could change expectations. Click here for the latest on advisories and warnings from the weather service office in Blacksburg. Meanwhile, snow continuing to fall in parts of Alleghany and Bath counties could accumulate a few inches, hence the snow advisories. Cold, windy weather will spread across the area later tonight, and those winds could carry a few snowflakes, but significant snow is not expected in most places tonight. Hopefully for watchers of the lunar eclipse, the clouds will at least become broken in the gusty winds by 10 p.m. A weird afternoon in Southwest VirginiaPosted Feb20, 2008 at 02:55 PMThe low passing through our area has drawn enough warm air northward to push our temperature in Roanoke to 51 degrees at 2 p.m.... yet just 90 minutes drive northwest there is heavy snow and 28 degrees at Hot Springs. A snow advisory is out for Alleghany and Bath counties westward into West Virginia. It's going to get weirder as cold air arrives across the area tonight and temperatures plunge across the area into the teens and low 20s This new Arctic air will set up the likelihood of a signficant winter weather event on Thursday night and Friday, with snow, sleet and ice all possible. I will be interested to see if the National Weather Service flies winter storm watches. We should know in the next couple of hours. Winter weather threat building for late this weekPosted Feb19, 2008 at 05:17 PMSome of you saw a few snow showers today with a passing disturbance, and a stronger one passing just north may bring some showers of snow and rain to the area on Wednesday. The bigger issue, though, is the potential for a winter storm in the Thursday night-Friday timeframe as disturbances in both the northern and southern branches of the jet stream move near the area. The Hydrometeorological Prediction Center is already calling for a moderate risk of substantial ice for our area on Thursday night and Friday. It's unusual to be in a moderate risk still 3 days out. That signals a pretty high degree of confidence by forecasters that wintry weather will affect the area, but it also allows 3 days time for things to change. The current thinking is that precipitation will start as snow and then change to sleet and eventually freezing rain. It looks as if cold air will be pushed down into our area by high pressure to the north as the precipitation moves in. Winter has not let go of its grip on the area just yet. First comes fire threat, then maybe some snowPosted Feb18, 2008 at 11:46 PMBefore we can really begin to pick apart the series of disturbances from Wednesday to Saturday and what they could bring in terms of winter weather, a few stronger gusts of wind combined with dry conditions could easily spread fires today. As a result, the National Weather Service has posted a red flag warning for much of the area from Roanoke south and east. A red flag warning signifies an enhanced fire risk. This should not be a repeat of Feb. 10, as the lower atmospheric winds are not as powerful as they were that day. But we could see some gusts topping 40 mph during the day. The first threat of snow comes Wednesday with an Alberta clipper diving southeast. If you've followed weather for a while around here, you know that most Alberta clippers do not produce accumulating snow for our area, but once in a while, one will. Additional disturbances pose a snow/ice risk through the weekend, with gradually warming temperatures. It remains a tricky forecast. Tricky weather for last half of weekPosted Feb18, 2008 at 10:23 AMThough we've started out warm today, a cold front will soon be moving through, and over the next couple of days we will be sinking back to cold wintry temperatures. The tricky part of all this comes in the Wednesday to Saturday time frame when a series of disturbances will be moving through, as well as a warm front lifting northward. The timing and placement of each disturbance, the thickness of the cold air and the speed of the warm front moving north will all come into play into determining precipitation chances. On one extreme, there could be off and on snow and ice throughout that time period. On the other extreme, the cold air could suppress the storms so much that little precipitation can occur until the warm front moves north, when it would only be rain for the weekend. Something in between those scenarios is most likely. Stay tuned. Probably no ice on Sunday, just some needed rainPosted Feb16, 2008 at 05:18 PMI think we're going to escape the freezing rain with Sunday's system. It's just not very cold and there's nothing to hold the cold air in place when the rain arrives, unlike last Tuesday night. As for rain amounts, looks like another decent but not especially soaking rain, as seen by the Hydrometeorological Prediction Center maps for the 24-hour period ending early Sunday evening and for the next 24 hours ending Monday evening. Add 'em up, and it might be half an inch. It will be helpful, but not a cure for the drought or even the lingering fires. As for wintry precipitation, we are going to have to keep an eye on the late week period, Wednesday-Friday or so. We may well see high pressure in southeast Canada forcing cold air southward as a moist storm moves in from the west. We've got a few days to watch that as it develops. Yet another flirtation with icePosted Feb15, 2008 at 04:40 PMThis winter seems to be good at one thing: Borderline chances of freezing rain. That will happen again late Saturday and early Sunday as a new storm system moves northeast into the Ohio Valley. It will sweep warmth and moisture from the Gulf of Mexico northward, but the front end of that moisture may overlap enough cold air at the surface for some freezing rain and sleet. Eventually, the warm air will win out and temperatures will rise above freezing, but the question is always how long the cold air will hang in and how much moisture will arrive before it pulls out. As it looks now, an ice storm is not likely, just a few icy spots before it warms above freezing. Roanoke records now date back to 1912Posted Feb14, 2008 at 09:37 PMIf you keep up with daily climate statements from the National Weather Service in Blacksburg, you may have noticed that some of Roanoke's record highs and lows now date to before 1947, which was the limit of the previous period of record based on the establishment of the Roanoke Regional Airport weather instrument site. In fact, those records now go back to 1912. This public information statement from the National Weather Service explains why. I hope to dig further into this in Weather Journal sometime in the near future. Some folks not far away got significant snowPosted Feb14, 2008 at 11:36 AMSouthside Virginia ended up getting the most snow Wednesday night, with as much as 4 inches in the Danville area, and 1-2 inches back to the west toward parts of Henry County. In the Roanoke area, there was off-and-on light snow for a couple of hours, but it didn't amount to much. The next chance of precipitation arrives Sunday and Monday, and though it looks like the low will take another track to our west that is not favorable for a huge winter storm, temperatures are just borderline enough once again that at least some of what falls could be icy. It might snow a little bit this eveningPosted Feb13, 2008 at 05:16 PM
New cold front will not bring strong windsPosted Feb13, 2008 at 09:42 AMIt did rise above freezing in most areas overnight, preventing a signfiicant ice storm that could have further messed up the power situation after Sunday's wind. The rain will dwindle this afternoon as a cold front moves through the area. It will get breezy and colder, but NOT nearly the kind of winds we saw Sunday, many factors aren't in place for that. A few snowflakes may dance through the air here and there this evening. Looks like we'll continue on the temperature seesaw the next several days, with chances of precipitation again Friday and around Sunday or Monday. Freezing rain hanging on longer than expectedPosted Feb12, 2008 at 10:02 PMBelow-freezing air is stubbornly hanging on in the New River and Roanoke Valleys and points north and east ... and as a result, freezing rain advisories now carry over to 3 a.m. Hardest hit have been areas of the Piedmont from Lynchburg up toward Charlottesville, where the most rain has fallen, but there is some ice on exposed objects and trees here in south Roanoke County, as well. Watch out on the roads tonight, particularly bridges and overpasses. A wee bit of ice here and therePosted Feb12, 2008 at 04:38 PMBe careful on your evening commute, as temperatures are flirting with the freezing mark in some locations in Southwest Virginia with light rain falling. I've noticed some ice on exposed metal objects in south Roanoke County. Temperatures should warm up a few degrees overnight, but there might be a patch or two of ice on bridges and overpasses early this evening. Special weather statement, National Weather Service-Blacksburg Tonight's rain likely not a soakerPosted Feb12, 2008 at 10:40 AMAs you can see from this morning's rain forecast map from the Hydrometeorological Prediction Center, the heaviest rain from this evening's storm system is expected to move west of us, so we may not get the soaking we really need to stamp out the wildfires. Still, several tenths of an inch of rainfall would be beneficial. Probably no ice or snow with this as temperatures will likely be above freezing when any rain arrives later today. Can't rule out a few pellets of the sleet on the front end, but any kind of significant wintry precipitation is just about entirely out of the question. Some much-needed rain on the way -- maybe a bit of ice and snowPosted Feb11, 2008 at 09:38 PMMuch-needed rain looks to be headed our way for Tuesday night to help quell the fires that have broken out. We might get a little freezing rain, sleet or snow on the front end during the day Tuesday, but probably not enough for significant problems. Anything cold and wet will be helpful for the fire problems, though we could use a whole lot more wet for the ongoing long-term drought that made things so susceptible to fire in the first place. This is being caused by a low pressure that will track northeastward to our west, drawing up some warm, moist Gulf air over the cold air at the surface. The Gulf air should overtake the cold air quickly, raising temperatures well above freezing before the bulk of the moisture arrives. |
