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115 posts from April 2011

April 29, 2011

Who Can Figure Out What Is Wrong With This Photo? **ANSWER INCLUDED**

We had a brilliant display yesterday of double rainbows. I have attached a few images from a co-worker Steve Nally. I will tell you there is something very different between the primary rainbow closer to the ground and the secondary bow which is higher up. Can anyone figure out the difference???


Double bow 1 


Double bow 2 


More pictures from Kathy Robinson...


Rainbow 003 











Answer Below


The pictures above show what we refer to as a double bow. That is two rainbows that share the sky and shape, but the secondary bow is always further away from the ground. To understand how a double bow works, you have to first understand how the primary bow is formed. We get rainbows when sunlight shines directly into a rain drop, then bounces off the back of the raindrop, and is reflected to your eyes. The water acts like a prism and spreads the light into the full spectrum of colors. When a secondary bow is formed, the light has to bounce twice off the back of the rain drop before it is reflected to your eyes. That means more light is muted by the rain drop (the cause of it being less bright) and like a mirror the colors are flipped backward to the primary rainbow since the light bounces off one more surface of the raindrop. So everytime the light bounces off the back of the drop, the reflection, much like a mirror, is flipped and reversed. This is same thing as when you look in a mirror everything looks backward. Here is a good illustration I drew up. Sorry if it is a bit crude. :)


Double Bow 

How Much Rain Did We Actually See In The Last Week?

A lot of people were curious about just how much rain we saw in the severe weather and heavy rain event in the Ohio Valley in the last week. It was a remarkable event that may take a long time to replicate. We have shattered the record for the wettest April of all time as we stand at 13.97" for the month. That is over a foot of rain just in the last 29 days!!! Thanks to the NWS for a great image displaying rainfall totals for the area...


Rainfall Totals NWS 



April 28, 2011

Kentucky Derby Festival / Oaks / Derby Forecast Discussion

One of the great outdoor times of the year for Kentuckiana is the Kentucky Derby Festival events and the races on Oaks/Derby. With all the major severe weather possiblities behind us for now, it is finally time to focus our attention on the coming 10 days worth of events.


Specific Event Forecasts For The Next 7 Days


To kick off the discussion, let's take a look at the 7-Day so you can pick out the days that are important for your events.




One of the big kick off events for the Kentucky Derby Festival is the US Bank Bank Great Balloon Glimmer in Waterfront Park and the kick off the Chow Wagon at 11 am today. We will have to watch out for a late evening / early overnight shower or thunderstorm and breezy conditions for this time period.


KDF 1 


Friday morning is the US Bank Great Balloon Rush Hour Race. It is always fun to watch the balloons fill the sky for those heading into work in the morning. A couple of years ago I helped with this event and I can tell you the winds are really important for this event. Surface winds will die down to around 5 - 10 mph by the morning but the winds they will fly at will be out of the west-northwest so the balloons should fly down Taylorsville road area.


KDF 2 


Sticking with the popular balloons, we move to the US Bank Great Balloon Glow Friday night. This tends to be packed and the weather looks stellar!


KDF 3 


Saturday is the marathon/mini, so weather plays a big role, plus opening night at Churchill Downs! The morning will be cool on Saturday, but that is good for the runners. Opening night at Churchill Downs looks fantastic. What a way to kick off the Spring Meet!


KDF 4 




Derby Week Highlights


Moving into next week, we will a storm from Sunday and exiting the area Monday. The early part of the week looks very nice with some chilly mornings. We will be live from the Backside of Churchill Downs if you do get a chance to wake up with us. The rain chances do start to increase on Thursday which could affect the Pegasus Parade. The GFS has been rather consistent from run to run showing rain late Thursday lending confidence to the longer range. The good news is this does not remotely look severe.




If indeed this scenario plays out as it does look like the most likely scenario, then we would likely end up with very nice Kentucky Oaks 137 and Kentucky Derby 137 weather. Oaks would be in the mid 60s and Derby would be in the lower 70s. Please understand this is still nearly 10 days out and the details are not solid yet, but I figured it was worth a mention. :)