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July 11-14 Severe Weather Event


Powerball

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But you need SW flow in that area to recover.  And if you look at velocity from DVN, you can see that even with SW sfc flow, there's over 90° of turning in the low-mid levels!

People seem to be forgetting that the winds aloft are WNW. We need to treat this as a typical setup turned 45 degrees such that SW winds aren't this kiss of death.

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But you need SW flow in that area to recover. And if you look at velocity from DVN, you can see that even with SW sfc flow, there's over 90° of turning in the low-mid levels!

17z obs show more stations with a SE wind now across northern IL. Let's just say I'm glad I'm out in the field today and not having to make a call for the NWS/SPC.
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AREA FORECAST DISCUSSION  

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  

1205 PM CDT MON JUL 13 2015  

   

MESOSCALE DISCUSSION  

 

1205 PM CDT  

 

MESOSCALE UPDATE...  

 

CONCERN REMAINS HIGH FOR SIGNIFICANT SEVERE THUNDERSTORM DEVELOPMENT  

ACROSS THE WFO LOT CWA THIS AFTERNOON AND EVENING.  

 

LINEAR MCS WHICH MOVED ACROSS THE AREA EARLY THIS MORNING HAD  

CLEARED THE CWA BY LATE MORNING...LEAVING AN OUTFLOW BOUNDARY  

TRAILING FROM EAST CENTRAL IL (BETWEEN CHAMPAIGN AND DECATUR AT 16Z)  

NORTHWEST TO NEAR THE QUAD CITIES (JUST SOUTH OF MOLINE). WHILE SFC  

TEMPS WERE 10-15 F COOLER NORTH OF THIS BOUNDARY...VISIBLE  

SATELLITE IMAGERY SHOWS LITTLE IN THE WAY OF EXTENSIVE CLOUD COVER  

ACROSS THE CWA IN THE WAKE OF THE MORNING COMPLEX. IN ADDITION...  

SFC WINDS HAVE ALREADY VEERED BACK TO THE SOUTH ACROSS THE AREA WITH  

DEW POINTS CLIMBING BACK INTO THE LOW-MID 70S ACROSS OUR WEST. ALL  

OF THIS STRONGLY SUGGESTS THAT THE ATMOSPHERE WILL BE ABLE TO  

RECOVER AND DESTABILIZE...WITH THE COMBINED WARM FRONT/OUTFLOW  

BOUNDARY LIKELY LIFTING BACK NORTHEAST INTO OUR CWA THIS AFTERNOON.  

 

WATER VAPOR IMAGERY...AS WELL AS 12Z RAOB ANALYSIS...INDICATE  

SEVERAL MINOR SHORT WAVE DISTURBANCES UPSTREAM FROM NORTHERN IL  

ACROSS WI/MN...WITH AN 85 KT 300 MB JET STREAK OVER IA. THESE LARGER  

SCALE FEATURES COMBINED WITH LOW LEVEL CONVERGENCE ALONG THE  

FRONT/OUTFLOW BOUNDARY...AND ADDITIONAL LESS ORGANIZED AREAS OF  

CONVERGENCE IN SMALLER BOUNDARIES OVER WI...SHOULD EASILY SUPPORT  

INITIATION OF CONVECTION ACROSS THE REGION THIS AFTERNOON. SATELLITE  

TRENDS INDICATE SOME CU GROWTH OVER SOUTH CENTRAL WI TO NEAR THE  

ROCKFORD AREA CURRENTLY...AND ISOLATED STORMS MAY INITIATE EARLY  

THIS AFTERNOON IN THOSE AREAS...WITH THE WARM FRONT/OUTFLOW BOUNDARY  

LIKELY BECOMING AN INITIATION FOCUS BY MID AFTERNOON. EXTREME  

INSTABILITY WITH MLCAPES IN EXCESS OF 4000 J/KG...EFFECTIVE DEEP  

SHEAR OF 70 KTS...AND STRONG LOW LEVEL SHEAR PARTICULARLY NEAR THE  

COMPOSITE OUTFLOW/WARM FRONTAL BOUNDARY ALL SUPPORT DISCRETE HP  

SUPERCELLAR STORMS OR CLUSTERS... WITH THE MAIN SEVERE THREAT  

LOOKING MORE LIKE HIGH END DAMAGING WINDS...POTENTIAL FOR A FEW  

STRONG TORNADOES...LARGE HAIL AND TORRENTIAL RAINFALL/FLASH  

FLOODING. IT IS STILL A BIT HARD TO SAY...BUT CORRIDOR WITH THE  

GREATEST THREAT LOOKS TO BE FROM NORTH CENTRAL IL SOUTHEAST ACROSS  

EAST CENTRAL IL AND PARTS OF NORTHWEST INDIANA...BUT IT IS STILL TOO  

CLOSE TO RULE OUT THE THREAT EVEN AS FAR NE AS THE CHICAGO METRO  

AREA. EVENTUAL UPSCALE GROWTH INTO A BOWING MCS...WITH PRIMARILY A  

DAMAGING WIND THREAT...LIKELY THIS EVENING TRACKING SOUTHEAST FROM  

OUR CWA.  

 

RATZER  

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Low level clouds moving north with earnest and mid level clouds moving east imby....not quite the "hauling ass" obs I "like" to see for these setups....

Bluest skies I have seen in weeks (not smoke filled) a few miles to my west

Low level thin scuds really moving now out of the south....winds have really kicked up too...out of the S SSW
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Dangerous day ahead for north central Illinois... especially with HP Supercells likely. Why is large hail not more of a concern? SARS shows that hail could be as large as baseballs, and even maybe some softballs. Also FWIW...as of 16Z STP was already up to 4 in west-central IL near DVN, and SB/MUCAPE in SE IA was up to 6000+J/KG

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He shouldn't be.  No one should be.  When you have a closed circ just NW of the region, a bore to mix and destabilize, and no stratiform precip to reinforce the cold pool, rapid T/Td recovery should NOT BE A SURPRISE

 

Seeing is believing.  The visible Sat loop depicts nicely the things you pointed out.  I'm 60 miles NNE of KIND. MCS came through here roughly around 11am.  Can see sunshine poking through the cloud deck off to the NW already.  

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