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June 16-25 Severe threat


snowlover2

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overall complex movement is already south of due east and the cold pool is just getting going.

 

still think south is the way to go from NE IA into NW IL during the overnight for best winds with the tail end back building south fueled by the llj into the morning.

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overall complex movement is already south of due east and the cold pool is just getting going.

 

still think south is the way to go from NE IA into NW IL during the overnight for best winds with the tail end back building south fueled by the llj into the morning.

 

I see what you mean but the lead cells look to be breaking off and moving due east through extreme S Minnesota.  I don't think the line trailing back W that is drifting SE will have as much effect on those lead cells yet.  I anticipate once it crosses the Mississippi River it will start to take its SE movement, meaning a corridor just to the NE of where you are pinpointing (WC Wisconsin into SC Wisconsin) will be most at risk.

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I see what you mean but the lead cells look to be breaking off and moving due east through extreme S Minnesota.  I don't think the line trailing back W that is drifting SE will have as much effect on those lead cells yet.  I anticipate once it crosses the Mississippi River it will start to take its SE movement, meaning a corridor just to the NE of where you are pinpointing (WC Wisconsin into SC Wisconsin) will be most at risk.

 

 

 

it's pretty clear looking at radar and the current instability axis that most models are going to be too far north with the main convective complex.

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it's pretty clear looking at radar and the current instability axis that most models are going to be too far north with the main convective complex.

Might want to loop the radar, the line is moving ENE along with the flow, and the 18z 4km NAM which has a good handle on this tracks the majority of the line through WI maybe clipping the far northern part of IL and into MI before dying and laying an outflow boundary across WI/MI in a WNW-ESE fashion. This boundary lights up tomorrow with supercells after 2-3pm.

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Might want to loop the radar, the line is moving ENE along with the flow, and the 18z 4km NAM which has a good handle on this tracks the majority of the line through WI maybe clipping the far northern part of IL and into MI before dying and laying an outflow boundary across WI/MI in a WNW-ESE fashion. This boundary lights up tomorrow with supercells after 2-3pm.

 

He is right though that it is a bit south of where most of the global models positioned the line the last day or two (of course, hi-res are the way to go anyway for severe weather typically).

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Might want to loop the radar, the line is moving ENE along with the flow, and the 18z 4km NAM which has a good handle on this tracks the majority of the line through WI maybe clipping the far northern part of IL and into MI before dying and laying an outflow boundary across WI/MI in a WNW-ESE fashion. This boundary lights up tomorrow with supercells after 2-3pm.

 

The flow is ENE, but it is still convection. 

 

In these types of setups, while the overall complex may move one direction, the best convection always propagates along the instability axis. 

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The flow is ENE, but it is still convection. 

 

In these types of setups, while the overall complex may move one direction, the best convection always propagates along the instability axis. 

Yes but that axis is also lifting NE as well.

 

He is right though that it is a bit south of where most of the global models positioned the line the last day or two (of course, hi-res are the way to go anyway for severe weather typically).

Yeah I am matching it up with the model that has it correct right now which would be the 4km NAM.

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Yes but that axis is also lifting NE as well.

 

But the million dollar question, as always with these setups, is at what speed will that axis lift NE (with the sun setting, that will slow it down) relative to the speed of the MCS.

 

Where it ends up overnight is most likely the best convection will propagate. 

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But the million dollar question, as always with these setups, is at what speed will that axis lift NE (with the sun setting, that will slow it down) relative to the speed of the MCS.

 

Where it ends up overnight is most likely the best convection will propagate. 

LLJ kicks up tonight so I would expect it to continue moving NE as models are showing.

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I get the feeling it will move due E for the next couple hours (hard to deny the primary movement atm is E), then start to drift ESE.  In other words, Madison and Milwaukee will be affected by the north half of the line, and the northern burbs of Chicago should be affected by the southern portion and any southward building storms that pop up overnight.

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What will lake breeze visible on radar do to this sucker? Or will strengthening LLJ later on knock it back and keep it a non-issue?

Definitely looks to have made it less far inland south of IL/WI border.

 

I'm wondering if it will affect the effective warm front.  As for the line itself, the northern portion looks to want to go N of E, and the southern/western portion is trying to push south.  Will it mean the demise of the line as a whole, or which portion will win?

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MKX:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
752 PM CDT MON JUN 16 2014

.UPDATE...
THE SHORT RANGE/HIGH RESOLUTION GUIDANCE HAD BEEN POINTING TO A
LATER SHOW FOR THUNDERSTORMS THAN WHAT IS UNFOLDING THIS EVENING.
BUT...IT/S NOT UNUSUAL FOR THESE MODELS TO BE SLOW WITH THE
EVOLUTION. THE MCS OVER SOUTHERN MN/NRN IA IS ORGANIZING INTO A
QLCS COMPLEX THAT IS EXPECTED TO ROLL INTO OUR FAR WESTERN
COUNTIES BETWEEN 9 AND 10 PM THIS EVENING. IT/S CURRENTLY MOVING
ABOUT 45 TO 50 MPH AND HAS NUMEROUS SEVERE THUNDERSTORM WARNINGS
AND A FEW TORNADO WARNINGS CURRENTLY ALONG IT.

THE AIRMASS OVER SOUTHERN WISCONSIN IS MOISTENING UP RAPIDLY AS
THE WARM FRONT LIFTS NORTH. DEWPOINTS IN THE MID 60S ARE CREEPING
NORTH JUST AHEAD OF THE LINE. BULK SHEAR IS IMPRESSIVE. SO...SEE
NO REASON THAT AN EXTRAPOLATION OF THE CURRENT LINE EASTWARD WILL
NOT BE EFFECTIVE. TYPICAL WITH THESE SYSTEMS...IT SHOULD EVOLVE
INTO PRIMARILY A WIND EVENT WITH AN ISOLD TOR POSSIBLE.
EVENTUALLY...AS WE HIT THE DIURNAL SLUMP...THE CONVECTION SHOULD
LOSE IT/S PUNCH AS IT GETS INTO EASTERN WISCONSIN. WE/LL HAVE TO
WAIT AND SEE ABOUT THAT. A COLD POOL/CDFNT WILL LAY OUT IN THE
WAKE OF THIS LEADING CONVECTION THAT COULD BE THE FOCUS FOR MORE
THUNDERSTORMS LATER TONIGHT INTO THE TUESDAY MORNING. WE/LL HAVE
TO KEEP AN EYE ON TRENDS FOR THE POTENTIAL OF ANY FLOODING.

IT WILL BE AN ACTIVE NIGHT...STAY UP TO DATE ON THE LATEST
FORECASTS AND TRENDS ON RADAR.

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I'm wondering if it will affect the effective warm front. As for the line itself, the northern portion looks to want to go N of E, and the southern/western portion is trying to push south. Will it mean the demise of the line as a whole, or which portion will win?

The combination of increasing low level winds and the end of diurnal heating should wash it out. I'm a bit worried the better instability doesn't make it up here but we'll see how things progress this evening.

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Watch coming

mcd1028.gif

 

 

 

MESOSCALE DISCUSSION 1028
NWS STORM PREDICTION CENTER NORMAN OK
0837 PM CDT MON JUN 16 2014

AREAS AFFECTED...SERN MN...SRN WI...NERN IA...EXTREME NRN IL

CONCERNING...TORNADO WATCH 304...306...

VALID 170137Z - 170300Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 304...306...CONTINUES.

SUMMARY...THE THREAT FOR WIDESPREAD DAMAGING WINDS AND A TORNADO OR
TWO CONTINUES ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA AND
SOUTHWEST WISCONSIN. A DOWNSTREAM WW WILL BE COORDINATED WITH LOCAL
NWS WEATHER FORECAST OFFICES PRIOR TO 0230Z FOR THE REMAINDER OF
SOUTHERN WISCONSIN AND EXTREME NORTHERN ILLINOIS.

DISCUSSION...WELL-DEVELOPED FORWARD PROPAGATING CONVECTIVE SYSTEM
WITH A HISTORY OF SEVERE WIND GUSTS/DAMAGE CONTINUES TO MOVE EAST AT
40 KNOTS ACCOMPANIED BY A WELL-DEVELOPED COLD POOL AND 3-4 MB/2 HR
PRESSURE RISES. WITH TIME...THIS SYSTEM SHOULD TURN MORE ESE ALONG
AN INSTABILITY GRADIENT AND MOVE ACROSS SOUTH-CENTRAL/SERN WI AND
EXTREME NRN IL. THIS SCENARIO IS SUPPORTED BY LATEST HIGH-RES
GUIDANCE...AND THUS A NEW DOWNSTREAM WW WILL BE NEEDED PRIOR TO
0230Z. IN ADDITION...A LOCAL AREAL EXTENSION OF WW 304...OR A NEW
WW...MAY ALSO BE NEEDED FOR THE WFO DAVENPORT CWA. THE PRIMARY
THREAT REMAINS DAMAGING WINDS...POSSIBLY SIGNIFICANT...WITH A
CONTINUED RISK FOR QLCS TORNADOES ASSOCIATED WITH THE MOST INTENSE
BOWING SEGMENTS. ISOLATED LARGE HAIL IS ALSO POSSIBLE...PRIMARILY
OVER THE SRN PORTION OF THE LINE.

..BUNTING/THOMPSON.. 06/17/2014
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