02/21/2015

Travelers Advisory Issued for much of Kentuckiana

The National Weather Service has issued a Travelers Advisory for much of the area tonight through early tomorrow.   Advisory details below...

Watch

...TRAVELERS ADVISORY OVERNIGHT AND EARLY SUNDAY MORNING...

COLDER AIR MOVING IN OVERNIGHT WILL CAUSE TEMPERATURES TO FALL
INTO THE 20S ACROSS MUCH OF CENTRAL KENTUCKY AND SOUTH-CENTRAL
INDIANA. THIS COULD CAUSE SOME RESIDUAL WATER ON ROADWAYS TO
FREEZE. ALSO...MOISTURE NEAR THE SURFACE OVERNIGHT COULD FREEZE ON
ROADS AND OTHER OBJECTS AS WELL. AREAS OF BLACK ICE ARE EXPECTED.
PATCHY FOG MAY ALSO OCCUR.

MOTORISTS OVERNIGHT AND SUNDAY MORNING ARE ADVISED TO USE EXTREME
CAUTION. BLACK ICE AND OTHER ICY PATCHES ON ROADS CAN BE VERY
DIFFICULT TO SPOT...ESPECIALLY AT NIGHT...AND BE VERY SLICK.
BRIDGES AND OVERPASSES WILL BE PARTICULARLY SUSCEPTIBLE.

WDRB Meteorologist Jeremy Kappell

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The NWS Has Issued Flood Warnings For Parts of Kentucky...

THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A 
FLOOD WARNING FOR...
EURO
* UNTIL 815 PM CST SATURDAY * AT 1117 AM CST...EMERGENCY MANAGEMENT OFFICIALS IN SEVERAL COUNTIES REPORTED WATER FROM DITCHES APPROACHING ROADWAYS DUE TO MELTING THE DEEP SNOW PACK. IN METCALFE COUNTY...SEVERAL ROADS WITH LOW WATER CROSSINGS HAD UP TO 4 FEET OF WATER OVER THEM. SEVERAL ACCIDENTS WERE REPORTED ON INTERSTATE 65 NEAR THE TENNESSEE LINE DUE TO DEEP PONDING OF WATER ON THE ROAD SURFACE. * LOW-LYING AREAS - INCLUDING ROADWAYS - ARE SUSCEPTIBLE TO PONDING WATER FOR SEVERAL HOURS AFTER THE RAIN ENDS. ADDITIONAL RAINFALL AMOUNTS OF UP TO AN INCH ARE POSSIBLE IN THE WARNED AREA. PRECAUTIONARY/PREPAREDNESS ACTIONS... MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN. IN HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS FLOODED ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF SWIFTLY FLOWING WATER TO CARRY VEHICLES AWAY.

-Rick DeLuca

Rick

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Rain & Snow Continue For Kentuckiana...

We have seen every type of winter precipitation out there today. Rain and snow continue to fall across parts of the area, but it all depends on your location. Southern Indiana is getting snow, most of  southern Kentucky is dealing with heavy rain/sleet, and areas along I-64 have more of a wintry mix...

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This is pretty much how the rest of today should play out before everything tapers off this evening. Roads are still slick and slushy so be extra careful. In fact, the NWS has issued a Travelers Advisory for a handful of counties due to ponding water on major roads and reports of black ice...

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Winter Storm Warnings and Flood Watches/Warnings remain in effect until later today as well...

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Future radar illustrates that rain/snow line hugging the Ohio all day long. That means more of this back and forth action through the afternoon hours...

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Louisville is right in the middle of the mix zone. The best chance for snow is to the north and plan for heavy rain down to the south that may cause flooding issues...

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This storm was all about the battle between warm and cold air. Temperatures made it just above the freezing mark and this cut back snow totals. Taking into account what you already picked up this morning, this is what we should end up with before all is said and done...

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Temperatures drop right back below 32 degrees tonight so get out and clean this slop up before heading to bed. Otherwise, is will be frozen rock solid by tomorrow morning. Jeremy Kappell will be in tonight will a full update. Have a nice weekend!

 

 

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather

 

 


Flood Watch For Our Area Posted

THE FLOOD WATCH CONTINUES FOR\
\
* PORTIONS OF NORTHWEST KENTUCKY AND SOUTH CENTRAL KENTUCKY
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\ \ * THROUGH THIS EVENING\ \ * HEAVY RAINFALL OF 2 TO 3 INCHES ON TOP OF A FROZEN GROUND AND\ MELTING SNOW PACK.\ \ * POSSIBILITY FOR AREAL FLOODING ESPECIALLY IN LOW LYING AND\ POOR DRAINAGE AREAS AS WELL AS URBAN LOCATIONS. IN ADDITION...\ MINOR FLOODING COULD DEVELOP ON SOME RIVERS.\ \ PRECAUTIONARY/PREPAREDNESS ACTIONS...\ \ A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON\ CURRENT FORECASTS.\ \ YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE\ FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE\ PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

\

-Rick DeLuca

\

Rick

\

https://www.facebook.com/RickDeLucaWeather

}

02/20/2015

Potentially Dangerous Winter Storm Poses HUGE Forecast Challenges

A Winter Storm Warning has been posted for the entire viewing area and remains in effect through 7 PM Saturday.  

Further west, it's a Winter Weather Advisory across Southwest Indiana and Western Kentucky.

Watch2

This storm is expected to impact a huge section of real estate across much of the Ohio, Tennessee and Mississippi River Valleys and even down into Dixie but the heart of it might very well end up in our backyard.  

Watch

So how much snow can we expect?

That is the million dollar question.  Even though this storm is only hours away, there is still a tremendous amount of uncertainty in the data.  Let's take a look at a couple of the models for instance.

12z AdvanceTrak (RPM)

The most recent run of AT is only showing an inch or two for most of the area with a narrow stripe of heavy snow, up to 6 inches, up along the highway 60 corridor near Seymour or North Vernon.

Snowfall projection rpm

The 12z NAM

On the other hand, you have the 12z NAM that shows a whopping 9 to 10 inches for areas along and just north of the Interstate 64 corridor.  

Meanwhile, only a county to the south, there could only be trace amounts of snow!  

Snowfall projection nam

What we know

We know that this system is going to bring with it the potential for very heavy precipitation.  Our central and southern counties will see a ton of precipitation with most models going better than 2 inches of liquid equivalent.

See GFS below showing 1.5" to nearly 3.0" from near I-64 south into our Kentucky Counties.

Gfs_tprecip_ky_6

What we don't know

The biggest question revolves around what form the precipitation will take.  Will it be primarily rain, sleet or snow?

A huge issue with forecasting a storm like this is figuring out the "thermal profile" of our atmosphere.  

You see, in addition to accurately forecasting temperatures near the surface, we need to figure out what temps will be doing several thousands of feet above us in order to correctly identify the main precipitation types.  

The Forecast Sounding

Take for instance the following series (below) of "forecast soundings" or "forecast profiles" for Louisville of the lowest 20,000' of atmosphere via the 12z NAM.  

We start at 2:00 at about the time heavier precip starts to fall.  Notice the 0°c (freezing line) that runs diagonally across the right part of the page.  

Now anywhere the red (temperature) and green (dew point) lines are to the left of the Freezing Line represents temps that are below freezing.  Anywhere they go to the right of the Freezing Line represents where temps are above freezing.

Profile 01

In the case of the 2 AM sounding above there is a pronounced "warm" layer (above freezing) at about 4 to 7,000 feet above us.  Below that is a a cold layer that extends from the surface to about 4,000'.  This is a classic freezing rain/sleet profile.

By around 4 AM the warm layer shrinks in size and descends down to between 3 - 5,000'.  However, the surface temp inches to just above freezing.  This would result in a sleet/rain profile. 

Profile 02

 By 8 AM the warm layer aloft completely disappears as surface temps remain near freezing.  This would result in a heavy snow profile.

 Profile 04

The profile hugs the freezing line and stays just cold enough to produce a heavy, wet snow profile through the morning hours

Profile 05

 At 2 PM the profile all the way up and down the atmosphere remains very close to freezing with temps in the lowest 2,000 feet rising to just above freezing.  This would result in a very cold rain.

Profile 06

 By 5 PM the profile cools back down enough to switch precip back over to a wet snow.

Profile 07

So what does this all mean?

You see, in the above soundings lies the biggest challenge that local forecasters have to deal with.  There will be a very fine line between precipitation that primarily falls as snow and precip that is primarily just rain from this storm.  

A couple of degrees really does make all the difference.   If temps warm just a little bit anywhere in the lowest 10,000' of our atmosphere then it makes this a rain event.  If temps stay as advertised by the NAM above, or if they cool, then this will primarily be a snow event.

The Current Snow Forecast

As of this writing, we are forecasting a stripe of 2 to 5" of snow from the Western Kentucky/Bluegrass Parkways up to near I-64.  

Further south, this system looks to be primarily just a rain maker for areas south of the Parkways with totals of up to an inch possible. 

For metro Louisville, areas along and north of 64 into Southern Indiana look to have the highest snow potential with 4 to 8" currently forecasted.  

What if it is really mostly snow?  

First, notice I didn't elaborate on the potential of much ice or sleet.  While I certainly think we will see some freezing rain and sleet during the early morning hours on Saturday, this really does look mainly like a RAIN or SNOW event for Louisville and our central counties.  

But to answer the above question, if the profile turns out to be cold enough to support mainly just snow, then I think we will be looking at A LOT of it!

Remember, we are talking about a HUGE amount of precipitation.  The latest models are all projecting somewhere around 2 inches of liquid equivalent (the amount of precip it would be if it was all rain) for this storm across our central counties and a little more than that for areas to the south.  

So if the bulk of that much precip falls in the form of snow, then we are talking about some LARGE NUMBERS.  

The 18z NAM

Take for instance the 18z NAM which came in while I was in the process of writing this blog.  It has trended a little colder with the forecasted profile and as a result, it is producing A TON of snow for our Central Counties.  

 Snowfall projection nam

The Dilemma

Now you see the dilemma.  We are dealing with a huge storm that will bring parts of the area a ton of rain and the potential for a stripe of very heavy snow.  

I really think that there's a good chance that someone sees up to a foot of snow in our viewing area from this storm.  

The question is where?

Right now, it looks like the best chance for this occurring would be somewhere near or north of I-64 where the "cold" thermal profile meets the heaviest precipitation.  

With that said, there will likely be a SHARP GRADIENT to the south of this POTENTIALLY VERY HEAVY STRIPE of wet snow.

As this system draws closer, we'll be able to dial in the locations and amounts with much greater accuracy that we can at this point.  

Moral of the story... In addition to some freezing rain at the beginning of this event, there is the potential for VERY HEAVY amounts of SNOWFALL and also RAIN from this system and everyone in the viewing area will be impacted by this large and dangerous storm.  

Marc will have a full update on timing and totals of this system tonight on WDRB News at 10.

WDRB Meteorologist Jeremy Kappell

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Tricky Forecasting for this Potentially Dangerous Winter Storm

A Winter Storm Warning goes into effect at 7 PM this evening for the entire viewing area and remains in effect through 7 PM Saturday.  

Further west, it's a Winter Weather Advisory across Southwest Indiana and Western Kentucky.

Watch2

This storm is expected to impact a huge section of real estate across much of the Ohio, Tennessee and Mississippi River Valleys and even down into Dixie but the heart of it might very well end up in our backyard.  

Watch

So how much snow can we expect?

That is the million dollar question.  Even though this storm is only hours away, there is still a tremendous amount of uncertainty in the data.  Let's take a look at a couple of the models for instance.

12z AdvanceTrak (RPM)

The most recent run of AT is only showing an inch or two for most of the area with a narrow stripe of heavy snow, up to 6 inches, up along the highway 60 corridor near Seymour or North Vernon.

Snowfall projection rpm

The 12z NAM

On the other hand, you have the 12z NAM that shows a whopping 9 to 10 inches for areas along and just north of the Interstate 64 corridor.  

Meanwhile, only a county to the south, there could only be trace amounts of snow!  

Snowfall projection nam

What we know

We know that this system is going to bring with it the potential for very heavy precipitation.  Our central and southern counties will see a ton of precipitation with most models going better than 2 inches of liquid equivalent.

See GFS below showing 1.5" to nearly 3.0" from near I-64 south into our Kentucky Counties.

Gfs_tprecip_ky_6

What we don't know

The biggest question revolves around what form the precipitation will take.  Will it be primarily rain, sleet or snow?

A huge issue with forecasting a storm like this is figuring out the "thermal profile" of our atmosphere.  

You see, in addition to accurately forecasting temperatures near the surface, we need to figure out what temps will be doing several thousands of feet above us in order to correctly identify the main precipitation types.  

The Forecast Sounding

Take for instance the following series (below) of "forecast soundings" or "forecast profiles" for Louisville of the lowest 20,000' of atmosphere via the 12z NAM.  

We start at 2:00 at about the time heavier precip starts to fall.  Notice the 0°c (freezing line) that runs diagonally across the right part of the page.  

Now anywhere the red (temperature) and green (dew point) lines are to the left of the Freezing Line represents temps that are below freezing.  Anywhere they go to the right of the Freezing Line represents where temps are above freezing.

Profile 01

In the case of the 2 AM sounding above there is a pronounced "warm" layer (above freezing) at about 4 to 7,000 feet above us.  Below that is a a cold layer that extends from the surface to about 4,000'.  This is a classic freezing rain/sleet profile.

By around 4 AM the warm layer shrinks in size and descends down to between 3 - 5,000'.  However, the surface temp inches to just above freezing.  This would result in a sleet/rain profile. 

Profile 02

 By 8 AM the warm layer aloft completely disappears as surface temps remain near freezing.  This would result in a heavy snow profile.

 Profile 04

The profile hugs the freezing line and stays just cold enough to produce a heavy, wet snow profile through the morning hours

Profile 05

 At 2 PM the profile all the way up and down the atmosphere remains very close to freezing with temps in the lowest 2,000 feet rising to just above freezing.  This would result in a very cold rain.

Profile 06

 By 5 PM the profile cools back down enough to switch precip back over to a wet snow.

Profile 07

So what does this all mean?

You see, in the above soundings lies the biggest challenge that local forecasters have to deal with.  There will be a very fine line between precipitation that primarily falls as snow and precip that is primarily just rain from this storm.  

A couple of degrees really does make all the difference.   If temps warm just a little bit anywhere in the lowest 10,000' of our atmosphere then it makes this a rain event.  If temps stay as advertised by the NAM above, or if they cool, then this will primarily be a snow event.  

What if it is really mostly snow?  

First, notice I didn't elaborate on the possibility of much ice or sleet.  While I certainly think we will see some freezing rain and sleet during the early morning hours on Saturday, this really does look mainly like a RAIN or SNOW event for Louisville and our central counties.  

But to answer the above question, if the profile turns out to be cold enough to support mainly just snow, then I think we will be looking at A LOT of it!

Remember, we are talking about a HUGE amount of precipitation.  The latest models are all projecting somewhere around 2 inches of liquid equivalent (the amount of precip it would be if it was all rain) for this storm across our central counties and a little more than that for areas to the south.  

So if the bulk of that much precip falls in the form of rain, then we are talking about some LARGE NUMBERS.  

The 18z NAM

Take for instance the 18z NAM which came in while I was in the process of writing this blog.  It has trended a little colder with the forecasted profile and as a result, it is producing A TON of snow for our Central Counties.  

 Snowfall projection nam

The Dilemma

Now you see the dilemma.  We are dealing with a huge storm that will bring parts of the area a ton of rain and the potential for a stripe of very heavy snow.  

I really think that there's a good chance that someone sees a foot or more of snow in our viewing area from this storm.  

The question is where?

Right now, it looks like the best chance for this occurring would be somewhere near or just north of I-64 where the "cold" thermal profile meets the heaviest precipitation.  

With that said, there will likely be a SHARP GRADIENT to the south of this POTENTIALLY very heavy stripe of wet snow.

As this system draws closer, we'll be able to dial in the locations and amounts with much greater accuracy that we can at this point.  

Moral of the story... There is the potential for very heavy amounts of snowfall and also rain from this system and everyone in the viewing area will be impacted by this large and dangerous storm.  

Marc will have a full update on timing and totals of this system tonight on WDRB News at 10.

WDRB Meteorologist Jeremy Kappell

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Email me at jkappell@wdrb.com

 

 

NWS Concludes Conference Call Concerning Approaching Winter Storm

Nws01

Nws02

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Marc will be in with a full update on timing and totals on this potentially dangerous system tonight on WDRB News. 

WDRB Meteorologist Jeremy Kappell

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Winter Storm Warning Issued

From Jude Redfield...

    Starting tonight through tomorrow a winter storm warning goes into effect for all of Kentuckiana. The heaviest snow will stay north of the river with a wintry mix of everything expected for the entire region. THIS IS A VERY CHANGEABLE FORECAST!!!!! Make sure to watch WDRB In The Morning starting at 5am through 9am for the latest on this forecast.

Stormview

02/19/2015

Snow & Ice Threat Friday/Saturday!

A large chunk of our area has been placed under a Winter Storm Watch from Friday afternoon through Saturday. All modes of precipitation are on the table including snow, sleet, freezing rain, and plain rain...

 

Warning

 

We tend to get a lot of storms like these in Kentuckiana where the freezing line divides us up. That means your exact location will ultimately determine what type of precipitation you get. Everyone is going to start off with snow roughly between 8 PM- 11 PM Friday. With arctic air in place, the snow will accumulate rather quickly. This is NOT going to produce snow totals like we had on Monday, but sections of our area could pick up higher accumulations. With temps so close to supporting snow, we really need to monitor this part close because an adjustment of a degree or two could increase snow totals quite a bit.

 

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Light southerly winds will push temperatures close to the freezing mark for some by Saturday morning. This should allow for a gradual transition from snow to sleet, then freezing rain, and maybe some plain rain. Our southern counties of Kentucky have the best chance at going to all liquid. Our northern counties of Indiana may end up staying in the snow for a majority of the event. Along and south of I-64, including Louisville, precipitation will go back and forth between freezing rain, sleet, and plain rain. There is still a lot of uncertainty in regard to how far north that freezing line will get. AdvanceTrak is having a very difficult time resolving this issue...

 

Blog5

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Canada Temps

Downs

 

As we get deeper into Saturday afternoon there is a better shot at getting more rain involved. That should help road conditions improve quite a bit. However, late Friday - early Saturday traveling could be dangerous, if not impossible at times. The storm will exit late Saturday...

 

Earthquake

Ef4

 

As you know, freezing rain is the WORST type of winter weather. We will have to watch the icing threat like a hawk because it can lead to big problems. Slick roads are likely with pavement temperatures running way below the freezing mark. Some power outages are not out of the question either. One thing I do want to mention is that the initial round of snow may help create a barrier before the freezing rain begins. It might turn out to be our saving grace by preventing ice from glazing directly on surfaces. Here is a look at precipitation types on Saturday... 

 

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With temperatures hovering around 32 degrees, it will make this one extremely difficult to forecast. Please check back in on a regular basis to get the very latest. Marc Weinberg will be on WDRB all night with updates and Jude Redfield will be on first thing tomorrow. Jeremy Kappell and I will also be here to keep you informed all weekend!

 

-Rick DeLuca

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National Weather Service Conference Call Summary...

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Marc Weinberg will be on WDRB with a full update at 4!

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather