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48 posts from February 2011

February 27, 2011

Tornado Watch for Parts of Kentuckiana

A Tornado Watch has been issued for parts of Kentuckiana by the Storm Prediction Center until 9 PM eastern time. This is only for areas south of the Ohio river and through Tennessee. In addition, there is already one storm in Tennessee with a tornado warning. Please remember we are setting up for a possible severe weather event across our area in particular Monday morning.


Severe T-Storm Tornado Watches 


For full details on the possibility for severe weather, please view the last blog entry listed here...




Monday Upgraded to Moderate Risk of Severe Weather

There is a slight risk of severe weather for the duration of Sunday, but parts of the area have been upgraded to a moderate risk of severe weather for Monday. That means a severe weather event could occur and we have to discuss the details.


Severe Weather Threat for Sunday


Sunday remains under a slight risk for severe weather. For more details on today's severe weather potential, please view the previous blog entry...




 Here is the latest radar image from StormViewHD as of 5:00 pm.




Notice some of the stronger storms do contain heavy rain and frequent lightning, but no watches or warnings are in effect now. The larger complex of storms is now getting fired over Missouri, Kansas, Oklahoma, and Akansas. Multiple warnings are already in effect for that part of the country.




Flooding remains a concern and a large portion of our area remains under a Flood Watch. Widespread 1" to 2" will fall over the next 24 hours in much of our area.




The Storm Prediction Center continues to indicate severe potential today on the warm front, and a greater threat tonight/tomorrow.


SPC Categorical Risk for Sunday


Spc 1 cat 


SPC Hail Threat for Sunday


Spc 1 hail 


SPC Wind Threat for Sunday


Spc 1 wind 


SPC Tornado Risk for Sunday


Spc 1 torn 



Monday Severe Weather Threat


On Friday, I felt it was important to include a severe weather risk for Monday and the Storm Prediction Center does agree. In fact, they have upgraded parts of our area to a moderate risk of severe weather.


SPC Categorical Risk for Monday


Spc 2 cat 


SPC Probabilistic Risk for Monday

Note SPC is showing the Ohio valley in the "hatched area". That means there is a 10% chance or great that within 25 miles of the hatched area that significant severe weather will occur.


Spc 2 prob 


I have said for days this system has had monster wind energy and instability would be very important. The latest model trends are indicating instability will not be a problem and that is a concern. In this setup, I like to see instability values of above 1000 units and the latest NAM is showing jinstability values of 1000 to 2000 across the Ohio Valley as of 7 am Monday morning. That is concerning.






 My Forecast


Isolated stronger thunderstorms may occur this evening, with primary threats as hail, isolated damaging winds, and lightning. Flooding remains a concern with much of the area under a Flood Watch. Please do not attempt to drive across any flooded roadway.


The main threat will arrive Monday morning and I will admit I am concerned this is going to be a widespread severe weather opportunity. The wind field is remarkably strong and that will support widespread damaging wind potential since we do have enough instability in the atmosphere. The directions of the winds at the surface would point to more of a damaging wind potential than tornado threat, but we cannot rule out isolated spin-ups. The damaging wind threat could be over a very large portion of our area and we really need to watch this. The timing looks during the early to mid morning across most of our area with a possible secondary line as the front comes through.


Lori Farmer is in the weather office ready if any severe weather will affect you tonight, and I will be in early so we can stay on top of this. Keep it on Fox 41 during the event and we will pass along the severe weather information you will need to know.





Sunday Update... Severe Weather and Flooding Threat Sunday/Monday

A quick Sunday update on the severe weather threat and flooding threat for our area of the next 24 - 30 hours. There are once again two distinct threats on this system, much like the last, flooding and severe weather.


Flooding Threat


Most of the computer models are spitting out around 1" to 2" of rain on this system and I think those are legit numbers. HPC agrees as well and have most of our area in a 1" to 2" rainfall total.




As there is much agreement here, I think the rain part of this storm is pretty certain. It doesn't look like as much rain as the last system, but as most of you know the ground is really saturated right now. Therefore the NWS has issued a Flood Warning for much of our area (image care of the NWS).




Severe Weather Threat


The severe weather threat remains very complicated. It still does appear that a line of storms will move across the area from tonight through mid morning on Monday. The GFS and NAM timing differences are getting smaller and both seem to be blending toward a middle ground. The warm front still will move across the river in the early afternoon time frame today in Louisville. Latest data suggest storms will accompany this warm front. It cannot be ruled out that a couple of these storms could go severe. Mid level winds and instability are sufficient to support a couple of strong to severe storms.

The second and more significant severe threat is Sunday night / Monday. It looks like a line or possibly mutlitple lines of storms will move across the area tonight and early tomorrow. The mid level winds are extremely strong and there will be enough instability to support severe weather. The wind field is setting up for one that supports more of a damaging wind threat than a tornado threat. Given the very strong wind field with some instability, I do think this is a legit severe threat. Damaging winds, hail, and frequent lightning are the primary threat and I would be suprised if a good part of our area doesn't see some severe watches or warnings in the next 30 hours.


SPC Catgorical Risk for Sunday


SPC Day 1 Cat 


SPC Hail Threat For Sunday


SPC Day 1 Hail 


SPC Wind Threat for Sunday


SPC Day 1 Wind 


SPC Tornado Threat for Sunday


SPC Day 1 Torn 


SPC Categorical Risk for Monday


SPC Day 2 Cat 


SPC Probabilistic Risk for Monday (note the higher percentages)



SPC Day 2 Prob 



The bottom line is I pushed for these severe weather risks in my blog on Friday. I feel SPC is in good agreement with what I believe from this event. I do think some severe weather will indeed affect our area in particular late tonight and early tomorrow. I believe damaging winds, hail, and frequent lightning will be the primarly threat. I also believe a flooding risk exists from the extra rain on our soggy grounds. Please avoid driving across all flooded roadways with no exception.