Sunday should be pretty much a repeat of Saturday … sunny, dry and maybe just a hair warmer, especially in locations west of Roanoke that didn’t make 70 on Saturday. Get out and enjoy it if you can.

The little low-pressure system show offshore on the Weather Prediction Center map for Tuesday morning is going to help keep the coming days from being another runaway summerlike warmup. This low tracking along the Gulf Coast and off the Southeast Coast is expected to absolutely soak some of that region. We’ll likely be too far north for much in the way of significant rain, but it may turn winds just enough to the east on Monday, maybe some of Tuesday too, for a bit of a wedge-like effect, with cooler, damp air banking against the mountains. We probably won’t see 70 and some places may not see 60 on Monday, with some showers or drizzle possible as moisture is lifted up the Piedmont and Blue Ridge. Fanning out to the larger weather map for Tuesday morning, another feature that may be very important this week is the high pressure system depicted off the Northeast coast. As this high moves more out to sea, its clockwise flow will keep some easterly and southeasterly winds into our region through the week. This is different than last week’s dry southwesterly flow that allowed a quick shoot to July-like average temperatures. Thinking about summer for a moment, we know that, generally, our hottest, driest weather challenging 100 degrees generally comes from the west, but our long stretches of sultry humid days in the upper 80s and low 90s leak in from the south and southeast. As the week progresses, this offshore high may mean our temperatures are not as hot as last week — perhaps some low to mid 80s from Roanoke southward and eastward by Wednesday — but it will be more sticky.

From this distance, I think the late week cold front will have more volatile potential for severe storms in and near our region than last week’s, because of the higher humidity providing more fuel and southeast winds producing low-level shear ahead of it. Friday would seem to be the best shot at this now, but perhaps some storms as early as Thursday, and at least some chance it bleeds into Saturday if the front slows. Whenever the front goes through, it will provide a pretty stiff cold shot, with some sub-freezing morning lows possible by late next weekend and early the following week.

As expected, severe weather was not widespread in Southwest Virginia on Thursday night and early Friday, but there were some localized areas of damage, especially in the counties bordering North Carolina. Homes were damaged near Hillsville by what the National Weather Service in Blacksburg has determined to be 80-85 mph straight line winds, and additional damage was also reported in Henry County. Lightning also caused some havoc in Botetourt County, both heavily damaging a home at Fincastle and at least temporariy disabling an Interstate 81 weigh station.  The Storm Prediction Center’s storm reports map for April 11 shows the scattering of severe weather reports across the Southeast on Thursday, including a deadly tornado in Mississippi.

Southwest Virginia has tried out winter and summer the last couple of weeks, jumping from accumulating snow to mid 80s to low 90s highs in 6 days. How would you like some actual spring temperatures now that it is actually spring? This weekend looks to provide just that, with lots of sunshine and dry conditions. High temperatures in the 60s and 70s, with lows in the 30s and 40s, near early to mid April norms, are expected across the region both Saturday and Sunday. It looks to be a simply gorgeous and comfortable weekend for outdoor activities. Temperatures will slowly warm through the early and middle part of the coming week — not sure we’ll make 90 again, but 80s are likely by Tuesday and Wednesday, at least from the Roanoke Valley south and east. This will precede the arrival of another cold front late next week that will, again, bring a round of showers and storms, with some potential for strong to severe storms. Early indications are that next week’s cold front will provide colder air than this week’s, so we may go into the packed April 20 weekend a little breezy and chilly. It doesn’t look to last long, with warmth again recovering a few days after the brief cold shot.

UPDATE 9:30 AM: Roanoke Times report of wind damage in Carroll County

Photos of Carroll County wind damage from blog commenter Johnny-KHLX

Several reports of wind damage from Carroll County east through Henry County.

Also — lightning strikes a house in Fincastle. END UPDATE

Latest warnings from National Weather Service-Blacksburg

Latest watches from Storm Prediction Center

Watch the storms approach this evening on Radar /Future Cast, linked here

I can’t say tonight is the first severe storm threat of the year for Southwest Virginia …. that came back on Jan. 30, leading to some wind damage in Pulaski County.  This the first of the spring season, though, and while it is ending a period of summerlike warmth, the setup for our region is actually more like a winter cold front, with strong winds aloft and very subtle directional shear (shifting from south at the surface to west-southwest aloft, rather than from east or southeast all the way to west or northwest) but not a great amount of instability. If you walk around outside today, you will notice that even though it is very warm for April, it is not all that humid — 50s dew points, not the juicy 60s/low 70s that are common in our more vicious severe outbreaks. So while a large-scale severe outbreak with widespread wind damage and/or multiple damaging tornadoes is NOT expected for Southwest Virginia, the strong lift of the approaching cold front, the temperature contrast across the front, a decent inflow of moisture in the evening and strong winds aloft very slightly turning with height, plus the momentum of a squall line moving in from the Tennessee Valley, may lead to some strong to locally severe (58 mph +) wind gusts as it moves in late tonight or very early Friday morning. Sometime between 10 p.m. and 3 a.m. appears to be the likely arrival time for the worst of the storms and rain – some brief heavy downpours possible. As it appears now, I would lean more toward the after-midnight period for the arrival of the bulk of any gusts, rumbles and downpours. It does not appear storm heights and updrafts will be sufficient for much hail once the line arrives, and any tornadoes that occur in or near our region should be isolated, brief and weak. That hasn’t been the case in Missisippi and Alabama today, where the parameters for severe weather have been much stronger, and at least one person has died in a tornado. 

Behind the front, the weekend looks dry and more springlike (not winter or summer) with highs in the 60s/70s and lows in the 30s/40s. We’ll rebound back into the high end of the 70s and the 80s by early to mid next week before another front approaches in the latter half of the week.

UPDATE 8 AM, 4/11: The Storm Prediction Center has put areas from the Roanoke/New River valleys southward in a slight risk of severe thunderstorms over the next 24 hours. Damaging winds are the greatest risk, but there is a slightly enhanced tornado threat into mainly Southside Virginia. A weak surface low forming along the front to our southwest may add just a bit more turn to the winds aloft than indicated below. UPDATE

North American Model projected radar early Friday morning.

Our summerlike streak of heat — driving Roanoke to 90 and Blacksburg to 83, both April 10 records, on Wednesday only 6 days after widespread snowfall — is going to come to an end by Friday as a vigorous cold front pushes eastward. With highs again reaching the 80s in many locations on Thursday, this might sound like the recipe for some violent storms — and there may be some strong to locally severe storms with high wind gusts as a primary threat late Thursday night and early Friday morning. But there are some reasons our region is likely to be spared a major severe weather outbreak. For one, the front is likely to push through at the coolest time of day, the early morning hours of Friday, not during the peak heating of Thursday, when the lift of the cold front and the instability of the daytime heating could combine for a much greater severe threat. Also, much of the upper-air wind dynamics that could support high-end, rotating storms will be carried far north of our area toward the Great Lakes with the low-pressure system — there will be plenty of strong winds aloft, but they will mostly be blowing parallel to each other, west to east generally, rather than easterly or southeasterly winds at the surface gradually turning to westerly aloft, the “veering profile” that sparks supercell storms. And while abundant moisture will stream in at many levels of the atmosphere, we won’t quite have that super-souped atmosphere with upper 60s/low 70s surface dew points that yields a lot of severe storms. The best chance of severe storms will be in the Deep South, where the front’s arrival can meet the greatest warmth and deepest moisture during the daytime. For Southwest Virginia, we likely get through most of the day Thursday without much rain … maybe some scattered showers toward mid to late afternoon, especially west of Roanoke. Rain and storms arrive by Thursday evening — do expect some rumbles and probably some gusts, maybe even a little hail here and there. An isolated tornado is possible, but unlikely. There may be some redevelopment of severe storms east of us during the day Friday, but it appears like this transition from summer back to more April-like weather (60s/70s highs and 30s/40s lows for the weekend) for Southwest Virginia will be mostly be some wind-blown sheets of rain, totalling no more than an inch for most.

It’s worth keeping an eye out Thursday and Thursday evening for changes with the parameters or evolution of the system that would lead to more severe weather, but it’s not looking like a big outbreak for Southwest Virginia. Of course, it only takes one gusty storm wherever you are to make it a big deal for you.

The weekend is likely to be dry and seasonable, a little breezy on Saturday, before a renewed warmup into early next week. The next cold front in about a week will probably bring a colder punch to Southwest Virginia than this one will.

We have taken a flying leap from the refrigerator into the frying pan. Roanoke’s high of 87 degrees on Tuesday equalled the normal high at the hottest time of year, late July and early August, and missed an April 9 record by just 1 degree (88 in 1929). Blacskburg didn’t quite tip 80, reaching 79, 5 off a record. There’s a good chance Blacksburg tops 80 and some chance Roanoke scrapes 90 on Wednesday as the summerlike heat less than a week after widespread snowfall reaches its peak. April 10 records of 82 at Blacksburg (2001) and 88 at Roanoke (1922) could be challenged.

And that reminds me: Today’s Weather Journal column (linked here) looks at how snow to 80s in less than a week really isn’t that uncommon when it does happen to snow measurably in late March or early April.

This summerlike warmth is NOT going to hang on for all of April. The overall pattern is not one for prolonged warmth, with broad high pressure trapped over us, but rather one for up-and-down waves of warmth and cooling as the west-to-east or southwest-to-northeast angled jet streams brings low-pressure systems across the nation, dragging cold fronts. The next such system its working its way across the central U.S., where it is kicking up a wild package of heavy rain, snow and thunderstorms. On Monday night, there was  confirmed tornado at the edge of a snow shield in Colorado, and on Tuesday, there were severe thunderstorm warnings for locations where snow or freezing rain was falling in Nebraska. As this cold front pushes into our warmth, there will be some risk of strong to locally severe thunderstorms late Thursday or early Friday — probably more like a squall line with gusty winds rather than intense supercells capable of violent tornadoes or extremely large hail. We’ll pinpoint more of the severe threat as more details become clearer. Rainfall estimates have been increased quite a bit — the Weather Prediction Center as of Tuesday evening showing widespread 1-plus inch amounts late Thursday into Friday — as there is some evidence on the models that the front may slow down to a crawl and/or develop a secondary low-pressure system to the south that could increase rain amounts, especially with upslope easterly or southeasterly flow into the mountains.

Once the front goes through, breezy winds will usher in more normal temperatures for the weekend, with highs backing into the 60s and lows into the 30s and 40s. Expect another warm rebound in temperatures early to mid next week before yet another front pushes in about a week after this one. It may have a bit colder kick to it, so don’t store away those coats just yet.

UPDATE 5:30 PM, 4/8: A day ahead of schedule, Roanoke hit 80 degrees on Monday, the first 80-degree reading since Oct. 25. Expect highs near or above that level both Tuesday and Wednesday at Roanoke, spreading to even more sites in Southwest Virginia. END UPDATE

The switch has flipped. Just 5 days after Thursday’s fast and furious April snowfall (news NWS-Blacksburg analysis linked), temperatures may well reach 80 degrees at Roanoke for the first time since October. Wednesday is likely to be the warmest day this week, as southwesterly wind flow around a strong central U.S. low-pressure system moving northeastward peaks. Many locations in Southwest Virginia are likely to be near or above 80 on Wednesday (NOAA graphical weather map for Wednesday at left projecting 82 for Roanoke, 79 for Blacksburg) with abundant sunshine. After that, an approaching cold front, pushed by the low moving toward the Ohio Valley and/or Great Lakes, will increase the chance of showers and thunderstorms — some of which may be strong to severe — by late Thursdaya and Friday. Numerous severe storms are likely in the state’s west of us through midweek. This is truly a classic spring pattern, following on the heels of an extended winter pattern. Once the front passes, temperatures will back off a bit for a few days (maybe a day with highs only in the 50s, lows 30s/low 40s), but will recover late in the weekend and early next week back to highs at least in the 70s before another low and cold front approach about the middle of next week. We may be in this repeating pattern of warmups, short cool-downs and chances of showers/thunderstorms in between for the rest of April and much of May too.

Thanks largely to last week’s statewide rain/snow storm, Virginia is now considered entirely free of drought according to the U.S. Drought Monitor.

Something missing from March so far in the United States is tornadoes. There has only one confirmed tornado — in Georgia on March 4. January and February were active in the Deep South and Gulf Coast region, but March has started slowly. Last March produced the extreme March 2-3 tornado outbreak in the Ohio Valley, but conditions curtailed much of the rest of the year, with 2012 being an unusually low year for tornadoes nationally. The reasons for 2012 being a low year for tornadoes were largely related to the extreme warmth early in the spring season shutting down a lot of the contrasting air masses tornadoes form along, and the presence of extreme heat and dry weather in later seasons squelching tornado development.  2013 is a little different. There continue to be vigorous low-pressure  systems, but so far in March, they have not quite drawn instability, shear and deep moisture together in a way for a tornado outbreak. My suspicion is that the tornado season will pick up a little later this spring, when warmer air and Gulf moisture tangle a little more regularly with colder air masses sinking in from the north.

Speaking of tornadoes, Weather Journal alum Kathryn Prociv has a post today on tornadoes in the mountains on USTornadoes.com. The Pulaski and Glade Spring tornadoes of 2011 are among those featured.

There are many St. Patrick’s Day-related activities scheduled for Saturday. The good news is that it will likely be the warmest day of the next week, and maybe the warmest day so far this month. Westerly wind flow will start pushing in some milder air the next couple of days, enhanced by downslope compression and warming as it moves over the Appalachians, pushing us into the 50s to low 60s on Friday and more widespread 60s on Saturday. 70 is not out of the realm of possibility for Roanoke and points south and east, if there happens to be more sun than clouds. The bad news, though, is that a bit more moisture coming in with that mild air and a low pressure system moving through the Ohio Valley may be able to squeeze out a few showers Saturday. It doesn’t look like a washout-type rain, but some light showers will be possible, so some umbrellas at outdoor events may be a good idea. Late Saturday, a new cold front pushes through, and it appears a wedge of cooler air may develop banked against our mountains Sunday and Monday. With moisture overrunning this cooler air mass, we may see more frequent and abundant showers than we do Saturday. At this time, it appears the wedged air mass will be colder than normal with highs in the 40s across much of Southwest Virginia, but not cold enough for frozen precipitation. I’m a bit leery of this, though, especially in 3,000+ elevations and north of I-64, where it’s possible it could get just cold enough late Sunday night and early Monday for some sleet or wet snow to reach the surface. Were it just a month earlier, there would be a more widespread threat of mixed precipitation, but the higher sun angle and longer days are far enough along now to have more effect on our near-surface temperatures. Even with that being so, it appears a cold front will renew colder than normal temperatures by mid to late next week, and long-term models continue to suggest normal to below-normal temperatures to be the rule through near the month’s end.

If you haven’t already, be sure and look up one of the many dramatic videos posted on YouTube of Sunday’s tornado in Hattiesburg, Miss. The tornado was rated EF-4, the second strongest level. Blessedly, no one died in the tornado, even though it tore into part of the University of Southern Mississippi campus. It may seem early for tornadoes, but mid to late winter is the start of tornado season along the Gulf Coast.

Though the wind advisory expires for western Virginia at 7 a.m., some breeziness will continue throughout Tuesday, but it will be mild with highs in the 50s as the westerly winds blowing down the Appalachian slopes compress and warm slightly. The fact that we’re not getting true Arctic or Canadian air out of this most recent cold front plays a significant role in our Wednesday weather.

The Hydrometeorological Prediction Center’s 1-inch snowfall map issued Monday evening, covering the time from 7 p.m. tonight to 7 p.m. Wednesday, delivers a pretty good idea of the current consensus expectations (as of late Monday) on where snow will be most likely with the next storm system. Guidance has generally closed on a track that will be somewhat south of us with the surface low, with the weak upper-level low tracking farther north. Generally, that’s a track that can lead to significant snow in our area, but there just isn’t much low-level cold air to support it, and the storm system does not appear to be dynamic enough to “create”  its own cold air as we saw with the Jan. 17 snow and even last Thursday night locally over the Roanoke Valley. It will be razor-thin margin on Wednesday between cold rain and snow, and as we’ve seen lately, it’s easy to cross over that line. For now, the chances of snow are better the farther north and west you are relative to Roanoke, especially at 2,500 feet and higher elevations. Most locations from the Roanoke Valley and Blue Ridge north and west will probably see a little snow by Wednesday evening, but the chances of a widespread accumulating event appear to be low … for now.  Stay tuned to forecasts, and keep an eye out the window Wednesday, just in case there are changes.

Some upper-level energy swinging around an eastern U.S. trough this weekend may trigger a snow event of some sort near or in our region. Forecast guidance is bouncing around with the specifics of that situation. One thing that will be much different than Wednesday is that the atmosphere will be much colder.

Latest updates from The Roanoke Times on Roanoke/New River flooding

Rainfall totals reported to NWS-Blacksburg through 4 a.m.

Latest flood and wind advisories and warnings

SW Virginia river stages and forecasts

VDOT road closures

UPDATE 10 AM, 1/31: The New River at Radford is nearing an expected crest of 21 feet — major flood stage, swamping vehicles at Radford University — and the Roanoke River is nearing an expected crest just above 12 feet at Walnut Avenue, 2 feet above flood stage, a low-end “moderate” flood. These rivers will be receding upstream from these points, and rising downstream, through the day, as widespread 2-6 inches of rain (and some higher amounts) continues to drain off of steep terrain and saturated soil.  Hundreds of roads are closed by flooding statewide. It appears to be our region’s worst widespread flooding event at least since late June 2006 and possibly since the triple-tropical-trouble (Frances-Ivan-Jeanne) of September 2004.  END UPDATE

UPDATE 12:05 AM, 1/31: The bulk of the rain is pulling east of Roanoke as I type this, with some showers remaining for the rest of the evening — and some windy, colder weather. Snowflakes may even fly in some locations, especially west of Roanoke and in higher elevations. The large amounts of water dumped on already wet ground will continue to runoff, with flooding on streams and some rivers continuing today, including the New and Roanoke rivers. A quick-moving disturbance from the northwest will bring a chance of light snow or snow showers into the area late Thursday night and early Friday, and a similar system may cause a second round late Saturday night and Sunday. We’ll plan to take a closer look at that on Thursday afternoon. END UPDATE

The severe storm threat has passed with the departure of the squall line (with considerable damage in Pulaski County), but the heavy rain/flooding threat is ongoing, with numerous flash flood warnings affecting the Roanoke and New River valleys and much of Western and Southwest Virginia. Moderate to heavy rain is likely to continue for another 3-5 hours over most of the region, with many areas already over an inch, and some already topping 4 inches, especially near the North Carolina border. This rain is falling onto soil that has become saturated from substantial rain and snow since Jan. 14, so much of it is running off into drainages and streams. Beware if traveling tonight for ponding on the roads or, even, creeks and rivers rising out of their banks across roadways.

Colder air will be moving in on Thursday behind an Arctic cold front and a series of Alberta clipper systems will bring chances of light snow through the weekend, with the better chances west of Roanoke.

SEVERE THUNDERSTORM WATCH RE-ISSUED FOR SOUTHWEST VIRGINIA UNTIL 10 PM

UPDATE 3:25 PM: The squall line resurgence is occurring along the Interstate 77 corridor, and this will spread rapidly northeastward toward the Roanoke and New River valleys and along the Blue Ridge in the next couple of hours, with strong winds and heavy rain possible as it passes. The Storm Prediction Center has indicated that a severe weather watch may be needed, once again.  Follow the latest watches and warnings from the National Weather Service-Blacksburg.  END UPDATE

UPDATE 1:20 PM: The severe thunderstorm watch issued earlier today for some counties west of Roanoke has been cancelled. The squall line is very poorly organized and continues to weaken as it has run out too far ahead of the cold front, the source of lift. Later this afternoon and evening we may some reorganizing of the line east of the Blue Ridge, in slightly better instability and as the cold front gets closer. For the Roanoke Valley/Blue Ridge and points west, it’s likely to be an afternoon of showers with some gusty winds, picking up into heavier rain by late afternoon or evening. Meanwhile, it’s already a deadly day to our south, with a confirmed tornado fatality in Georgia, ending a record 220-day streak nationally without a tornado fatality. Here is a video of the tornado at Adairsville, Ga.END UPDATE

UPDATE 8:50 AM; A severe thunderstorm watch has been issued through 4 p.m. for Craig, Pulaski and Carroll counties westward. It does appear the squall line is moving ahead of the schedule shown on last night’s NAM model output below — it’s already entering the far southwest corner of Virginia, and will likely cross I-77 by early to mid afternoon, entering the New River and Roanoke valleys shortly thereafter, with some heavy rain and gusty winds continuing into the evening. Stay abreast of the current location on our radar view available on the right margin. END UPDATE

It looks like we’re headed more for a late afternoon-evening period for the heaviest of the weather on Wednesday, which in Southwest Virginia, will likely consist of a squall line of heavy rain showers, possibly accompanied by strong winds and maybe a little thunder. Though we are in a slight risk zone for severe weather, the cloud tops may be relatively low, which often precludes lightning and thunder. Strong winds are the greatest risk, as  downdrafts in the squall line may bring some of the very strong winds aloft to the surface. The frame at left is the approximation of what radar should look like about 10 p.m. Wednesday, with the heaviest rain blowing through western Virginia. Long before this line arrives just ahead of the cold front Wednesday night, gusty winds will pick up from the south to south-southwest, prompting a high wind warning along and west of the Interstate 77 corridor and a wind advisory elsewhere. Historically, the localities in the high wind warning have seen 60 mph gusts in similar setups as southerly to southeasterly winds crash against the ridges and roll over like waves into lower elevations. It’ll be another warm day as we await the line moving at us from the west, with 60s to low 70s possible, and perhaps some intermittent showers as moisture is squeezed out against the higher terrain. Rainfall amounts of 1-2 inches are expected.

The cold front blasts through overnight Wednesday bringing us back to normal late January/early February temperatures, 30s-40s for highs and 20s for lows. A series of relatively weak “Alberta clipper” type disturbances will dive at us from the northwest over the weekend. Each one will bring a chance of light snow or snow showers, especially west of the Blue Ridge, from Thursday through at least Sunday. The first arrives Thursday night into Friday, and another may push through on Saturday. Don’t expect a ton of snow, but it’s possible a dusting could be laid down even east of the Blue Ridge with one or more of the clippers.