Severe Weather Threat May 7th - 13th

[wisconsinwx]

Note the cells now beginning to flourish under the spreading anvils as longwave radiational cooling begins over the anvil tops and the LLJ starts to kick in. If we continue to get development underneath this area, we may see the development of a decent cold pool and thus an MCS.

Do you think that MCS, if it happens, would move SE? The models were in good agreement with an MCS moving across the UP, so that may be what you are looking at developing.

[csnavywx]

Do you think that MCS, if it happens, would move SE? The models were in good agreement with an MCS moving across the UP, so that may be what you are looking at developing.

It has a ways to go, but my guess is if it does, then it would ride out to the east.

[brettjrob]

Concerning tomorrow's potential...

The 0z NAM has development from S. Nebraska down into S. Texas between 15-18z.

Definitely noticed that, and it only makes an already-complex situation that much harder to pin down. The early convection appears to be several counties out ahead of the DL, and is something SPC has mentioned in their outlooks since yesterday.

It seems possible that this activity will develop far enough E and move out early enough not to hinder later development immediately along the DL. But if it does linger too long and/or develops too far W, then it could be trouble.

Overall, I'm becoming a bit less skeptical of tomorrow's potential, as the short-term trends are pointing toward a slightly broader and less sharp/pinched H5 trough evolution. This should keep things a bit less meridional and minimize upper-tropospheric backing with height, at least S of the OK-KS border. Given that (a) early convection does not mess things up too badly, and ( low-level moisture does not mix out too much due to early veering of low-level winds and the drought conditions, I think there's moderate to substantial tornado potential in the DUC-JWG-PTT corridor in the early evening timeframe.

In general, low-level shear improves with northward extent while deep-layer directional shear improves with southward extent, so it will be quite interesting (and nerve-wracking for chasers) to see which wins out. I like the OK section of the DL best right now, but the low-level hodograph size in C and NW KS is fairly jaw-dropping. Things will definitely get somewhat messy, regardless, given the deeply meridional winds and storm motions only ~45° off the boundary.

[Helicity]

Smh at tomorrow in general.

Toughest forecast in my life, especially considering me chasing is conditional on the fact that track practice gets canceled so I have to guage whether that will happen, then pull the trigger after my calc final to head out to PTT.

Whatever.

[ICEHOCEY77]

I'm quite interested on how tomorrow plays out, the NAM is all over the place. Only place that really shows good potential is the Greensburg-Pratt, KS area at 24Z. Guess will have to wait to see how the RUC has it in a few hours.

[k***]

I'm quite interested on how tomorrow plays out, the NAM is all over the place. Only place that really shows good potential is the Greensburg-Pratt, KS area at 24Z. Guess will have to wait to see how the RUC has it in a few hours.

24Z FTW

[Helicity]

I really like what the GFS does with crapvection, pretty much eliminating it from being too big of an issue however its lower level wind fields in SC KS are not as good as one would ahve hoped after seeing the 0z NAM run in.

It also moves the dryline a tad bit further east which is fine with me.

[ICEHOCEY77]

24Z FTW

haha, that's what I get for doing 3 things at once.

[Ian]

im definitely focusing on 24-25z for big action.

[Chicago Storm]

We're already getting development in E. New Mexico/W. Texas as the main wave begins to eject out into the Plains.

[Stebo]

im definitely focusing on 24-25z for big action.

oops

[Thundersnow12]

put me in the HYS-GBD area tomorrow with another possible tornado maxima further south between JWG and LAW.

[JoMo]

Day 1 is out.. Tornado probs

[jcwxguy]

THE MAIN UNCERTAINTY WITH THE FORECAST IS STORM COVERAGE. MOST OF

THE MODELS KEEP CONVECTIVE COVERAGE ACROSS WRN OK AND WRN KS

RELATIVELY ISOLATED. THIS IS PROBABLY DUE TO THE UPPER-LEVEL LOW

WHICH IS FORECAST TO SLOW DOWN CONSIDERABLY...KEEPING MOST OF THE

LARGE-SCALE ASCENT WEST OF THE DRYLINE. AT THIS POINT...THE NAM

SOLUTION AT 00Z APPEARS REASONABLE SUGGESTING THE STORMS MAY TEND TO

REMAIN WIDELY GAPPED. IN SPITE OF THIS...THE SYNOPTIC PATTERN WITH A

STRONG LOW-LEVEL JET RESPONSE...EJECTING MID-LEVEL JET AND

WELL-DEVELOPED DRYLINE SHOULD RESULT IN A HIGHER-END SEVERE THREAT.

FOR THIS REASON...WILL MAINTAIN A MODERATE RISK ACROSS WCNTRL KS AND

WRN OK.

part of day 1 text

[jcwxguy]

new day 2 is out as well

[OceanStWx]

Here is the current satellite/lightning with the 00z raob objective analysis superimposed on top. You can see the edge of the cap roughly approximated by the 8C 700 mb temp.

[SEMIweather]

Does anyone else the crapvection in the Texas Panhandle right now could be a major problem unless it dissipates quickly?

[Helicity]

Does anyone else the crapvection in the Texas Panhandle right now could be a major problem unless it dissipates quickly?

Me, The thing is I don't see it really dying out for a while. Its got decent support

[A-L-E-K]

decent looking MCS rounding the top of the ridge, something to watch for Michigan posters.

cool look aat lake fog. Looks like we'll have a 2-3 more hours of sun before clouding over.

[Ed Lizard]

Mentioned it in Iam thread, but I like a smidge closer to I-35 than SPC, based on SREFs.

Potential big city system. SigTor is maxed on the 03Z SREFs near OKC.

[Helicity]

Mentioned it in Iam thread, but I like a smidge closer to I-35 than SPC, based on SREFs.

Potential big city system. SigTor is maxed on the 03Z SREFs near OKC.

Agreed, ICT isn't looking to bad, which saves me gas.

[Indystorm]

And SPC downgrades risk to slight due to poor handling of the present convection by the models and insolation issues. The potential is there, but this looks like a nowcasting day at present. for KS and OK.

[Ed Lizard]

I think OKC may benefit by not being too badly clouded over by existing convection, as compared to favored SPC areas to the North.

And a little CINH is a good thing, isolated has a better chance of photogenic tornadoes.

[wisconsinwx]

Wow, they just made some major upgrades. Nearly all of Wisconsin is under slight risk, and tornado probs in Southwest and SouthCentral Wisconsin are up to 5%.

[wisconsinwx]

Dewpoints are almost up to 60 even in Milwaukee with the cool lake nearby. Going to be some good destabilization occurring.

[TimChgo9]

SPC has put most of NE/N IL in the Slight Risk, with the exception of the SE counties.

Looking at the Meso Analysis page, looks like the CAPE is there, but so is the cap...Wonder if we will get anything to break through that?

NWS has backed off of the temps a bit, going for mid 80's for a high,. Locally we hit 92.4 degrees yesterday.

[wisconsinwx]

SPC has put most of NE/N IL in the Slight Risk, with the exception of the SE counties.

Looking at the Meso Analysis page, looks like the CAPE is there, but so is the cap...Wonder if we will get anything to break through that?

NWS has backed off of the temps a bit, going for mid 80's for a high,. Locally we hit 92.4 degrees yesterday.

Should still be plenty of moisture. LSX is expecting thunderstorms to break out in their area between noon and 3, and then move north and east from there, so even if the cap doesn't break right in the Chicago area, storms may be able to survive the trek east.

[A-L-E-K]

Wow, they just made some major upgrades. Nearly all of Wisconsin is under slight risk, and tornado probs in Southwest and SouthCentral Wisconsin are up to 5%.

Dewpoints are almost up to 60 even in Milwaukee with the cool lake nearby. Going to be some good destabilization occurring.

I think the prospects for organized severe east of I90 in Wisconsin are pretty low with shear values pretty sucky and best forcing west. As for moisture, looks like another juicy day and you can see some minor pooling of dps along the warmfront in southern wisconsin and northern illinois with ORD at 75/68. It also looks like sbcape will be greater than earlier thought with clouds holding off and a few more hours of good sun likely. Lack of good forcing will keep things in check but anything that does pop up should be an efficient rain producer and have fequent lightening, with a hail threat in the most intense cells.

[wisconsinwx]

I think the prospects for organized severe east of I90 in Wisconsin are pretty low with shear values pretty sucky and best forcing west. As for moisture, looks like another juicy day and you can see some minor pooling of dps along the warmfront in southern wisconsin and northern illinois with ORD at 75/68. It also looks like sbcape will be greater than earlier thought with clouds holding off and a few more hours of good sun likely. Lack of good forcing will keep things in check but anything that does pop up should be an efficient rain producer and have fequent lightening, with a hail threat in the most intense cells.

You're probably right, but they weren't expecting any organized severe when the Day 1 outlook first came out, so it is a positive development nonetheless.

[A-L-E-K]

SPC has put most of NE/N IL in the Slight Risk, with the exception of the SE counties.

Looking at the Meso Analysis page, looks like the CAPE is there, but so is the cap...Wonder if we will get anything to break through that?

NWS has backed off of the temps a bit, going for mid 80's for a high,. Locally we hit 92.4 degrees yesterday.

Reading LOTs discussion, i think they expected cloud cover to overspread the region quicker than it looks like it will. Based off the current vis sat and 75 degree reading at ORD as of 9am, i think they bust too low on the 82 point high.