Thursday, April 22, 2010

Tornado Threat Increasing Rapidly Today and Tomorrow...Finally

Spring has finally arrived here in Canada with leaves showing their light green faces all over the Capital region of Alberta. Dave in Winnipeg has also reported some leaves starting to emerge in and around the city. What has been an early Spring for us has been an earlier Spring for people in the Southern Plains...albeit a quiet one.

Things are about to change today as a Low Pressure system moves in from Colorado setting the stage for a two, possibly three day severe thunderstorm outbreak. All facets of severe weather can be expected today and especially tomorrow.

I don't want to really get into the meteorology leading up to my decision about where the greatest tornado threat would be, but I will say that areas 50 miles North, East and South of Childress, Texas look amazing in terms of tornado potential.

A Warm front play is uncertain today because of cloud cover (tomorrow looks amazing). The greatest play would be in the Eastern Panhandle area of Texas where I think the dryline will bulge out allowing discrete storm development ahead of it. Shear profiles are great with capping being removed by 21z. Forcing along the dryline should trigger development by around 3pm CDT. Storms should rapidly begin rotating as they move East into juicier air. As cloud bases drop in the increasingly moist boundary layer, the attendant tornado threat will increase and I think the tornado show should begin around 5pm CDT. We have the 4 ingredients today...moisture, instability, shear, and a trigger. RUC models do show the cold front catching up to the dryline eventually, if the two forcing features stay separated, similar target areas might see a one-two punch, with the tornado threat and all modes of severe weather first, then a large hail and wind threat during the late evening/overnight hours.

Remember, tornadoes will likely occur in other areas today, I'm just addressing where I think the greatest potential will exist. Here is where I think the long lived tornadoes might develop. My name is F5's only for a reason...

Tomorrow is another story...this could actually be the bigger story in terms of the area affected. Moderate to high risks might be tagged on tomorrow's outlook once the Low takes shape and models get a better handle on the situation poised to unfold tomorrow. If cloud cover moves off and if convective boundaries from today's convection exist...then tomorrow could be a tornado outbreak for the books. My best bet for large cyclical supercells capable of producing long-tracked tornadoes will be centered 50-75 miles North, East, South and West of Falls City, Nebraska. Here the warm front may the the culprit for several tornadoes. I will go into more details tomorrow, but for interested readers...look at the Pipestone, Manitoba tornado from June 23rd, 2007 or the Aurora, Nebraska tornado from June 17th of last year. Those were warm front initiated tornadoes...and they were good'ers.

To chasers...remember warm front plays are tricky. DO NOT CHASE a storm that is way ahead of the warm front. It may look good on radar, but it will not produce a tornado...I REPEAT...it will not produce. The supercell is elevated which simply means that it is not tapping into air from the surface...therefore a surface based circulation cannot exist. A storm forming near the warm front that reaches the warm front is the golden ticket to the main event. It will be elevated initially but as the storm moves toward the boundary or if the warm front lifts to where the supercell is...then the storm can tap into surface based instability where a tornado threat can rapidly increase. Again, warm front plays are tricky...they can be unsuccessful most of the time due to storms forming ahead of the front and staying there with only a large hail/strong wind threat existing for hours. If one does root into the boundary layer along the front or south of it...then get ready for a major league tornado. I've been a bit repetitive here...I just want to burn it in the readers minds that warm fronts can fool many chasers. For further details about warm front plays...maybe Dave can shed some light on this matter.

Anyways...that's it for now...good luck out there to anyone chasing...it should be a good one...and if today doesn't work out for you...well then you have tomorrow.

7 comments:

  1. SPC has upgraded to a Moderate Risk for tomorrow. They are thinking an outbreak of tornadoes may occur around NE TX, Northern LA and Southern Arkansas during the late evening/overnight hours. The Low Level Jet really gets going tomorrow evening so the moisture transport will really get going creating a moisture laden boundary layer. Combine these lower cloud bases with instability, amazing wind fields, and lift...well then you have the ingredients for a tornadic storm.

    The area in Southern Nebraska still looks great for tomorrow...I'm still holding my target area to be centered around Falls City, Nebraska!

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  2. For chasing, yes. But I also agree with the SPC on upgrading. 2 reasons I'd have to be dragged kicking and screaming to chase there:

    1) Bad chase territory in terms of rolling hills and trees everywhere
    2) Fast-moving storms

    Looks like I'd meander east today, as the better moisture is just not sticking around. As I type this Amarillo is 21/14, whereas Childress is 19/16 and there are 17 and 18 dews to the south and east of there.

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  3. Tornado watch for farther north along the warm front in Kansas and Colorado.

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  4. Tornado reports in Colorado now. Looks like the moisture made it. I guess capping wasn't an issue in the warm sector. Ahh, warm fronts. I am still favoring the dryline set-up later on though. The big storms should fire around Childress around 3pm with tubes by 5pm...lol! Dewpoints are already in the 60's with temps in the 70's. Bring on the dryline. Any storms that fire and remain discrete will be well-oiled tornado producing machines...guaranteed!!!

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  5. Moderate risk. Nice.
    Some of the storms in SE CO look pretty good, but I'm still betting on the TX play.

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  6. Moderate risk now in the eastern Texas panhandle/western Oklahoma. With the low level jet kicking in later on into this evening, it will be interesting to see if any storms do decide to go tornadic. (Almost seems like a given.) Reports via Stormtrack say there was a large cone tornado on the ground for a few minutes in Colorado earlier.

    Awesome blog guys...!

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  7. Not long now before the first tornado touches the ground along the dryline. Ahh I want to be there so bad. Reminds me of May 2008...the WaKeeney and Quinter, Kansas tornadoes.

    My new center point extending 30 miles around the point would be at Memphis, Texas.

    Check out that chaser convergence!

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