Cold mornings giving way to a couple of warm afternoonsPosted Apr30, 2008 at 06:18 PMThere was no freeze in Roanoke this morning, where the temperature officially fell only to 37, but many surrounding areas did experience freezing temperatures on this last day of April. May is going to start with a couple days warmup (70s, maybe low 80s) before a new cold front brings a chance of rain and thunderstorms Saturday. This is not as strong a cold front as the one early in the week, so we will probably not get as much heavy rain, the temperatures after it will not be as cold as they were this morning, and hopefully no one will experience the tornadoes that southeast Virginia got with the last system. Flirting with freezing late tonight, Wednesday morningPosted Apr29, 2008 at 04:13 PMWednesday may be the last day of April but temperatures will start out cold. The mercury will probably fall below the freezing mark in the New River Valley and points westward, so a freeze warning has been issued in that area. Temperatures will probably hover near or slightly above freezing from the Roanoke Valley south and east, so a less-stringent frost advisory is in effect for those counties. It would probably be a good idea for everyone to take in any sensitive plants tonight. For the record ... if Roanoke does happen to dip to 32 on Wednesday morning ... it would be the latest freeze in the spring since May 4, 1986. We had an April 28 freeze in 1998. This year's current last freeze date, April 16, matches 2005 as the latest since 1998. Latest frost/freeze advisories from the National Weather Service Destructive tornadoes strike Southeast VirginiaPosted Apr28, 2008 at 07:14 PMPhotos of tornadoes in Hampton Roads area Storm chaser films tornado at Suffolk Reports are still coming in, but tornadoes have struck Southeast Virginia this afternoon with injuries and destruction. This was caused by the same cold front that pushed in all the heavy rain here, but hit more warmth and wind shear to our east. The latest from the Associated Press A beneficial rain will help April end as wet monthPosted Apr28, 2008 at 05:45 PMRoanoke picked up .74 inch of rain as of 5 p.m. and .52 inch on Sunday ... a total of 1.26, and since all of Sunday's rain fell from after 6 p.m., that makes it the first 1-inch-plus rain total in a 24-hour period since Oct. 26. If you want to be technical, we sill haven't had an inch on any particular calender day since the October date. In all, we got 1.71 inches of rain since Friday, on top of 1.44 inches over 4 days a week ago, pushing our April total to 4.94 inches, more than an inch and a half above normal as the month comes to a conclusion Wednesday. We may see a few more showers overnight and early Tuesday, but it's unlikely that rain total will go up much more. It'll be our first month more than an inch above normal in precipitation since October. While the strong cold front pushing through the area has meant beneficial rain for us, it has also produced a spate of tornado reports in the Hampton Roads area. The next couple of mornings will be cold, relative to the season. A few snowflakes could fly in higher elevations, maybe even down to the New River Valley, on Tuesday morning, and Wednesday morning could bring patchy frost to Southwest Virginia. Now, this should help dent the droughtPosted Apr28, 2008 at 09:14 AMRoanoke is in a break at the moment but another round of moderate to heavy rains is poised to the west. It would appear that today's rainfall will be the Star City's first inch-plus rain in a 24- hour period since October and also ensure that April is our first significantly above-average rainfall month since October. This is all ahead of a strong cold front that will bring some chilly mornings back to the area, possibly some spring frost to the deeper valleys by Wednesday morning, and maybe even some snow showers to higher elevations tonight. It will also be interesting to see on Thursday, when the new Drought Monitor comes out, how much today's rain will roll back the drought status in the area. First, rain and storms; then, cold temperaturesPosted Apr26, 2008 at 08:15 PMAfter a few rumblers that kicked out some hail and gusty winds, but mostly just heavy rain and lightning, there will be a little break on Sunday, before the stronger front begins pushing through Sunday night into Monday. This will not be last week's meandering, in-a-hurry-to-get-nowhere low pressure system that spun out showers for 4 days ... this one means business and will push through with gusto Monday night. Some storms could be strong to severe, especially on Monday. 
So a chance of strong thunderstorms, then chilly temperatures. What a way to close April. Follow the flip-flopping frontsPosted Apr26, 2008 at 11:04 AMToday a weak cold front will begrudgingly move through the area. On Sunday, that same front will move back through as a warm front, having got stuck in North Carolina. On Monday, a strong cold front will push through and sweep all this mess out. The result will be a chance of scattered showers and thunderstorms today and Sunday, and a likelihood of showers and thunderstorms overnight Sunday into Monday. Then, some unseasonably cold weather will set in for a couple of mornings -- maybe some frost in the deeper valleys. The Hydrometoerological Prediction Center is suggesting we might get about 2 inches of rain out of all this over the next 5 days, nearly all of which would fall over the next 3 days. If that is true, and we start getting rains like that fairly regularly, we could start to take some bites out of the long-term drought. But I'm a little skeptical that we'll get quite that much rain. Afternoon thunderstorms: A familiar pattern beginsPosted Apr25, 2008 at 04:41 PM
Another showery weekend?Posted Apr24, 2008 at 11:42 PMToday should be a warm, dry day ... but there will be chances of showers and storms the next 4 days as a variety of fronts and disturbances move through, none of which look extreme. So we probably won't get enough rain to make a dent in the drought, but neither will the weekend be an entirely dry one for outdoor activities. Potentially, a bummer for everybody. A thunderstorm or two slipping in the backdoor?Posted Apr24, 2008 at 08:24 AMA weak cold front slipping to the south near or into our area today -- a so-called "backdoor" cold front -- might be enough to trigger a thunderstorm or two as it interacts with the warm air in place. This front will not be strong enough to make major changes in our weather, as it will either wash out or retreat, but might provide a boundary for a few showers or storms to fire in the afternoon heating. More significant cold fronts will be headed into our area from the more typical westerly direction Saturday and Monday. The Storm Prediction Center is even projecting a signficant severe weather risk just east of us for Monday. Well, let's try again to get the sun outPosted Apr22, 2008 at 11:13 PMAfter three days of cool, damp weather from a persistent (somebody got on to me for saying pesky, though it may fit by now) low pressure system wandering around aimlessly along the coast, maybe today will finally offer some longer breaks of sun as the low moves farther away. This low has been frustrating by keeping dank, drizzly, showery weather in place while not producing enough rain to really do anything for the drought. Thursday and Friday look dry and warmer, but we'll just have to see how fast the wedge gets broken as to whether today will be any different than the last three have been. Still a few showers, but winding downPosted Apr21, 2008 at 06:49 PMThe persistent upper-level low and its surface reflection are slowly moving southeast away from us, and the effects from the system will gradually diminish overnight into Tuesday. Still, the northeast wind whirling around it will push Atlantic moisture against the Blue Ridge overnight, and there could be some showers or light drizzle, which could even hang onto into the morning hours on Tuesday. Amounts will be likely be light, as the bulk of moisture, atmospheric wind shear and instability will be drifting farther south. An unusual spin on the showers moving throughPosted Apr20, 2008 at 11:21 PMRain has been moving into the Roanoke Valley area from an unusual direction tonight ... from the east and northeast. It's because the center of the upper-level low has shifted southeast of the area, and the spin around it is bringing in the moisture. Expect to see showers and some storms moving in from a similar direction at times overnight into Monday, though showers should slowly dwindle as time goes along. A few showers might linger into early Tuesday before the low moves far enough east for its effects to drift away. A close call on getting additional significant rainPosted Apr20, 2008 at 06:58 PMWhether or not we can add to the .64 inch of rain we got in Roanoke from showers and storms the last 24 hours (similar amounts across the area) depends on whether the upper-level low, as it moves east and slightly south of the area, can throw back enough moisture for a rain band to develop in our area overnight and early Monday. Right now, it appears the heaviest rain will occur just northeast of the area, but these sluggish upper-level lows often wobble and whirl a bit, so being off a few miles could make a major difference in the forecast. Latest National Weather Service-Blacksburg radar By the way ... severe weather reports from eastern Virginia and eastern North Carolina have included a few tornado reports today. Some severe potential this eveningPosted Apr19, 2008 at 09:09 PMThe Storm Prediction Center has put out a "mesoscale discussion" for Southwest Virginia, extending south into the Carolinas, for the potential of localized severe weather this evening. A line of moderate to heavy showers and storms pressing eastward ahead of a cold front may encounter enough atmospheric shear -- winds changing direction with height -- for enough spin to develop to kick out some brief severe-level wind gusts in a few isolated areas. The Storm Prediction Center even suggests that "a brief tornado" could be possible. Latest National Weather Service-Blacksburg radar Latest warnings and advisories from National Weather Service-Blacksburg Band of rain pushing toward Southwest VirginiaPosted Apr19, 2008 at 01:02 AMA band of rain is moving across Tennessee and Kentucky overnight ahead of a slow-moving low-pressure system and cold front, and should arrive in western Virginia in some form during this afternoon or evening, a little faster than earlier forecasts. The Storm Prediction Center even thinks there may be enough daytime heating, leading to instability, plus enough winds aloft for a small chance of severe-level thunderstorm winds (58 mph or greater) and hail (3/4 inch or more). The 5 percent threat on the map indicates a 5 percent chance that such winds or hail will occur within 30 miles of any given location. It's looking more like half-inch type rain rather than widespread rains of an inch or more, but the showers could linger well into Sunday. Rainy period ahead?Posted Apr17, 2008 at 11:08 PM
From the freezer to the frying panPosted Apr17, 2008 at 10:18 AMI neglected to mention that Blacksburg's low of 24 on Wednesday morning set a new record, breaking the old April 16 record of 25 set in 1963. There will be no record cold this afternoon, as highs soar into the 70s. We might see 80s on Friday. An official freeze in RoanokePosted Apr16, 2008 at 09:40 AMRoanoke's temperature at 7 a.m. was 31 degrees, meaning that the city officially experienced a freeze. The average last spring freeze from 1948 to 2007 was April 12, so this would only be 4 days later than average, provided there is not another freeze later in the spring. The latest date on record for a last freeze was May 11 in 1966, though it dropped to 33 on May 22, 2003, missing a freeze 11 days later by 1 degree. The earliest date for a last spring freeze was March 18 in 1978. The last spring freeze was very early that year even though it followed an extremely cold winter. Temperatures almost everywhere else in Southwest Virginia were below freezing for a few hours this morning. There is the potential for damage to anything that is budding or blooming, but that seems to be much less than last year, since our March wasn't as warm. A few areas may get to freezing again Thursday morning, though the overall trend the next several days will be for much warmer weather. Roanoke will have to drop fast to get to 32Posted Apr15, 2008 at 10:12 PMRoanoke is still sitting at 52 degrees at 10 p.m. The dew point is low, 18 degrees, so there is plenty of room for the temperature to fall. It will have to do so hurriedly in the after-midnight hours to get us to freezing. It can do it, but I would not be surprised if the urban areas of Roanoke escape with temperatures just above freezing. Still, a close enough call to get in some sensitive plants. We'll see how it pans out. Most outlying areas will drop below freezing by Wednesday morning, the second in a row for many locations. A freeze warning is in effect for most counties from Roanoke south and east. The counties north and west of Roanoke will get to freezing, too, but their growing season is not far enough long to warrant a freeze warning, according to the National Weather Service. Click here for current temperatures at stations across the area Frost could be widespread by Wednesday morningPosted Apr14, 2008 at 10:16 PMIt's been a little too warm for snow except in the higher elevations around Southwest Virginia ... we've just had chilly sprinkles with temperatures in the 40s in the Roanoke Valley. The real issue could be how much frost develops by Wednesday morning across the area. There could be some frost on Tuesday morning if the cloud blanket rolls away overnight, allowing radiational cooling to take temperatures near freezing. Tuesday night into Wednesday, however, clear skies and calm winds may take temperatures below freezing across almost all of the area, and this could allow for a widespread frost. A frost advisory is in effect for Tuesday morning and a freeze watch is in effect for Wednesday morning, which may be upgraded to a freeze warning sometime Tuesday. Though Thursday morning could be pretty cold, a warmup is expected to set in Thursday afternoon into Friday. One can never be totally certain, but there is a good chance this will be our last bout of near freezing weather this season. Cold snap should end by Wednesday afternoonPosted Apr13, 2008 at 11:33 PMTemperatures will be noticeably chilly, relative to this time of year, through Wednesday morning. But with record lows for this time of year generally running in the mid 20s for Roanoke and the lower 20s for the New River Valley, this should not be anything historic. The best chance of a widespread freeze will come Wednesday morning, when clear skies and calm winds may allow temperautres to fall a few degrees more than the next two cloudy, breezy mornings. Still, this should not be anything like last April, which had four consecutive mornings of temperatures well below freezing and two weeks of off and on chill. A few snow showers are possible in the higher elevations today through Tuesday as weak disturbances continue to move thorugh from the northwest and squeeze out what little moisture there is. Don't expect much with any of these, and the lower elevations may only see sprinkles of rain. Temperatures should start rebounding toward normal by Wednesday afternoon and be decidedly warm by the end of the week. A few inches of snow possible in some higher elevationsPosted Apr12, 2008 at 10:06 PM
All of this is being caused by a series of disturbances -- pockets of very cold air aloft -- that will be moving southeastward during the next 48 hours over the Canadian air mass that has moved in at the surface behind the cold front that moved through today. These pockets of very cold air will allow somewhat warmer air with some moisture to be lifted upward and squeezed out, producing showers of rain and snow on Sunday and Monday. As is typical in setups like this throughout the winter, the western slopes of the mountains will be favored for the heaviest precipitation, as the northwest winds guided up the mountain slopes produce extra lift. But even the lower elevations, such as the base of the Roanoke Valley, may see at least some flakes flying through the air by late Sunday night or early Monday. It may seem a little weird to have snow this late in the season, but really, it's not an extremely unusual event. In fact, we had snow showers in mid-April just last year, and the highest elevations in our region sometimes see at least some snow into May. The high Sierras tornado of 2004Posted Apr12, 2008 at 07:19 PMI mentioned a tornado occurring at 12,000 feet in the Sierras in my Friday column about mountain effects on tornado activity. Here is a link to a Web site with photos and description of that tornado. It is believed to be the highest-elevation tornado ever observed in the United States. Colder weather, possibly snow showers on the wayPosted Apr12, 2008 at 10:49 AMThe approaching cold front managed to squeeze out some showers and even a few thunderstorms this morning. The threat of severe weather will be farther southeast, where the cold front will be pushing into more sun-warmed air. Later today, we'll see the winds pick up and things turn sharply colder overnight and into Sunday. With an upper-level low moving overhead late Sunday into Monday, it appears that a mix of rain and snow showers will occur across the area, as winter makes a brief mid-April encore. There probably will not be any accumulation of snow except at higher elevations, primarily 3,000 feet or more. Storms will have hard time getting over the mountainsPosted Apr11, 2008 at 04:42 PM
Big storm system may only give us a glancing blowPosted Apr10, 2008 at 11:17 PM
Interestingly, more precipitation is expected behind the front on Sunday and Monday than is expected by the national experts with the front itself. Some of this precipitation might not be rain, but rather snow, especially in higher elevations. I'm beginning to believe that even the Roanoke Valley could see snow showers late Sunday or early Monday. We'll get a winter encore for a few mornings, with lows near or below freezing Monday and Tuesday. Hope you haven't put out all your plants just yet. Next week: A freeze/frost threatPosted Apr09, 2008 at 04:51 PM
I wouldn't even rule out the possibility of seeing some snowflakes in the air about Sunday or Monday, especially over the higher elevations. Nation's mid-section likely to light up with severe stormsPosted Apr09, 2008 at 12:53 AMToday and Thursday carry the risk of a large-scale severe weather outbreak developing in the nation's heartland. The Storm Prediction Center has, as of very early this morning, placed a moderate risk of severe weather each day, moving from the southern Plains states today to the lower Mississippi River valley come Thursday. (Click here for the latest storm outlooks from SPC) A strong low pressure system will be winding up, pulling up moisture through the central U.S. from the Gulf of Mexico. The low will also drag a cold front and dry air to collide with the warm, moist air. Even more importantly, winds aloft will be shifting from southerly and southeasterly near the surface to more southwesterly and westerly the higher one gets from the ground. These changing wind directions are called "shear" and can give an extra spin to thunderstorms, the kind of spin that creates long-lasting supercells, very large hail, extremely high winds, and possibly tornadoes. None of this is abnormal -- it is April, after all -- but the intensity of the situation could be extreme. Most of this activity will stay west of us -- we might get some showers or storms out of this system by the weekend. Severe weather where it's supposed to be in early springPosted Apr09, 2008 at 12:51 AMOne thing that has been normal about this spring is the pace at which severe weather has progressed northward across the United States. Through the late winter and into early March, the nation’s worst storms broke out along the Gulf of Mexico coast, the Deep South, the lower Mississippi River Valley, and occasionally into the Tennessee Valley. The Feb. 5 tornado outbreak that killed 59 was extreme by any definition, bu |
