Absolute Vorticity

Trevor wrote: ↑Thu Jan 19, 2023 2:14 pm

young pup wrote: ↑Thu Jan 19, 2023 1:58 pm T Storm watch with a chance of some snow flurries later. Never have I seen that before.

It’s more common than you’d think. Not out of the ordinary at all around these latitudes. We just haven’t had much in the way of cold season severe events in recent years so it’s easy to forget.

Thanks. Let's hope it is not to severe later on.

SB CAPE and Lapse Rate update:

dce wrote: ↑Thu Jan 19, 2023 2:18 pm

tron777 wrote: ↑Thu Jan 19, 2023 1:36 pm 12Z Euro for next week's system has brief snow and sleet then going over to rain as the low cuts into Western KY then passes SE of Cincinnati. An IND Special on this run. Returning you now to our t-storm coverage in progress.

6 days out. More adjustments to come.

Definitely! I'm almost scared to start any threads. Look at today's severe wx potential with no separate thread started.

Dews around 60 in middle January. These developing cells are going to have some stuff to work with (fuel and wind energy). Also around peak heating for this time of year. Nearly ideal conditions. We shall see!

Hey Trev, you mentioned dew points around 60. I show upper 30's at the moment. Maybe I am missing something here and just wanted to double check. The one thing that can and does happen often is the southwest part of this system is where tornado's can form with a cell by itself. Not saying that will happen but something to watch over the next few hours.

Dews have definitely mixed down as Tim said so that will limit how much instability we can get. However, with the very steep lapse rates, low freezing levels, and very high wind shear, combine that with a few hundred J/KG of CAPE and this event still has the potential for damaging winds and small hail. Tornado risk is low but not zero.

Cumulous field has worked into the area and the showers are not far behind. These things are cooking!

I see the first severe thunderstorm warning just southwest of Muncie

tron777 wrote: ↑Thu Jan 19, 2023 2:36 pm Dews have definitely mixed down as Tim said so that will limit how much instability we can get. However, with the very steep lapse rates, low freezing levels, and very high wind shear, combine that with a few hundred J/KG of CAPE and this event still has the potential for damaging winds and small hail. Tornado risk is low but not zero.

What’s your Dew at down there?

Trevor wrote: ↑Thu Jan 19, 2023 2:44 pm

tron777 wrote: ↑Thu Jan 19, 2023 2:36 pm Dews have definitely mixed down as Tim said so that will limit how much instability we can get. However, with the very steep lapse rates, low freezing levels, and very high wind shear, combine that with a few hundred J/KG of CAPE and this event still has the potential for damaging winds and small hail. Tornado risk is low but not zero.

What’s your Dew at down there?

39

Help me settle something. I shared the Severe Thunderstorm Watch text with my neighbor, highlighting the high winds, and he sent back the wind advisory text from earlier and said it's the local valid source for winds, not the T storm watch... In my mind, the wind advisory is for non- thunderstorm winds. So who's right?

I have a dew point of 38 and has been falling quickly since this morning

tpweather wrote: ↑Thu Jan 19, 2023 2:44 pm I see the first severe thunderstorm warning just southwest of Muncie

Yes sir for 60 mph wind gusts and quarter sized hail. We should be seeing more of these types of warnings popping up as time goes on.

Angelika wrote: ↑Thu Jan 19, 2023 2:46 pm Help me settle something. I shared the Severe Thunderstorm Watch text with my neighbor, highlighting the high winds, and he sent back the wind advisory text from earlier and said it's the local valid source for winds, not the T storm watch... In my mind, the wind advisory is for non- thunderstorm winds. So who's right?

You are correct Ang. The wind advisory was issued for non t-storm winds. A t-storm watch was issued for the potential of storms to create wind gusts in excess of 58 mph.

Per ILN's Criteria page:

Wind gusts of 46 MPH to 57 MPH
...or...
Sustained winds of 31 MPH to 39 MPH for one hour
Issued during non-convective weather

https://www.weather.gov/iln/criteria

Angelika wrote: ↑Thu Jan 19, 2023 2:46 pm Help me settle something. I shared the Severe Thunderstorm Watch text with my neighbor, highlighting the high winds, and he sent back the wind advisory text from earlier and said it's the local valid source for winds, not the T storm watch... In my mind, the wind advisory is for non- thunderstorm winds. So who's right?

Not a met here but Angelika I believe you are correct as the two are different even though you can have both a wind advisory and T storm watch at the same time. The thunderstorm watch is too add possible thunderstorm that can have high winds but also hail,thunder,lightning and even an isolated Tornado.

Angelika wrote: ↑Thu Jan 19, 2023 2:46 pm Help me settle something. I shared the Severe Thunderstorm Watch text with my neighbor, highlighting the high winds, and he sent back the wind advisory text from earlier and said it's the local valid source for winds, not the T storm watch... In my mind, the wind advisory is for non- thunderstorm winds. So who's right?

The wind advisory is for non-thunderstorm related winds. Pressure-gradient winds as we are seeing right now.

The severe thunderstorm watch covers thunderstorm winds.

Thanks guys!

NWS says our low dew points and too much moisture mixing due to winds has killed the severe threat for us and NKY. This may be a non-event in the Tri-State area. Up towards I-70, completely different story.

I checked the SPC's sounding page and the map for the 18Z sounding is there, but nothing from ILN. Only DTW (Detroit) and a couple of others in NY are listed.

fyrfyter wrote: ↑Thu Jan 19, 2023 3:00 pm NWS says our low dew points and too much moisture mixing due to winds has killed the severe threat for us and NKY. This may be a non-event in the Tri-State area. Up towards I-70, completely different story.

So far, the radar around and esp N of IND is way more impressive for sure.

fyrfyter wrote: ↑Thu Jan 19, 2023 3:00 pm NWS says our low dew points and too much moisture mixing due to winds has killed the severe threat for us and NKY. This may be a non-event in the Tri-State area. Up towards I-70, completely different story.

Don’t ruin my fun, Aaron!

But yes they are not incorrect thus far. Struggle bus on any significant convective development.

ILN Sounding finally got posted.

And Louisville just recorded a 50kt gust from a shower. This should be interesting.

As of 3pm, CVG gusted to 38 mph. Dews are down to 34.

This heat miser will take this as a victory regardless. Love me some storm clouds in January.

Having said that, I’d caution against writing this off just yet. As is obvious thus far, some conditions are inhibiting convective development. But there are still several parameters in favor for something to pop. Let’s wait and see.