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June 22-23 Severe Weather Outbreak


Stebo

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AFD's from WFO La Crosse and Milwaukee, both are pretty on board about Monday... 

ARX:

ATTENTION TURNS TO 2-PART SEVERE THUNDERSTORM POTENTIAL MONDAY INTO
MONDAY EVENING. DETERMINISTIC MODELS IN PRETTY GOOD AGREEMENT
SHOWING LOW PRESSURE TRACKING EAST OUT OF THE INTERMOUNTAIN WEST
SUNDAY NIGHT AND INTO SD BY MONDAY MORNING. INCREASING 850MB
MOISTURE TRANSPORT/ISENTROPIC LIFT AHEAD OF THE LOW AND WARM FRONT
LOOKS TO DRIVE AN MCS ACROSS THE AREA DURING THE MONDAY MORNING
HOURS...WITH HEAVY RAIN AND DAMAGING WINDS BEING THE MAIN THREATS.
THEN...IN THE AFTERNOON...WILL BE WATCHING A COLD FRONT DROP
SOUTHEAST THROUGH THE AREA AS THE SURFACE LOW TRACKS INTO THE U.P.
BY EARLY EVENING. AMPLE 0-6KM BULK SHEAR OF 50-70KT PER THE NAM
COMBINED WITH 0-1 MLCAPE AROUND 6000J/KG WILL PRODUCE AN EXPLOSIVE
SUPERCELL ENVIRONMENT WITH VERY LARGE HAIL/DAMAGING WIND/TORNADOES
ALL POSSIBLE. OF COURSE...THIS WILL BE DEPENDENT ON CLEARING IN THE
WAKE OF MORNING CONVECTION. IN ANY EVENT...WILL MAINTAIN A VERY
VIGILANT EYE ON THIS POTENTIALLY DANGEROUS SEVERE STORM ENVIRONMENT.

 

MKX:

HIGH PRESSURE WILL MOVE EAST SUN NT WITH LOW PRESSURE ORGANIZING
OVER THE MID MO RIVER VALLEY BY 12Z MON. THE ONSET OF LOW TO MID
LEVEL WARM...MOIST ADVECTION WILL BRING SMALL CHANCES OF
SHOWERS/TSTORMS TO THE WRN CWA BEFORE 12Z. THE SHORTWAVE TROUGH
ASSOCIATED WITH THE LOW WILL THEN TRACK ACROSS CENTRAL WI ON MON
WITH A 1000 MB LOW REACHING NE WI OR ADJACENT UPPER MI BY 00Z TUE.
STRONG LOW TO MID LEVEL WARM...MOIST ADVECTION ON A DEVELOPING LLJ
IS EXPECTED FOR MON WITH THE NRN CWA AND CENTRAL WI EXPECTED TO
SEE REPEATED ROUNDS OF TSTORMS. A STRONG N-S MLCAPE GRADIENT WILL
SET UP OVER THE SRN HALF OF WI WITH STRONG DEEP LAYER AND LOW
LEVEL SHEAR AS A 70 KT 500 MB WIND MAXIMUM MOVES EAST ACROSS
CENTRAL WI. THE SEVERE POTENTIAL WILL DEPEND ON WHETHER MLCAPE
VALUES CAN CLIMB ABOVE 1000 J/KG. A SLIGHT TO ENHANCED RISK IS
CURRENTLY FCST BY SPC. SOME SVR STORMS WILL LIKELY OCCUR EVEN WITH
LOW CAPE GIVEN THE LIFT AND STRONG WIND SHEAR BUT HIGHER CAPE
VALUES WOULD INCREASE THE PROBABILITIES OF MORE SIGNIFICANT SVR
STORMS INCLUDING SUPERCELLS AND TORNADOES. ALSO CONCERNED ABOUT
FLASH FLOODING TOWARD CENTRAL WI DUE TO REPEATED ROUNDS OF
CONVECTION AND PWS OF 1.5-1.7 INCHES. THE CONVECTION AND SVR
POTENTIAL WILL CARRY INTO MON EVE WITH THE COLD FROPA. NWLY SFC
WINDS TO FOLLOW INTO TUE WITH HIGH PRESSURE BUILDING INTO WI
LATER ON TUE.

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Looking better and better for a regional severe weather outbreak Monday into Monday night.  Shear is f'ing redonkulous and so is CAPE for that matter.  A good portion of the western and central great lakes are probably going to get clocked.

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Parameters off the charts once more. If you look at H7 vertical velocities and then look at 2m temp for the isobars, there's a secondary 998mb low in that same area. Probably more convective feedback this run, backing the winds more at low levels, therefore increasing the veering of the winds and helicities in general..

Though not unrealistic, i think it's a little over-done.
Even with the winds veered at the surface later, the sounding still shows a very impressive environment from a storm relative point of view.

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Looking better and better for a regional severe weather outbreak Monday into Monday night. Shear is f'ing redonkulous and so is CAPE for that matter. A good portion of the western and central great lakes are probably going to get clocked.

One thing we can say is that a lack of capping probably won't be an issue. :lol:

Total powderkeg...storms should go severe very quickly in that environment.

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Somewhat random but does anyone recall July 2, 2000?  Are there any major similarities in the synoptic setup from that event to this upcoming one on Monday?  That was one of the more intense evenings of convective action I can remember, and it included a tornado moving through the south side of the county.

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All I can say is that the Crazy Uncle NAM fell of his rocker again. If that verifies a significant severe event is likely. Crazy shear and high CAPE makes for a very volatile environment.

Honestly im not sure if someone could modify an environment to look this insane and perfect... 00z 4KM NAM and 18z GFS are both in agreement with the NAM as well in progging insane parameters: SCP's of 30+ across a large area, and STP's >10 as well, and obviously high cape and very high shear, lets see what the 00z GFS and ECMWF do.. If the euro shifts to the more aggressive solution like the other three, we could see at least a MDT by either D2 update tomorrow, but more so the 1730z update probably... High Risk maybe even? But seems like SPC would wait till the day of due to concerns of capping and morning convection. 

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Wonder if we'll get a day 2 MDT. 

 

0z NAM alone is beyond a scary solution IMO the more I look at it. 

 

as is....I think if the 12Z continues it should be there for the afternoon update....if euro follows similar suit (given it's tendencies in general) tonight, then we could see it on the first round later tonight.  Things seems to be lining up thus far for a possible dangerous situation...besides the obvious "caveats" that come with mid summer instability and spring time set ups

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On paper, Monday certainly looks high-end based off of the model solutions, particularly the GFS and NAM.

 

With that said, there are caveats. The 00z RGEM develops an MCS over the Dakotas early Monday morning and that rolls into Wisconsin by Midday. Although you'd think that would have more of an effect on instability, the RGEM still shows strong heating across southern Wisconsin. The precip fields don't appear to show intense convection during the afternoon though.

 

Edit: The 00z GFS shows a similar MCS scenario.

 

Not making a forecast by any means, but pointing out that observation.

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Somewhat random but does anyone recall July 2, 2000?  Are there any major similarities in the synoptic setup from that event to this upcoming one on Monday?  That was one of the more intense evenings of convective action I can remember, and it included a tornado moving through the south side of the county.

 

http://www.spc.noaa.gov/exper/archive/event.php?date=20000702

 

I'm no expert (I don't take synoptic meteorology until the fall), but nothing stands out to me in terms of the synoptic setup. Here's a link if you'd like to examine some of the upper air analyses and discussions. I can't specifically recall it (I was six years old at that time), but most likely I staring out my bedroom window.

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Interesting for the Metro Detroiters, though we'd probably be on the far eastern fringe of the activity, is that the big Ford Fireworks show downtown along the Detroit River is at 10:06pm Monday night, where over a million people line up along the river on the US and Canadian side.

That could get crazy if a derecho plows through shortly before or after.

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I went through the list of high risk convective outlook days. Needless to say, it would be very unusual to see a high risk convective outlook issued primarily for a tornado threat this late in the season.

I wouldn't expect there to be a high risk for this threat, I'd say there will most likely be a moderate with a high damaging wind and moderate-high tornado risk if things turn out they way they look to.

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Wonder if we'll get a day 2 MDT. 

 

0z NAM alone is beyond a scary solution IMO the more I look at it. 

 

 

Would like to get yours and others opinions on the convective mode.  To me, there's no overwhelming reason to think there will be a really quick transition to linear mode.  Directional shear does become less as we go through the evening but the better forcing is well north / longer capping potential also makes one wonder about the coverage farther south.   

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