04/29/05: TALK: OK/MO/AR/IL/KY/TN

[nickgrillo]

I'm getting ready for Friday to potentially become a large event, possibley a outbreak across AR/MO. A few NWS offices are already taking notice of the major changes, and Jackson hits the potential pretty good....

Originally posted by Jackson NWS HWO+--><div class='quotetop'>QUOTE(Jackson NWS HWO)</div>

ANOTHER POTENT DISTURBANCE WILL MOVE OVER OUR REGION FOR THE WEEKEND AND TRIGGER STRONG TO SEVERE THUNDERSTORMS AS A COLD FRONT MOVES ACROSS THE AREA. THE EXPECTED POSITION...AMOUNT OF MOISTURE...AND STRENGTH OF THE SYSTEM HISTORICALLY SUPPORTS STRONG TO SEVERE THUNDERSTORM DEVELOPMENT.[/b]

<!--QuoteBegin-Paducah NWS HWO
STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE...ESPECIALLY ON FRIDAY AND FRIDAY EVENING.

No such thing as a target when a system is still 3 days out, but I'd pick Eastern AR, or maybe north towards Southeast MO...

..Nick..

 

[Marcus Opitz]

That area of the region is very hilly, The bootheel of mo is good and flat though.

 

[Robert Dewey]

Too early for me to put any real forecast in the FCST thread, but the current NAM would produce quite a bit of severe weather, with a high probability of tornadoes. We will see if this pattern holds...

 

[Mikey Gribble]

Storm motion could be a serious problem with this setup.

 

[nickgrillo]

Originally posted by Michael Gribble
Storm motion could be a serious problem with this setup.

How so?

 

[Mike Hollingshead]

Michael Gribble wrote:
Storm motion could be a serious problem with this setup.


How so?

http://www.wxcaster2.com/CENTRAL_ETA_ATMOS...MOTION_84HR.gif

 

[Nic Wilson]

The NAM is forecasting the spring's most intense 500 mb jet, extending 60 to 70 kts from LA, AR, MO, KY, TN to IL with 85 to 90 kt jet core lagging in central TX. This will create some very favorable kinematics for storm development, but not so much in the means of "storm chase-ability". Long-track tornadoes are more favorable in these set-ups, largely because of the increased distance traveled by the storm during the same time duration.

A tornado on the ground for 15 minutes moving at 60 knots will travel 17.3 miles as opposed to one moving 20 knots that will only cover 5.8 miles.

Definitely an interesting set-up with this persistent upper-level low setting up in Manitoba over the next day or two. Action won't be centered on the Southern Plains for the foreseeable future.

 

[Robert Dewey]

Originally posted by Michael Gribble
Storm motion could be a serious problem with this setup.

Agreed. This setup looks more like an "intercept" type of event, but if I was down in the area, I sure wouldn't miss it! Latest 18Z NAM looks like it's similar to the 12Z, but it's really the 00Z and 12Z runs that dictate any significant trends. NAM also shows good moisture return from the Gulf... We shall see...

 

[Ben Prusia]

Latest 18Z NAM Run shows the Low has deepened again at 0Z Saturday, down to 992mb, centered in extreme southern Illinois, near Cape Girardeau, Missouri. Combined with fast storm motion speeds, this thing is gonna be a mover!

 

[Mikey Gribble]

I just glanced over the NAM for Friday and it looks like storms will form East of the surface low and along the warm front. Storm relative helicity will be unreal along the warm front. With the storms moving that fast, if I decided to go I would setup in southern Illinois/SE Miss. and try to catch them as they tracked along the warm front. I don't know if I am willing to drive that far for storms moving that fast though.

 

[Matthew Havin]

CPC NCEP has updated their discussions for the event...

http://www.cpc.ncep.noaa.gov/products/pred...ts/threats.html

 

[Ben Prusia]

GFS is trending back towards a previous run in the latest 18Z run for 0Z Saturday. The GFS is having a hard time gripping this system as it had bounced the system around from being centered in Oklahoma at 0Z Saturday, to have it centered at the Mississippi River at 0Z Saturday. Now, it's about midway from the two.

Looks like we just gotta wait until Thursday before the models can agree on this one.

 

[Robert Dewey]

Posting here again, as this isn't really a forecast... The past three runs of the NAM have pushed the SFC low further southeast each run... This latest 0Z run is roughly ~170KM further southeast than the 12Z run. GFS also trending further south and east, and deeper than the previous 18Z run...If this trend continues, the threat for severe weather will likely be too far south and east into non-chaseable terrain. Given that this system is embedded within the northern stream trough, it will likely make a sharp hook to the northeast, shooting it up into the upper Ohio valley.

Not that this belongs in the Target Area, but given the strength of the system, and the trend in the models, it looks like mother nature could play another cruel joke on the Great Lakes area with a bit of snow - If only we could push this beast westward, and advect some mid 60's td's in, we would have a Palm Sunday goin on!! :roll: :lol:

 

[Mikey Gribble]

It looks like there might be a problem with morning precipitation with this system. At 12Z there is widespread precipitation. It looks like rain along the front could be fueled all morning by the low level jet. Someone else who knows a little more might want to comment on this.

 

[George Tincher]

Well, I subscribe to a bunch of forecasts. Checking this morning's, it seems nearly all of them are similar, in thinking this is going to be a big deal.

Larry Cosgrove says this system is very similar to the one that affected much of TN on April 16, 1998 (the Nashville F3 day and the F5 farther S). He also seems to think Saturday will be potent as well across the SERN US. He says it may be the most potent threat of the year so far.

Andrew Revering's forecast is also calling for significant severe weather. His full forecast is in the fcst thread.

I have yet to see Robert Lattery's forecast. But I'm sure it will be similar when it arrives.

The one constant with this one is that nearly everyone agrees it will be a big severe weather producer. Apparently, so does the SPC. They have a 25% hatched area on their day 3 with the mention of long track tornadoes possible.

This keeps getting more interesting. I certainly feel Friday may be a pretty big deal if things continue to look the way they look now. Right now, ERN AR appears to be the bullseye, at least in my opinion. Little Rock to Memphis better be on high alert Friday, as well as surrounding areas. It's looking like this will at the very least be a solid moderate type day, maybe more.