WDRB Weather Blog

FLASH FLOOD & SEVERE STORM UPDATE: Timing Tonight's Rain...

Severe storms with powerful winds knocked a number of trees down leading to scattered power outages today. Well, another round of rain arrives tonight. Check out future radar at 11 PM that shows storms moving into our western counties...  

By 1 AM, locations from Louisville points north could be dealing with storms. Downpours, lightning, small hail and gusty wind are the main threats. Luckily, the severe risk looks much lower due to all of the rain that occurred. Strong storms are certainly still possible, maybe even a severe west of I-65. It would be nothing like what happened earlier today... 

While the severe risk has come down, the flash flooding risk has come up. Many zones picked up a couple inches of rain so it won't take much to create problems. Right now, we need to keep an eye on south-central Kentucky. Notice the red on AdvanceTrak, an indication of very heavy rain coming down over a short period of time. If you have to travel tonight please avoid water-covered roads...  

Later tonight is when the southern half of our area has a better shot for storms. There would be even less fuel for storms at this hour, so I wouldn't be too worried about waking up to severe weather...  

Friday starts of with some rain along and south of the river according to this computer model. It stays sticky and warm before additional hit or miss storms flare up during the afternoon hours.  

 Marc and I will be on WDRB tonight tracking the next wave of storms and talking about when high temperatures get knocked down into the 70's. 

 

 

-Rick DeLuca

https://www.facebook.com/RickDeLucaWeather

 

Severe Thunderstorm Watch Issued

UPDATE: 

A few counties have been removed from the initial watch, while others have been added. 

A Severe Thunderstorm Watch has been issued for a portion of our viewing area now until 6 pm EDT and includes Louisville. 

Below is an image of the counties included in both watches as well as detailed information from the National Weather Service.

SEVERE THUNDERSTORM WATCH INFORMATION:

THE NATIONAL WEATHER SERVICE HAS CANCELLED SEVERE THUNDERSTORM
WATCH 136 FOR THE FOLLOWING AREAS

IN INDIANA THIS CANCELS 4 COUNTIES

IN SOUTH CENTRAL INDIANA

CRAWFORD DUBOIS ORANGE
PERRY

IN KENTUCKY THIS CANCELS 1 COUNTY

IN NORTHWEST KENTUCKY

HANCOCK

THIS INCLUDES THE CITIES OF ENGLISH, HAWESVILLE, JASPER,
LEWISPORT, PAOLI, AND TELL CITY.

 

THE NATIONAL WEATHER SERVICE HAS EXTENDED SEVERE THUNDERSTORM
WATCH 136 TO INCLUDE THE FOLLOWING AREAS UNTIL 6 PM EDT /5 PM
CDT/ THIS EVENING

IN KENTUCKY THIS WATCH INCLUDES 21 COUNTIES

IN EAST CENTRAL KENTUCKY

BOURBON BOYLE CLARK
FAYETTE FRANKLIN GARRARD
HARRISON JESSAMINE MADISON
MERCER NICHOLAS SCOTT
WOODFORD

IN NORTH CENTRAL KENTUCKY

LARUE WASHINGTON

IN SOUTH CENTRAL KENTUCKY

CASEY GREEN HART
LINCOLN MARION TAYLOR

THIS INCLUDES THE CITIES OF CAMPBELLSVILLE, CARLISLE, CYNTHIANA,
DANVILLE, FRANKFORT, GEORGETOWN, GREENSBURG, HARRODSBURG,
HODGENVILLE, LANCASTER, LEBANON, LEXINGTON, LIBERTY,
MUNFORDVILLE, NICHOLASVILLE, PARIS, RICHMOND, SPRINGFIELD,
STANFORD, VERSAILLES, AND WINCHESTER.

 

SEVERE THUNDERSTORM WATCH 136 REMAINS VALID UNTIL 6 PM EDT /5 PM
CDT/ THIS EVENING FOR THE FOLLOWING AREAS

IN INDIANA THIS WATCH INCLUDES 6 COUNTIES

IN SOUTH CENTRAL INDIANA

CLARK FLOYD HARRISON
JEFFERSON SCOTT WASHINGTON

IN KENTUCKY THIS WATCH INCLUDES 14 COUNTIES

IN EAST CENTRAL KENTUCKY

ANDERSON

IN NORTH CENTRAL KENTUCKY

BRECKINRIDGE BULLITT HARDIN
HENRY JEFFERSON MEADE
NELSON OLDHAM SHELBY
SPENCER TRIMBLE

IN NORTHWEST KENTUCKY

OHIO

IN SOUTH CENTRAL KENTUCKY

GRAYSON

THIS INCLUDES THE CITIES OF BARDSTOWN, BEDFORD, BRANDENBURG,
CORYDON, ELIZABETHTOWN, HARDINSBURG, HARTFORD, JEFFERSONVILLE,
LA GRANGE, LAWRENCEBURG, LEITCHFIELD, LOUISVILLE, MADISON,
NEW ALBANY, NEW CASTLE, SALEM, SCOTTSBURG, SHELBYVILLE,
SHEPHERDSVILLE, AND TAYLORSVILLE.

Stay tuned for the latest information. Storms are around the area now and will likely become more numerous with time. Marc, Rick, and I are here and keeping you informed for the rest of today. Be sure to watch the news this evening with Marc and Rick on WDRB for the latest information. If and when storms go severe, we will be updating all of our social media pages, and cut into programming if necessary. The links to my social media pages are below. 

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw 

 

Severe Weather Update

From Jude Redfield...

    Scattered severe storms will develop this afternoon and tonight. Kentuckiana has the likelihood of going under some sort of severe weather watch

    Hail larger than 1" in diameter is possible this afternoon and early evening. The hail threat should diminish later tonight. It is possible some areas that end up with multiple rounds of storms could pick up more than 2" of rain. This merits a flash flood threat. The primary hazard with this severe weather situation comes in the form of damaging straight-line wind. some gusts could be greater than 60mph. While a tornado warning or two can't be ruled out, at this point the risk for tornadoes remains relatively low.

    The first round of severe weather takes aim along and north of the I-64 corridor this afternoon.

    Another round of potentially severe weather arrives tonight. The risk for severe storms will be a notch lower in the locations that pick up the the afternoon storms due to the rain cooled air.

    The severe weather threat should diminish after midnight. Make sure to follow the weather team the remainder of the day as storms move through -Jude Redfield-

Watch Likely to be Issued

The Storm Prediction Center is monitoring the conditions for our area for severe weather for the next day. Based on the data, it is likely that a thunderstorm watch will be issued.  The main threats are going to be gusty, damaging winds, hail, frequent lightning, heavy rain. Isolated tornadoes are possible as well. Read what SPC has to say about the threat below and be sure to stay weather aware.

 

Probability of Watch Issuance...60 percent

SUMMARY...Line of storms has recently intensified. Trends will be
monitored for a possible watch.

DISCUSSION...Radar, satellite, and lightning trends all suggest that
cluster of storms over southern IL has recently intensified and has
accelerated in its eastward movement. Storm motion is now over 40
knots, and localized damaging winds have recently been reported.
The air mass ahead of the storms is becoming increasingly unstable
with dewpoints in the 70s and strong heating. Given the increasing
organization of the cluster, a severe thunderstorm watch may needed
soon.

Stay tuned for the latest information. Storms are around the area now and will likely become more numerous with time. Marc, Rick, and I are here and keeping you informed for the rest of today. Be sure to watch the news this afternoon at 11:30 and 12:30 on WDRB. I will have the latest information. If and when storms go severe, we will be updating all of our social media pages, and cut into programming if necessary. The links to my social media pages are below. 

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw 

Breaking Down Thursday's Severe Weather Threat

Our threat of severe weather is increasing for Thursday, specifically the afternoon and late night.  Almost all of our WDRB counties are included in a Slight Risk (level 2 out of 5) with our northeastern counties in the Marginal Risk (level 1 out of 5).  It's certainly possible the SPC could put out an Enhanced Risk (level 3 out of 5) Thursday morning in or near our area. 

SETUP

Believe it or not, this severe weather threat is not solely caused by Alberto, the tropical system to recently move past us.  As Alberto leaves, that opens us up to the approaching cold front and the warm/moist air mass it will push ahead of it (ushered in by Alberto). 

Let's start by looking up through the atmosphere.  This low level flow shows a jet - an area of stronger wind - centered over us late Thursday.  As we will look at below, there are two waves of storm chances Thursday.  These large-scale factors are driving both. 

In the mid-levels of the atmosphere, we look at vorticity which is basically spin.  How these areas of "spin" move is most important in storm forcing.  You can clearly see the area of higher vorticity (red/orange) here Thursday night.  The fact that it's positioned right next to an area of weak or negative vorticity (dark blue) shows us we will have positive vorticity advection in our area late Thursday. That means the area of positive vorticiy is moving into the area of negative vorticity, creating movement and spin in the atmosphere. 

In the upper levels of the atmosphere, we can look at the jet stream.  At first glance you might think this map doesn't show you much, but look again.  The white lines showing wind direction seem to separate from each other over Kentuckiana.  That movement apart is called divergence, and divergence aloft leads to rising air in the atmosphere.  We need rising motion to support storm development and growth. 

INGREDIENTS AND TIMING: ROUND 1

The first round of storms starts in the early afternoon, and will be driven by daytime heat and humidity.  This first wave should enter our western counties around 2 PM, closer to Louisville around 3 PM, and our eastern counties by 4 PM. 

The AdvanceTrak image above shows that temperatures will be in the middle to upper 80s by this time of day, providing ample heating.  It also shows breaks in clouds.  Those small pockets of sun will increase our instability during the day. 

Full disclosure: these numbers are on the high end of possibility.  A safe bet for CAPE numbers will be 1500-2500 during peak heating.  The higher the number here, the more energy storms have available to them. Numbers in the 2000-3000 range are high for this area. 

Dewpoints will also be high- lower to middle 70s.  Through the morning you will notice the air feels humid.  Moisture is a key ingredient in storm development, and we definitely have that here. 

INGREDIENTS AND TIMING: ROUND 2

First, we need to recognize that whatever happens with this earlier round will impact the later round.  If the earlier storms are stronger, it would likely rob the later storms of some energy.  If the early round doesn't come together as planned, that leaves more energy for the evening storms. 

Dewpoints will still be high for our second round of storms.  CAPE numbers won't be as high because we lose the daytime heating, but we will still have ample moisture. 

This second round will be forced more by a weak front, so we will start to see more storms after sunset.  You can see in these images how this becomes more organized the longer it stays "alive." 

These will intensify rapidly "blowing up" as they move across Kentuckiana.  The trick here will be watching how they interact with each other.  Those interactions can cause either strengthening or weakening depending on what happens, so those will become "nowcast" situations. 

Models suggest this becomes a Mesoscale Convective System ("MCS").  That means it will be larger than individual thunderstorms; think like a cluster of strong cells all grouped together. 

This is truly an overnight event as we don't clear these clusters out until nearly daybreak! Make sure you have a way to receive weather alerts while you are asleep in case we need to share warnings with you. 

THREATS

The main threats will be large hail and damaging wind gusts.  Hail could be larger than 1" diameter and wind gusts could be stronger than 60 mph.  The smaller threats are heavy rain (leading to flooding) and isolated tornadoes. Marc will continue to share updates with you on WDRB News tonight. 

Hannah's Facebook Page

Hannah's Twitter Page

-Hannah Strong

Severe Weather Risk On The Rise

From Jude Redfield...

    Plenty of ingredients come together to produce a solid chance for severe storms on our Thursday. Heat, excessive moisture & ample wind energy headline the severe storm recipe that looks to make for a turbulent Thursday in spots.  The primary threats include damaging straight-line wind and damaging hail. If more than one round of storms goes up some localized flooding could develop.

    I feel the highest potential for severe weather is centered up on Kentuckiana. (see map below)

    At this point the exact timing of storm formation is a bit fuzzy. As temps warm to near 90 on Thursday expect development during the afternoon. The main trigger (upper level low pressure) arrives during the night. This could mean two rounds of storms, one with heating of the day and the other at night.

    We haven't had much severe weather this season so don't let your guard down on our Thursday potential. Keep up to date with the weather team on this one! -Jude Redfield-

Changes to Flash Flood Watch

The National Weather Service dropped several WDRB counties from the Flash Flood Watch ahead of heavy rainfall from Alberto saying, "The track of the remnants of Alberto will stay far enough west to keep the heaviest of the rainfall along and west of the I-65 corridor."

This is the updated map that still includes Louisville. 1"-3" of rain will be possible where we see the heavier rain from thunderstorms. Not everyone will see that much rain! The Flash Flood Watch is in effect now and continues through Wednesday.  Marc will update you tonight on WDRB News with the track of Alberto and projected rainfall totals. 

Hannah's Facebook Page

Hannah's Twitter Page

-Hannah Strong

A Few Severe Storms Possible

From Jude Redfield...

    Daytime heating (self destruct sunshine) gets the t-storm game going once again this afternoon/evening. Scattered storms flare across sections of Kentuckiana and some will be strong. A few severe storms are possible as well over the next few days. We aren't expecting widespread severe storms, but locally high wind is a possibility. With the remnants of Alberto heading our way it provides enough circulation in the atmosphere we could have a tornado warning or two. This is not uncommon with tropical systems as they move across land. Quite often the rotation is weak and leads to only a minimal tornado risk. A few flood warnings are possible where the most extreme downpours occur. Please see the future radar images below to get an idea of what we have coming.

    Scattered storms will cover a large region in Kentuckiana today and tonight, but don't expect 100% coverage.     

    The center of circulation in Alabama is moving northwest this afternoon and remains well to our south for now. It approaches overnight and moves to near Evansville, IN by Wednesday morning. 

    The swath of widespread, heavy rain is about 100 miles wide and directly underneath the low pressure. This looks to remain west of I-65.

    The greatest flood potential will follow the path of this low pressure.

    As the low pressure heads north tomorrow afternoon it takes the bowling ball of rain with it. We still expect scattered showers and storms on the south side of this as daytime heating develops Wednesday afternoon/evening. Follow Hannah and Marc later today as the radar becomes more active with strong storms -Jude Redfield-

The Remnants Of Tropical Storm Alberto Could Bring A Flash Flood Threat. Discussing Rain Totals...

This has been an interesting May thus far. We are on pace to break the record for the "warmest May" on record and it is not even close. The by product of this warm May has been spotty t-storms that have either brought you a lot of rain or next to nothing. We have seen large ranges in the rain totals, but some very clearly still need some rain. You can see the lack of rain in areas as many lawns and farms are already looking stressed. Alberto will give us an opportunity for some solid rain in areas, but I am not convinced we all get the soaking rain. We also know tropical systems can bring too much rain and times and a flash flood threat is real for some with this storm. Let's jump in and look at potential rain totals.

 

Tropical Storm Alberto Is Approaching...

 

Tropical systems are well know for producing sizable rain totals near the center, but not always everywhere. That means it becomes critically important to note where this low is going, so we can assess heavy rain potential. Alberto has made landfall in Florida and it is making it's move to the north as we speak. Notice the swirl of the clouds near the Gulf of Mexico with the bands spread out as far as southern KY.

 

 

Alberto is forecast to make a move to the north and through western KY. The consistency within the data is high lending a lot of credibility to the track of this storm. This is called a "spaghetti plot" showing all the various computer models we use to forecast. Notice how tightly clustered they are on the track through western KY.

 

 

No surprise on the NHC track showing Alberto moving northward then across our western counties late Tuesday into early Wednesday. You can see the sustained winds are not impressive at all as it approaches, so the concern for widespread strong winds are low.

 

 

How Much Rain Does The Data Indicate?

 

This is a setup where there clearly will be "tropical downpours" since this is a sub-tropical storm. The storm will weaken by the time it arrives, so the tropical storm force sustained winds will not be a concern. Looking through the data, we can see quite a range still. It is critically important to note that with tropical downpours, there can be a large variations in rain totals from one location to the next. What we do see is consistently more rain along the track of the low and that likely means the heaviest rain could fall west of I-65. As you look through the data, note the name of the computer model and the time period on the top right of each image. The NAM only goes out 84 hours, so it stops late Thursday while the GFS and EURO go through Friday.

 

 

 

 

 

The WPC (branch of the NWS) is forecasting some very solid rainfall for our area through Friday. You can see they also bias the heaviest close to the track of the low in western KY / IN, but show 1" - 2" near and east of I-65. Closer to the low, they are forecasting 2" - 3.5" west of I-65 with the higher totals from Madisonville, KY to Evansville, IN.

 

 

 

My Thoughts On Rain Timing & Totals

 

With the remnants of Alberto moving across our area on Tuesday and Wednesday, the NWS has issued a Flash Flood Watch for much of the area that goes into effect late Tuesday. This watch does include the Louisville area.

 

 

Tuesday does not look like an all day rain. The rain chance should increase late on Tuesday with the best chance on Tuesday night. With tropical systems, we traditionally see the heaviest rain near the low which travels through western KY. I think the greatest chance of more widespread heavy rain therefore falls along and west of I-65. That said, there is a lot of moisture with this system and even your general storms can produce extremely heavy rain within a setup like this. The window for the heaviest is late Tuesday and Wednesday, but scattered storms remain on the table for Thursday.

 

I think this is a good candidate for 1" to 3" of rain for our area. I think the areas that would be on the lower edge are likely east of I-65, but there will be some locations along and west of I-65 that could exceed 4" or 5" of rain. I think the greatest potential for the heaviest rain will be west of I-65 and closer to Owensboro and Evansville. Since these waves will be convective (t-storms) in nature, we can see wide ranges for the areas that get caught under repeated t-storms. The heavy rain potential is something I will be watching closely.

 

It is also worth noting that the right side of tropical systems can and do produce short lived, quick tornadoes at times. We are in the right side of Alberto, so I cannot rule out a couple quick tornado warnings late Tuesday or Tuesday night. The threat is not large, but there is definitely a chance of a couple of warnings. 

 

 

 

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

 

 

Alberto's Impacts Start TODAY: Memorial Day Hour By Hour

All is quiet, for now, in Kentuckiana. It is warm and humid again with a mix of sun and clouds. However, once again, we have a chance for showers and storms. But these are being brought to us courtesy of Subtropical Storm Alberto. If you look below, you can see there is a lot of moisture of ahead of the main circulation and that outermost band will make it to our neck of the woods today. That means our shower and storm chance is not just heat driven and will not wrap up when the sun sets. It actually increases.

Our shower and storms chances only increase this week from the remnants of Alberto. 

 

Memorial Day Hour By Hour: 

For any of your outdoor plans and events, the first half of the day looks to be dry. Showers and storms return by mid afternoon. I have about a 20% chance for showers and storms by 5 pm, but increase that to 40% by 8 pm and 50% by 11 pm. Highs will be in the mid to upper 80s, but with sticky dew points, it will feel even warmer, in the low to mid 90s. 

Scroll through the images of Advancetrak to see more about the timing of showers and storms this Memorial Day. 

The rest of this morning and early afternoon look dry. 

By mid to late afternoon (2-4 pm), we will introduce more shower and storm chances. Starting off isolated to scattered at first. Also, the more south you go, the better chance you have for showers and storms. Heavy downpours are once again likely. There are also some flooding concerns (especially in areas that saw heavy rain yesterday). Gusty winds and frequent lightning are also on the table. 

Showers and storms become more numerous with time and move more north. They will be moving from east to west as Alberto churns in a counter clockwise rotation. I have increased our rain chance for tonight (since this weekend and this morning) as the latest data came in, but the good news is that most of our events will be over at this time. It appears we could have decent coverage in the southern half of our viewing area this evening and tonight from the northern edge of this outer band associated with Alberto. 

This looks like it could continue through tonight and through a portion of the overnight, before tapering off tomorrow morning. Another round of showers and storms will arrive on Tuesday, as Alberto's remnants heads toward Kentuckiana and more of the area will feel impacts. 

Speaking of Tuesday, heavy rain is likely to fall and severe weather is also possible. The heaviest rain will be along and west of Interstate 65 in central Kentucky and southern Indiana. 1 to 2 inches of rain is expected Tuesday through early Wednesday with locally higher amounts possible. Flash flooding is a concern. Severe weather is also a possibility because we will be on the NE side of the low when it passes through, which is notorious for spin ups. 

 

Be sure to join us this evening on WDRB News this evening with Marc for the latest updates.

Let's connect! The links to my pages are below! 

Katie McGraw's Facebook Page

Katie McGraw's Twitter Page

-Katie McGraw