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54 posts from March 2017

03/27/2017

SEVERE THUNDERSTORM WATCH...

The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     Far southern Indiana
     Central Kentucky
     Middle Tennessee

   * Effective this Monday afternoon and evening from 225 PM until
     1000 PM CDT.
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* Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Within a moderately moist and unstable environment, multiple corridors of severe thunderstorms including some supercells will continue to move east-northeastward across the region through the late afternoon and evening hours. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles northeast of Louisville KY to 80 miles south of Nashville TN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1).
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PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes.

 

 

 

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather

Severe Weather Update

From Jude Redfield...

    Scattered storms develop later this afternoon and roll into the evening. A few of the storms will be severe. The graphic below is an easy to see map showing regions where severe storms are possible vs being likely. Locations along and south of I-64 stand the greatest chance at seeing severe storms.

Lawrence County Tornado

    Some of the storms could produce hail up to 1.5" in diameter along with damaging straight line wind. Some weak rotation is noted in the atmosphere which could lead to a couple tornado warnings.  Rain amounts of 1" - 2" are possible by tomorrow morning with the highest totals likely in Kentucky. NOT EVERYONE IS GOING TO HAVE MORE THAN AN INCH OF RAIN.

RadarHelp

    One of the key ingredients allowing for severe storm development is a few hours of dry conditions during peak afternoon heating. It is my belief along with multiple recent computer models that this break will occur and takes place early this afternoon.  We could even experience brief breaks in the clouds allowing for extra warming from the sun. Severe storm development looks likely between 3pm - 6pm. The risk for severe weather should diminish shortly after sunset.

Rainamounts

Roster

Shoes

    Make sure to catch Jeremy Kappell's updated forecast on WDRB News from 11:30 am - 12:30 pm  -Jude Redfield-

03/26/2017

SPC: Risk of Severe Weather Tomorrow!

On the heals of this weekend's rainmaker, our weather stays active this week with a threat for severe weather arriving promptly on Monday.

Spc

The Storm Prediction Center has a Slight Risk for severe weather posted from Dixie all the way into the Lower Ohio Valley.  

Let's time it out with AdvanceTrak...

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AT starts us off cool and quiet in the morning.

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Clouds increase and a few showers are possible during the early afternoon hours.

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Showers and storms become scattered by late in the day with the main line not arriving until evening.

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AT brings in a ROBUST looking squall line during the early to mid evening hours.

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Storm intensity diminishes by late evening with pockets of heavy rain and thunder. 

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So what do I think?

I think we do have some ingredients coming together including sufficient wind energy aloft, good turning of winds in the lower levels, decent low level moisture (dewpoints in the low 60's), a forcing mechanism in the form of a cold front late and for some of the area, enough instability to fuel strong - severe storms.  

With that being said, I think that instability will be the limiting factor for much of the area including along and north of the Ohio River where SPC has included in the Slight Risk. 

Spc2

In my opinion this is too far north as clouds and possibly showers will likely reduce the amount of heating in these area, hence reducing the amount of instability.  I think the risk is real though further south into Central and Southern Kentucky say along and south of the Western Kentucky Parkway where damaging winds, hail and isolated tornadoes will be a possibility.  

We'll see what SPC does on the next update, but I would expect a shift to the south in the Slight Risk.  

Beyond tomorrow's weather maker, the busy weather pattern continues as another large storm arrives from the Pacific Northwest.  

Gfs vort

This one could bring more strong storms on Thursday.  We'll be watching!  

WDRB Meteorologist Jeremy Kappell

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More Storms: Severe Weather on the Table

The Storm Prediction Center has issued a slight risk of severe weather over the majority of our viewing area for Monday. The main threats are going to be damaging gusty winds, hail, and isolated tornadoes.

Image 1

The system that will move into the area on Monday is a progressive shortwave trough currently over the Four Corners region and will track east-northeastward. In comparison to yesterday, we have more atmospheric ingredients for severe weather production and I do believe we will see at least a few strong to severe storms develop during the late afternoon and evening tomorrow. 
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It will be warm and dew points will be increasing, therefore there will be a relatively moist and unstable air mass in the warm sector of the low, where scattered afternoon thunderstorms will develop. First they will be isolated and become more numerous with time. The main difference between yesterday's ingredients and tomorrow's is the instability. It is much higher. The more unstable our atmosphere is; the more likely strong to severe storms are to occur. Below is an image showing the Convective Available Potential Energy or CAPE. The highest the CAPE gets tomorrow is around 2000 J/kg, which is definitely sufficient for the development of severe weather. 
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There is also decent wind energy. It is not overwhelming, but it is decent, around 30-35 kts. There is also decent deep layer shear, which would provide the potential for hail growth. There is also the potential for bowing segments - capable of damaging winds or perhaps an isolated tornado as storms spread across KY and southern IN during the evening. So it is a day to be weather aware. Be sure to keep up to date with the weather on WDRB with Jude, Jeremy and Marc and Rick tomorrow! 
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Timing: Showers and storms will taper off tonight around 9 pm and we will be briefly dry through early Monday afternoon. A few isolated showers and storms will pop up from 12-3 pm and then they will become more scattered from 3-5. This is when they will begin to strengthen as well. 
At 1

Notice that as time goes on, there will only be more showers and storms and they will move across the area from west to east. Timing is subject to change but the most likely chance for severe weather will be late in the afternoon and evening. 
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They will continue to move across the viewing area and at this point there will be a full squall line of showers and storms and there could be a few supercells as well. 
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The lowest chance for severe weather is our far eastern counties because it appears it will be later in the day and we will lose daytime heating. 
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Overnight, there will be just a few lingering showers, but they will end before the morning commute on Tuesday morning. The rest of Tuesday will just be cloudy and slightly cooler. 
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Again, be sure to keep up to date on the forecast because the timing could change as the system approaches Kentuckiana. Join Jeremy this evening on WDRB News because he will have the latest information. If these storms become severe, we will be the first to let you know. A great way to stay informed is by following us on social media. The links to my pages are below. 

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw 

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03/25/2017

Pair of Systems bring Potential for Heavy Rain and Severe Storms!

We are tracking a pair of storm systems that will bring us a good bet for rain and storms over the next few days. 

Satrad

The first low, located over Missouri, will bring a round of potentially heavy rain tonight before the second storm located over the Four Corners Region arrives by late Monday with the potential for strong thunderstorms.  

Let's time it out with AdvanceTrak...

AT shows heavy rain arriving after midnight.  

At1

At2

Some areas could pick up locally better than a half inch tonight alone. 

At3

The main slug of rain is expected to exit towards the northeast in the morning.  

At4

Scattered showers redevelop during the afternoon.  A few t-showers possible, but nothing severe.

At5

We'll need to watch Monday with the arrival of the second system.  AT is bullish on the idea of strong-severe storms late day.    

At6

While this is a possibility, it will be contingent on getting some good heating during the day on Monday.

The Storm Prediction Center has a Slight Risk located across much of the Lower MS Valley.  A small jog to the north would put us in the risk area.  

Spc

We'll be watching.  Katie has a full update on the severe threat tomorrow morning. 

WDRB Meteorologist Jeremy Kappell

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Tracking Today's Storms

Good news! After being under a marginal risk for severe weather for a few hours, the Storm Prediction Center shifted the risk back over to the west and I agree with this change. While we could still see a rogue strong or severe storm, the likelihood is pretty low.  The best chance would be west of I-65. As the storms continue to progress east later tonight, they will hit more stable air and the storms will diminish in strength. 

Image 1

We are still currently positioned in the warm sector of this low pressure system out to the west. That means we are between the warm and cold front. Why does it look like two cold fronts? That's because the warm front is shifting south as a cold front! The cold front and the low to the west will slllllowwwwly progress toward the area and pass through our region tonight and into tomorrow morning. Latest guidance suggests a later and later arrival time. 

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Currently we are just seeing  mix of sun and clouds and it is breezy and warm! All showers are residing west. The atmosphere needs to be worked over before the rain can actually make its way into Kentuckiana. 

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So why is the severe threat relatively low? That's because of the instability or CAPE, the Convective Available Potential Energy. It looks even lower than yesterday and that's because the timing has slowed, so this makes sense. It is only around 200 J/kg and is not that sufficient for severe weather. 

Image 6

We do have sufficient wind energy, about 30-40 kts, however, without the instability, the likelihood of severe is considerably lower. It will more than likely just be gusty showers with a few storms embedded within the line. 

Image 7

As I mentioned above, the latest model guidance suggests a later arrival time of the showers and storms. We could see a few isolated showers early in the afternoon, but most of our day will be dry with filtered sunshine and breezy conditions. By this evening, our rain chances spike. Notice below, by 7 pm, our western counties are seeing the rain and storms.   

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They will slowly push toward the metro area from 8-10 and linger for the rest of your night. If you have evening plans, keep this in mind. 

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Notice, the line seems to slow even more, before it pushes fully east of I-65. 

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And there are still showers and storms around the area overnight and into Sunday morning. The widespread rain should end before 8 am, however we will still have hit or miss showers during the day and evening on Sunday as well. 

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Not much has changed with how much rain we expecting. Below is the raw model data of the GFS and the Euro through Monday morning. So this includes the scattered activity on Sunday. Notice they are in good agreement about the amount of rainfall possible, just over half an inch to under the 1'' mark.

Image 3

Be sure to tune into the news this evening with Jeremy. He will have the latest information as the storms are moving through the area. You can find me and get updates on the forecast with the links below! 

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw 

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03/24/2017

GREEN ICE? What's Causing This Colorful Display...

You never know where phytoplankton will turn up next. From space, we regularly see colorful blooms of them swirling in the world’s oceans. Inland basins and waterways support them too, such as Florida’s Lake Okeechobee, Washington’s Hood Canal, and North America’s Great Lakes.

Even the waters off the coast of Antarctica can sustain blooms. We recently showed a satellite image in which algae in a harbor near the Ross Sea had turned the sea ice a wild shade of green. As this photograph shows, they also appear to thrive on the snow and ice capping the southern continent.

N2421.Orne_Island_algal_bloom-720x477

Image Credit: NASA

“I was in Antarctica in February 2013 and saw plenty of algae happily growing in the ice (green, yellow, and red),” said ocean scientist Norman Kuring of NASA’s Goddard Space Flight Center. “I took this photo on Orne Island showing lots of green snow and ice.”

Kuring notes, however, that the type of phytoplankton inhabiting the snow and ice on Orne Island — on the opposite side of the continent, near the Antarctic Peninsula — is probably different from the species that bloomed in the Ross Sea. Direct sampling and analysis is the best way to know for sure, but that’s not always possible, especially in remote regions.

Antarctica_oli_2017064

Image Credit: NASA

 

 

-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather

Saturday Storms: Timing & Impacts

A system out to our west is going to continue pushing east toward Kentuckiana and will arrive just in time for the weekend. We are currently positioned in the warm sector of this low pressure system, in between the warm and cold front. And I'm sure you have noticed! Temperatures have surged in the past 24 to 48 hours thanks to that warm front!  Tomorrow the cold front will pass through the area and bring with it showers and storms. 

Image 1

Now that we are in the spring season, chatting about severe weather is a must! For now, the Storm Prediction Center does not have us under anything other than a general thunderstorm risk. However, there is a marginal risk for severe weather just to the SW and I agree. If there was a best chance to see severe, it would be tomorrow evening and west of I-65. As the storms continue to progress east, they will hit more stable air and the storms will diminish in strength. A rogue strong to severe storm is not off the table. 

Image 1

The CAPE or instability has also been pretty low with this system, but still sufficient for a strong or severe storm. Notice on the image below, there is an area of blue to the SW. That is a higher area of instability and one of the reasons why there is a better chance for severe storms to develop south and west. 

Image 5

There is also sufficient wind energy, in Kentuckiana (30-40 kts), but once again the strongest winds are to the SW (50 kts). However, these two images do not exactly line up. The wind image is for three hours prior to the highest instability. Winds begin to weaken as the system progresses east.   

Image 6

Timing: 

The best chance for showers and storms tomorrow is going to be in the late afternoon/evening. We can't rule out a few scattered showers earlier, but the more widespread showers and storms will hold off until Saturday evening. Notice that at 1 pm, we are just seeing mostly cloudy skies and warm temperatures once again. 

At 1

A few scattered showers will start in the late afternoon/early evening, particularly in our western counties. 

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The squall line then will progress toward the region, in our western counties and notice how more numerous they have become. This would be the time frame we could see some strong to severe storms. 

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They will continue to push east toward the metro area and will still have the potential for some gusty winds and small hail. 

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Once it crosses the I-65 line and heads into more stable air, notice the strength of the line weakens and is more of a soaking rain. 

At 5

Speaking of rain: how much are we expecting to see with these storms? The GFS and the Euro are both below and notice they are in good agreement about the amount of rainfall possible, roughly half an inch. But there is more rain in the forecast in the coming days, that will take us over the 1'' mark. 

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So the general gist is Saturday will have dry time, mainly early. While the severe risk is not overwhelming, there is a possibility for a rogue severe storm or two and the rain will not clear out completely on Sunday. There will be a few more lingering showers then as well. 

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Marc and Rick will track out the showers for Sunday and also discuss the severe potential for Monday as well! Be sure to join them this evening on WDRB News. I will see you bright and early tomorrow morning! Until then you can find me on my social media pages. The links are below!  

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw 

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03/23/2017

Has Spring Sprung: How long Will Warmth Continue?

From Freeze Warnings to Warming!

The Climate Prediction Center released their 6-10 day and 8 - 14 day outlook that takes us through the rest of the month and the beginning of April! A quick glance a the map suggests a 60% chance of above average temperatures for our area for the 6-10 day period ...

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And suggests about a 50% chance of above average temperatures for our area for the 8-14 day period ...

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Let's see if CPC's word holds true and do some investigating.  We will check the Global Ensemble Forecast System (GEFS) 2-m temperature anomaly maps. It looks as though the warmest days are in the beginning of the period, which would be Saturday and Monday. We have forecasted highs in the mid 70s for those days. Temps do look to dip just slightly on Sunday into the upper 60s. 

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But the rest of the two week period continues to show above average temperatures as well. Overall, it seems the CPC forecast of above average temperatures by the end of March and beginning of April should hold true. 

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However, there have been several runs of this model pointing to a cool down on day 14 as well. Right at the end of the period and showing BELOW average temperatures. This shows it is not safe to plant yet! Remember the age old rule for Louisville: Wait to plant until after Derby! 

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There is one more thing to note about this pattern of warmth. We may end up paying for it later, particularly in the second week of April, in the form of severe weather or at least heavy rain. While we are seeing warmth, the SW will be experiencing below average temperatures. If you look at ECMWF EPS Ensemble Mean Geopotential Height & Anomaly chart, you can see the cause of that is an upper level low. It is possible that upper level low will trek toward the Ohio River Valley and cause problems for us in the weeks ahead and is something we will be watching.

Image 6

Katie McGraw's Facebook Page

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-Katie McGraw 

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03/22/2017

MULTIPLE RAIN CHANCES: How Much To Expect Over The Next Week...

March can be a moody month and we've certainly seen our fair share of temperature swings, but what about rain? So far this month, 2.54" of rain has fallen in Louisville, which is only a touch below the average of 2.90". Now that spring has sprung, a lot of people are trying to work on the yard. I've been asked several times about rain chances because people want to fertilize their grass. We have a slim shower chance late Thursday. Our next good opportunity for rain arrives over the weekend as the first of a couple low pressure centers move into the Ohio Valley...

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How much can we expect? At this point, not enough to cause any flooding issues and just enough to give your yard a decent drink of water. Both the GFS and EURO models are painting about 1" of rain over the next 7 days. Just wait a few more days for the soil to warm up since these last couple of night have been quite cold. You will know it's time when the grass starts to grow. If you want specific timing on those multiple rain and storm chances, make sure you join Marc and I tonight on WDRB!  

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-Rick DeLuca

Rick

https://www.facebook.com/RickDeLucaWeather