March 15/16 Severe Wx

[kystormspotter]

Thoughts? 

[HillsdaleMIWeather]

18Z GFS is very volatile,  not showing a super large tornado threat but a >2.75 inch (in Illinois)  hail risk and lot's of damaging winds, especially in North Central IL, 12Z GFS also had a good threat.

 

Sounding west of Detroit

 

[IllinoisWedges]

Haven't looked into it all too much, but I heard there was a big ole cap. Total flip fron 2015.

[HillsdaleMIWeather]

Haven't looked into it all too much, but I heard there was a big ole cap. Total flip fron 2015.

 

Yep, 18Z GFS shows the cap breaking around 06Z on the 16th with convention moving into areas with the high parameters. 

[IllinoisWedges]

Yep, 18Z GFS shows the cap breaking around 06Z on the 16th with convention moving into areas with the high parameters.

Not too excited. Rather have the cap break earlier than at night. Owell, we'll see how it evolves.

 

00z GFS demonstrates that there still are some kinks to work out, atm.

[HillsdaleMIWeather]

0Z GFS still has the threat.

[andyhb]

Thanks for the great information.

[HillsdaleMIWeather]

Thanks for the great information.

 

No problem buddy.

 

To go more in depth:

 

0Z GFS shifted highest instability to the southeast, still looks like a pretty decent hit for most of the subforum.

[tornadohunter]

0Z shifted surface low NNE. 988 Centered over minnesota. 

18z had 986 surface low over Eastern Nebraska. 

 

0z backed off on instability like hillsdale pointed out. 

 

Definitely some drawbacks right now but this is worth keeping an eye on 

 

 

 

 

...D7-8/TUE-WED IN THE CNTRL STATES...
GUIDANCE IS FAIRLY CONSISTENT WITH A LARGE-SCALE UPPER TROUGH
DEVELOPING INTO THE WEST EARLY TO MID WEEK. HOWEVER...SUBSTANTIAL
DIFFERENCES EXIST IN THE DEPICTION OF VARIOUS SHORTWAVE
TROUGHS...RENDERING LOW CONFIDENCE IN THE SYNOPTIC PATTERN FOR A
GIVEN DAY. NEVERTHELESS...OVERALL SETUP SHOULD RESULT IN POLEWARD
LOW-LEVEL MOISTURE TRANSPORT BENEATH AN EML PLUME FROM THE WRN GULF
TOWARDS THE UPPER MIDWEST. ONE OR MORE SLIGHT-RISK AREAS WILL LIKELY
BE IDENTIFIED IN LATER OUTLOOKS ONCE CONSISTENCY INCREASES REGARDING
INDIVIDUAL SHORTWAVE FEATURES.

[andyhb]

But really it isn't, the trough is quite flat with rather weak wind fields and very poor boundary layer moisture depth. This thing is going to have to slow down a bit and drop further south initially to encourage more poleward moisture transport and amplify the LLJ axis.

[nwburbschaser]

0Z GFS still has the threat.

The 0Z GFS would represent just about the weakest case scenario because it's too fast for anything significant to happen. I haven't looked, but I'd imagine that the ensemble mean is a bit slower, but I could be wrong on that. 

[RCNYILWX]

No problem buddy.

To go more in depth:

0Z GFS shifted highest instability to the southeast, still looks like a pretty decent hit for most of the subforum.

In all honesty, please read more and post less until learning more. There's several very knowledgeable posters on here whom which you could learn a lot from. I've learned a lot myself from reading on this subforum and others over the years in addition to on the job experience. You're very interested in the weather obviously as we all are, but it takes away from the discussion (and can/does annoy others) to recite what you think a model is showing without having a stronger meteorological reasoning/backing behind your thoughts. I think you could get to that point by reading here and elsewhere.

[Stebo]

In all honesty, please read more and post less until learning more. There's several very knowledgeable posters on here whom which you could learn a lot from. I've learned a lot myself from reading on this subforum and others over the years in addition to on the job experience. You're very interested in the weather obviously as we all are, but it takes away from the discussion (and can/does annoy others) to recite what you think a model is showing without having a stronger meteorological reasoning/backing behind your thoughts. I think you could get to that point by reading here and elsewhere.

Thank you, you said what I was about to post.

[weathergy]

Not sure if anyone's mentioned this yet anywhere else, but the sustained wind field on the 18z GFS is awesome.

 

[IllinoisWedges]

Not sure if anyone's mentioned this yet anywhere else, but the sustained wind field on the 18z GFS is awesome.

 

sfcmw.png

I mentioned it on the old Twitter. I'd take that over a mediocre severe event in March, for sure. Winds above the surface are also awesomesauce. (Is that even a thing anymore?)

[andyhb]

Someone in the Lakes would be having a rather serious problem looking at the 00z GFS/UK runs in for next Tuesday if it weren't for the poor BL moisture depth. That low deepens 15 mb between 96 and 120 hrs on the GFS. Would need it to slow further for a higher threat.

[HillsdaleMIWeather]

Someone in the Lakes would be having a rather serious problem looking at the 00z GFS/UK runs in for next Tuesday if it weren't for the poor BL moisture depth. That low deepens 15 mb between 96 and 120 hrs on the GFS. Would need it to slow further for a higher threat.

0Z Soundings around hour 117 are really interesting, especially around Indy

[HillsdaleMIWeather]

SPCs thoughts

...DISCUSSION...

...D5/TUE IN THE MIDWEST...

CONSISTENCY HAS INCREASED SUBSTANTIALLY AMONG GUIDANCE WITH THE

DEPICTION OF A SHORTWAVE TROUGH AMPLIFYING OVER THE LOWER MO VALLEY

TO GREAT LAKES AREA. THIS WOULD RESULT IN PRONOUNCED CYCLOGENESIS AS

A POWERFUL MID-LEVEL JET INTENSIFIES IN THE MID-MS VALLEY TO

MIDWEST. BOUNDARY-LAYER MOISTURE WOULD PROBABLY REMAIN MODEST WITH

PREVAILING LOW-LEVEL WLYS IN PRECEDING DAYS ACROSS THE NRN GULF.

THIS MAY ONLY YIELD WEAK BUOYANCY ACROSS THE MIDWEST. BUT GIVEN THE

STRENGTH OF THE DEEP-LAYER WIND FIELD...POTENTIAL EXISTS FOR A

FAST-MOVING STRONGLY FORCED CONVECTIVE LINE. WILL AWAIT ANOTHER DAY

TO SEE IF THIS MODEL TREND HOLDS AFTER POOR PREDICTABILITY IN 10/00Z

DETERMINISTIC GUIDANCE AND STILL MODERATE SPREAD FROM THE 11/00Z

ENSEMBLE RUNS /ALBEIT CLEARLY REDUCED FROM THE 10TH

[IllinoisWedges]

4-8 day mentioned the possibility of a forced convective line due to the wind fields. Also mentioned how confindence has increased and they were going to wait another day before intoducing a risk to see if it withstands. So it begins.

[andyhb]

12z GFS is closer to getting a rather significant severe threat into the region. Looks like the trough in some of these recent runs has a bit more equator-ward extent initially, which pulls slightly better deep moisture over a wider axis. Check out this EML plume at 105 hours.

 

[JasonOH]

One thing to note, and this is based in the GFS, is a cap. There appears to be forcing, but we will have to see if the presence of the cap/inversion forces the storms to be elevated. There is excellent turning in the hodographs, with increasing winds and veering all the way to 300mb, so no sickle shape. Overall, this setup looks decent based on the GFS only. Based on this, i would expect a squall line along the cold front, and possibly some supercells IF the cap/inversion does not materialize. I do not have access to the EURO so i do not know what it shows.

Edit: I'll be back in Ohio for spring break which is why I'm so interested in this. I don't want to jinx this since my last issue with a cap eneded in a blue sky bust on Monday in Western OK.

[ClicheVortex2014]

I'm impressed by the forecast parameters for the lower OV. Especially for GFS's standard of underestimating moisture. 

 

But to my untrained eye, it looks like the warm/dry layer between 850mb and 700mb may be a limiting factor for tornadoes. Am I right, and/or is it something to be concerned about regarding tornado potential? No doubt, if that layer was cooler/more moist, this would be a very ugly setup. The parameters would probably be reminiscent of March 2.

 

 

Also... any early thoughts on storm mode?

[andyhb]

But to my untrained eye, it looks like the warm/dry layer between 850mb and 700mb may be a limiting factor for tornadoes. Am I right, and/or is it something to be concerned about regarding tornado potential? No doubt, if that layer was cooler/more moist, this would be a very ugly setup. The parameters would probably be reminiscent of March 2.

 

Well the main problem is that the boundary layer moisture still isn't quite where it needs to be in order to break that cap. Further into IN looks a bit more uncapped via forecast soundings (probably because there isn't as much of a warm nose between 850 and 700). Still think this needs to slow more in order to really be able to tap the shear profiles displayed here.

[ClicheVortex2014]

Well the main problem is that the boundary layer moisture still isn't quite where it needs to be in order to break that cap. Further into IN looks a bit more uncapped via forecast soundings (probably because there isn't as much of a warm nose between 850 and 700). Still think this needs to slow more in order to really be able to tap the shear profiles displayed here.

Indeed. And the parameters in Indiana aren't bad either. The warm layer decays as the day progresses... so, if GFS is right, there may still be a window of opportunity for the cap to be weak enough between 21z and 00z so that storms could form south of the Ohio River.

 

When you get to 00z, the problem is no longer the warm layer... it's more of a surface-based problem. Sounding for SW OH:

 

 

It'll be interesting to see what NAM does. 

[Stebo]

Well the main problem is that the boundary layer moisture still isn't quite where it needs to be in order to break that cap. Further into IN looks a bit more uncapped via forecast soundings (probably because there isn't as much of a warm nose between 850 and 700). Still think this needs to slow more in order to really be able to tap the shear profiles displayed here.

Yeah eventually the ascent would bust that warm layer which would lead to explosive development, the more moisture added the more severe the potential would be.

[JasonOH]

Another thing to note is that the GFS is terrible with BL moisture.  We will need to wait for the NAM or look at the EURO to get a better feel for the BL environment. Slowing the system down would help a lot, especially with my confidence of moisture return.

[andyhb]

Another thing to note is that the GFS is terrible with BL moisture.  We will need to wait for the NAM or look at the EURO to get a better feel for the BL environment. Slowing the system down would help a lot, especially with my confidence of moisture return.

 

From what I've seen, the Euro has even poorer moisture than the GFS.

 

Edit: And that doesn't look to change with the 12z run. It is just so flat, there is barely any amplification whatsoever.

[RCNYILWX]

From what I've seen, the Euro has even poorer moisture than the GFS.

Edit: And that doesn't look to change with the 12z run. It is just so flat, there is barely any amplification whatsoever.

This. Very low confidence forecast because of the variance in the operational and ensemble guidance. The 12z GEM has a stronger wave but still much flatter with the trough and surface doesn't deepen much. So it's still far away from the amped up 12z GFS solution. On the 12z ensembles, the GEFS is even more amped than the operational run, while the Canadian ensembles only have 2 very amped members. Will be interesting to see the 12z EPS rolling out shortly.

[ClicheVortex2014]

Even 12z Euro has enough instability in the lower OV for at least a decent looking squall. 

 

It is weird to see the GFS showing the most aggressive solution. Not sure what to think.

[HillsdaleMIWeather]

Dr Forbes has a 3-4 TORCON on Tuesday, likes a large squall line idea it seems