06/13/05 FCST: Central US

[tom hanlon]

Curious about the setup for Monday. I imagine that this one is hard to forecast.

The remains of Arlene will somewhere along the Ohio Valley. A surface front will be sitting S to NE along the plains with a couple of surface lows. I found one AFD or HWO for the IL/IA region that discussed an upper level disturbance with negative tilt coming through the area.

I like the looks of IL or Iowa for Monday. Dewpoints will be high although the north flow around the back of Arlene makes for a potentially convoluted mix of dewpoints and surface temps. Cape is plentiful.


Cloudcover and heating will be the tricky part along with the movement of Arlene. I do however see some potential in the interaction of Arlene and the systems in the plains.

From the ST Louis HWO
...EARLY NEXT WEEK AS SEVERAL UPPER LEVEL DISTURBANCES MOVE THROUGH THE REGION. THESE DISTURBANCES WILL ACT UPON VERY WARM AND UNSTABLE AIR ENTRENCHED OVER THE MID MISSISSIPPI VALLEY TO PRODUCE STRONG THUNDERSTORMS.

From the Quad Cities AFD
MONDAY...MODELS SUGGEST THAT THE MAIN CHUNK OF UPPER ENERGY IN THE SOUTHWEST WILL BEGIN LIFTING NORTHEAST...POSSIBLY NEGATIVELY TILTED. THIS SHOULD BE THE PERIOD OF HIGHEST PREDICTABLE COVERAGE IN THE NEXT SEVEN DAYS. ALSO...DEPENDING ON TIMING...SIGNIFICANT SEVERE WEATHER MAY ALSO RESULT MONDAY AFTERNOON AND EVENING.

Central IL HWO..
A RENEWED THREAT ON MONDAY NIGHT AND TUESDAY AS A FRONTAL SYSTEM MOVES SOUTHEAST ACROSS ILLINOIS, AND THE REMNANTS OF ARLENE DRIFT OVER EASTERN ILLINOIS.

 

[beaudodson]

We are defin watching Arlene down here in the Paducah, Kentucky area. Appears that the system is going to track slightly east of PAH. The highest probability of tornadic storms would be across Central/Western Tennessee and into portions of Central and Western Kentucky. It appears this would be slightly east of Paducah. This would be Sunday and Monday.

If we can get some heating then I would think Monday would be a pretty active day for portions of the Missouri and Ohio Valleys. Wild card is Arlene and just how fast she moves through. Birmingham, Alabama, NWS, believes Arlene won't be moving as fast as some forecasters think. Read their AFD from this morning and last night.

 

[tom hanlon]

Arlene seems to be more or less on track. North of the Ohio I am not so much looking for Hurricane spawned tornadoes off of the front right flank of Arlene but looking for the interaction of the Arlene's advection combined with the system in the plains to produce some action.

Not that Arlene won't spawn some tornadoes, she might but I expect that today and perhaps tomorrow. I doubt that Arlene will have enough shear by Monday to have tornadoes on the right flank.

The action I am hoping for may get pushed back till tuesday but East of the Mississippi we certainly have a chance for some action as a surface low on the plains moves interacts with the remains of Arlene.

From the NE IN HWO
A MORE SIGNIFICANT SEVERE WEATHER THREAT IS EXPECTED ON MONDAY AND TUESDAY AS THE REMNANTS OF TROPICAL STORM ARLENE MOVE NORTH AND INTERACT WITH A STRONG STORM SYSTEM APPROACHING FROM THE WEST.

Will need to watch the timing of the low as it moves out of the plains. Destabilization will of course be an issue cloud cover will most likely be the cause of a bust. Cloud cover and too much moisture are the cause of most Great lakes busts.

--
tom hanlon

 

[Alex Lamers]

I'm also looking at somewheres in the WI/IL/IA vicinity for a good nader or two. Theres a warm front that won't be moving very fast in any direction with screwed up flow from Arlene's remanants (northeasterly across N Lk MI will keep the wf south) and also the fact that the low will probably occlude and become closed off and stall. I think theres a good chance of a tornado somewhere from IA through S WI and N IL near the wf...then squall line evolves from supercells and pushes east across the area in the evening and overnight.

Day 2 outlook moderate risk? It's possible. We shall see.

...Alex Lamers...

 

[tom hanlon]

Well the SPC places a slight risk in the Iowa and surrounding states. They mention Supercells but I ran a few forecast skew-t's for the region in question and I see good severe weather but not supercells. Not questioning the SPC forecast just not seeing enough of the forecasts "few" supercells to give me confidence that I will get to chase a supercell. I hope to get lucky of course.

So quick development into a squall line is my prediction unless something changes. Nice low LCL though throughout the region and I like that.

As I chase from Ohio I may target central IA. If I lived further west I would target NW IA and prepare to head E or SE.

As for finding something more focussed to target on.... I think that will have to wait til Monday morning. Models are still not in agreement and todays convection will play a role.