Absolute Vorticity

12z HRRR looks quite UN-impressive for this afternoon. I am guessing it keeps the cap mostly in place.

12Z NAM blows it up east of Cincinnati. How many times have we seen that before?

81 / 77 at CVG... There will be no shortage of fuel for the storms to work with. Shear isn't impressive and the forcing is weak with this frontal system,. but it should be enough to spark 50 / 50 coverage. The degree at which the cap breaks will dictate how bad or not so bad this event turns out to be.

Mid morning update from the boys:

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A surface low and upper level shortwave continues to move east
across the Great Lakes today as an associated cold front drops south
into the Ohio Valley. Southerly flow will increase ahead of the
approaching front through the morning hours leading to increasing
moisture (dew points 70+) as temperatures heat up (90+). By 1PM, the
heat and humidity combine to make the heat index push 95-100 across
the area. A Heat Advisory has been issued from 1PM-8PM for locations
where the heat index will likely reach above 100.

Another impact from the combined heat and humidity later today will
be increasing instability that could fuel storm development ahead of
the cold front while weak capping erodes. By the afternoon and
evening, large values of instability (2000+ J/kg) overlap moderate
deep shear (25 knots+ effective shear) with veered low level
hodographs. This favorable parameter space suggest strong, organized
storms are possible if storms form ahead of the front. Storm mode
could initially be supercellular followed by multicellular
structures with many cell to cell interactions due to boundary
parallel shear ahead of the front. While there is still uncertainty
regarding to storm coverage and occurrence, SPC has issued a slight
risk for the conditional chance of strong storms that could produce
strong winds and perhaps some hail and a tornado or two. The
timeframe for storm development starts around 2-3pm northwest of
Dayton. The storm threat then expands south and east through the
late afternoon and evening hours before ending by midnight across
southern and central Ohio.

Just a wow as the dew point has skyrocketed to 78 at CVG. So much heat and humidity to work with today and no doubt this has increased chances for some decent storms. Of course the problem is they will be rather quick in nature so most folks will have less than an hour where its actually storming but can get some heavy rains in a short period of time.

The derecho comp is building to about an 8 over ILL and Western IN. That is where your better shear is currently with the front.

Seems like the short term models are somewhat less bullish on storms later today than earlier runs. I wish I knew how the models were programmed and with the higher than normal temps the models may tend to less aggressive with the storms as we get closer. Only time will tell and knew all along its a now cast and something we start to look at later this afternoon.

Latest thinking from the boys at IND.

.Forecast Update...
Issued at 1106 AM EDT Wed Jul 20 2022

Not many changes made with this update as the forecast is in good
shape so far. Currently satellite shows a thin layer of low clouds
progressing eastward across the area as a boundary moves through.
There is still the potential for scattered storms to form along the
boundary this afternoon to early evening given ample heat and
increasing moisture at the surface but confidence is still low as to
when and where storms will form. Confidence is higher for the SE
portion of the forecast area to see some showers and potentially
isolate severe storms with damaging winds being the main threat. The
prohibiting factor is still that the air aloft is very dry and won`t
allow for much growth for at least initially.

It will also be hot and humid today with heat indices expected to
get as high as 112 degrees in the south. Limit time outside and stay
hydrated.

tpweather wrote: ↑Tue Jul 19, 2022 7:11 am I know the national news will be all over the heat and they have talked about western Europe which has no doubt been very hot. The problem is when parts of Australia saw their coldest temps ever in June I never saw a story on that with the national media. Must give both sides if you want folks to believe your crap. Of course eastern Europe in western Russia is very cool at the moment so yes once again mother nature will balance itself out and only wish the national media could live by the standard.

I was listening to Mike McConnell this morning and he talked about the heat in London, and asked why the media chose to show images of a housefire there as their visual component to the story, as if they were trying to imply that the house burst into flames just because it was so hot outside. And now I hear that President Brandon wants to declare a "Climate Emergency" whatever the heck that is.
By the way, did anyone hear there was a new landmark on google maps called "Brandon Falls?"

Another one of days where there is a steady breeze blowing to take the edge off the heat/humidity

House of Cards wrote: ↑Wed Jul 20, 2022 12:51 pm

tpweather wrote: ↑Tue Jul 19, 2022 7:11 am I know the national news will be all over the heat and they have talked about western Europe which has no doubt been very hot. The problem is when parts of Australia saw their coldest temps ever in June I never saw a story on that with the national media. Must give both sides if you want folks to believe your crap. Of course eastern Europe in western Russia is very cool at the moment so yes once again mother nature will balance itself out and only wish the national media could live by the standard.

I was listening to Mike McConnell this morning and he talked about the heat in London, and asked why the media chose to show images of a housefire there as their visual component to the story, as if they were trying to imply that the house burst into flames just because it was so hot outside. And now I hear that President Brandon wants to declare a "Climate Emergency" whatever the heck that is.
By the way, did anyone hear there was a new landmark on google maps called "Brandon Falls?"

If I would have seen that reported like that I would have busted out laughing to the insinuation . Its just so over-the-top, but alas, it seems more and more people eat that garbage up like they're starving to death

As of 1pm... 88 / 79 / 103 at CVG. No thank you.

T-storm watch box issued for Eastern Michigan and NW Ohio until 8pm EDT. This should be the beginnings of the line. How far SW does it develop is the question for us, later on.

At the moment I am sitting at 89 with a dew point of 77.

House of Cards wrote: ↑Wed Jul 20, 2022 12:51 pm

tpweather wrote: ↑Tue Jul 19, 2022 7:11 am I know the national news will be all over the heat and they have talked about western Europe which has no doubt been very hot. The problem is when parts of Australia saw their coldest temps ever in June I never saw a story on that with the national media. Must give both sides if you want folks to believe your crap. Of course eastern Europe in western Russia is very cool at the moment so yes once again mother nature will balance itself out and only wish the national media could live by the standard.

I was listening to Mike McConnell this morning and he talked about the heat in London, and asked why the media chose to show images of a housefire there as their visual component to the story, as if they were trying to imply that the house burst into flames just because it was so hot outside. And now I hear that President Brandon wants to declare a "Climate Emergency" whatever the heck that is.
By the way, did anyone hear there was a new landmark on google maps called "Brandon Falls?"

The fires are directly related to the heat and dry conditions... London's busiest day for firefighters since WW2.

https://www.bbc.com/news/uk-62232654

90 / 80 / 108 now at CVG!

Latest thinking from our guys!

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A cold front continues to approach the Ohio Valley from the
northwest with increasing southwesterly flow ahead of it.
Temperatures have warmed into the middle 80s early this afternoon
and dew points have to risen into the upper to middle 70s. Heat
Advisory appears on track with highlighted areas already reaching
heat indices over 100. Elsewhere, the heat index continues to rise
into the 90s with increasing temperatures and humidity. Heat
headlines drop after peak heating at 8PM.

With the heat headlines on track, focus is shifting toward the
possibility for thunderstorms this afternoon. SPC mesoanalysis
depicts MLCAPE continuing to grow in response to increasing heat,
humidty, and an approaching upper level trough. Visible satellite
imagery also depicts a growing area of cumulus ahead of the cold
front and upper level shortwave in far northwestern Ohio and
Indiana. The expectation is for some of the cumulus to grow into
towering cumulus through the middle afternoon eventually allowing
for some possible thunderstorm development by early evening. With
MLCAPE exceeding 2500 J/kg, effective shear over 25 knots, and
curved low level hodographs, the threat for severe storms warrants a
Severe Thunderstorm Watch north of I-70 as of early this afternoon.
The main threat from any storms that form is damaging winds and some
hail although a tornado threat cannot be ruled out. If storms do end
up forming, storm mode may start off as isolated cells or supercells
in northwest Ohio before congealing into multicell and linear
clusters due to boundary parallel southwesterly shear. As the front
continues to progress southeast this afternoon/evening, the
favorable storms environment may reach further south. The main
threat for severe storms runs from 2pm to 10pm.

The storms threat ends by midnight tonight after FROPA. Temperatures
don`t drop much behind the front and winds shift toward westerly.
Forecast lows are in the upper 60s.

Do we know the convective temp?

SPC extended slight risk way southwest covering all of Kentucky, due to the off the charts instability down that way.

Bgoney wrote: ↑Wed Jul 20, 2022 2:35 pm Do we know the convective temp?

Waiting for the 18Z sounding from the ILN Special balloon sounding to come in. Hopefully near or shortly after 3pm on SPC's soundings page.

EDIT: Convective temp was missing from the 12Z sounding.

While we are waiting... the closest info I have is a 17Z sounding that was done at DTX (Detroit) and the convective temp there was 87. Ours of course is in the 90s just not sure how high as of yet.

91 / 80 / 109 now lol Atmosphere def is primed should we get any sort of forcing or lift.

One of those days where the temp and dew points change due to increased cloud cover at times. My current reading is temp of 93 dew point 76 which makes sense as the sun is rather bright at the moment

Looks like a line is trying form between Toledo and Indy. Will watch this over the next hour or two.

92 here, Dp-77, with a steady breeze