12/18/2014

Chance For A White Christmas? Let's Discuss That Likelihood This Year And Historically...

This is the time of the year that everyone asks if we will see a white Christmas. In tonight's blog, I want discuss how often we actually have a white Christmas in the Ohio Valley and the chance of us seeing one this year.

 

How Often Do We See A White Christmas?

 

 

Louisville has about a 9% chance of a white Christmas with southern Indiana closer to the 15% category. This means Louisville statistically has a white Christmas about once every 10 years.

 

AdvanceTrak 1

 

It feels like we see a white Christmas more often than that, but this is what the statistics indicate.

 

A White Christmas This Year?

 

The fact is there will likely be a very strong storm somewhere from the Great Lakes to the Northeast US on Christmas Eve and winding down a bit on Christmas day. The brunt of this storm will miss us, but windy conditions will dominate our entire region on Christmas Eve. The real question is if this storm can produce snow here. Both the EURO and GFS put us on the back side of this complicated low on Christmas Eve. The details of this low are going to be extremely difficult to resolve now because the potential for a powerful nor'easter is on the table if the Great Lakes low tries to transfer it's energy to the New England coast. The EURO and GFS disagree on some of the details of the storm system, but both put us in a ploom of some snow showers on Christmas Eve.

 

GFS Forecast For Midday Christmas Eve

Notice the GFS shows light snow showers on Christmas over our area, but it is clear that the intensity is not very high. These are wrap around snow showers and traditionally don't leave an accumulation.

 

Gfs mslp 3

 

With only these wrap around snow showers, you can see the GFS shows virtually no snowfall accumulation with this storm. Considering that it would 53 degrees the day before the snow showers, this would have nearly not chance of accumulating.

 

GFS

 

The EURO computer model shows the same complex "double barrel" low transfering energy from the Great Lakes to a powerful nor'easter. The EURO also does put us in the back side snow shower zone, but again not any major snowfall.

 

EURO Forecast For Midday Christmas Eve

Notice the EURO shows a similar signal for snow showers on Christmas eve. The intensity is rather light and the EURO shows surface temperatures above freezing. This is a setup that would mitigate any chance for accumulations.

 

EURO MSLP

 

Looking at the normally wild EURO snowfall totals, you see it shows no indication whatsoever that we will have a white Christmas.

 

EURO

 

 

My Thoughts On Our Chances For A White Christmas...

 

Its funny, earlier I asked a few people what they considered a white Christmas and I was surprised to hear different responses. Some felt that if snow showers occur, then it is a white Christmas while others said it had to be accumulated on the ground. I fall into the category that a white Christmas means the ground is covered in snow. With that, I will consider a white Christmas as one with a covering of snow on the ground.

 

The EURO and GFS computer models continue to show large storm system that will occur in the middle of next week then on Christmas Eve transfer it's energy to a nor'easter. How this process unfolds is still not clear within the data thus far With that said, there is no reliable data to show anything more than snow showers will affect us on Christmas Eve with windy conditions. In fact, look at the projected wind gusts by the EURO on Christmas Eve and you can see winds over 30 mph could occur.

 

AdvanceTrak 2

 

While I feel we will see snow showers with blustery winds on Christmas Eve, none of the data shows any legit snow accumulation so the prospect of a white Christmas looks very low at this point. We will keep watching the data since the complex details of this powerful low next week are not set in stone at this point.

 

 

 

It is winter storm season and if you want to be one of my storm spotters, you can join me on my facebook or twitter page. Just follow the link below and click "like" or "follow".

 

If you ever have any question, please remember I can be reached on facebook or twitter easily! Just follow the link below to my facebook or twitter page and click "LIKE/FOLLOW"!

 

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NASA Can See Our Christmas Lights From Space!

City lights shine brighter during the holidays when compared with the rest of the year, as shown using a new analysis of daily data from the NASA-NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. Dark green pixels are areas where lights are 50 percent brighter, or more, during December.

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Image Credit: NASA

This new analysis of holiday lights uses an advanced algorithm, developed at NASA's Goddard Space Flight Center in Greenbelt, Maryland, that filters out moonlight, clouds and airborne particles in order to isolate city lights on a daily basis. The data from this algorithm provide high-quality satellite information on light output across the globe, allowing scientists to track when – and how brightly – people illuminate the night. A daily global dynamic dataset of nighttime lights is a new way for researchers to understand the broad societal forces impacting energy decisions and to look at how people use cities, from an energy perspective.

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Image Credit: NASA

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather

12/17/2014

WPC Places Us In Their Probabilities For 2"+ Of Snow Accumulation On Saturday! Let's Discuss...

The storm approaching on Saturday has recieved plenty of attention. It is now within the grid of the Weather Prediction Center (branch of the NWS), so they have started issued forecast info on this storm system. Let's discuss their forecast, what the computer models indicate, and my thoughts on Saturday in tonight's blog.

 

Computer Model / Weather Prediction Center (NWS) Snow Forecast For Saturday

 

I have to say, the computer models continue to trend this storm system south on Saturday as I suspected would happen. I have called it minor since day 1 and the data shows the precipitation would be minor at best for our area. Notice the GFS and EURO are showing very, very little impact from this storm on Saturday. You will see the name of the computer model on the top right part of each image.

 

EURO

 

GFS

 

With the data showing nearly no impact from this storm on Saturday, the WPC (branch of the NWS) are oddly showing probabilites of 2"+ of snow. While the probabilities are small, it still seems awefully aggressive to me. The WPC have a 20% - 30% chance of 1" or more of snow for most of our area on Saturday.

 

WPC Snow

 

The WPC has a small probability of 2" or more of snow for our area on Saturday mainly south of the river. They list the probability as 5% - 10%.

 

WPC Snow 2

 

Even more curious is their chance of 4" or more snowfall accumulation for our area. I understand it is small at 1%, but it sure seems unnecessary to me when not an ounce of data suggests that could happen.

 

WPC Snow 3

 

 

My Thoughts On The Storm Friday Night / Saturday...

 

If there was ever a classic example why meteorologists should not share raw computer model data 8 or 9 days in advance, this storm is it. 9 days ago, the EURO computer model showed a potential snow for our area. To be honest, I see this 15 times a year as a meteorologists and virtually none ever amount to anything. I call it computer model fantasy. Anyone living in the Ohio Valley knows virtually all of the "computer model" snows never turn into anything so why share it with the public knowing it will scare them? It makes you wonder what is the motivation?

 

For Saturday's storm system, the EURO is trending toward the GFS computer model and supressing most of this storm to the south. While a little wintry mix or light snow is still on the table, there is nothing that suggests this storm will be a problem for our area. With the jet stream lacking any of the ingredients necessary to pull this storm north, I think it is becoming clear it will not have a major impact on our area. I will continue to watch it closely, but I just don't see anything major from this storm on Saturday.

 

Christmas Eve / Day Storm Over The Great Lakes

 

It is worth noting that the computer models are starting to show an absolutely monster of a storm developing on Christmas Eve / Day over the Great Lakes. The latest GFS and NAM drop this storm to about 960 mb by Christmas day which is tremendously strong. The GFS shows 959 mb which is a titanic low pressure system! When both the EURO and GFS show a monster storm in nearly the same place, it raises an eyebrow.

 

Gfs mslp 1

 

Right now, it appears the main impact from this storm would be rain on Tuesday, then changing to snow showers on Wednesday. Nothing shows an accumulation at this point, but windy conditions with snow squalls seems likely now on Christmas Eve. The storm is a long way out, but we will be monitoring it.

 

 

It is winter storm season and if you want to be one of my storm spotters, you can join me on my facebook or twitter page. Just follow the link below and click "like" or "follow".

 

If you ever have any question, please remember I can be reached on facebook or twitter easily! Just follow the link below to my facebook or twitter page and click "LIKE/FOLLOW"!

 

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Discussing First Of Several Snow Chances...

A colder and active pattern looks to set up shop in the Ohio Valley. Even with breaks of sun this afternoon, tempertaures get stuck in the 30's.  A weak piece of energy sliding in from the west will bring us the chance for flurries and snow showers tomorrow...

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While everyone is fair game, our *southwestern* counites have the best shot at seeing the flakes fly. I do think a *dusting* is possible in a few sports on elevated surfaces like cars and rooftops. The NAM & GFS have painted a very similar picture regarding this minor event. The EURO isn't too far off either. They all show a couple tenths of an inch in areas west of I-65 and south of I-64...

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NOT everyone will see the snow this time around as anything that fall will be scattered in nature. There may even pockets of wintry mix or some sprinkles at times in areas that do see the precipitation. Join Marc Weinberg later today on WDRB for a full update on the other chances for wintry weather. Have a nice day!

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather

12/16/2014

Wintry Mix Seems Likely For Part Of The Weekend... An Analysis Of Snow Potential!

The storm system for Friday into Saturday has recieved a lot of attention. Part of the reason is that raw computer model snowfall forecast was taken as fact way too far into the future and again it spread like wild fire. Once the can is open, it cannot be closed so we will continue to share facts about the weekend storm and if any accumulation is on the table in tonight's blog. I will follow last night's blog structure so you can easily find the info you are looking for.

 

A Discussion Of The Friday Night / Saturday Storm System...

 

The storm for this weekend really a complex system. There are two lows that will combine to create the upper level low that moves across our area on Saturday. The closest (near California) is now about 2,000 miles from our area and the scond and more significant low is nearly 3,000 miles away. This storm a long way from our area, but the first enters the US tonight and the second Wednesday night. At that point, the data should become more reliable.

 

AdvanceTrak 3

 

Why does the data get more reliable once the storm enters the US? It is a good question. First, he US launches weather balloons twice daily at every one of it's upper level observing stations. Second, we collect "ACARS" data from jets that fly in the US. This data allows us to get a true look at the storm system and allows the computer models to initialize correctly. Starting correct means ending with better data, so getting the storm in the US grid is critical to forecasting storms accurately. This is why forecasting "significant snow" 7-10 days in advance is not just wish-casting but quite frankly irresponsible.

 

As one would expect, the computer model data hasn't consolidated quite yet and likely won't until Wednesday. The GFS computer model remains the warmest, but the EURO computer model is trending warming. Since we really have no "source" for arctic air on this storm, I would expect the data to have a greater likelihood to warm than cool. Have a look at the latest data.

 

GFS Computer Model Forecast Saturday

Notice the GFS still shows mainly rain and the result is virtually no snow accumulation in our area on Friday night and Saturday. It continues to show a slightly weaker storm than the EURO. The GFS has a slightly slower timeline bringing the storm in on Saturday which seems viable with the track of the upper level low.  Note the GFS snowfall totals in the second image.

 

Gfs mslp 1

 

GFS

 

The EURO computer model has warmed a little on it's most recent runs. With that said, it is subtle. The problem with the EURO computer model is that it has poor skill at forecasting temperature profiles in snow and it's resulting snow algorithm can be very bad. For this reason, I look at it's storm track but never trust its snow forecast totals.

 

EURO Computer Model Data Saturday Near Midday

Notice the EURO shows a very similar low and track as what it had yesterday. The main precipitation still appears early on Saturday per the EURO. The only difference is the EURO is slightly warmer and hence it has slightly lower snow totals today.

 

EURO MSLP

 

EURO

 

 

My Thoughts On The Friday Night / Saturday Storm System

 

Anytime there is snow in the forecast, I always emphasize that we are not going to enter the race to be the first to forecast snow. We are in the race to be the most accurate. I mention that a lot, but I can say that I find it particularly frustrating when people are scared unnecessariliy by the words "significant snow". We refer to this as "hype forecasting" or "click bait" and is something I find very damaging to my science.

 

This storm is not in the US yet and that means the computer models will struggle until Wednesday night when the full low enters the US. This means the actual computer model data will not be reliable until runs on Thursday morning. With that said, this storm really lacks any legitimate connection to cold air. That means light stuff could mix but for the storm to generate more precipitation normally would require some kind of warm surge. As you know, warm surge and snow don't really go together. Interestingly, the storm track is one that is favorable for snow here, but the lack of cold is a problem that the weather pattern seems to have no solution for. I think a light rain-snow mix seems most likely on Friday night / Saturday, but some light slushy accumulations cannot be ruled out yet.
 

 

In the next day and a half, we will see many shifts in the computer model data. Some mets will give you the play by play with every computer model run but we know that data is flawed. By late Wednesday night, the storm enters the US and the data will start to become more accurate. This is a storm of interest and we will be watching closely. We will give you accurate details as the data allows.

 

 

 

It is winter storm season and if you want to be one of my storm spotters, you can join me on my facebook or twitter page. Just follow the link below and click "like" or "follow".

 

If you ever have any question, please remember I can be reached on facebook or twitter easily! Just follow the link below to my facebook or twitter page and click "LIKE/FOLLOW"!

 

https://www.facebook.com/pages/Marc-Weinberg/171330336238674#!/pages/Marc-Weinberg/171330336238674

 

http://twitter.com/MarcWeinbergWX

 

 

Weather Blog: Snow Possible Thursday, Then...

From Jude Redfield...

    Lots of talk about our snow potential this weekend, but lets not forget about a chance on Thursday. I do think some of us in Kentuckiana will see some light snow. Areas along and west of I-65 have the best chance. Right now I would place us in a 40%-50% range.  Minor accumulations on grassy surfaces, etc.. can't be ruled out if this *LIGHT* snow band does indeed make it in. This will be a weakening area of energy so it should be falling apart as it swings through Kentuckiana. With pavement and air temps just above freezing Thursday I don't expect a big impact on the roads.

    While minor accumulations are possible Thursday, a **POSSIBLE** larger storm could take shape overnight Friday into Saturday. I still see no reason to be in a frantic state at this point. We are so far away from the possible event that we have too many questions to try and answer right now. If we're going to see widespread snow the biggest hurdle to overcome will be a lack of cold air available for this possible storm. This will probably take a favorable track to produce snow in a normal December scenario **HOWEVER** the lack of cold air in place and what is coming with it will most likely limit the amounts and coverage of the snow. I have my updated snow zone below that shows where I think snow is most likely at this point. This map will change daily so keep up to date with the situation if you have any travel plans at this time. -Jude Redfield-

Radar

Missouri

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SPC New Look

12/15/2014

Some Of The Data Shows Accumulating Snow This Weekend. My Assessment Inside...

This storm for Friday night into Saturday is already generating buzz in the area. Some of the data is indeed showing some accumulating snow in our area and we obviously need to discuss the scenarios. In tonight's blog, I will take a look at where the storm is located and some of the scenarios the computer models are spitting outfor Friday night and Saturday

 

A Discussion Of The Friday Night / Saturday Storm System...

 

The thing that isn't mentioned many times when computer models show snow is where the storm is located. Right now this complex storm is nearly 4,000 miles away from our area. Think about that for a second... that is REALLY far away!

 

AdvanceTrak 1

 

The storm is not in the US, not without our grid of upper level balloons to sample, and days away from us getting reliable data about it. Many mets will give you the "play-by-play" on this storm every single run for the next 100+ hours, but remember that the data is going to be unreliable until this storm enters the US on Wednesday. At that point, we should be able to dial in the storm more.

 

The data is all over the place and that is expect with a storm so far away from our area. In fact, we are seeing the GFS computer model showing virtually all rain as the storm moves across our area late Friday night and Saturday morning whle the EURO computer model shows snow accumulations. Let's start by looking at the GFS computer model.

 

GFS Computer Model Forecast Late Friday

Notice the GFS shows mainly rain and the result is virtually no snow accumulation in our area on Friday night and Saturday. It is showing a weaker storm than the EURO and a storm system that moves across faster with the main precipitation Friday night. Note the GFS snowfall totals in the second image.

 

Gfs mslp 1

 

GFS

 

The EURO computer model shows a very different storm and honestly it does make sense to see this difference considering how far the storm is from our area. The EURO shows a stronger and slower storm. It also shows accumulating snow in southern Indiana and northern Kentucky Friday night and specifically Saturday morning.

 

EURO Computer Model Data Saturday Near Midday

Notice the EURO shows a more compact and slower low. It pops accumulating snow late Friday night through early afternoon on Saturday. You can see the dark blue line as the "freezing line" on the EURO and it clearly is well south of the River when the heaviest precipitation is falling. Notice the EURO accumulations in the second graphic below.

 

EURO MSLP

 

EURO

 

 

My Thoughts On The Friday Night / Saturday Storm System

 

Anytime there is snow in the forecast, I always emphasize that we are not going to enter the race to be the first to forecast snow. We are in the race to be the most accurate. That is a philosphy that means we tend to do things a bit different. Since the storm is nearly 4,000 miles away from our area, we know that tiny mistakes in the computer model now blow up into large changes in the medium range. In fact, the subtle differences expand in the GFS computer model to all rain and the EURO computer model to all snow. Is this a surprise? Not at all. We see this nearly every day as meteorologists. In the social media era, everytime a computer hints at snow it gets posted online and causes a panic.

 

What we know is the storm is a long way from our area. When the storm enters the US on Wednesday, then and only then, will we have reliable computer model data. The storm track across the southwest US normally creates surface lows that can produce some wintry precipitation in our region. Looking at the data, the actual storm track looks legitimate and I don't see any real problems with the location that this low will travel. This is indeed a track that can produce snow in our region depending on the quality of the cold air. With that said, nearly every computer model shows only a marginally cold air mass will be in place Friday night and Saturday. That means all snow in this setup can be difficult. We also know the EURO has a cold bias and is notorious for forecasting bogus snowfall totals if any mix is in play. This means the EURO snowfall totals should be taken with a grain of salt.

 

In the next two days, we will see many shifts in the computer model data. By late Wednesday, the storm enters the US and the data will start to become more accurate. This is a storm of interest and we will be watching closely. We will give you accurate details as the data allows.

 

 

 

It is winter storm season and if you want to be one of my storm spotters, you can join me on my facebook or twitter page. Just follow the link below and click "like" or "follow".

 

If you ever have any question, please remember I can be reached on facebook or twitter easily! Just follow the link below to my facebook or twitter page and click "LIKE/FOLLOW"!

 

https://www.facebook.com/pages/Marc-Weinberg/171330336238674#!/pages/Marc-Weinberg/171330336238674

 

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Weather Blog: Snow Discussion

From Jude Redfield...

    The buzz has already begun on a possible winter storm impacting the Ohio Valley this weekend. I do feel the storm will develop and take aim on sections of our region. Before this potentially significant storm arrives we have a small chance at light rain/snow by Thursday. This delivers a 30% chance.

    Not lets being the focus on the weekend. As is often the case, predicting the exact track this far out is nearly impossible. We are looking at a potential storm overnight Friday into Saturday. The amount of error that can come into play between now and then is monumental. The other aspect to make this set up challenging is the lack of cold air in place as the storm approaches.  This is not to say we can't get significant snow in the heart of Kentuckiana. This is simply saying we need the perfect scenario to unfold for the heaviest snow to set up along the Ohio River. Climatology suggests the southern track that is currently projected by some of the models will shift a bit north over the coming days. When we are this far out I would tend to bias a bit to this solution. I don't feel the storm is going to cut all the way to the Great Lakes, but a northern shift even to the KY/TN border might be a bit too far north for all snow in locations along the Ohio River since an abundance of cold air isn't established.

    The projected path below shows the zone where the center of the storm could wind up. Bottom line...The farther north it moves the more rain that is likely. The farther south it moves the more snow that is likely.  As it stands right now (this will change daily) in my opinion, the highest probability for snow exists in southern and central Indiana.  This has the potential to be a high impact storm for travelers Friday night and Saturday in the Ohio Valley. If you plan to travel make sure to keep checking in with this forecast. Marc will be updating this starting at 4pm today on WDRB News -Jude Refield-

Radar

Rainestimates1

New Landmarks

Landmarks To Add

12/14/2014

Active Weather Coming. Rain Tomorrow, Snow for Weekend???

Gloomy conditions continued again this weekend.  I don't think we even saw a hint of sun the last couple of days and it has been a remarkably dismal start to the month of December.  

So far in Louisville 12 of the first 14 days of the month have featured either cloud or mostly cloudy conditions.  Only on two days have we seen appreciable sunshine. 

Gfx

Factor into the equation the fact that climatologically this is the darkest time of the year and it only makes it worse.  We only average around 9 1/2 hours of daylight and conversly about 14 1/2 hours of darkness!

Now, after a stagnant last several days, it looks like we are about to go into a much more active weather pattern which will bring us some good and bad news.  

The good news is that we should be able to filter in some sunshine here and there.  The bad news is that we'll still see our share of clouds and we'll see multiple chances of precipitation.  

The first one arrives tomorrow!

Satrad2

We are tracking a low pressure system across the Central US that will bring us rain tomorrow and into the day on Tuesday.  

Let's time it out with AdvanceTrak...

AT shows low clouds holding strong out the door tomorrow morning, but we remain dry. 

Advancetrak

A southerly breeze develops and should help to bring us some clearing during the morning and into the first part of the afternoon as rain approaches from the west.

Advancetrak2

Rain arrives along the I-65 corridor by late afternoon with mild temps into the 50's.

Advancetrak3

Scattered, mainly light, showers continue Monday evening and Monday night.

Advancetrak4

Tuesday looks pretty nasty with more overcast conditions, colder temps and additional showers.  

Advancetrak5

The Big Picture

Now let's look at the big picture.  After going more than a week with no measurable precipitation, an active pattern is emerging in the upper levels.  

Embedded in those jet stream winds are three areas of low pressure that look to impact our weather this week.

As mentioned above, the first one is located across the Central US and looks to bring us rain late tomorrow through Tuesday.

Satrad

The second one is located just off the coast of California and appears to be a relatively minor system for us but looks to spill more clouds our way on Thursday and will bring a slight chance for rain or a few flurries.  

It is the third low that seems to have everyone's attention. This one is located way out there, in the Gulf of Alaska currently, and will bring us the potential for a soaking rain or perhaps an accumulating snow this weekend.  

So what are the models saying?

Currently, there are two camps as is typical at this range.  The GFS and the EURO have two distinctly different solutions and would bring us two completely different scenarios.  

Let's start with the GFS...

The GFS is advertising a low pressure system to form over Northern Texas on Friday and then ride right up and into the Ohio Valley on Saturday.

StormTrak 1

A scenario such as this would bring us mainly just plain ol' rain with the possibility of a few snow showers as the system exits.

On to the EURO...

The EURO weather model tracks this low a few hundred miles further to the south going from South Texas to the Gulf Coast and then through Southern Appalachia.  

StormTrak 2

This is a classic snow track for us in Southern Indiana and Kentucky.   

So what do I think?  

First off, we are still five days out from this potential storm system that is currently located about 5,000 miles away.  

With that being said, I think there is a pretty high level of confidence that we will see some form of precipitation from this storm.  I also think there's a really good chance that some, if not all, of the precip could fall in the form of snow.  

The main reason I believe this is because of the EURO's historic performance at this range (5 to 7 days out) is typically better than the GFS.  The EURO has also displayed more run to run consistency with this particular storm over the last few days and is displaying a reasonable track.

So at this point, I think it is wise to lean towards the colder/snowier solution of the EURO.  

Could it accumulate?  

Indeed it could.  **IF** the current solution advertised by the EURO is correct, then the answer is YES.  

Now don't miss that "if".  There is certainly nothing set in stone yet, but with Christmas right around the corner and a big travel weekend ahead, this has the potential to be a high impact storm.  

Be sure to catch Jude with a full update on what to expect first thing on WDRB in the Morning.

Meteorologist Jeremy Kappell

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12/13/2014

Time-lapse Video: Grand Canyon Sea Of Clouds..

You need to see this stunning time-lapse video from Thursday when the Grand Canyon was filled with fog! This phenomenon is known as a temperature inversion. It typically occurs in the winter when there are long nights, clear skies, and calm winds. Cool air gets trapped underneath warmer air and if any moisture is present in that layer, it can form fog. The action in this 1 minute video would take 15 minutes in real time. It almost looks like a tide coming in and going out...

 

Video Courtesy: RT America

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather