Absolute Vorticity

MVWxObserver wrote: ↑Mon May 06, 2024 3:35 pm

tron777 wrote: ↑Mon May 06, 2024 10:16 am

cloudy72 wrote: ↑Mon May 06, 2024 9:11 am High risk issued for parts of Oklahoma today!

Could Moore, OK get whacked for yet a third time??? Sure hope not. Prayers for sure go out to those folks! I read the discussion from the SPC and it makes you go

Hi Les,

Moore is where our weather friend Jeremy Moses e.g. resides. He's a northern KY native.

Yep! He moved out there and is with Corey Ecton if I remember correctly. Corey is an avid storm chaser. I am sure he is going to be very busy doing that very thing with this event.

Good afternoon folks! Great posting as usual this afternoon and I thank everyone for chipping in around here! Been seeing some light rain here at home for the last hour or so since I got home from work. Updated totals as of 5pm....

CVG - 0.09"
Me - 0.12"
Boone Co Mesonet - 0.38"

Radar is rather busy from Cincy and points south with everything drifting to the north. There is a weak low down in East TN tracking NE so the flow around that shortwave is kind of our storm motion at the present time. The more unstable air, better lapse rates, wind shear etc. is poised off to our SW. Once the warm front moves NE tomorrow, we will start to get into a better air mass for severe wx. I like the SPC's Outline for tomorrow and also what Tim mentioned about the warm front. I am certainly in agreement with the better severe threat being to our north closer to where the warm front is forecast to be by tomorrow afternoon and evening. The threat for all of us is there, but the greatest threat for large hail and especially tornadoes, will be in the vicinity of the warm front. Specifically for Cincinnati and the Tri-state, our degree of instability is in question because of a decaying complex of storms that should move in sometime tomorrow morning / late morning timeframe. How much of this activity will remain intact as well as the degree of cloud cover is in question. Definitely worth keeping an eye on things most certainly esp for our I-70 Crew as mentioned.

Then for Wed... we'll see how things go but I think we will see some sunshine on Wed leading up to a volatile set up with that deepening surface low moving thru the region as I've said for days and days now. We have a very busy 48 hours plus ahead!

tron777 wrote: ↑Mon May 06, 2024 5:16 pm

MVWxObserver wrote: ↑Mon May 06, 2024 3:35 pm

tron777 wrote: ↑Mon May 06, 2024 10:16 am

cloudy72 wrote: ↑Mon May 06, 2024 9:11 am High risk issued for parts of Oklahoma today!

Could Moore, OK get whacked for yet a third time??? Sure hope not. Prayers for sure go out to those folks! I read the discussion from the SPC and it makes you go

Hi Les,

Moore is where our weather friend Jeremy Moses e.g. resides. He's a northern KY native.

Yep! He moved out there and is with Corey Ecton if I remember correctly. Corey is an avid storm chaser. I am sure he is going to be very busy doing that very thing with this event.

Nice dose of rain once again here and for the day 0.44 which gives me 2.25 since Saturday morning. Looks like folks in southwest Ohio east of Clermont county getting hit hard again and folks in southeast Indiana. These batches of showers and thundershowers are slow moving so if you get hit with one that last a few hours the totals add up. I know some folks are still under 1/2 inch since Saturday but hopefully before all is said and done this week everyone is in the 1-3 inch range and yes some folks probably closer to 4.

Parts of the central plains as expected getting hit with severe weather.

CVG got to 75, DAY 73 and CMH 70 on Mon.

Good morning all! CVG's event total is now up to 0.64". 0.72" at the Boone Co mesonet and around 0.70" here. These totals are since May 4th. After a foggy start this morning, showers and t-storms will once again be likely from around midday onwards thru the evening hours. All Locations are now under the enhanced risk area today for 10% hatched tornadoes, 15% wind and 10% hatched for hail. Keep a weather eye to the sky folks this afternoon and evening!!

For tomorrow, the worst of the weather should be to our south. An enhanced area for NKY on south and a slight risk to the north. My thoughts all along were that Wed was going to be the worst of it. That looks to be wrong and it's going to be today per the SPC outlooks anyway.

6Z Hi-res models bring in convection during the early afternoon (a weakening trend) then we get the bigger storms later this evening. We'll see I guess how things go. Sometimes it is just better to NOWCAST and we will probably need to check soundings today and SPC Mesopage / radar etc.

Latest thinking from the boys:

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Vigorous low pressure over the northern Plains will lead to a moist
southwest flow of air across the Ohio Valley today. A decaying band
of showers with isolated thunder is expected to slide east through
the region late this morning through early this afternoon. Severe
storms are not expected with this band.

As a shortwave is ejected northeast from the southern Plains into
the Ohio Valley, an increase in mid- level flow and backing low-
level winds will be seen in the vertical profile by later in the
afternoon. A surge in warm, humid air will likely occur just ahead
of the shortwave`s arrival. Forecast soundings from the HRRR are
concerning, with surface CAPE late this afternoon into the early
evening approaching 2,500 J/kg and effective shear reaching around
60 knots. Curved hodographs lead to effective SRH exceeding 200
m^2/s^2.

The latest guidance suggests a less forced environment late this
afternoon, so scattered, discrete supercells are expected. All
hazards appear likely with these storms. High temperatures will
reach into the upper 70s to lower 80s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
A cold front associated with the shortwave will shift east across
the local forecast area late this evening through midnight. While
hodographs are a bit less curved for this period, an increase in
forcing leads to higher coverage of thunderstorms, and likely a more
organized linear mode. Can`t rule out some embedded supercells as
well based on persistent bulk shear ahead of the front.

The shortwave will exit to the east late tonight, leading to a
quieter conditions extending into Wednesday. Bright May sunshine
allows high temperatures to exceed 80 degrees across the middle Ohio
Valley. We may see some increase in cloud cover late in the period
as another shortwave begins to eject northeast into the middle
Mississippi Valley.

Good Morning Les and both days seem very likely for some severe weather. One key item from the boys and that is a sudden surge in the warm humid air and these almost always leads to thunderstorms and then we wait see and how strong they actually end up being. A nice foggy morning as expected in my hood. Will start looking into more items this morning and yes this is likely going to get very busy by late afternoon

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Just starting to look at the overall picture the next 3 days. I believe the one item that is sort of on the back burner in this set up is flooding. The flooding could be flash flooding which is the worse since you have very little time to see it coming. Not sure how much some of the areas in Adams county and nearby counties have received but quite a bit and even in my hood 2.25 so the ground is saturated. We saw some training of showers and thundershowers late yesterday afternoon and that looks less likely today I believe once again it picks up on Wednesday and really late at night and early Thursday could be a period of the heaviest rainfall. By later Thursday hopefully most folks are in that 1-3 total since Saturday but my guess is some folks could reach over 5 inches by Thursday and even the upcoming weekend does not look completely dry. This is my thoughts just on the flooding chances and will look more into the other types of severe.

Hey Trev.... those maps look good my friend! Nice work! I believe the next update from the SPC comes out at 9am with regards to today's convective outlook. We should be able to see the morning sounding from ILN as well.

For now... great post Tim with regards to flooding. The ground is saturated in a lot of areas so any additional heavy rainfall, which we know is likely the next 2-3 days.... is just going to aggravate the situation. We continue to be active even after this week. Saturday is looking fairly wet in the afternoon with that cold front dropping in from the NW which will reinforce the trough already in place behind Thursday's cold front.

A lot of clouds out there this morning / fog per the visible satellite picture. However, there will still be plenty of dynamics in play especially with the warm front later this afternoon and evening. All of the good shear, helicity, and CAPE are along and SW of the warm front in the warm sector which is currently located over Western KY, SW IN, and East Central ILL regions. We will have to wait and see how long the convection to our West can hold up as it races towards the OV today. I don't think we will see any severe wx with that approaching line as it will have outrun the best dynamics as well as CAPE by then. The line is approaching Central ILL into SE MO as of this post and whatever is left of it, should arrive around midday to early afternoon. Once it passes, then we get that surge of warm, humid, and more unstable air that the boys were talking about in their overnight AFD. We should then see a round of strong to severe t-storms sometime this evening IMO. As always, things can and do change in weather but this is my latest thinking right now. Most of the hires guidance I have seen has scattered storms late this afternoon and early this evening with the more potent line approaching later this evening in that 9-11pm window. Things should be calming down after midnight tonight.

We get a break for Wed as things heat up. With the approaching surface low, we should get another good round of strong to severe storms overnight Wed night. That action ends with the passage of a cold front sometime Thurs morning. Then we get the upper low Thurs afternoon and evening with a small shower chance. Friday now looks to be dry but much cooler in the 60s with lows in the 40s. Another cold front for Sat with likely POPS in the afternoon. Sunday should offer up a small shower chance in the afternoon with continued cool weather. Finally... by early next week we dry out a bit as the 70s return along with some sunshine. Next week continues to look fairly active through so the break IMO will be short lived. Just a brief synopsis folks of the pattern over the next week and change.

Yeah tomorrow is questionable for sure. It’ll be close. Best threat is south but we still stand a risk for isolated to scattered severe up this way.

6Z Hires NAM sounding near CVG valid around 8pm this evening. Pretty concerning...


6Z HRRR also agrees!


These are model projected soundings don't forget. But man... this could be a very busy evening if this is even close to being correct. 12Z Hi res guidance will be very important once we get a peak at it. Below is the 3Z SREF significant tornado ingredients map with a 60% probability for us... that is pretty concerning. Time is valid for 8pm this evening. 9Z run will be out soon.

Great Post Les!!! Will be watching this afternoon to see how unstable the atmosphere becomes and my guess some isolated showers in the afternoon but probably not until after 7 or 8pm to see some of the stronger storms. The one thing I know for sure is how damp it is and the almost constant headache since Saturday. Get a good shower or thundershower and the headache leaves for a few hours only to ramp up before the next round. Hopefully by later on Thursday the headaches are done for the most part.

That is rather concerning Les and with the storms to the west weakening this morning you are left with some nice boundaries and then with a warm front approaching this can lead to a nice setup for tornado's. Will no doubt be busy later today again we are looking at models and what they see happening so its not perfect but plenty of items that could lead to some decent severe weather.

tpweather wrote: ↑Tue May 07, 2024 8:04 am Great Post Les!!! Will be watching this afternoon to see how unstable the atmosphere becomes and my guess some isolated showers in the afternoon but probably not until after 7 or 8pm to see some of the stronger storms. The one thing I know for sure is how damp it is and the almost constant headache since Saturday. Get a good shower or thundershower and the headache leaves for a few hours only to ramp up before the next round. Hopefully by later on Thursday the headaches are done for the most part.

Thanks Tim! My allergies have been terrible also due to the rain and explosion of growth outside. Hopefully, the cooler air (and lower dew points) coming up down the road will give us a little relief, if only for a few days.

tpweather wrote: ↑Tue May 07, 2024 8:09 am That is rather concerning Les and with the storms to the west weakening this morning you are left with some nice boundaries and then with a warm front approaching this can lead to a nice setup for tornado's. Will no doubt be busy later today again we are looking at models and what they see happening so its not perfect but plenty of items that could lead to some decent severe weather.

Great post Tim... I totally agree with this idea. It is better to be safe then sorry. We know the data is not always correct, but when it is showing what it's showing, we need to always keep that one eye open just in case. That is a big reason why we are here lol

Barely a drop of rain here - yes my wife planted her flowers so the dome is back!

Def need to watch mesoscale features for later today as it could get quite busy!

cloudy72 wrote: ↑Tue May 07, 2024 8:35 am Barely a drop of rain here - yes my wife planted her flowers so the dome is back!

Def need to watch mesoscale features for later today as it could get quite busy!

Good morning Mike! Glad you're here. Always appreciate your posts and analysis especially during severe wx events.

12Z ILN sounding is out now and you can go here to see it for yourself. Convective temp is 75 degrees today which of course isn't going to be a problem exceeding that temp.


https://www.spc.noaa.gov/exper/soundings/24050712_OBS/


No changes to the Day 1 Outlook from the SPC that was just issued. Below is the discussion for the Ohio Valley:

...Ohio Valley and vicinity...
A complex and multi-episode severe threat exists today over the
region. First, an ongoing band of strong/isolated severe
thunderstorms was apparent across portions of IL, southwestward over
southeastern MO and northeastern AR. Though favorable moisture and
buoyancy exists in the foregoing warm sector (along and south of the
warm front), height falls aloft and deep-layer lift will be greatest
over the middle and northern parts, near and just south of the warm
front and mainly north of the Ohio Rover. What does not overtake
too much of the warm frontal zone and dissipate in the next few
hours may reintensify as it encounters diurnally destabilizing low
levels, related both to low-level theta-e advection and cloudiness-
restrained surface diabatic heating. At least isolated severe gusts
would be the main concern with any such convection, which should
diminish as it moves over/past eastern IN/western OH while
outrunning already marginally favorable inflow-layer buoyancy.

The more-substantial severe concern exists for thunderstorms forming
this afternoon along/ahead of the cold front, then impinging on a
corridor of favorable heating and warm/moist advection behind the
morning activity. Surface dewpoints should recover into the mid-
upper 60s F, beneath a plume of steepening midlevel lapse rates that
is part of a remnant, somewhat modified EML spreading over the area
of low-level destabilization. Superposition of these processes
should yield peak MLCAPE in the 2000-3000 J/kg range over the
"enhanced" area, narrowing and weakening northward into Lower MI.
Favorable wind profiles are forecast, with effective-shear
magnitudes in the 55-65-kt range and large-enough hodographs to
support 200-400 J/kg effective SRH. To the extent an supercells
that develop can remain relatively discrete, hodographs in the
lowest couple km appear favorable for tornadoes (some possibly
strong). Damaging, large to very large hail also is a concern with
any such supercells. Buoyancy should be even greater with
southwestward extent into steeper midlevel lapse rates and greater
boundary-layer moisture of the Mid-South, and also southward over
the Tennessee Valley into AL, but with weaker overall forcing and/or
vertical shear otherwise, coverage and organization of strong-severe
convection are likely to be less.

9Z SREF is out far enough now and for late this afternoon, it's got Cincinnati pegged at 75% for the significant TOR ingredients map! That drops to 60% by 8pm then 45% by late evening. Wow... I am concerned about that. Let's hope that is wrong. I'm logged on via the customer side here so I cannot post the image right now unfortunately.

12Z HRRR is running and so far from what I have seen, that line to our West weakens significantly as it arrives very early on this afternoon. Then we get scattered supercells that are discrete forming around 4 or 5pm. Then by this evening we get that line coming in from Indiana late this evening. I also looked at the HRRR sounding near CVG valid around 5pm and the curved hodograph that it shows is particularly concerning along with 260 M2S2 of helicity in the 0-3KM layer. Dew points are in the upper 60s as well so plenty of moisture to work with. SB CAPE between 2500-3000 J/KG is also being shown so plenty of fuel for these storms to work with as well. With any supercell, very large hail is also a concern with strong updrafts being shown. By late evening the sounding still has a lot of helicity, decent SB CAPE and still showing curved hodographs too. DCAPE values by this time rise to over 1100 J/KG so damaging winds are also going to be a factor.

Took the morning walk and a nice breeze so not bad. Watching the line of storms to the west an I was expecting it to weaken already but if anything it looks rather nice especially on the southern end which could be the input from the warm front. Interesting and will continue to watch that line this morning