WxSynopsisDavid

Disagree, Idalia does not even have an established CDO yet so what's happening tonight is not in relation to CCC. Idalia's issue is shear ATM. Once convection can stay consistent and shear/minimal dry air can abate, this thing takes off. Pretty much...the vertical column is not stacked yet and that is Idalia's hinderance in the short term.

That link is for TS Franklin, not TS Idalia.

When the circulation becomes vertically stacked you have a Category 1. So of course, circulation is not stacked as we don't have a category 1 yet.

At the very least, I am more interested on the data they collect out ahead of the system across the Gulf. Curious to know if the models are right concerning the non-existence of dry air and the observations yielding decreasing shear.

Agreed, and it is not good that as forecasters we have no limiting factors in play here to discuss. It's come down to how long it lingers near the Yucatan....really feels like dejavu from some of the previous big gulf storms we have forecasted.

Looking at the shear values in the environment around TD 10, there's are a noticeable decrease in shear. Earlier today, the system was completely shrouded in 40kt shear. Now this evening, we see a big time decrease in shear to the northeast and some relaxation to the north. Not a good trend because this falls right in-line with those hurricane models earlier today. They seem to indicate the relaxation of shear this evening/overnight and better organization and development tomorrow.

Angle of approach is concerning, that would be a strengthening Category 3 approaching landfall. Frictional induced intensification through landfall.

Diurnal minimum is correct, this is typically when we see tropical systems lose that photogenic appearance. Big thing here is that during the day the centers of circulation are starting to organize. We are starting to see this system get a tad more symmetrical and some noticeable spin. What we ultimately are waiting for is the low, mid, and upper level circulations to stack. Once this thing starts to ventilate than we will have a better grasp on this system. Big thing everyone should be paying attention to is the environment out ahead of this system. With a lack of dry air and decreasing shear, it sets up a near pristine environment over 90+ degree SST's. There are some noticeable warm eddies in the Gulf too, not to mention how warm the Gulf Loop Current is right now. There are a lot of factors in play working for this thing to take off vs hindering it. With that said, recon data will be vital tomorrow. I'm curious to know if indeed we get an anticyclone development and I'm also curious to know if Recon Hunters find that shear and dry air are more significant than what models are showing.

New couplet to the south, just south of banner

The 3k NAM rolling in right now is equally bad. Tries to pop rogue cells in Georgia while keeping everything else linear.

Something just appears off with these runs this morning. Mixing issues and capping issues are more prevalent right now. Concerning Wednesday, the HRRR has very little STP and parameters for the OH/TN Valley which seems odd.

Wednesday is really starting to look like a Major Severe Weather Outbreak. When the models started to slow the arrival of the front and short wave ejection, it was evident where we were going with this. The activity tomorrow, considering it initiates around or after sunset, will track east and lay down boundaries. Really be interesting to see if a cluster/MCS develops tomorrow night or early morning Wednesday. That tends to always happen the morning of a Major outbreak in the OH/TN Valleys and Great Lakes region.

Overall there’s very little discrete. The models that do have daytime convection tomorrow, it’s either linear or a multi-cell cluster. RAP, RRFS-A, HREF initiates discrete after sunset close to midnight. The tornado threat appears to be primarily nocturnal now. Early Wednesday morning into Wednesday afternoon.

Latest HRRR and RRFS-A showing morning convection going through the warm sector

Synoptically, this setup is different and not similar. This past outbreak actually had similarities and the analog was shown in the soundings. Just not seeing the similarities this time around.

I remember leading up to this past Friday, the HRRR had a few runs where it did that early on but corrected within 18hrs to the start of convection. Also not the first time I've seen the HRRR do this, seems to be a typical bias of the model.

Great analysis and comparison there. With the fail modes in place, April 7 2020 could be the floor. I still believe tonight's event was the "fly in the ointment" that caused the CAM to back off a tad with concerns to Tuesday. Interesting to note, the EURO stuck to the scenario and the RAP and now the HRRR are caving towards the EURO scenario. Will be interesting to see how tomorrow's convection impacts the environment for Tuesday.

That's a substantial trend higher with STP compared to previous runs. Seems like the CAM is having a better handle/grasp on Tuesday now that tonight's event is wrapping up.

I should of chose better terminology when I said struggling. My apologies, but yes I am in agreement with that. Correct me if I'm wrong but the more high-end, severe outbreaks we seen in years past always featured a short wave out ahead of the dryline, early day surface low or mcs, to help breach the cap and lay down boundaries to set off convection.

Factor in the stuff from 3/31 and yes. But concerning 4/1, there's a gap in central PA where there were no wind reports.

Here's another potential thing to think about. The "fly in the ointment" was tonight's event when models started to show a much more significant event for today they backed off for Tuesday. Considering tonight's event underperformed, I wonder if the models will start to go back to a more high end solution for Tuesday with these capping issues and mixing/lcl issues resolved.

Main issue the models been struggling with is the cap. Some models like the RAP now showing the cap being breached hours before sunset. EURO been showing this however. Others like the NAM and HRRR breach the cap at or just after sunset. Interesting to point out, both the EURO and RAP are different in how the cap breaches.

Big tick upwards in parameters on the RAP. NAM seems to be trending to that scenario but still holds convection off until around sunset like the HRRR. This is a promising "potential" trend by the RAP.