WINTER WEATHER ADVISORY EXPANDED EASTWARD … now includes Franklin, Bedford, Henry and Pittsylvania counties … continues for all localities to the west.

UPDATE 1:15 PM: It appears the heaviest snow is likely to end in the Roanoke and New River valleys by 3 p.m., with some flurries or patchy freezing drizzle continuing into the evening. Snow amounts of 1/2 to 2 inches are being reported so far, so the 1-3 inch expectations appear to be well on track. END UPDATE

UPDATE 11:45 AM: It appears that a heavier patch of snow is moving through much of the New River Valley and will spread into the Roanoke Valley during the lunch hour. The snow rate will pick up such that any roads not already covered may become white fairly quickly. Accumulations totaling 1-3 inches with some heavier amounts are still expected. END UPDATE

UPDATE 10:15 AM: Snow is now rapidly overspreading the New River Valley, and appears likely to begin in the Roanoke area by 11 a.m., roughly an hour ahead of the moved-up times I listed below. Expect roads to deteriorate rapidly. Some sleet may occur at the outset of the snow in some locations. END UPDATE

UPDATE 8:30 AM: Moved up start times of snow by 1 hour. Snow by 11 a.m. in New River Valley and by noon in Roanoke Valley. That is “by” not “at” so possibly a little earlier. END UPDATE

Radar is picking up echoes, some heavy, in central/eastern Tennessee and Kentucky, even edging into far southwest Virginia, as of just before 7 a.m. That’s not what you’re seeing at left — the inset image is what the NAM forecast model “thinks” the radar will look like about 1 p.m. today. Everything appears to be on track for a quick burst of snow — 3 hours or so of moderate, even heavy for a brief spell — that will likely accumulate 1-3 inches widely (not necessarily every single point) across Southwest Virginia and perhaps more in some heavier bands. The  showery looking echoes in Tennessee and Kentucky are expected to become more solid in coverage, but there may still be some “mesoscale banding” or regions of more intense snow that, in some cases, may align west/east and move over the same location for an hour or two. That’s what could boost some local snow totals above forecasts. The moisture will be hitting very dry Arctic air as it heads eastward, so you may see an hour or two of radar echoes over your head before you see snowflakes, especially at lower elevations.

Approximate start time is spreading over the region west of Interstate 77 by 10 a.m. (already has begun in far southwest corner of the state), as far east as the New River Valley (Blacksburg/Chrsitiansburg/Radford/Pulaski) by 11 a.m. and into the Roanoke Valley by noon   (I say “by” not “at” because it’s more likely to be a bit earlier rather than much later.) With the consistently cold weather we’ve had the last several days, snow will accumulate on untreated roads very quickly, and so slick conditions will develop rapidly even with minor amounts of snow. As we’ve noted, it will be a fluffy snow that is unlikely to cause large-scale power outages, as the Jan. 17 heavy wet snow did.

From here, it’s a radar-watching and waiting game.

WINTER STORM WARNING NOON TO MIDNIGHT

UPDATE 11:30 AM: A short update to say, well, not much has changed. NWS-Blacksburg is estimating 3 p.m. for rain to snow changeover in the Blacksburg area and 4 p.m. for Roanoke. That could vary an hour or two either way.  Some wintry mix and snow reports are occurring on the northwest fringe of the moisture shield in West Virginia into the far southwest corner of  Virginia. The Radar / Future Cast link at right on this blog will give you an approximate idea where the mix (pink) and snow (blue) are being reported. END UPDATE

Summary: All indications are that the region is on track for 4+ inches of wet snow beginning early to mid-afternoon and continuing into the evening. Snow will be heavy at times with reduced visibilities and rapid collection of slushy accumulation on some road surfaces near rush hour. It should be over by 10 p.m.

It’s snowing this morning – in Jackson, Mississippi. And so begins a slow, sloshing trudge from a not-all-that-cold rain this morning in Southwest Virginia (temperatures in the 40s, mostly) to a potential heavy, wet snow event by late afternoon and early evening. The cold pocket aloft with the upper-level low spinning over Mississippi will slide northeastward, and a surface low forming just east of Atlanta will begin pulling cold air southward as the day progresses. We’ll likely see the rain/snow line begin to slip southeastward through West Virginia by mid to late morning as snow reports also begin to increase in central/eastern Tennessee and into some of Kentucky and eventually far southwest Virginia with the advancing upper low. During the afternoon, say between 1 and 4 p.m., temperatures are expected to be cooled in the low and mid levels of the atmosphere enough over Southwest Virginia east of I-77 (may happen before then to the west) that snow will begin reaching the ridgetops first, then progressively lower, with air temperatures also decreasing to near or barely above the freezing mark. If you’re anxiously waiting on snow this morning, this process will be like watching paint dry. Snowfall amounts by all available guidance appear to be on track for widespread 4+ inches across the region, with some amounts up to 12 inches, or maybe a little more, especially in higher elevations along the I-81 corridor southwest of Roanoke and westward. The snow won’t last long, probably no more than 5 to 8 hours at any location, but will likely come down fast and furiously at times, with some low visibilities developing near rush hour. It’s that intensity that is expected to overcome a relatively mild, moist ground, collecting on grass and exposed objects first, then forming a slushy layer on the ground once the rate of snowfall exceeds the melt rate. Once the thin layer of slush develops, snow can collect on top rapidly. In the heaviest periods of snow, roads may become slushy and even ice/snow covered — I-81 southwest of Roanoke is a particular concern, with its steep hills and curves, and considering the trouble that ensued there from heavy snowfall rates in December 2009. Due to the heavy, wet nature of the snowfall, especially in its early stages, there may be some tree and power line damage, similar to what we saw last Feb. 19. This snow will probably be moving east of us by 10 p.m., and a cold night with lows in the upper teens and 20s will ensue that will freeze slush and water on streets.

Another dense fog advisory has been issued overnight/early Sunday for a similar portion of the region as last night. Fog probably won’t be as widespread as late Friday and early Saturday, but could be dense and hamper travel in some locations.

There is so much going on with the weather pattern, short term and long term, that it’ s hard to boil all of it down. Perhaps this is a format I can replicate in the future. Here are the “Big 5″ weather points, based on impact and likelihood, for Southwest Virginia looking forward from Sunday.

(1) Record highs likely again on Sunday. Roanoke’s 73 and Blacksburg’s 71 on Saturday set new standards for Jan. 12, eclipsing previous marks from 2005. Roanoke’s high made for the hottest January day in 8 years, while Blacksburg’s appears to be the second-warmest January day in its entire period of record, dating to 1952, beaten only by a 73-degree day on Jan. 30, 1975. The same southwesterly winds at the surface and aloft, plus in-and-0ut  sunshine, will continue the springlike weather for another day, with many temperatures topping 70. Roanoke’s record high for Jan. 13 is 73, set in 1932; Blacksburg’s record is 64, set in 2005. It appears Blacksburg’s record is very likely to fall and Roanoke’s has a good chance. Sunday will be the end of the record warmth, and quite likely the last truly springlike day we’ll see for weeks — maybe even until spring itself.

(2) Good chance of soaking rain Monday-Wednesday. As the leading edge of much colder air that has invaded the western half of the U.S. grinds against high pressure off the Southeast coast that has helped bring us record warmth, the cold front will stall, and only sluggishly advance eastward through the early to middle part of the coming. Waves of low pressure moving along the slowing front will bring abundant moisture from the Gulf of Mexico, leading to periods of rain, especially on Monday and Tuesday, maybe leaking into Wednesday too. The Hydrometeorological Prediction Center is expecting 2-plus-inch amounts to be common this week, mostly falling during the 72 hours ending Tuesday evening (which really means the 48 hours beforehand, since no rain is expected through Sunday evening). Rainfall will be enhanced some by southeasterly winds blowing up the slope of the Blue Ridge as low-pressure centers move up the front. Roanoke has not topped 2 inches in a single rainfall event since Sept. 17-18. Much of the region continues in moderate drought, so though it will be messy outside, the rainfall is needed.

(3) Much colder period ahead for late January. This will become a huge weather story, not just locally, but nationally, if what many long-range forecast models show comes to reality. Extremely cold air, displaced southward by a “sudden stratospheric warming” event over the North Pole that began about3 weeks ago, is expected to move southward through central and eastern North American over the next 1-2 weeks. While the first chunk of this cold, in a greatly modified fashion, will bring our temperatures back down from intensely warm this weekend to near-normal January cold by late week, it is the subsequent pushes of cold air afterward that will have the potential to bring unusually cold weather to much of the central and eastern U.S., including Southwest Virginia, generally in the Jan. 20-30 timeframe. It’s hard to tell exactly how cold it will get, but it would be a good time to review what to do about your water pipes and make sure heating systems are in top-notch working order just in case the most extreme cold scenarios comes to fruition.

(4) Some ice/snow risk as cold penetrates back side of precipitation shield Tuesday. The cold air will only be grudgingly moving eastward, but enough of it may move in by Tuesday that some ice or snow may be possible, primarily in the highest elevations (3,000+ feet) and along/north of the I-64 corridor. The Hydrometoerological Prediction Center has highlighted a few higher spots around the region on its map for a slight risk of heavy ice (.25 inch or more ) mostly on Tuesday. The HPC also has posted maps showing a low-end risk of 1 or more inches of snow generally along and north of the I-64 corridor for the 24 hours ending at 7 p.m. Tuesday, and also a slight risk for light icing farther south in the same time frame.  This is an iffy situation and will most likely be spotty, if it develops at all.

(5) Late-week snow chance not entirely out of the question just yet.  The forecast models have been bouncing around on some upper-level energy moving across the South on or near next Friday. This just remains something to keep one eye on, as there is at least some potential for snow (or mixed precipitation, or cold rain) if a sizable low were to throw moisture over marginally cold air late in the week.

Temperatures have been pretty even-keeled in the first week of January — seasonable cold bouncing between the 20s and 40s, mostly, with more clouds than sun most days, and not much precipitation. We’ll continue that general pattern of temperature through Monday night — but then, a wild roller-coaster ride begins, not just for Southwest Virginia but much of the U.S., that may continue much of the rest of January. I think there’s a good chance Roanoke will have a high above 70 and a low below 10 before this month is over.

The coming spurt of intense warmth is the most certain element of this roller coaster — we can see the hill we’re climbing, but don’t have a clear picture yet of where the track leads beyond the summit, except knowing it will generally be downward. Prevailing southwesterly wind flow, surface and aloft, will sweep in milder air starting Tuesday, when highs may poke above 50 in much of Southwest Virginia, more so on Wednesday, when a few low 60s are possible. The southwesterly wind flow will also bring in enough Gulf of Mexico moisture for a chance of rain Thursday and Friday — this may coincide with a temporary wedge of colder air from the northeast that will pull highs back into the 40s for a day or maybe two. But once the rain system goes by, even warmer air arrives for next weekend. We’re likely talking widespread 60s and some 70s during the Saturday-Monday stretch. Record highs for Roanoke on Jan. 12-14 are 71 (2005) for Jan. 12 (that may be reachable Saturday), 73 (1932) for Jan. 13 (that may be reachable Sunday) and 81 (1932) for Jan. 14, the hottest January temperature on record (it’s not going to get THAT warm this time!).  The warm air will be curtailed rather rapidly sometime  in the middle to latter part of next week. This will not be the Arctic motherlode, but the leading edge of a colder pattern easing in from the west that may hold in for several days.

How cold it gets during the colder pattern is somewhat fuzzy, but there are signals of significant blocking highs in the northern latitudes on forecast models and movement of a weakening polar vortex — the core of coldest air — into Canada and toward the U.S. that would suggest a long, very cold outbreak will be possible after Jan. 15. Also totally up in the air are the prospects of winter storms — will mid-late January be a cold, dry period, or have frequent winter storms, or something in between?  It all depends on exactly where major features set up. Whatever the case, be sure and enjoy the warmth outside next weekend if you can, whether you are a sun seeker or snow lover. It won’t last long, and may not return again for several weeks or even a couple of months.

********

Snow meter
1/7-1/13

Chance of 1 inch of snow on scale of 0 to 10

Roanoke  — ZERO snowflakes
Blacksburg — ZERO snowflakes

Outlook: This week will bring a warm-up as southwesterly winds dominate, bringing in much milder temperatures after two seasonably cold weeks that yielded only a little snow and ice. Highs may reach the 60s a couple of days this week, and any precipitation that falls will be rain. I can’t find a reason to give either site even a single flake on the snow meter this week. Colder weather will return, possibly in force, but that will not happen until at least Jan. 15.
Looking back: My last-minute downgrade of the snow meter with new data last weekend put this week in the victory column, as no significant snow fell at Roanoke or Blacksburg, and my snowflake numbers were below five for each. Current records: 5-0 for Roanoke, 4-1 for Blacksburg.

My Wednesday Weather Journal column in The Roanoke Times, linked here, was about white Christmases locally — and how this probably won’t be one

Weather journal alumna Kathryn Prociv posts on the three-year anniversary of the Dec. 18-19, 2009, snowstorm in the Washington Post’s “Capital Weather Gang”

Near the end of a Weather Journal column about Superstorm Sandy at the end of October, I wrote this line:  “Roanoke’s winds peaked at 40 mph sustained and 60 mph gusts. We may have a cold front or two this winter with winds almost that strong.” We may be about to test the truth of that statement for the first time this winter.  The National Weather Service has raised a high wind watch (likely becoming a warning on Thursday) from Thursday evening through Saturday afternoon for the potential of some 60 mph winds in much of our region. A strong Arctic front is going to slam through on Thursday evening, bringing with it a blast of cold air that will be a quite a shock after so many days of 60s this month (Roanoke’s high of 64 on Wednesday was the 10th 60+ degree day of December, the most since 11 in 2006.) The tightening pressure gradient around a strong low that will track to our west and north, and only poke eastward across New England, will keep us in strong northwest wind flow for about 36-48 hours. (This strong low is triggering a blizzard, severe weather risk and dust storms in various portions of the central U.S.) As these winds hit the mountain ridges, choppy waves will develop that bring stronger winds aloft to the surface. It’s one of the hazards that goes along with living in our lovely Appalachians — recall that many locations east of Roanoke in the more level terrain didn’t crack 50 mph with wind gusts on Oct. 29, while 60 mph gusts roared through our trees with Superstorm Sandy. I would not at all be surprised to see a 60 mph wind gust at Roanoke or other regional locations — 40 mph sustained winds probably won’t occur, though, at least anywhere below the 4,000-plus ridgetops,  just because that’s usually not the nature of these Arctic cold frontal events. Do expect 20-35 mph sustained winds with 50 mph gusts, at least, during this time frame.  There will likely be scattered power outages. And it will be cold wind, with highs probably not getting out of the 30s anywhere on Friday.

There will be some precipitation, too — a good chance of quick-hitting rain showers, perhaps accompanied by thunder or a gust of wind, ahead of the cold front on Thursday, then upslope snow showers with the northwest winds climbing the Appalachians overnight Thursday into Friday. Several counties of West Virginia remain under a winter storm watch with 5-plus inches expected on west-facing slopes and in higher elevations, areas that will keep getting pounded by snow squalls into Saturday. This appears to be a strong enough upslope event that there will be some spillover into western Virginia — expect to see off and on snow showers early Friday in the New River Valley and west of I-81, with perhaps a few snow showers blowing even farther east into the Roanoke Valley and even some of the western Piedmont. Just by having such strong winds, it’s going to be hard to keep at least a few snowflakes from blowing into Roanoke. As for the rain — the Hydrometeorological Prediction Center is only predicting 1/4 to 1/2 inch for most of our region, and it seems these predictions have been a category too high for the past several rain events. There may be some heavy downpours, but not long-lasting. Any rain helps the dryness, though.

On that score — here is the HPC’s new experimental 7-day precipitation product, which shows rather copious rains over the next week. This would be the result of the post-Christmas storm we have been talking about, and likely presuming a track west of us that enhances southeasterly upslope flow from the Atlantic to the Blue Ridge, and flushes in milder air for a couple of days after near-seasonal cold hangs in through Christmas or so. Some models have started to bring the storm farther east, a trend that needs to be monitored, especially with some evidence that blocking features in Canada could force a farther south/east track. If it ends up a coastal storm, snow potential would be high locally; a track west of us, mostly rain; and near or just east of us, perhaps some of both. And there’s always a chance we don’t get much of either. That seems to be the recent local luck with moisture.

Roanoke has topped 60 degrees on 9 days in this warm December, and Wednesday has a shot at being the 10th. It may also very well be the last 60-degree day of 2012. Clouds and showers will likely hold it below 60 on Thursday, and then the passage of an Arctic cold front will slap us with blustery winds from the frozen north on Friday. The HPC weather map for Friday shows a double-barrel low to our north and lots of isobars, or lines of equal pressure, packed together. This is a sign of strong winds, blowing in from the northwest in this case. Some 50+ mph gusts will be possible Friday. A winter storm watch has been issued in several West Virginia counties as these winds lifting over the western slopes of the Appalachians sill squeeze out intermittent snow squalls and snow showers from Thursday night through Saturday, with accumulations of 5-plus inches expected especially in higher elevations and along west-facing ridge slopes. Some snowflakes will get carried in the breeze eastward into the New River Valley on Friday — a dusting is possible for anybody that gets under a heavier snow squall for several minutes — and perhaps even into the Roanoke Valley and points east.  Temperatures may not get out of the 30s even at Roanoke on Friday, and several mostly dry days of 40s highs/20s lows will follow, likely into Christmas.

Then there is the matter of the after-Christmas storm. The HPC weather map locates its infancy in Louisiana on Christmas. This one could be a headline-maker for much of the country, though there remains much conjecture on its eventual track. Even a track west of us could lead to some wintry precipitation if cold-air damming develops (as the position of some of the highs to the north on this map suggest would be possible).  There remains a chance that blocking features in Canada will force the storm much farther south and east and increase our region’s snow threat. Wherever it goes, Arctic air will pour around its back side toward us late next week, so even if it were to go far west and swing in some milder air, it would last only a day or two. We will continue to watch the models play with it the next few days. Anyone traveling for Christmas should be aware that this storm will have the potential to hamper transportation in a wide swath of the nation for a couple or three days after the holiday.

UPDATE: 10 AM, 12/14: Amending the section below about rain chances — new model data suggets the best chance of rain may come Sunday, though not very heavy rain, with an initial push of moisture and a fairly weak storm system. It appears the larger storm system we’ve been discussing will form much farther north, so rain chances in the Monday-Wednesday time frame are looking lower, and snow chances just about nil. Colder air from Canada is expected to arrive late week. END UPDATE

We don’t get a chance to graduate someone from Weather Journal very often, but in a way, that’s what we are doing with Kathryn Prociv. Kathryn filled in on Weather Journal on 9 days in the last 2 months as I took some vacation time. She taught an introductory meteorology class at Virginia Tech this fall, after finishing her master’s degree in geography the previous spring. The semester is ending, and Kathryn is returning to the Washington, D.C., area, where she spent her teenage years, to pursue some new opportunities. One of those opportunities is a part-time gig with the Capital Weather Gang, the Washington Post’s weather blog. Scroll down on this link and the first female face you’ll see is Kathryn’s, with a short biography. Kathryn’s posts on the Post’s blog won’t be on a regular schedule … I’ll make note of some of them from time to time when I know she’s up. Once again, I offer my sincerest appreciation to Kathryn for filling in for me so seamlessly on the Weather Journal blog and also for being steady eyes on the radar and the forecast models when I was keeping my eyes on the road (and the sky right in front of me) in three years of storm chasing. Happy trails, KP! She might be back on here again for a few posts someday, you never know.

The forecast models are starting to come together a little more on next week’s storm, and it’s about what we’ve been talking as a strong possibility — a somewhat inland, late-developing storm system that will not be able to pull down enough cold air fast enough for widespread snow in Southwest Virginia. Really, there’ll be sort of a 1-2-3 punch next week — a late Sunday-Monday chance of showers with an initial storm system tracking northwest of us, the potential Tuesday storm system that will likely be rainy, and then a couple days later, a push of Arctic air when the low gets wrapped up tightly north of us. There may be some chance of snow in the higher elevations in West Virginia and far southwest Virginia with Tuesday’s system, and then some upslope snow showers once the Arctic blast kicks in. Otherwise, it’s mainly a question of how much rain we can get to offer some relief to the long-term drought that we’ll be feeling pretty hard if it’s still hanging around by summer. The Hydrometeorological Prediction Center is suggesting a widespread rainfall of about 0.75 inch may occur by Tuesday evening. This may be tweaked up or down some, but I don’t think this one is going to really dig the deep moisture or be tightly wrapped enough to deliver a 2-inch soaker or anything of that magnitude. I still have some concern that the storm may skip us just a little bit, with heavier rain to the southwest in the Tennessee Valley (as depicted on the map) and perhaps again northeast of us once the coastal low takes shape. We probably get at least a little wet early next week, and likely get pretty cold toward the latter part of the week.  The wet and the cold don’t look to overlap too much, though, this time around.

In the meantime, we look to have 4 days with highs in the 50s, maybe a few low 60s on Saturday. There will be some chance of showers Saturday and Sunday as moisture builds ahead of the next storm system, but it appears the best chances of rain will be in the Sunday night to Tuesday period. The weather for Friday night’s Stagg Bowl, the NCAA Division II national championship football game, at Salem Stadium looks unusually placid, with a mostly clear night and temperatures in the 40s — which won’t be all that chilly  for teams and fans from Ohio (Mount Union) and Minnesota (St. Thomas). Many local snow fans fondly remember the weather this game brought to our region on Dec. 18-19, 2009.

Guest blogger Kathryn Prociv stands in while Kevin is away for a few days:

The strong cold overnight that passed through overnight certainly ushered in a different air mass! This morning was a complete 180 from yesterday morning with bright sunshine (almost blinding) and cooler, biting air. Today will be what I like to call “deceptively chilly:” bright sunshine but chilly temperatures with highs only reaching the mid-40s for most of the area. The other factor chilling the air out there will be the breezy NNW winds. With clear skies continuing into the evening, overnight lows will be quite COLD, dipping down to the mid-20s for the areas west of the Blue Ridge and upper 20s to low 30s east of the Blue Ridge. The National Weather Service map shows the projected low temperatures overnight. Tomorrow looks similar to today, with the exception of winds shifting around to the east and a slight increase in cloud cover.

With relatively quiet weather to talk about for today and tomorrow, I thought I would shift gears and discuss the potential coastal storm for next week. Many people, especially in the northeast, are thinking “not again!” The good news is early model data indicates this storm will be weaker than last week’s nor’easter, and also warmer meaning more of a wind/rain event and less of a snow/blizzard event. Many of the models have yet to agree on timing, strength, and track of the storm but most are hinting at a Sunday-Wednesday timeframe, likely impacting Virginia earlier rather than later Sunday through Monday. The GFS model shows the location of the low and precipitation shield on Monday pretty far off the coast impacting only coastal locations. Impacts for southwest Virginia will depend largely on track of the low pressure system; the farther inland it tracks, the more likely we are to see precipitation on the western edge of the storm. A lot could still change, but it is worth keeping an eye on for anyone planning on traveling toward the coast this weekend or for the holiday, and especially if you’re planning on heading to the Northeast as any coastal storm could impact that region later in the week.

By Kathryn Prociv

It’s Kathryn again on this cold, wet, and dreary day in southwest Virginia.  In Blacksburg today is what we call a “Bleaksburg” kind of day.  How much rain did everyone get overnight? Some rainfall totals around the area included between 0.20 and 0.36 inches around the City of Roanoke, the City of Danville and Botetourt County both received about a half an inch, and some of the higher totals were found further south in the bordering North Carolina counties.  The heaviest of the rain has moved east and away from the area, so just expect some light showers tapering off throughout the day.  Temperatures today will be pretty cool, with highs reaching only the upper 40s and mid-50s.  You’ll notice we’re pretty clouded outside.  Expect these clouds to last through the day and into the overnight hours.  You can see the extent of the cloud cover on the visible satellite from this morning.  These clouds will also serve to keep us warmer tonight and decrease the chance for widespread frost tonight into early tomorrow morning.

Don’t expect too much improvement tomorrow, as we will have similar conditions to today:  high temperatures of 40s and 50s, and another round of rain due to an upper-level disturbance approaching from the southwest.  Tomorrow we will experience what I like to call “wedge-weather.”  Wedge-weather means that high pressure sets up over the Atlantic to our northeast.  Clockwise winds rotating around the high pressure system shifts our winds to the northeast pulling down cool, moist air from the Atlantic Ocean.  This cool, moist air encounters the mountains and literally “wedges” in place.   When this happens areas under the wedge can be stuck in cloudy and drizzly conditions.  Check out the image showing temperatures for 2pm tomorrow afternoon using the GFS model.  Notice the cooler temperatures in a wedge-like shape stretching all the way down on the North Carolina mountains.  Models suggest the wedge holds on through Tuesday, and finally breaks down Wednesday as drier air and warmer temperatures rebound for our region.

Until Wednesday keep your jackets, umbrellas, and warm drinks handy.  Also, it might not be a bad idea to listen to weather-inspired music; search “songs about rain” and you’ll have some groovy tunes to get you through the next few days.

By Kathryn Prociv

This time tomorrow, it will finally feel like fall.  In fact, it may feel like we went straight from summer to winter skipping fall altogether.  The culprit?  A strong cold front.  As discussed in yesterday’s blog post, we will be impacted by a cold front that has been marching across the country over the past several days.  It finally arrives today, bringing colder temperatures, gusty northwest winds, and drier air.  The timeline of the front looks to be between 11am and 2pm for the New River and Roanoke Valleys, and will be completely through Southside by 5pm. Image shows current temperatures around 10am where you can clearly pick out the location of the front.  Don’t expect too much precipitation with the passing of the front, however, as it is fairly dry and lacking upper-air support to generate enough lift for precipitation. Nonetheless pay attention to the passing of the front: you should notice an increase in cloud cover and feel the winds pick up and switch directions around to the northwest.  Not to mention a drop in temperatures!  I saw a report on Twitter this morning that at around 10am it was 41 degrees in Columbus, OH and 66 degrees in Roanoke.

As the title suggests, this cold front will live up to its name. Sure we’ve had a few cold fronts swing through over the last couple weeks, but none really brought a dramatic temperature decrease. Get ready, because this one will pack a punch.  It will pack such a punch that I’m going to mention the s-word. S-N-O-W.  (Kevin what have you done leaving me to mention the first possibility of snow?!) Before you get too excited, I’m not entirely convinced that snowflakes will fly.  However, I still think it’s worth mentioning.  Tomorrow looks to be very wet in our area.  Check out the HPC forecasted precipitation totals for this morning through Monday morning.  Now the real question will be: will the coldest air line up with the precipitation?  Models are conflicting a little bit regarding how far south the cold air will surge, i.e. that 0-degree Celsius line at 850mb that will support snow.  The NAM model is slightly colder than the GFS (pictured) showing that freezing line hovering just north of our area tomorrow afternoon.  Here’s a snippet from the Blacksburg NWS area forecast discussion this morning: “850MB TEMPS DO DROP INTO THE -2C RANGE SUN ACROSS THIS REGION…BUT CURRENT THINKING IS THAT THE DEPTH OF THE COLD AIR WILL NOT BE SUFFICIENT TO SUPPORT ICE CRYSTAL GROWTH TO ANY EXTENT. THUS…HAVE NOT INCLUDED ANY MENTION OF S- AT THIS POINT.”  Like me, they are not convinced flakes will fly.  However, my final take: IF (a BIG if) there are snowflakes tomorrow, I think they will be very isolated in nature and at the higher elevations (above 3,000ft) of West Virginia, Pocahontas, Bath, and Highland counties so north of our region.  Further north is also where there will be more upper air support to possibly incite enough lift to generate some snowflakes.

Conclusion: Break out your umbrellas and winter coats because tomorrow looks wet and cold.  Tomorrow should be a great day for indoor activities, such as watching football, and a hot soup kind of day.  Monday morning could see frost, so plan accordingly for any outdoor plants.  I’m ready for the onslaught: the S-word has been served!