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snowlover2

2019 Short/Medium Range Severe Weather Thread

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Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1130 AM CDT Mon Aug 12 2019

   Valid 121630Z - 131200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IA TO
   WEST-CENTRAL IN...

   ...SUMMARY...
   A few tornadoes, a couple possibly strong, and significant damaging
   winds will be likely across southeast Iowa through central Illinois,
   mainly this evening.

   ...IA/IL/IN...
   An upgrade to Moderate Risk for tornado and/or wind may become
   necessary in later outlooks today. 

   A leading MCV is tracking east into eastern IA with a lingering
   surface cyclone centered over west-central IA. This latter feature
   should move east into northern IL through this evening. Diffuse
   convective outflow from remnant leading MCS over southern IL has
   been shunted across southeast to northwest MO. Nevertheless, air
   mass recovery is underway north of the boundary into extreme
   southern IA and west-central IL. Further erosion of the prior cold
   pool amid cloud breaks should yield at least weak to moderate
   surface-based buoyancy by late afternoon in IA to northern IL. More
   robust destabilization is expected farther south where greater
   unimpeded insolation occurs while a plume of 77-81 F surface dew
   points is advected north from the Mid-South. Despite relatively warm
   mid-level temperatures, the very rich boundary-layer moisture and
   surface heating should yield a plume of large buoyancy with MLCAPE
   likely reaching 3000-4000 J/kg across much of MO into
   central/southern IL. 

   Renewed thunderstorm development is probable towards late afternoon
   near the surface cyclone in southeast IA and during the early
   evening to the southeast in central IL within a corridor of
   strengthening low-level warm advection. The initial storms will
   likely be supercells capable of producing all hazards, given the
   enhanced low-level shear/hodograph curvature near the cyclone/warm
   front. Hodographs aloft should tend to favor relatively quick
   upscale growth, but even semi-discrete supercells will pose a risk
   for at least a few tornadoes, a couple of which be may strong. A
   forward-propagating MCS should eventually evolve along the MLCAPE
   gradient from central IL into central IN where severe wind gusts
   will remain a threat before weakening overnight. 

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3 minutes ago, yoda said:

1630z SPC OTLK ramped up TOR probs significantly in W IL and extreme SE IA... 5% at 1300 to 10% hatched on 1630z... hatched wind added to 30% on 1630z OTLK as well

And the disco mentions an upgrade to moderate risk might be needed later.

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2 minutes ago, snowlover2 said:

And the disco mentions an upgrade to moderate risk might be needed later.

Yup.  45% hatched wind is mod on wind chart while 15% hatched is mod on tor chart

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COD is down, but there's an odd quirk.  While I cannot make any fresh connections to the site, the two radar loops I had running yesterday when COD went down are still working and continue to refresh.

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Enhanced added to the IA/IL/MO border area for hail although a 5% tornado area added also.

Quote

..KS TO LOWER MI  
 
ELEVATED CONVECTION IS ONGOING WITHIN A LOW-LEVEL WARM ADVECTION  
REGIME ACROSS THE MID-MO VALLEY AND NORTHERN IL. ROBUST  
BOUNDARY-LAYER HEATING IS UNDERWAY IN THE WAKE OF THIS MORNING  
ACTIVITY BENEATH AN ELEVATED MIXED LAYER THAT IS ATTEMPTING TO  
ADVECT NORTHEAST FROM THE CENTRAL GREAT PLAINS/LOWER MO VALLEY. IN  
CONJUNCTION WITH SURFACE DEW POINTS INCREASING INTO THE UPPER 60S TO  
LOWER 70S SURFACE DEW POINTS, A STRONGLY UNSTABLE AIR MASS WITH  
MLCAPE OF 2500-3500 J/KG SHOULD DEVELOP AHEAD OF A  
SOUTHWEST-NORTHEAST COLD FRONT FROM EASTERN KS TO THE IA/IL/MO  
BORDER AREA.  
 
DESPITE NEAR-NEUTRAL MID-LEVEL HEIGHT TENDENCY, GUIDANCE IS FAIRLY  
CONSISTENT WITH THE PRESENCE OF A MID-LEVEL SPEED MAX DEVELOPING  
ACROSS NORTHEAST KS THIS AFTERNOON AND REACHING THE IA/IL BORDER  
AREA THIS EVENING. WHILE THE BULK OF INITIAL CONVECTIVE DEVELOPMENT  
MAY BE ATOP A MORE STABLE BOUNDARY-LAYER FROM CENTRAL IA TO SOUTHERN  
WI, SUFFICIENT CONVERGENCE SHOULD EXIST FOR STORM DEVELOPMENT ALONG  
THE FRONT AND INTO THE WARM SECTOR FROM ITS INTERSECTION WITH THE  
DIFFERENTIAL HEATING BOUNDARY IN NORTHERN IL TO THE DRYLINE  
INTERSECTION IN SOUTH-CENTRAL KS. THE GREATEST CONVECTIVE COVERAGE  
SHOULD RESIDE NEAR THE IA/IL/MO BORDER REGION WITH MORE SCATTERED  
COVERAGE BACK INTO EASTERN KS.  
 
LOW TO DEEP-LAYER WIND PROFILES WILL FAVOR POTENTIAL FOR SEVERAL  
SUPERCELLS DURING THE EARLY EVENING WHICH WILL PROBABLY CONSOLIDATE  
INTO MULTIPLE ORGANIZED CLUSTERS THROUGH LATE EVENING. LARGE HAIL  
WILL BE THE MOST PROBABLE HAZARD WITH SCATTERED SEVERE WIND GUSTS  
EXPECTED AS WELL. GIVEN RICH BOUNDARY-LAYER MOISTURE AND AN ENLARGED  
LOW-LEVEL HODOGRAPH, CERTAINLY A TORNADO RISK WILL EXIST WITH ANY  
SUPERCELLS JUST AHEAD OF THE FRONT. 12Z HREF GUIDANCE AND RELATED  
CAMS ARE INDICATIVE OF HIGHER-END TORNADO COVERAGE. HOWEVER, WITH  
CYCLOLYSIS EXPECTED, THE OVERALL SYNOPTIC PATTERN SHOULD BE A  
LIMITING FACTOR. STILL, GIVEN THE POTENTIAL FOR AT LEAST A FEW  
TORNADOES, WILL DOUBLE-UPGRADE FROM LESS THAN 2 PERCENT TO A 5  
PERCENT AREA WITH THIS OUTLOOK.

 

swody1_categorical.png

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1 hour ago, IWXwx said:

Looking forward to 'nado vid that Cyclone is gonna snag

Best parameters are just a smidge sw of him although I presume they will move into his territory as the day progresses.  2500 MLCAPE, 8,5 mid level lapse rates, low LCL's, 3km helicity up to 350.  Heck, I'm even wondering if there could be some action down my way later tonight or just north of me across IL and IN.  87/64 here now.

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1 hour ago, Indystorm said:

Best parameters are just a smidge sw of him although I presume they will move into his territory as the day progresses.  2500 MLCAPE, 8,5 mid level lapse rates, low LCL's, 3km helicity up to 350.  Heck, I'm even wondering if there could be some action down my way later tonight or just north of me across IL and IN.  87/64 here now.

40% EF2+ tornado probs in the watch area. 

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Gonna have a hard time getting tornadoes with such a stable near surface environment. The only potential for surface based storms appears to be S of 74. Probably gonna be some decent hail reports regardless.

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10 minutes ago, hlcater said:

Gonna have a hard time getting tornadoes with such a stable near surface environment. The only potential for surface based storms appears to be S of 74. Probably gonna be some decent hail reports regardless.

you can tell on the Visible there may be some sort of inversion layer in the "warm"sector...so storms may be elevated

 

.and its late september now....so peak heating over 

 

also 5+ inches here in north side of  the city so far today

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21 minutes ago, janetjanet998 said:

you can tell on the Visible there may be some sort of inversion layer in the "warm"sector...so storms may be elevated

 

.and its late september now....so peak heating over 

 

also 5+ inches here in north side of  the city so far today

Some wild flooding photos and videos coming out of the Peoria metro. 

 

8605457C-7FD2-4248-B696-8C20EBCC2676.jpeg

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5 minutes ago, SchaumburgStormer said:

Some wild flooding photos and videos coming out of the Peoria metro. 

 

8605457C-7FD2-4248-B696-8C20EBCC2676.jpeg

Northwoods Mall is off to the right of that picture across the road..Lowpoint is about 15 miles NE of Peoria

0315 PM     HEAVY RAIN       4 NW PEORIA             40.79N 89.66W   
09/27/2019  M5.25 INCH       PEORIA             IL   PUBLIC            
  
            NEAR NORTHWOODS MALL  

 

0415 PM     HEAVY RAIN       LOW POINT               40.88N 89.32W   
09/27/2019  M7.82 INCH       WOODFORD           IL   BROADCAST MEDIA   
  
            RELAYED VIA WEEK-TV  
     

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Wouldn't be surprised to see a 5% introduced across central IA later. Plenty of 0-3km CAPE available, along with half decent turning in the low levels. Just hinges on discrete/semi discrete activity. 

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1 hour ago, hlcater said:

Wouldn't be surprised to see a 5% introduced across central IA later. Plenty of 0-3km CAPE available, along with half decent turning in the low levels. Just hinges on discrete/semi discrete activity. 

They did add a 5% tornado area but from NE KS to SW/South Central IA.

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Watching the system at the end of next week.  Could have some severe potential.  Currently looks like the duration of moisture return is going to be somewhat limited but could be good enough.  

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Guidance is in better agreement now on the slower solution.

One of the negatives in this setup looks like junky mid level lapse rates.  That could be overcome to some degree if forcing is strong enough but still a bit too far out to get into the finer details on system evolution.  

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Interesting CIPS... there are a few big fall outbreaks in there, a couple smaller ones and quite a few that produced no severe wx in the region.  Take your pick lol.  

I'd probably lean away from the bigger ones toward one of the smaller ones at this point given the concern about instability/mid level lapse rates.  Usually it's sort of hard to reverse the mid level lapse rate problem on the models once it's there.  Maybe pure advection can drive the temps up above guidance and help out the instability a bit.

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