The National Weather Service has extended the Winter Weather Advisory further south into portions of the metro area. The latest on who could see snowfall accumulations and how much...
...ACCUMULATING SNOW AND WINTRY MIX TONIGHT ACROSS PORTIONS OF
SOUTHERN INDIANA AND NORTHERN KENTUCKY...
.PLAN ON SNOW TO DEVELOP LATE THIS EVENING ACROSS SOUTHERN
INDIANA AND PORTIONS OF NORTHERN KENTUCKY. SNOW ACCUMULATIONS OF 1
TO 2 INCHES ARE POSSIBLE BEFORE PRECIPITATION CHANGES OVER TO A
LIGHT WINTRY MIX EARLY SUNDAY MORNING. THE HIGHEST ACCUMULATIONS
ARE EXPECTED TO BE ACROSS DUBOIS TO JEFFERSON COUNTY INDIANA.
...WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM EST /6 PM CST/
THIS EVENING TO 10 AM EST /9 AM CST/ SUNDAY...
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A WINTER
WEATHER ADVISORY FOR LIGHT SNOW AND WINTRY MIX...WHICH IS IN
EFFECT FROM 7 PM EST /6 PM CST/ THIS EVENING TO 10 AM EST /9 AM
* TIMING: LATE THIS EVENING THROUGH MID MORNING SUNDAY
* MAIN IMPACT: 1 TO 2 INCHES OF SNOW ACCUMULATION FOLLOWED BY A
LIGHT WINTRY MIX OF SLEET/FREEZING RAIN RESULTING IN SLICK AND
EXPECT SLICK SPOTS ON ROADS AND BRIDGES...ESPECIALLY UNTREATED
SECONDARY SURFACES AND BRIDGES. USE EXTRA CAUTION IF TRAVELING.
Aside from a few flurries, today looks pretty quiet with more clouds than sun and highs in the 30's. A Winter Weather Advisory goes into effect at 7 PM for parts of Southern Indiana, and continues through 10 AM Sunday morning...
Areas along and north of I-64 should plan on a wintry mix of rain, sleet, and snow developing later this evening and lasting into the overnight hours. I think snow will be the dominant precipitation type, especially north of the river. This could easily cover up the roads and cause slick spots. Be sure to use extra caution if you have any travel plans. By early Sunday morning the freezing line is going to push further north changing any frozen precipitation over to liquid. You can see that happening in these future radar images...
After some morning showers, a good chunk of the Sunday may end up dry, especially across the Bluegrass. Rain moves back in later in the day out ahead of a cold front. It's going to be cold enough that we may see a wintry mix on the backside of the storm as it pulls away Sunday night. Impacts should be low for the Monday morning commute as we start to dry things out, but with temperatures near the freezing mark, there could be localized icy spots...
How much snow are we going to see? Well, Southern Indiana is in the target zone for some LIGHT accumulations. Here is a look at the latest snowfall totals from the NAM, GFS, EURO, and AdvanceTrak through Sunday morning...
Don't expect to walk out the front door Sunday morning and see much snow if any. Any new snow, and even some of the old snow, will get washed as we transition over to rain. That means the accumulation map below will be highly dependent on WHEN you look outside. With that said, there could be a brief dusting on the ground in Louisville tonight. Most of Southern Indiana gets less than an inch. Finally, our northern row of counties may get 1 - 2" before the rain takes over, temperatures climb above 32 degrees, and the snow vanishes...
Make sure you join Jeremy Kappell tonight on WDRB as he tracks the wintry mix moving in!
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM 7 PM EST /6 PM
CST/ THIS EVENING TO 10 AM EST /9 AM CST/ SUNDAY.
* TIMING: LIGHT SNOW WILL BEGIN THIS EVENING AND CONTINUE THROUGH
MID MORNING SUNDAY.
* MAIN IMPACT: 1 TO 2 INCHES OF SNOW ACCUMULATION IS EXPECTED
CAUSING ROADWAYS TO POTENTIALLY BECOME SLICK AND HAZARDOUS.
EXPECT SLICK SPOTS ON SOME ROADS AND BRIDGES. USE EXTRA CAUTION
What connects Earth's largest, hottest desert to its largest tropical rain forest?
The Sahara Desert is a near-uninterrupted brown band of sand and scrub across the northern third of Africa. The Amazon rain forest is a dense green mass of humid jungle that covers northeast South America. But after strong winds sweep across the Sahara, a tan cloud rises in the air, stretches between the continents, and ties together the desert and the jungle. It’s dust. And lots of it.
For the first time, a NASA satellite has quantified in three dimensions how much dust makes this trans-Atlantic journey. Scientists have not only measured the volume of dust, they have also calculated how much phosphorus – remnant in Saharan sands from part of the desert’s past as a lake bed – gets carried across the ocean from one of the planet’s most desolate places to one of its most fertile.
A new paper published Feb. 24 in Geophysical Research Letters, a journal of the American Geophysical Union, provides the first satellite-based estimate of this phosphorus transport over multiple years, said lead author Hongbin Yu, an atmospheric scientist at the University of Maryland who works at NASA's Goddard Space Flight Center in Greenbelt, Maryland. A paper published online by Yu and colleagues Jan. 8 in Remote Sensing of the Environment provided the first multi-year satellite estimate of overall dust transport from the Sahara to the Amazon.
This trans-continental journey of dust is important because of what is in the dust, Yu said. Specifically the dust picked up from the Bodélé Depression in Chad, an ancient lake bed where rock minerals composed of dead microorganisms are loaded with phosphorus. Phosphorus is an essential nutrient for plant proteins and growth, which the Amazon rain forest depends on in order to flourish.
Nutrients – the same ones found in commercial fertilizers – are in short supply in Amazonian soils. Instead they are locked up in the plants themselves. Fallen, decomposing leaves and organic matter provide the majority of nutrients, which are rapidly absorbed by plants and trees after entering the soil. But some nutrients, including phosphorus, are washed away by rainfall into streams and rivers, draining from the Amazon basin like a slowly leaking bathtub.
The phosphorus that reaches Amazon soils from Saharan dust, an estimated 22,000 tons per year, is about the same amount as that lost from rain and flooding, Yu said. The finding is part of a bigger research effort to understand the role of dust and aerosols in the environment and on local and global climate.
Dust in the Wind
"We know that dust is very important in many ways. It is an essential component of the Earth system. Dust will affect climate and, at the same time, climate change will affect dust," said Yu. To understand what those effects may be, "First we have to try to answer two basic questions. How much dust is transported? And what is the relationship between the amount of dust transport and climate indicators?"
The new dust transport estimates were derived from data collected by a lidar instrument on NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, or CALIPSO, satellite from 2007 though 2013.
Image Credit: NASA Goddard's Scientific Visualization Studio
The data show that wind and weather pick up on average 182 million tons of dust each year and carry it past the western edge of the Sahara at longitude 15W. This volume is the equivalent of 689,290 semi trucks filled with dust. The dust then travels 1,600 miles across the Atlantic Ocean, though some drops to the surface or is flushed from the sky by rain. Near the eastern coast of South America, at longitude 35W, 132 million tons remain in the air, and 27.7 million tons – enough to fill 104,908 semi trucks – fall to the surface over the Amazon basin. About 43 million tons of dust travel farther to settle out over the Caribbean Sea, past longitude 75W.
Yu and colleagues focused on the Saharan dust transport across the Atlantic Ocean to South America and then beyond to the Caribbean Sea because it is the largest transport of dust on the planet.
Dust collected from the Bodélé Depression and from ground stations on Barbados and in Miami give scientists an estimate of the proportion of phosphorus in Saharan dust. This estimate is used to calculate how much phosphorus gets deposited in the Amazon basin from this dust transport.
The seven-year data record, while too short for looking at long-term trends, is nevertheless very important for understanding how dust and other aerosols behave as they move across the ocean, said Chip Trepte, project scientist for CALIPSO at NASA's Langley Research Center in Virginia, who was not involved in either study.
"We need a record of measurements to understand whether or not there is a fairly robust, fairly consistent pattern to this aerosol transport," he said.
Looking at the data year by year shows that that pattern is actually highly variable. There was an 86 percent change between the highest amount of dust transported in 2007 and the lowest in 2011, Yu said.
Why so much variation? Scientists believe it has to do with the conditions in the Sahel, the long strip of semi-arid land on the southern border of the Sahara. After comparing the changes in dust transport to a variety of climate factors, the one Yu and his colleagues found a correlation to was the previous year's Sahel rainfall. When Sahel rainfall increased, the next year's dust transport was lower.
The mechanism behind the correlation is unknown, Yu said. One possibility is that increased rainfall means more vegetation and less soil exposed to wind erosion in the Sahel. A second, more likely explanation is that the amount of rainfall is related to the circulation of winds, which are what ultimately sweep dust from both the Sahel and Sahara into the upper atmosphere where it can survive the long journey across the ocean.
CALIPSO collects "curtains" of data that show valuable information about the altitude of dust layers in the atmosphere. Knowing the height at which dust travels is important for understanding, and eventually using computers to model, where that dust will go and how the dust will interact with Earth's heat balance and clouds, now and in future climate scenarios.
"Wind currents are different at different altitudes," said Trepte. "This is a step forward in providing the understanding of what dust transport looks like in three dimensions, and then comparing with these models that are being used for climate studies."
Climate studies range in scope from global to regional changes, such as those that may occur in the Amazon in coming years. In addition to dust, the Amazon is home to many other types of aerosols like smoke from fires and biological particles, such as bacteria, fungi, pollen, and spores released by the plants themselves. In the future, Yu and his colleagues plan to explore the effects of those aerosols on local clouds – and how they are influenced by dust from Africa.
"This is a small world," Yu said, "and we're all connected together."
The weekend has arrived! If you have any plans I would keep reading because traveling at certain times in select locations might get tricky. Saturday doesn't look that bad. Expect more clouds than sun with highs in the low 30's. Sure 30's aren't the 50's we typically get this time of the year, but at least it stays mainly dry. I say "mainly dry" because the data has shown the chance for flurries during the day. Nothing major. Late Saturday night and into early Sunday morning is when a wintry mix could create a few slick spots on the roads. After midnight, a combination of rain, sleet, and snow move in from the west...
Areas along I-64 should be in that mix zone where all modes of winter precipitation are possible. If you live south of there I would just expect some light snow before quickly changing over to plain rain. People who live north of that corridor have the best chance at seeing snow/sleet mixing in a bit longer. This will last for several hours before EVERYONE changes over to ALL rain late Sunday morning...
The good news is that most people won't be on the roads from about 2 AM- 6 AM when this wintry mix is possible. However, if you work crazy hours or have a trip planned during that time frame, I would be extra cautious. Parts of Southern Indiana may end getting some light accumulations out of this but it won't be around for long. The combination of rain and temperatures rising above freezing on Sunday will wash away any new snow, and probably a lot of the old snow as well...
Sunday looks raw, chilly, and soggy with on & off rain and numbers in the 40's. It's possible that a light, brief wintry mix could fall as this system pulls away Sunday night. A couple more waves of rain move through early next week and could lead to flooding issues. We will watch this very closely through the weekend. Join Marc Weinberg tonight on WDRB for more on our rain/snow chances, plus a warming trend that sends temperatures in the 50's, if not near 60 next week!
After dealing with one of the coldest February's on record, the first week of March shows signs of spring. Temperatures will finally get back to normal as numbers climb well into the 50's, if not near 60 in couple spots by Tuesday. Here's the catch, with milder air comes the threat for heavy rain and storms. Both the GFS and EURO show 2 - 4 inches of rain over several days...
The rain is going to come in waves from Monday- Wednesday, which usually helps limit the flood potential. Unfortunately, the ground will take a while to thaw out and this increases run-off. We also have to take in account the leftover snow pack that will melt and irritate the flooding potential. Street and river flooding is something that we will have to keep and eye on next week. The good news is that heavy rain will help ease the drought that has set up in Kentuckiana...
Join Marc Weinberg tonight on WDRB for the very latest!
Niagara Falls is the collective name for three waterfalls that straddle the international border between Canada and the United States. Over 3,000 tons of water flows over the world-famous falls every second! The tremendous volume of water prevents the falls from completely freezing over, but this winter's arctic attack has turned it into an icy spectacle. A drone flying hundreds of feet above the Niagara Falls captured a one-of-a-kind view...
You've probably seen the thundersnow video from a couple weeks ago with Jim Cantore. I bet you haven't seen these versions. Even if you aren't a weather geek you will get a good chuckle while watching these youtube clips. Thank you Jim Cantore!
There are two pieces of energy we are keeping a close eye on. The first is a strong storm that is moving to our south, and the other is a weaker disturbance diving in from the northwest...
While a majority of the precipitation is going to miss us, parts of southern Kentucky may get brushed with some light snow. Areas south of the parkways could see a dusting, maybe up to an inch of snow down in Adair county by tomorrow morning. The further south you travel down I-65, the better chance you have at dealing with slick roads...
Let's talk about the second snow chance. Everyone in Kentuckiana is fair game for light snow late Thursday. A clipper-like system passes through with enough lift to squeeze out scattered snow showers and flurries. While this doesn't appear to produce widespread accumulations, those of you that do get hit could see a quick covering. This is something that you should keep in mind for the afternoon/evening commute...
As soon as we get through these snow chances, our attention goes back to the cold. More record cold looks likely, especially Saturday morning as we drop into the single digits!
With sunshine, today's high temperature of 32° felt almost balmy compared to what we've been accustomed to lately.
Despite the reprieve we saw today from the intense cold, our temps today were still almost 20 degrees below what's considered normal (departure from average) for late February. In fact, believe it or not, we "should" be in the lower 50's for a high this time of the year!
We have been NO WHERE NEAR THAT for more than two weeks now with temperatures regularly in the 20 to 30 degree below "normal" range.
So how has this February compared to normal?
Through the first 24 days of February 2015, our temperature has averaged out to be 28.1°. This is a full 10 degrees below normal so far for the month, which is REALLY impressive for such a large period of time.
Our average temp of 28.1° ranks us tied with the 8th coldest on record for the city of Louisville which has been keeping records since the 1880's, more than 130 years of record keeping!
So how will February 2015 stack up historically?
That depends largely on what our temps do over the next few days as we wrap up the month.
The Cold Returns, Again...
Currently, we are on track to receive YET ANOTHER blast of intense arctic air by the end of the week.
In fact, the current run of the Euro is projecting temps to plummet to some 30 to 40 degrees below normal, into RECORD territory AGAIN, Friday and into Saturday (final day of Feb).
The arctic air combined with snow still on the ground means the record low-high on Friday (currently 20° - 1934), the record low on Saturday (9° -- 1993), and the record low-high on Saturday (28° - 1884) are all in jeopardy of being tied or broken!
This looks to push our departure from average even lower from where it is now and we are currently forecasting this February to finish up in the top 5 coldest of all time with an average temperature somewhere in the neighborhood of 27.2°
To put that into perspective, we haven't seen a February that cold since 1978 (37 years ago) and most of us know how cold that one was.
For those who eagerly await a long overdue warm up, be sure to join Marc with the latest details on a much milder (although wetter) start to March in the extended forecast tonight on WDRB News at 10.