August 1-14, 2022 | Heat Wave & Severe Weather

[ClicheVortex2014]

New pattern regime = new thread.

EHI in this case has high potential to be misleading when you have 500mb maps like this. 0-3km EHI is based on 0-3km SRH and sbcape. You can have 3+ EHI without sufficient speed shear for organized storms... especially in a heat wave where you have copious instability but modest low-level shear driven by strong low-level directional shear and weak low-level winds.

Edited August 14, 2022 by ClicheVortex2014

[ClicheVortex2014]

Monday snuck up on me.

Edited July 30, 2022 by ClicheVortex2014

[ClicheVortex2014]

Ok, Monday could actually be a big deal. As expected for an August event, the tornado threat isn't likely to be the biggest factor... but significant hail/wind would be the most likely hazard. Especially considering how populated SW OH/N KY is.

In the day 3 outlook, SPC mentioned 30-35 knots effective shear. 35 knots is enough for a reasonable threat for supercells... 30 knots is more borderline.

 

Flash flooding also looks likely in this scenario. That's 7.5" over southwestern Butler county.

Edited July 31, 2022 by ClicheVortex2014

[Chinook]

After looking at the 00z NAM, some extreme CAPE up to 4900 J/kg should exist near the cold front in Indiana and Illinois. The mid-70's dew points to 80 dew points will be the area, as moisture advects from the Southeast. 500mb winds will increase into the 30-40 kt range with an upper level trough. Models have some 0-6km shear of 25 kt in Indiana and northwest Ohio. It seems to me this should be an active cold front with maybe some shear that could get to 35 kt in some areas, even though the models don't quite agree on this. The HRW-FV3 model shows discrete cells for western Ohio on Monday. Important note: the CAM models kind of stink with higher CAPE and lower forcing, at 45 hours anyway.

[snowlover2]

Wouldn't surprise me to see a slight risk added on the new day 2.

[snowlover2]

Or maybe not.

Quote

DAY 2 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1253 AM CDT SUN JUL 31 2022  
  
VALID 011200Z - 021200Z  
  
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE CENTRAL PLAINS...LOWER MISSOURI VALLEY...MID MISSISSIPPI  
VALLEY...NORTHERN OHIO VALLEY AND LOWER GREAT LAKES...  
   
..SUMMARY  
  
THUNDERSTORMS ASSOCIATED WITH MARGINALLY SEVERE WINDS AND HAIL WILL  
BE POSSIBLE ON MONDAY FROM THE CENTRAL PLAINS INTO THE MID  
MISSISSIPPI VALLEY AND LOWER GREAT LAKES.  
   
..NORTHERN OHIO VALLEY/LOWER GREAT LAKES  
  
AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE GREAT LAKES REGION ON  
MONDAY, AS NORTHWEST MID-LEVEL FLOW BECOMES ESTABLISHED ACROSS THE  
CENTRAL U.S. AT THE SURFACE, A COLD FRONT WILL ADVANCE  
EAST-SOUTHEASTWARD INTO THE MID MISSISSIPPI VALLEY AND LOWER GREAT  
LAKES. AHEAD OF THE FRONT, SURFACE DEWPOINTS IN THE UPPER 60S AND  
LOWER 70S F SHOULD RESULT IN MODERATE INSTABILITY BY AFTERNOON.  
SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP ALONG AND AHEAD OF  
THE FRONT, WITH THESE STORMS MOVING EAST-SOUTHEASTWARD ACROSS THE  
NORTHERN OHIO VALLEY AND LOWER GREAT LAKES. NAM FORECAST SOUNDINGS  
ALONG THE INSTABILITY AXIS FOR 00Z/TUESDAY GENERALLY HAVE 0-6 KM  
SHEAR IN THE 35 TO 45 KNOT RANGE. THIS COMBINED WITH STEEP LOW-LEVEL  
LAPSE RATES SHOULD BE ENOUGH FOR A MARGINAL WIND-DAMAGE THREAT  
DURING THE LATE AFTERNOON.  
   
..CENTRAL PLAINS/LOWER MISSOURI VALLEY  
  
WEST NORTHWEST MID-LEVEL FLOW WILL BECOME ESTABLISHED ACROSS THE  
CENTRAL U.S. ON MONDAY. AT THE SURFACE, A CORRIDOR OF MAXIMIZED  
LOW-LEVEL MOISTURE WILL BE LOCATED FROM NORTH-CENTRAL MISSOURI  
EXTENDING NORTHWESTWARD INTO NORTH-CENTRAL NEBRASKA. SURFACE HEATING  
ALONG WITH SURFACE DEWPOINTS FROM THE MID 60S TO LOWER 70S F WILL  
CONTRIBUTE TO MODERATE INSTABILITY BY MIDDAY. ISOLATED THUNDERSTORMS  
ARE FORECAST TO DEVELOP ALONG AND NEAR THE INSTABILITY AXIS DURING  
THE MID TO LATE AFTERNOON. FORECAST SOUNDINGS HAVE MLCAPE PEAKING IN  
THE 2500 TO 3500 J/KG RANGE, WITH 0-6 KM SHEAR IN THE 30 TO 40 KNOT  
RANGE.  THIS SHOULD BE ENOUGH FOR MARGINALLY SEVERE WINDS AND HAIL.  
HOWEVER, WARM AIR ALOFT SHOULD TEMPER THE THREATS SOMEWHAT.  
  
..BROYLES.. 07/31/2022

 

 

[StormfanaticInd]

August tends to produce anymore around here so this will be worth watching 

[NWOhioChaser]

Nothing but hot, humid, and hazy this upcoming week. Probably won't see in the much of rain too. Not very optimistic about anything formidable, maybe a pop up storm if the cap breaks. 

[snowlover2]

ILN morning update says they believe an upgrade in probs for tomorrow is possible.

Quote

.LONG TERM /MONDAY THROUGH SATURDAY/...
A shortwave trough is still expected to be moving through the
Great Lakes on Monday, with the primary attention focused on the
potential severe threat during the afternoon and evening hours.
Ahead of the primary shortwave, subtle warm-air advection and
deeper moisture should allow for scattered shower activity
across southern locations. As this activity moves eastward,
mostly cloudy skies scatter allowing for more efficient surface
heating into the early afternoon. Temperatures warm into the mid
80s with dewpoint temps in the low to mid 70s.

Details on the severe threat Monday: The afternoon and evening
periods are now within the late portions of shorter range
guidance, presenting the first look at potential convective
evolution. A common theme across the HREF ensemble compared to
the more coarse global guidance is an overall faster arrival to
thunderstorm development. Forecast soundings indicate the
potential for elevated thunderstorm initiation over
central/northern Indiana during the mid- morning hours. These
thunderstorm are initiated due to warm-air advection processes
as the incoming LLJ max moves into the region. As these
thunderstorms advance eastward into the rapidly destabilizing
air mass, thunderstorms become surface-based in large part due
to cooled-pool boundary layer thermal dynamics. From the late
morning into the early afternoon, various CAM solutions diverge
with outcomes ranging from a progressive line of storms (WRF-
NSSL/ARW & NAM3km) to back-building supercells (HRRR & FV3). It
is likely too soon to focus on any particular outcome. Instead,
focus on the broader parameter space indicates some increased
confidence in severe potential due to the unstable air mass and
co-located 0- 6km shear of 30-40 knots. Overall, lower
tropospheric flow is well above climatological normals with
early August typically the weakest time of year. Depending on
convective evolution, these anomalous wind flows may stretch
low-level hodographs, increasing storm-level effective helicity
fields. Putting all of this together suggests that all storm
modes are possible come Monday afternoon.

Probabilities from SPC are Marginal for Day 2, but with
additional short range guidance, these probabilities may
increase for the local area.

Tuesday-Saturday: Given the faster convective evolution Monday
night, chances for thunderstorms continues to decrease for
Tuesday afternoon. Will maintain some mention across southern
Ohio/northern Kentucky, but even these could decrease in later
forecasts.

There is continued support for well above normal temperatures
Wednesday afternoon as southwesterly surface flow increases and
the mid-level ridge builds in. Forecast temperatures are in the
low 90s area wide with heat indices between 95 and 100. Heading
into Thursday, there is now increasing confidence following the
previous forecast with regards to the signal for a cold front to
push southeast into the area late Wednesday night into
Thursday. Instead of an extended warm stretch, this pattern now
favors more widespread cloud cover and several rounds of
rainfall Wednesday night into Friday. Due to these changes, have
removed heat wording for Thursday and Friday in the HWO.

Due to this anomalous shortwave trough moving through the Great
Lakes during an odd time of year confidence is low for the
overall forecast outcomes Friday and Saturday.

 

 

[Bman10]

Ohhh yeah exciting! This snuck up on me too

[ClicheVortex2014]

I don’t understand the rationale for marginal risk. They’re talking about moderate instability with up to 45 knots 0-6km shear. 45 knots supports supercells given directional shear, but it’s easily enough for a squall/bowing segments/MCS. I don’t understand what’s holding them back from a slight risk

[Chinook]

I'd still say that over 4500 J/kg of CAPE in Indiana, with a little less in Ohio is good enough for some severe storm reports. 

I was watching a few Youtube videos recently about tornado events of past years. I looked up a video on the Plainfield Illinois Tornado of 1990. It's near Chicago. The large supercell storm, in AUGUST, was driven by over 6000 J/kg of CAPE. The 0-6km shear was sneaky. The 0-6km shear, and wind speed at 300mb increased during the day, perhaps surprising meteorologists a bit. The 0-3km SRH was not indicative of large tornadoes. Usually you would look for forecast SRH values over 300 m2/s2, but it wasn't close to that. Then, Plainfield, Oswego, Crest Hill, and Joliet got tornado damage with Wheatfield Plains getting F5 damage. This was the only F5 tornado rating in the month of August. I don't believe any EF5 tornadoes have happened in August in the Enhanced Fujita era. It would have been rated with the Enhanced Fujita system if it happened today. I wonder if EF5 would have been the final conclusion. The extra bad part of it was that the NWS didn't get the warning out. There were no tornado sirens as it was hitting dozens of houses. Hopefully this breakdown in warning capabilities will not happen again.

[snowlover2]

Slight risk introduced for wind.

Quote

DAY 2 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1245 PM CDT SUN JUL 31 2022  
  
VALID 011200Z - 021200Z  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO  
VALLEY...  
   
..SUMMARY  
  
AT LEAST ISOLATED SEVERE STORMS ARE EXPECTED MAINLY ACROSS PARTS OF  
THE MIDWEST AND OHIO VALLEY MONDAY AFTERNOON AND EVENING.  
   
..MIDWEST/OHIO VALLEY INCLUDING INDIANA/OHIO/KENTUCKY  
  
HAVE INTRODUCED A CATEGORICAL SLIGHT RISK FOR PARTS OF THE REGION,  
INCLUDING PORTIONS OF INDIANA/OHIO/KENTUCKY. MODERATE TO STRONG  
DESTABILIZATION IS EXPECTED INTO MONDAY AFTERNOON ESPECIALLY ACROSS  
THE LOWER/MIDDLE OHIO RIVER VALLEY, NORTHWARD ACROSS EASTERN INDIANA  
AND WESTERN/CENTRAL OHIO. THIS WILL BE NEAR/AHEAD OF A  
SOUTHEASTWARD-ADVANCING FRONT, AND TO THE SOUTH-SOUTHWEST OF  
POSSIBLE RESIDUAL OVERNIGHT CONVECTION AND CLOUD COVER THAT MAY BE  
LOCATED OVER MICHIGAN/NORTHERN INDIANA VICINITY MONDAY MORNING.  
  
AN AMPLIFYING BELT OF MODERATELY STRONG WESTERLIES (30-50 KT AT 500  
MB) WILL INFLUENCE FORCING FOR ASCENT AND PROBABLE STORM  
DEVELOPMENT/LONGEVITY MONDAY AFTERNOON AND EVENING. THIS COULD  
POTENTIALLY INCLUDE SOME SUPERCELLS ASIDE FROM MORE PREVALENT  
MULTICELLS AND SOUTHEASTWARD-MOVING BANDS/LINEAR SEGMENTS. WIND  
DAMAGE WILL BE THE PRIMARY RISK OVERALL.  
   
..CENTRAL PLAINS/LOWER MISSOURI VALLEY  
  
AN INITIALLY SOUTHWARD-SETTLING FRONT WILL DECELERATE/STALL AND  
BEGIN TO RETURN NORTHWARD LATE MONDAY AFTERNOON AND MONDAY NIGHT.  
MODERATELY STRONG NORTHWESTERLY WINDS WILL OVERLIE THE FRONT. THE  
POTENTIAL FOR DEEP CONVECTIVE DEVELOPMENT SHOULD REMAIN LIMITED  
SOUTH OF THE FRONT OWING TO STRONG CAPPING, HOWEVER ISOLATED STORM  
DEVELOPMENT MAY OCCUR LATE MONDAY AFTERNOON AND NIGHT NEAR/NORTH OF  
THE BOUNDARY, PARTICULARLY ACROSS PORTIONS OF NEBRASKA WHERE A  
NEAR-BOUNDARY ZONE OF MODERATE TO STRONG DESTABILIZATION SHOULD BE  
MAXIMIZED ACROSS MUCH OF CENTRAL NEBRASKA TO SOUTHEAST NEBRASKA.  
WHERE STORMS DO FORM, A FEW SUPERCELLS COULD OCCUR, ALONG WITH THE  
POTENTIAL FOR STORM ORGANIZATION AND UPSCALE GROWTH NEAR/NORTHEAST  
OF THE BOUNDARY. LARGE HAIL AND DAMAGING WINDS MAY OCCUR, WITH  
DAMAGING WINDS A VIABLE POSSIBILITY ON THE COOL SIDE OF THE FRONT  
OWING TO THE STEEP LAPSE RATE ENVIRONMENT/DRY AIR ABOVE THE MORE  
STABLE BOUNDARY LAYER.  
  
PORTIONS OF CENTRAL AND POSSIBLY EAST-CENTRAL/NORTHEAST NEBRASKA  
COULD ULTIMATELY WARRANT AN UPGRADE TO A SLIGHT RISK PENDING HIGHER  
CONFIDENCE IN CONVECTIVE INITIATION/DEEP CONVECTIVE DEVELOPMENT  
WITHIN AN OTHERWISE SEVERE-FAVORABLE ENVIRONMENT.  
   
..NORTH DAKOTA  
  
THE MAIN THUNDERSTORM POTENTIAL SHOULD BE RELEGATED TO THE MORNING  
AND/OR ACTIVITY POTENTIALLY CROSSING THE INTERNATIONAL BORDER LATER  
IN THE DAY NEAR/NORTH-NORTHEAST OF A FRONT ACROSS THE REGION. A FEW  
STRONG TO SEVERE STORMS COULD OCCUR GIVEN THE STRONG WIND PROFILES  
AND MODERATE SURFACE-BASED BUOYANCY NEAR THE FRONT AND ELEVATED  
BUOYANCY TO ITS EAST-NORTHEAST.  
  
..GUYER.. 07/31/2022  

 

 

[ClicheVortex2014]

Discussion makes more sense now. Kinda surprised about no tornado risk but one step at a time.

[snowlover2]

27 minutes ago, ClicheVortex2014 said:

Discussion makes more sense now. Kinda surprised about no tornado risk but one step at a time.

Me too especially with ILN mentioning that all modes are possible.

[snowlover2]

ILN afternoon update. Also talking about a stormy end of the week.

Quote

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
242 PM EDT Sun Jul 31 2022

.SYNOPSIS...
A warm front will lift north across the area tonight into
Monday morning, followed by a cold front late Monday night into
Tuesday. This will lead to a chance for showers and
thunderstorms, primarily Monday afternoon into Monday night.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Circulation from the mid level short is evident on visible
satellite imagery moving east across southwest Ohio attm. There
is still some lingering light pcpn associated with this feature
across southeast portions of our fa, but this should taper off
over the next couple of hours. Diurnal cu elsewhere across our
area should dissipate toward sunset.

A warm front will lift north into southern portions of our area
through tonight. This will lead to an increase in clouds from
the south later tonight along with the potential for some
scattered shower activity. Lows tonight will be in the mid to
upper 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
The warm front will continue to lift north across the area
Monday morning with low level moisture/dewpoints increasing
from the south. As temperatures climb into the mid 80s, decent
instability will develop across our area with ML capes in the
1500-2500 J/KG range possible through the afternoon hours.

Mid level short wave energy and an associated cold front
will drop down from the northwest Monday afternoon into Monday
night. This will lead to an increasing chance of thunderstorms
through the day. There are some differences in storm
evolution/mode among the hi res CAMs. Some are indicating
storm initiation more across our north, with the storms then
feeding southwest into the better instability through late
afternoon into early evening. Meanwhile, others are swinging
scattered storms from northwest to southeast across the area
Monday afternoon into Monday evening. Nonetheless, with
increasing mid level flow and effective shear in the 25-35 knot
range, some severe storms appear possible during the afternoon
and evening hours across our entire area. With DCAPES likely in
excess of 1000 J/KG, damaging wind will be the main threat.
However, some of the CAMs are showing some slightly better lower
level shear so it will be tough to also rule out an isolated
tornado. Locally heavy rainfall will also be likely with the
storms. The thunderstorm activity will taper off later Monday
night as the short wave swings off to the southeast.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
On Tuesday morning, a shortwave trough will be moving east of the
Ohio Valley, as an area of surface high pressure floats into the
southern Great Lakes from the west. Subtle height rises aloft are an
indication that the forcing will be departing the area, leaving just
some low-end precipitation chances in the southern part of the CWA
on Tuesday, where conditions may be a little more moist and unstable
on the southern periphery of the surface high. The ever-so-slightly
cooler and drier air mass will still be quite warm, especially with
mostly sunny conditions, so highs in the mid to upper 80s are
expected.

As the surface high moves off to the east, deep-layer SSW flow will
set up over the region by Wednesday morning, with a slight
amplification in the ridging over the area at 500mb. This will set
up what will likely be the warmest day of the week. This warm
advection pattern will combine with mostly sunny skies (and
essentially no chance of precipitation) to bring highs into the
lower 90s, with dewpoints increasing by about 5 degrees from Tuesday
to Wednesday as well. Heat indices in the upper 90s are worth
noting, with heat advisory criteria (heat index of 100F or above)
not out of the question.

The ridging over the area on Wednesday will dampen with time going
into the rest of the week, which will set up a bit more active of a
flow pattern across the Great Lakes on Thursday and Friday. The
winds in the low levels on Thursday will remain generally
southwesterly ahead of an approaching front, with the ILN CWA well
in the warm sector. A fairly well-defined area of high pressure will
be located on the back side of this front, indicating a sizable
change in air mass behind the boundary. However, this boundary is
unlikely to ever completely clear southward through the region, as
it appears likely to get hung up in the largely-unidirectional WSW
deep-layer flow. With very moist and unstable air near and south of
the boundary, and well-defined low-level convergence near the
boundary, it will likely act as a continued focus for shower and
storm development during the time frame from Thursday afternoon
through Friday. Thus, there is high confidence in active and stormy
conditions at the end of the week, and at least some potential for
heavy/repeated rainfall and maybe some stronger storms.

There is very low confidence in the forecast beyond Friday, with a
wide range of model signals regarding any further movement or
oscillation of the frontal boundary.

 

 

[snowlover2]

18z HRRR is pretty crazy. Highest total i came across just west of Dayton is 9.54" which falls in less than 5 hours!

[NWOhioChaser]

I

38 minutes ago, snowlover2 said:

18z HRRR is pretty crazy. Highest total i came across just west of Dayton is 9.54" which falls in less than 5 hours!

Clear lack of love for Northern Ohio.😩 Desperately need more rain up here. Getting pretty dry here pretty quickly.

[ClicheVortex2014]

1 hour ago, snowlover2 said:

18z HRRR is pretty crazy. Highest total i came across just west of Dayton is 9.54" which falls in less than 5 hours!

Especially scary since we’ve just had two catastrophic flooding events in the region. 9” in 5 hours is on par with both events.

[Neoncyclone]

Woah, Canada you good???

 

[ClicheVortex2014]

11 minutes ago, Neoncyclone said:

Woah, Canada you good???

 

If the quality of radars we have on Radarscope is indeed the best quality they have in Canada, I'd imagine they're gonna be much more liberal on tornado warnings than the US. I'd imagine it doesn't take much more than a hook echo to issue a tornado warning for them... like what we did in the 60s-80s. 

Wild that they don't have at least better quality radars. Obviously, it's not like they don't have a dangerous tornado season. 

Edited August 1, 2022 by ClicheVortex2014

[Neoncyclone]

7 minutes ago, ClicheVortex2014 said:

If the quality of radars we have on Radarscope is indeed the best quality they have in Canada, I'd imagine they're gonna be much more liberal on tornado warnings than the US. I'd imagine it doesn't take much more than a hook echo to issue a tornado warning for them... like what we did in the 60s-80s. 

Wild that they don't have at least better quality radars. Obviously, it's not like they don't have a dangerous tornado season. 

Yeah I always thought the same thing, I figured that was why they make such large warning boxes too.

 

[ClicheVortex2014]

Won't be surprised to see an enhanced risk tomorrow especially if there's a 15+ knot LLJ. Always a big red flag when you have 30+ knots at 500mb in August overlapping the warm sector.

Note: second image is 500mb, third is 850mb.

[ClicheVortex2014]

Aside from the south/southwest-ward movement, these cells don't look like something you'd see in August. Nasty potential.

Obviously, there's questions as to where in the OV gets the worst of the severe weather. I think the current slight risk really pinpoints the area at most risk, though I'm sure some of it will be trimmed and/or parts may be increased.

Per tornadoarchive.com, looks like Kentucky's strongest August tornado was several EF2s. 

 

Impressive UH tracks, too.

Edited August 1, 2022 by ClicheVortex2014

[snowlover2]

0z HRRR is rather disappointing here.