Tuesday, March 6, 2012

Global Temperature Update

The global temperature anomaly has been released for the month of February, and the average global temperature has cooled by 0.12 degrees celsius. This decline in global temperature follows a cooler-than-average January. The global temperature anomaly shows the departure in average global temperature as compared to the 30-year average for that month. The current 30-year average used is from 1981-2010. -Zach

Monday, February 27, 2012

Weather Blog: See the Celestial Line Up Tonight

With clearing skies tonight, it will be a great opportunity to see 4 planets (and the moon) lined up across the sky. You will need an unobstructed view of the western sky to see Mercury, and of the eastern sky to see Mars. The two graphics I've included show the positions of the planets on March 1st, which will be very similar to tonight. Here's where to look: Start by looking east about 30-45 minutes after the sun sets tonight. Official sunset is at 6:01 PM, so try to shoot for around 6:45. Look toward the western horizon where the remaining glow of the sun lies, and you'll see Mercury, appearing as a faint star. Higher in the sky lies Venus, the most brilliant star-like object in the sky. Next in the line a little higher in the sky is Jupiter, with a very bright and more yellowish hue.
Well east of the moon and fairly low on the eastern horizon is Mars, with a very noticeable reddish orange color. The sky will get darker the later you go out and Mars will rise higher in the east, but Mercury will also be setting soon after the sun sets. It's for that reason, that you need to be out around 6:45 to see all of these objects together in the same sky. All of these planets are easily viewed by the unaided eye, and it will be well worth the effort to go out and see them. Happy viewing! -Zach

Monday, February 20, 2012

Here Today, Gone Tomorrow

We'll maybe not all of it, but the heavy wet snowfall we received yesterday will be fighting an uphill battle trying to maintain its frozen status over the next few days. We reached the mid 40s today, and I expect our highs to reach the low 50s tomorrow, low 60s Wednesday, and hit 70 on Thursday. That's a lethal lineup for even the deepest drifts found in the hardest hit areas of west-central Virginia. And then there's that problem with black ice that will be an issue for the next couple of mornings. I noticed my children this morning were wet rather than cold when they came inside from playing in the winter wonderland. This is nothing new to Virginians, as we've seen this scenario many times, especially as we approach Spring.
If you're a snow lover and the totals weren't enough to satisfy you for the season, take comfort in knowing that some of the biggest snows we've had in our state's history have occurred in the month of March. Nothing very promising is showing up in the pattern over the next week or so, with the only system of even minor interest arriving around the first of March. I'll be tracking any potential closely, and will have the latest on the air, at wtvr.com/weather, and on my facebook page. Enjoy the week, and the snow while it lasts. -Zach

Sunday snowfall will mostly melt Monday

All of central Virginia began Monday morning with a Winter wonderland still on the ground. Here's the sunrise view from Downtown Richmond looking toward Oregon Hill (left side of picture), where nearly 3" fell Sunday night.

The better snowfall was in the west-central and southwestern parts of Virginia, though, as depicted by this morning's post-snow storm snow depth map:

Areas in red on this snow-pack temperature map are the most prone to rapid melting today, especially aided by sunshine and highs in the upper 40s!

Here's some selected snowfall reports from Sunday's storm in central Virginia:
5.1" Glen Allen (Henrico Co)
5.0" Midlothian (Chesterfield Co)
4.0" Hanover (Hanover Co)
4.0" Ruther Glen (Caroline Co)
3.9" Richmond Intl Airport (Henrico Co)
3.8" 4 miles W of Bowling Green (Caroline Co)
3.5" 1 mile WSW of Brook Hill, City of Richmond
3.5" Victoria (Lunenburg Co)
3.5" 5 miles N of Boydton (Mecklenburg Co)
3.3" Caret (Essex Co)
3.0" Westover Heights, City of Richmond
3.0" Hampden Sydney (Prince Edward Co)
3.0" 7 miles NE of Disputanta (Prince George Co)
2.5" Chesterfield (Chesterfield Co)
2.5" Chester (Chesterfield Co)
2.5" Amelia Courthouse (Amelia Co)
2.5" 2 miles WSW of Meltons (Louisa Co)
2.5" 2 miles E of Blackstone (Nottoway Co)
2.0" Newland (Richmond Co)
2.0" City of Colonial Heights
2.0" South Hill (Mecklenburg Co)
1.7" 1 mile NW of Wakefield (Sussex Co)
1.5" Louisa (Louisa Co)
1.5" 1 WNW of Bottoms Bridge (New Kent Co)
1.3" 1 NW of Wakefield (Sussex Co)
1.0" Norge (James City Co)
0.8" Gloucester (Gloucester Co)
0.5" Jamestown (James City Co)

Here's another snowy sunrise shot from Ashland at the campus of Randolph-Macon College:

Stay with CBS 6, we'll keep you ahead of the storm!
--Meteorologist Carrie Rose

Friday, February 17, 2012

Snowfall Forecast Map

Winter Storm Watch In Effect

A winter storm watch is in effect for Sunday across the northwest part of Virginia. A significant accumulation is expected in the watch area, with more than a half of a foot likely in many area. Other counties will be added to the watch area after the adjacent National Weather Services have a chance to issue. -ZD

Thursday, February 16, 2012

Dense Fog Advisory In Effect

A dense fog advisory is in effect through the remainder of tonight. Visibilities will be reduced to 1/4 of a mile or less at times. Caution is advised for any overnight travel. Be extra cautious and slow down when encountering foggy conditions. The density of fog in situations like tonight can change rapidly over a very short distance. -ZD

Weather Blog: Snowless Winter Ends This Sunday

So far this season we've only had a few very minor brushes with wintry weather, with nothing more than a trace of snow and ice. That should all change on Sunday. All of the most reliable weather models are now showing a temperature and moisture scenario that should at least give us a measurable snow greater than a trace, even at the seemingly snow-resistant precip gauge at RIC. How much snow is still in question, and won't be determined with true accuracy until the system has come and gone. The model solutions are many, and the number of opinions across the blogosphere are exponentially greater.

I won't snow you, no pun intended, with confusing model lingo and acronyms, but I'll get into some specifics of what I think will occur in the Richmond area as this storm moves through. So here we go. We should begin to see rain developing during the morning hours on Sunday. A cold front will move through the metro around 6 AM on Sunday, and I expect the temperature to be around 40 degrees at sunrise. Forecast vertical temperature profiles, which we call soundings, show the precip to begin as rain. As the rain falls, we will see temperatures begin to fall as well, but only until the air becomes saturated. The point of saturation is called the wet bulb temperature, and with small differences in the temperature and low-level moisture (called dew point depression), we'll see the surface temperatures fall only into the mid 30s by noon. A northerly wind will continue to bring lower dew point air into the region during the day, so we will continue to see the temperature slowly fall to near freezing just after sunset. Although the surface temps might not reach the freezing mark until after dark, I think we will see a change from rain to snow during the afternoon hours. The snow will be heavy and wet and will only initially accumulate on grassy and elevated surfaces, but as the temps approach freezing, we should still have enough moisture around for a quick accumulation before everything comes to an end. Slick spots will be likely by Monday morning, as I expect temps to fall into the upper 20s.

This event is coming at a perfect time, with a light commute to school and work expected on Presidents Day. There will of course be some changes in the track and intensity of the storm, so I'll be back with an update and any necessary tweaking of the forecast tomorrow. Feel free to share this with friends, and you're welcome to drop by my facebook page and leave your thoughts, questions, and comments. Thanks to Claire Powell for the daffodil photo. -ZD

Three-month outlook for Spring

The three-month temperature and precipitation outlook is out from the Climate Prediction Center, showing a continued warmer-than-average trend for Virginia that has persisted all Winter. It looks likely to continue into our Spring as La Nina gradually weakens in the equatorial Pacific. ENSO Neutral conditions should be reached by this Summer.

Here's the temperature outlook for Spring (March, April, & May):

Here's the precipitation outlook for Spring (March, April, & May):

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Tuesday, February 14, 2012

Snow or No Snow This Weekend?

The model giveth and the model taketh away. Whether you want a big storm or 70-degrees and sunshine, when we're peering into the future more than a few days ahead, computer model data is all we have to go on. And while weather modeling has becoming increasingly accurate over the past few decades, we sometimes tend to forget that the solutions they give us aren't real. The pretty graphics they generate are based on many approximations, and regardless of how great a storm might look several days away, any one model is only as good as its initial conditions. If it fails to resolve a feature in the atmosphere when it initializes, it will give an incorrect solution for the future. That's why we often approach the extended forecasts with due caution, knowing good and well that things can and will change, even if every model out there shows the same thing. We've seen some pretty big changes in the model forecasts in the past 24 hours for the potential snow this Sunday, and it now looks less likely we'll see much of a storm. But before you write this one off completely, understand that we could just as easily see a move back in the other direction over the next day or two. The system is just now coming on shore near Seattle and Portland, and the models should have a better handle on what it will do in subsequent runs.
Here are a couple of things I like and don't like about the potential for snow this weekend: I like the fact that this is a pattern that has been depicted by the GFS model for over week now. It looked like something could happen around the 17th-19th of the month, and the system is due on the 20th. I also like that while the models are in agreement with a more southerly track that doesn't effect Virginia much, at least all of the models are showing a storm in the region. You can't have a storm shift it's course north if it's not there to begin with. I don't like that the main vort max becomes nearly cut off across the southwest U.S. on Friday. Cut off lows can be a nightmare for forecasting. I also don't like the lack of a Greenland block. Even the most aggressive model takes the storm on a SW to NE track, which has a much better chance of completely missing us to the south. If we had more of a blocking pattern (indicated by a negative phase of the North Atlantic Oscillation (NAO)), this would allow a more southern extent to the cold air, and would also cause the storm to track more S to N, or right along the coast. And the last red flag, and a very important one, was the lack of near-freezing surface air during the time of the event. Our in-house model generated a whopping 0.7" of snow yesterday when the Euro model looked its most impressive. Similar to what happened here on Saturday, it can pour snow, but if temps are in the mid to upper 30s, it won't amount to much. But again, it's a model, and it too will change.
So all this leads to me making no changes to my forecast for Sunday. I'm leaving us at 40% for snow, and won't move it until we get a little closer. As I type this, the midday GFS run has completed through the weekend, and is more favorable for snow. But I don't like the midday and overnight model runs. Confused yet? Be ready for snow on Sunday, and a plan for some decent weather as well. Mother Nature will take care of the details. -ZD

Friday, February 10, 2012

Weather Blog: Snowfall Forecast

I was sitting at the dinner table with my wife last night complaining about how this time of the year is the worst for a sports fan like myself. As passionate as I am about weather, my love of sports is not too far off. The NFL is over, as is college football, the NCAA tournament doesn't begin for another month, spring training for baseball hasn't started, the PGA tour schedule is pretty weak, and I've never been a big fan of the NBA or NHL which are in full swing. I'm certainly blessed with a great family and friends, and a few hobbies, but I still tend to get bored without a good lineup of sports on the weekend to either play or watch, or...some interesting weather to forecast. It's just a minor event, and the term itself might even be a stretch, but at least Mother Nature has thrown me a bone this weekend and given me and other snow lovers something to be excited about. The system arriving this weekend will come in two waves. We'll have a round of rain overnight tonight, with a round of light snow late Saturday night. The state of West Virginia and the mountains of west-central Virginia will see a decent snow, with Snowshoe Ski Resort likely enjoying around 10" of powder for the weekend skiers and riders. Amounts in central and eastern Virginia will be far less, ranging from and inch or two across northern and eastern VA, to a dusting to an inch across Richmond and vicinity. The snow will occur after dark in the metro, likely occurring between 9 PM and 2 AM, adding the perfect romantic touch to lovers out on a late night stroll enjoying an early Valentine evening together. Wow, did I really just type that? Anyway, whatever falls will be blowing around mightily on the backs of northwest winds of 15-25 mph. A little light snow collected next to the dog house or on a parked car could be all the evidence left of the system by Sunday morning. I'll have a fire going, the TV off, and a fiercely competitive game of scrabble going wife my wife Saturday evening as I wait for the first flakes to fall. The graphic above is my snowfall forecast through Sunday morning. I'll have updates on my facebook page, so drop by and send me a note and hit the "like" button while your there. Feel free to share this with others, and have a great weekend. -Zach

Weekend Weather Preview

A strong storm system will move through the Mid-Atlantic Saturday, and we'll start to see the signs of it today as cloud-cover increases over us from the west. Here's the early Friday morning infrared satellite picture of the U.S.:

I'll point out two features to you. The first of note is the cold front also associated with the clouds you see moving through the Upper Midwest. That front will move through Virginia Saturday. The second feature is the low pressure system tracking from Texas and pulling in moisture from the Gulf of Mexico into the Mississippi Valley region and the Southeast. As these two features converge in the Mid-Atlantic Saturday, we'll have rounds of cold rain in central Virginia, with snow in the mountains of western Virginia in the colder air. However, as that cold front sweeps through along with the digging upper trough (see the 500mb vorticity picture Saturday evening below) and brings in deeper, colder air, we'll have more snow mixing in with the rain Saturday afternoon and after dark.

It currently does not look like there will be any chance for an accumulating snow in the metro, as surface temps should remain well above freezing during the time of the precipitation (in the 40s). A winter weather advisory will likely be issued for areas to our northwest on Saturday (especially along I-81). After the surface cold front passes Saturday afternoon and evening, you can expect windy and much colder weather, with wind chills plummeting into the 20s and teens. If you have Saturday evening plans, be prepared for a blustery, cold night out! There may be a quick burst of snow in central Virginia on the back side of this storm system as that good upper-level energy passes overhead, including in the Richmond Metro, between 7 p.m. and 11 p.m. Saturday. This may lead to a dusting of snow on vehicles and roofs, but no significant accumulation is expected. Here's one forecast map (NAM) of snowfall potential from that final gasp of snow Saturday night:

Sunday will be mostly sunny, very cold with high temperatures struggling to get out of the upper 30s, and also a bit windy behind Saturday's system. The air mass will moderate some on Monday before the next storm system arrives Tuesday morning. The temperature profile for this second storm system will be similar to Saturday's, with the best chance of wintry weather lying just a little north of Richmond.

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose
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Wednesday, February 8, 2012

Some parts of Virginia will see snow Wednesday

A storm system will move east into the Mid-Atlantic today, bringing snow to west-central and far north-central Virginia. Accumulations from this afternoon into early evening should be light in the 1"-3" range, but this will make travel hazardous during the Wednesday evening commute as moderate snow falls and accumulates on roads.

Locations just southeast of the Advisory may also see some snow mixing in with rain showers today, but no significant accumulations will occur as temperatures remain above freezing there. The best snow accumulations will be along ridge-tops and at higher elevations.

Overnight as the storm system moves offshore into the Atlantic and colder air wraps around the backside into Virginia, there may be a few lingering flurries in central Virginia that will not lead to any accumulation.

If you're on Facebook, be sure to "Like" my page here and receive weather updates. You can also follow me on Twitter @SouthernRedRose.

Stay with CBS 6, we'll keep you ahead of the storm.

Tuesday, February 7, 2012

New snow plow tracker released by the City of Richmond

A new snow plow tracking webpage is now available for public use whenever the City of Richmond snow plows are on the move. Now you can track their progress toward your neighborhood, seeing where plows have already been and where they are heading next. The map will display the City's emergency routes and also the "Priority 1 and Priority 2 routes." Those routes are the major roads, like Broad Street, the Midlothian Turnpike and Belvidere Street. Also on the map: fire stations, police precincts and hospitals, as well as City schools and fire hydrants.

City of Richmond Mayor Dwight Jones released this statement Monday, February 6, 2012 upon the public release of the snow plow map: “Even though we’ve had a very mild winter thus far, we want to be thoroughly ready for any possible inclement weather. Ensuring that our snow removal equipment is up to par and that information is readily available and easily accessible will do much to improve our overall performance in the event of a weather occurrence.”

No additional costs were required to produce this "Snow Plow Tracker" because the City of Richmond says it was developed in-house, using GIS software the City already owns.

You can check out the map on your computer or smartphone at this link: https://richssl.ci.richmond.va.us/applications/GIS/snowmap/

The mayor is correct about this being a mild Winter so far! Here's the latest Richmond snowfall update:

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Wednesday, February 1, 2012

Richmond January 2012 weather summary

As many snow-lovers have noticed (and loathed), January 2012 passed quietly by with only a Trace of snowfall. Although our temperatures generally remained milder most days in January, the average temperature still didn't break into the Top 10 warmest on record for January in Richmond. You can check out that list by clicking here. 2006 holds the number 10 spot with an average monthly temperature of 45.0 degrees, and 1950 in January was the record warmest with an average temperature of a whopping 49.7 degrees! That puts our mild January to shame, really. Here are the complete temperature and precipitation stats for Richmond International Airport this January:

So far this Winter in the Mid-Atlantic, La Nina appears to be impacting our temperature and precipitation trend. Here's what La Nina can do to the U.S. during the Winter Months:

Looks like we are indeed warmer and drier! The jet stream to our north has primarily prevented deep, cold air from plunging into our region and lingering for weeks. The Pacific Northwest also testifies to a cold, wet Winter thus far, with some of the worst winter storms there so far in recent memory. Click here for the summary on their latest winter storm.

Our Winter-to-date snowfall deficit now stands at 6.2" below average. February is typically our snowiest month with about 4.9" of snow on average.

Let me know: do you love a mild Winter, or are you hoping for snow? Join the conversation on Facebook!

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Monday, January 30, 2012

Strong Aftershock Rocks Central Virginia

A magnitude 3.2 aftershock occurred at 6:39 PM this evening 5 miles south of Louisa and was felt across much of central Virginia. This aftershock was one of the strongest since the original quake back in August. I've been getting a lot of questions on my facebook page about these aftershocks, and specifically when we can call them a new earthquake. Technically, all of these aftershocks are earthquakes, but we call them aftershocks because they are smaller earthquakes associated with the larger seismic event (the 5.8 magnitude quake). If an aftershock is stronger than the original earthquake, it will be deemed the main quake, and all subsequent seismic activity will be referred to as foreshocks. Here's hoping tonight's was the last of them, but I doubt it. -Zach

Be Careful What You Wish For

I'm a big fan of severe and unusual weather, and find myself always looking forward to the next big storm. I'll never wish for anything that would cause loss of life or widespread property damage, but a good thunderstorm or winter weather event challenges and fascinates the scientist in me. I just returned to Virginia two nights ago from spending a week visiting my in-laws, and on the flight out of Richmond last Saturday, I got what I wished for. Flying with three children ages four and under is no picnic even with no delays, and my wife and I now have a new level of airline stress by which to measure future flights. We were able to get everyone on the plane and in their seats with relative ease, and aside from the constant raising and lowering of tray tables and pushing the flight attendant call button, the kids were behaving pretty well. After waiting on the tarmac for about 15 minutes, the pilot made an announcement that the freezing rain we had been having in Richmond required deicing the aircraft, and we'd have to wait about 30 more minutes for the process to be completed. We finally taxied and took off after the delay on the ground and made our way to Oklahoma City, with a stop in Atlanta. The flight from Richmond to Atlanta is a short one, usually about an hour in the air, but after an hour had passed we were still cruising along at altitude. The pilot then made another announcement confirming my suspicion that something wasn't right, informing us that the Atlanta airport had just shut down due to severe thunderstorms, and we'd be circling until further notice. We circled for about an hour before landing, and were treated to turbulence that rivals even the best Busch Gardens has to offer. Once on the ground, the fun continued with another two hours of delays as severe storms which prompted tornado warnings continued to hammer the airport. (Keep in mind, this is January.) My son was overly tired from missing his nap and somehow ended up running shirtless down the middle of concourse C in the worlds busiest airport. We finally boarded our connecting flight to Oklahoma City and arrived a mere three and a half hours later than scheduled, being treated to a fine dose of winter and spring weather. The second flight was thankfully pretty smooth, and aside from taking a bath in a large cup of iced apple juice that my daughter dumped in my lap, I couldn't complain. So the next time I wish for a little crazy weather, I'll remember this day, and will be very careful of exactly what I'm wishing for. It's good to be back home in Virginia. Have a great week! -Zach

Thursday, January 26, 2012

Rain and thunderstorms are likely early Friday

A broad low pressure storm system that has a history of producing severe weather and heavy rainfall from Texas into the Southeast U.S. will reach Virginia in the pre-dawn hours of Friday. Here's a view of the upper level vorticity reaching the Appalachian spine by Friday sunrise:

Thursday, southerly flow into the Mid-Atlantic ahead of the system tracking into the Ohio River Valley is transporting richer low-level moisture. This means that there will be greater instability present overnight into Friday morning once the upper-level lift arrives in addition to the approaching surface cold front. In purple, you'll see some relatively "weak" CAPE (an indicator of instability for thunderstorm development) reaching into central Virginia:

Therefore, a Slight Risk for severe thunderstorms will exist for the areas in yellow on this map, including extreme south-central Virginia:

Even if most of the Commonwealth technically does not have storms that reach severe limits, the rain and storms moving through pre-dawn Friday morning from west to east will likely contain gusty winds and heavy downpours. As of right now, the timing of that line's arrival in western Virginia is around 2-3 a.m. Friday, and affecting the I-95 region by 5-7 a.m. Rain should end in Richmond after 9 a.m., with rapidly clearing skies behind the surface cold front's passage late Friday morning. All of the Commonwealth will be dry by mid-afternoon Friday behind the cold front.

I'll be in early Friday morning monitoring the line of rain and storms as they track into central Virginia. If you're on Facebook, be sure to "Like" my page for updates there. You can also follow me on Twitter @SouthernRedRose.

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Tuesday, January 24, 2012

Fog developing in parts of Virginia this Tuesday morning

Behind a cold front that is moving through central Virginia early this Tuesday morning, skies are clearing with light winds. Considering the recent dreary, damp days, there's plenty of moisture at the ground to support the development of fog where skies are clearing. As a result, visibilities are dropping to a quarter-of-a-mile in some parts of central Virginia. There is a Fog Advisory until 9 AM for the areas highlighted in grey on this map:

But other locations outside of the Advisory are also getting some light fog, including Jarratt. Here's a picture submitted this morning on Facebook by one of our CBS 6 viewers Debbie Lynn Allen of the fog in Jarratt, VA:

If you have fog pictures to share with us this morning, you can post them at my Facebook page by clicking here for the Wall. You can also tweet your pictures to me @SouthernRedRose.

Stay with CBS 6, we'll keep you ahead of the storm.

Thursday, January 19, 2012

Update on Freezing Rain Potential

Evening data continues to suggest the threat for some freezing rain late Friday evening into early Saturday morning. The push of low-level cold air could be far enough south to include all of the metro area in a risk to see some light icing. The primary time period to see freezing will be between 9 PM and 3 AM, with freezing drizzle possible for a few hours longer, especially north of Richmond. I've updated the risk graphic to indicate where I think we'll see the best chance of ice. -Zach

Tuesday, January 17, 2012

Freezing Rain Possible Saturday Morning

It appears as though the least welcomed type of winter weather could make an appearance in the state this weekend. A fairly strong (1028 mb) area of high pressure will build into New England Friday into Saturday, with the wind flow around this high moving in a clockwise direction. This air mass will be cold and dry, with the coldest air hugging close to the surface because of its relatively high density. The air will move freely southeast, south, and southwest, but will not be able to move west over the Appalachians. Instead of flowing up and over the mountains, the cold air will funnel down the east side of the mountain chain. This process is called "cold air damming", or "the wedge effect", and allows the shallow cold air associated with strong high pressure to spill as far south as Georgia along the east side of the Appalachians. Because the sub-freezing air will be so shallow, rain will fall in liquid form, but will freeze on contact to all objects at the surface. While the rain should be light during the time of sub-freezing surface temperatures, even a minor accretion of ice will cause problems. The graphic I created indicates where I think icing will be possible, and highlights where I think the greatest risk will exist. I'll continue to monitor the latest model data, and will have another update here tomorrow. -Zach

Monday, January 16, 2012

Second coldest morning of Winter

The coldest morning so far this Winter season is still January 4th, when Richmond International Airport reported a low temperature of 17 degrees. But this morning was almost as cold as that, with lows area-wide in the upper teens and low 20s:

Richmond's low of 19 degrees is our second coldest this Winter, and only our second morning this season of falling into the teens.

Here are Richmond's other cold Winter mornings thus far this season:
Jan 15, 2012: 23 degrees
Jan 2, 2012: 23 degrees
Dec 29, 2011: 25 degrees

--Meteorologist Carrie Rose

Wednesday, January 11, 2012

Update on Snow Chances for the Weekend

So this is what we've been reduced to. The winter of 2011-2012 has been so miserably unfulfilling to snow lovers, that the mere mention of the possibility of seeing a few flakes gets us all giddy. Yes, I said "us". I'm a big fan of Virginia's varied weather with four solid seasons, and a trace of snow just doesn't cut it for me. Perhaps I'm spoiled from the past two winters, but whether you like the cold weather or not, it's just not winter without one good snow. I saw this type of winter coming with a La Nina in full swing ala 2006, but banked on one decent storm this season when I made my winter weather forecast. And I'm still banking on one, it just won't be this weekend. The type of system that will affect the area this weekend is a clipper. It moves quickly, is moisture starved, and rarely produces much of an accumulation around here. Computer models tend to under forecast precipitation in this type of scenario, so I'm putting more weight in the pattern than in what the model actually shows for precip. Even so, much of what develops and falls will evaporate in the very dry air that will be in place. I'm still looking forward to seeing even the lightest of what Mother Nature throws our way. I'll have another update tomorrow. -Zach

Slick spots devloping in western Virginia this morning

As rain expands northeast into the higher terrain of western Virginia this morning, some slick spots are developing while temperatures are below freezing. This Winter Weather Advisory lasts until 10 AM for the purple highlighted areas on the map:

Once temperatures rise above freezing late morning, the hazardous traveling conditions will dwindle. However, heavy rain will overspread all of the Commonwealth mid-day through this evening, making driving hazardous as heavy rain reduces visibilities and creates a hydroplaning risk.
Stay with CBS 6, we'll keep you ahead of the storm.

Tuesday, January 10, 2012

Tracking the Potential for Snow this Weekend

The pattern for the upcoming weekend continues to look interesting, and several models are now agreeing on bringing some light snow into the area Sunday morning. The nor'easter the GFS was trying to blow up over the area on Monday is gone in the medium range solution, but both the GFS and ECMWF (Euro) are showing a shortwave clipper swinging through the region after very cold air has settled into the state. The GFS has actual precipitation (snow) depicted, while the Euro is dry with generally the same upper-level pattern. Based on the PVA that should be present ahead of the clipper that the Euro is showing, snow would likely be generated in the same manner as the GFS solution. The NAM only goes to 84 hours from the current time, so we can't see what it says for Sunday, but what it does show is in agreement with a short wave affecting the region by Sunday. The amount of snow should be on the light side, but the surface temps will be plenty cold enough for whatever falls to stick. This scenario is still about 4.5 days out, so things will change, but it's the only decent chance I see for us in the next week. I'll have another update tomorrow. -Zach

Dense Fog Tuesday Morning

After Monday's rain, winter mix, and snow (in northern and western Virginia), low-level moisture at the ground remains high causing fog to develop in most of the Commonwealth. The fog is particularly dense in the western third of the state, where some locations there are under a Dense Fog Advisory until mid-morning for significantly reduced visibilities to a quarter of a mile or less.

Visibilities are reduced elsewhere in central Virginia outside of the Advisory, though, so please use caution on your commute this morning. The fog can be at its densest in low-lying spots, along waterways, and in agricultural areas. Use your fog lights or low-beam settings while driving this morning, even after sunrise.

I mentioned the snow from yesterday in parts of Virginia. Here's a beautiful shot of the snow falling Monday in King George, VA by Breanna Marini:

This photo was posted on my Facebook page by Breanna. You can share your snow pictures, at my page by clicking here, too.

--Meteorologist Carrie Rose
Carrie's Facebook Page
Carrie's Twitter

Friday, January 6, 2012

Help Provide Warmth For a Deserving Family

We've only had small doses of frigid temperatures this winter, and only a trace of snow to date, but there have been plenty of cold nights and it's likely wintry weather will make an appearance over the next two months. Most of us are blessed with the means to heat our homes during the winter, but there are families that could really use some help this winter. Woodfin, CBS 6, and the Better Housing Coalition are teaming up to provide a new furnace to a deserving family in need. Go to www.wtvr.com/warmerwinter and fill out the form to nominate a deserving family. Thanks in advance! -Zach

Thursday, January 5, 2012

A Question About Wind Chill

I received the following e-mail from a CBS 6 viewer a couple of days ago addressing wind chill, and who or what is affected by it. Read the message first, and then continue reading for my explanation below.


While over at a friends farm Monday it was cold and windy. We got in his golf cart to go look at something and the gas engine stumbled and stammered at first and my friend blamed it on the wind and cold. I tried to explain the wind didn’t make the engine any colder but he wouldn’t hear of such a foolish thing. It might be worthwhile if you or Carrie try to explain the difference between wind chill and ambient temp while this dip has everyone's attention!


A lot of people will tell you that wind chill does not affect inanimate objects, while others will tell you wind chill affects everything, both living and otherwise. The answer is actually not that cut and dry. The simplest way to put it, is to say that wind chill affects all objects that are emitting heat, causing them to cool to the ambient air temperature faster. So in the example above, the cold could be a reason for the engine to struggle, but not the wind. In the same way, if a lake is 33 degrees and the wind is calm, the lake will not freeze if the wind increases to 20 mph and the wind chill drops into the teens. The wind chill will be sensed by humans and other objects warmer than the surrounding air temperature, but the temperature of the water will not cool lower than the air temp and freeze. Wind chill accelerates the cooling process of objects, and if those objects are already at the ambient air temperature, they won't get any colder regardless of how low the wind chill drops. -Zach

Wednesday, January 4, 2012

A Few Snow Flurries Possible Tonight

The best location will be across the northern half of Virginia as a shortwave trough (indicated by the red and orange colors in the graphic above) moves through the region. Models have not handled the precipitation with this feature very well and there is currently a lot more on radar (shown below) than expected. The air mass is still extremely dry, and the mountains will hurt a little as well, but a few flurries will still be possible north of Richmond. Nothing to write home about, but it's the only shot we have to see a flake or two before temps in the 60s return to the area. -Zach

Coldest morning of this Winter Wednesday morning

Wednesday morning's low temperatures were the coldest of this Winter season thus far, and will likely remain the coldest for the near-future. Here are a selection of low temperatures reported this morning in central Virginia:

As bitterly cold as it was this morning, it still wasn't close to record cold low temperatures for today's date. The record low for Richmond International Airport for January 4th is -1 degree from 1918. The average low temperature is 28 degrees, which means we were about ten degrees colder-than-average across all of central Virginia.

The upper-level trough that has been in our region for the past couple of days providing this cold weather, dry air, and blustery winds will begin moving away from us today. By tomorrow, morning lows will remain in the mid to upper 20s with afternoon highs back to average in the upper 40s and low 50s.

Our next blast of cold air may arrive mid-month, but as of right now, there's still no strong signal for our first significant winter precipitation event in the next couple of weeks. The system that will bring rain to Virginia this Sunday should exit to our northeast before it pulls in cold air deep enough to change the rain over to snow.

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Tuesday, January 3, 2012

Coldest Night So Far This Season

And yes, the winter season is still young, but overnight lows in the teens across the majority of the state will easily eclipse our previous coldest night of 25 degrees in Richmond on December 29th. The wind speed will decrease significantly as the night wears on, but even a 3 mph wind at a temperature of 19 degrees will result in a wind chill of 15 degrees. We'll have one more breezy and cold day on Wednesday before a nice warm-up heading into the weekend. A few central Virginians were treated to snow showers this afternoon, but any significant wintry weather might still be quite a stretch away. There are two chances that I see over the next 10 days for wintry weather in and around metro Richmond, and they are both associated with similarly structured storm systems. The big question for each of these systems will be whether or not the air mass will be cold enough to support snow. Most of the rain will be gone by the time the cold air moves in during the first event this Sunday, with still a lot of uncertainty with the second system slated to arrive next Thursday the 12th. Neither system looks impressive at this point. I'll keep one eye on the models tonight, and the other on the Hokies down in New Orleans. Hopefully they can put Michigan away and spread a little warmth north. I'll have another update tomorrow. -Zach

Bitter cold for first meteor shower of 2012

If you can bear the brutally cold wind chills in the teens early Wednesday morning before sunrise, you could be treated to the first great meteor shower of 2012. This will also be the first good shower to view in months because the bright Moon previously interfered with optimal viewing of other showers in 2011.

The Quadrantid Meteor Shower peaks early Wednesday, January 4th, particularly between 2 a.m. and Dawn. At this peak, as many as 100 meteors per hour could be visible! Our visibility should be pretty good in central Virginia with clearing skies and the moon setting around 3 a.m. Best meteor shower visibilities are always a distance away from high concentrations of man-made light. Those of you outside of the cities should see the most meteors. Here's a sky map of where to look (the point of origin from our perspective on Earth of the meteors...look northeast and up):

(IMAGE CREDIT: Starry Night Software)
Notice that the meteors appear to come at us from the constellation of Quadrans Muralis (in between Draco and Bootes), leading to the shower's name. The meteors associated with the Quadrantids originate from asteroid "2003 EH1," which itself is probably a broken piece off of a comet from several hundred years ago. This meteor shower was first documented in 1825. NASA expects the debris from that asteroid to impact Earth's atmosphere at a speed of about 90,000 mph, and disintegrate 50 miles above the ground.

However, please be aware that Wednesday early morning temperatures will fall into the teens and low 20s, with wind chills in the low teens. If you plan to watch this meteor shower for a couple hours, make sure you are well-equipped for the cold weather, paying particular attention to keeping your hands, feet, neck, face and head warm! Take extra blankets, water, snacks, and maybe some hot chocolate to enjoy while you stargaze. You can click here to read more about the bitter cold lingering through Thursday morning.

Other meteor watching tips:
*Allow at least ten to 15 minutes for your eyes to adjust to the dark.
*Lie flat on the ground and scan the sky, not focusing on any specific point.
*Look for flashes of swiftly moving light from the northeast streaking across the sky. Some of these may appear to have various colors other than just a bright white.

Click here to post your meteor sightings at Carrie's Facebook Wall.

Monday, January 2, 2012

Tracking Our Sub-Freezing Wind Chills

The coldest and driest air mass of the season continues to move into the region this evening, and with a persistent and brisk northwesterly wind, the wind chill in Richmond and areas to the north and west will remain below freezing for a fairly long duration. I drew the red line above to indicate what I think the wind chill will register over the next few days, and also drew a light blue horizontal line to show the freezing line at 32 degrees. We'll be close to seeing wind chill values crack the freezing mark Wednesday afternoon, but it's likely we'll experience wind chills at or below freezing for about 63 hours, especially in areas north and west of here. The deep trough responsible for this cold snap will shift east of the area on Thursday, giving us a break from the cold heading into the weekend. And yes, I expect us to be in the low 60s on Saturday, so the confusion to vegetation and wardrobe planning will continue. As for any precipitation, the chances are very slim, with just a slight chance for a little light rain on Sunday. The medium range models continue to show flashes of an east coast winter storm in the extended period, but nothing very focused at the moment. I'll keep an eye on it and let you know if something looks promising. In the meantime bundle up, and check back for another update tomorrow. -Zach