PatrickSumner Posted April 18, 2011 Share Posted April 18, 2011 OMG...Up to 50 on that tor probability for south central Indiana? Am I seeing that correctly? We haven't had too many 50's yet this season. Did not look at progs for the Carolina outbreak. And the WRF. EHI values. 54 hours out...cap will def be gone by then... Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 18, 2011 Author Share Posted April 18, 2011 Somebody tell the NAM Elevated complex that developed in MO late Monday night/Tuesday morning. Still capped where it counts. Link to comment Share on other sites More sharing options...
BrentO Posted April 18, 2011 Share Posted April 18, 2011 http://beta.wxcaster.com/cgi-bin/parse_skewt_trace.cgi?model=NAM&fcsthr=051&STATIONID=kevv ......well if we could get the CINh to go away and boost the 0-3KM CAPE could work with that EHI of 12.1 and STP of 10.2 Link to comment Share on other sites More sharing options...
Hoosier Posted April 18, 2011 Share Posted April 18, 2011 A bit of a veer-back-veer pattern but this is a scary sounding for 2 AM Link to comment Share on other sites More sharing options...
PatrickSumner Posted April 18, 2011 Share Posted April 18, 2011 A bit of a veer-back-veer pattern but this is a scary sounding for 2 AM Yeah, I got a gut feeling its going to get ugly around here Tuesday night... Link to comment Share on other sites More sharing options...
Hoosier Posted April 18, 2011 Share Posted April 18, 2011 Elevated complex that developed in MO late Monday night/Tuesday morning. Still capped where it counts. Ok, but look at the sounding I just posted. Even if the mode trends more linear with time, I am concerned about a tornado threat lingering well into the night. Link to comment Share on other sites More sharing options...
snowlord81 Posted April 18, 2011 Share Posted April 18, 2011 A bit of a veer-back-veer pattern but this is a scary sounding for 2 AM Wow, CAPE is still over 2000 and EHI looks impressive. Im not a severe weather forecasted by any means but that does look conducive. Link to comment Share on other sites More sharing options...
Hoosier Posted April 18, 2011 Share Posted April 18, 2011 Wow, CAPE is still over 2000 and EHI looks impressive. Im not a severe weather forecasted by any means but that does look conducive. And 0-3 km CAPE is near 150 on that sounding. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 18, 2011 Author Share Posted April 18, 2011 Ok, but look at the sounding I just posted. Even if the mode trends more linear with time, I am concerned about a tornado threat lingering well into the night. I was only disputing the cap issue. The overall threat is legit and will last well after dark...otherwise I wouldn't be chasing. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 Still like the area between St.Louis, Springfield IL, and Hannibal Missouri. The new NAM dropped things a bit further south compared to previous runs, but hopefully the trend's about over. The SREF looks a bit too far east as usual. I'm not too worried about the cap with the incoming shortwave and associated height falls. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 Love the high theta-e feeding north-northwest into the area north of St. Louis at 925mb on the new NAM. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 18, 2011 Share Posted April 18, 2011 Going to be strongly dependent on the quality of the upper phase. Latest GFS shows what a poor phase can do. Looks Euro like. Link to comment Share on other sites More sharing options...
Indystorm Posted April 18, 2011 Share Posted April 18, 2011 Agree with you Cyclone. But I will still be watching the I-70 corridor eastward into IL and IN that evening and night. Cap may not be insurmountable since it is spring and not summer. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 The new GFS is much quicker compared to the 12z. Timing wise it matches the 00z NAM pretty well. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 FWIW, the 00z RGEM ignites convection along the warm front eastward through Indiana. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 18, 2011 Author Share Posted April 18, 2011 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT MON APR 18 2011 VALID 191200Z - 201200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF AR/MO/IL/INDIANA/KY AND FAR WESTERN TN... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS TO THE MIDWEST/OH RIVER VALLEY... ..MIDWEST/OZARKS AND OH/MIDDLE MS RIVER VALLEYS A VERY ACTIVE SEVERE WEATHER DAY IS EXPECTED ACROSS THE REGION ON TUESDAY/TUESDAY NIGHT...INCLUDING THE POSSIBILITY OF SOME STRONG TORNADOES IN ADDITION TO LARGE HAIL AND WIDESPREAD DAMAGING WINDS TUESDAY AFTERNOON/NIGHT. INITIALLY...EARLY DAY ELEVATED TSTMS /SOME CAPABLE OF SEVERE HAIL/ WILL BE ONGOING ACROSS THE MIDWEST/OH RIVER VALLEY...ON THE NOSE OF A STRONG SOUTHWESTERLY LOW LEVEL JET AND ON THE EDGE OF A NORTHEASTWARD BUILDING ELEVATED MIXED LAYER /EML/. SUCH A HAIL THREAT COULD INCLUDE DOWNSTATE PORTIONS OF IL/INDIANA INTO KY/SOUTHERN OH THROUGH THE MORNING. OTHERWISE...BENEATH AN EML-DRIVEN CAP...LOW LEVEL MOISTURE WILL CONTINUE TO AGGRESSIVELY RETURN NORTH-NORTHEASTWARD AS STRONG SOUTHWESTERLY LOW LEVEL WINDS ARE MAINTAINED THROUGH THE DAY. WITH RELATIVELY RICH MOISTURE /AROUND 70 F SURFACE DEWPOINTS AND REFERENCE THE 00Z OBSERVED CORPUS CHRISTI RAOB/ ALREADY RETURNING INLAND ACROSS SOUTHEAST TX EARLY TODAY...IT IS PLAUSIBLE THAT A BROAD CORRIDOR OF LOWER TO MIDDLE 60S F SURFACE DEWPOINTS WILL BECOME INCREASINGLY ESTABLISHED TO THE EAST OF A LOWER MO VALLEY SURFACE LOW AND ALONG/SOUTH OF A NORTHWARD MOVING WARM FRONT ACROSS THE OH RIVER VALLEY/MIDWEST. BENEATH THE STRONG EML/PLUME OF STEEP MID LEVEL LAPSE RATES...MODERATELY TO STRONG INSTABILITY WILL LIKELY EXIST ACROSS THE PRE-COLD FRONTAL WARM SECTOR BY AFTERNOON...WITH UPWARDS OF 2000-4000 J/KG OF MLCAPE POSSIBLE WITHIN A CORRIDOR FROM EASTERN OK AND AR INTO THE SOUTHEAST HALF OF MO/DOWNSTATE IL AND ADJACENT PORTIONS OF THE MIDDLE MS VALLEY. A SOUTH-CENTRAL ROCKIES/CENTRAL PLAINS SHORTWAVE TROUGH EARLY TUESDAY IS EXPECTED TO GRADUALLY AMPLIFY AND ADVANCE NORTHEASTWARD/TAKE ON A MORE NEGATIVE TILT ESPECIALLY TUESDAY NIGHT TOWARD THE UPPER MS RIVER VALLEY/UPPER GREAT LAKES REGION. ATTENDANT LARGE SCALE FORCING FOR ASCENT/HEIGHT FALLS AND THE ASSOCIATED COLD FRONT SHOULD ERODE AN OTHERWISE STRONG CAP...WITH SURFACE BASED TSTMS LIKELY TO ERUPT BY MID/LATE AFTERNOON INTO EARLY EVENING AHEAD OF THE DEEPENING LOWER MO VALLEY/MIDDLE MS VALLEY SURFACE LOW AND NORTHEAST-SOUTHWEST ORIENTED COLD FRONT. SUCH VIGOROUS DEEP CONVECTIVE DEVELOPMENT CURRENTLY APPEARS MOST LIKELY TO INITIALLY OCCUR ACROSS CENTRAL/SOUTHWEST MO AS WELL AS WESTERN IL AND NORTHWEST AR/NORTHEAST OK. AMPLE LOW LEVEL MOISTURE/VERY STEEP LAPSE RATES AND DEEP LAYER SHEAR OF 40-50 KT COINCIDENT WITH THE COLD FRONT/ADJACENT WARM SECTOR WILL BE FURTHER ACCENTUATED BY LONG/CURVING LOW LEVEL HODOGRAPHS AIDED BY 40-55 KT WINDS WITHIN THE LOWEST 1-2 KM. WHILE VERY LARGE HAIL AND TORNADOES /PERHAPS A FEW STRONG/ WILL BE POSSIBLE WITH INITIAL SUPERCELLULAR DEVELOPMENT...SEVERAL FACTORS IMPLY A QUASI-LINEAR EVOLUTION IS PROBABLE SEVERAL HOURS AFTER DEEP CONVECTIVE INITIATION /ESPECIALLY MID EVENING AND BEYOND/ ACROSS THE MIDWEST/OH VALLEY. THIS INCLUDES THE LIKELIHOOD/DOMINANCE OF COLD FRONTAL-TYPE INITIATION /GIVEN A STOUT EML OTHERWISE ACROSS THE WARM SECTOR/...AS WELL AS RELATIVELY MODEST HIGH LEVEL FLOW/SHEAR AS COMPARED TO THE LOWER-MIDDLE TROPOSPHERE. UPSCALE GROWTH INTO AN INCREASINGLY WELL-ORGANIZED/ACCELERATING SQUALL LINE...INCLUDING LEWP/BOW EVOLUTIONS....IS PROBABLE TUESDAY NIGHT ACROSS THE OH VALLEY. AS SUCH...A WIDESPREAD DAMAGING WIND AND ISOLATED TORNADO THREAT SHOULD EVOLVE BY MID/LATE EVENING...AND CONTINUE INTO THE OVERNIGHT. A RELATIVELY BROAD WARM/MOIST SECTOR ASIDE...THIS WILL BE SUPPORTED ON THE LARGE SCALE BY THE ANTICIPATED DEEPENING PHASE OF THE SURFACE CYCLONE TOWARD THE UPPER GREAT LAKES AND A REINVIGORATION OF A NOCTURNALLY ENHANCED LOW LEVEL WIND FIELD /50-60 KT SOUTHWESTERLY WINDS AROUND 1-2 KM/. ..SOUTHERN PLAINS/ARKLATEX PARTIALLY ATTRIBUTABLE TO MORE MODEST LARGE SCALE FORCING FOR ASCENT AT THESE LATITUDES...A RELATIVELY MORE ISOLATED SEVERE THREAT WILL BE POSSIBLE IN VICINITY OF THE NORTH-SOUTH DRYLINE ACROSS EASTERN OK/NORTHEAST TX INTO WESTERN AR/FAR NORTHWEST LA. SUPERCELLS CAPABLE OF LARGE HAIL AND PERHAPS A TORNADO WILL BE POSSIBLE TUESDAY LATE AFTERNOON/EVENING. THE COLD FRONT WILL GRADUALLY OVERTAKE THE DRYLINE FROM NORTHWEST TO SOUTHEAST ACROSS EASTERN OK INTO AR AND EVENTUALLY NORTH TX/FAR NORTHWEST LA TUESDAY NIGHT. FARTHER WEST...OTHER MORE ISOLATED/MARGINAL SEVERE TSTMS WITH A HAIL/WIND RISK COULD DEVELOP ALONG THE WESTWARD EXTENSION OF THE SOUTH-SOUTHEASTWARD MOVING COLD FRONT ACROSS OK AND THE TX PANHANDLE TUESDAY LATE AFTERNOON/EARLY EVENING. ..GUYER.. 04/18/2011 Link to comment Share on other sites More sharing options...
Stebo Posted April 18, 2011 Share Posted April 18, 2011 Kind of surprised how far the risk area goes north, although I suppose north of the WF will probably be some elevated hailers. Link to comment Share on other sites More sharing options...
CUmet Posted April 18, 2011 Share Posted April 18, 2011 Honestly, I'm leaning towards this being more of a widespread damaging wind event than a massive tornado outbreak like we've seen. The reasons are very well outlined in the 06z Day 2 outlook. This is not to say that the tornado threat is minimal at all, though, as I expect quite a few to form Tuesday regardless, with a few strong. Link to comment Share on other sites More sharing options...
Stebo Posted April 18, 2011 Share Posted April 18, 2011 Honestly, I'm leaning towards this being more of a widespread damaging wind event than a massive tornado outbreak like we've seen. The reasons are very well outlined in the 06z Day 2 outlook. This is not to say that the tornado threat is minimal at all, though, as I expect quite a few to form Tuesday regardless, with a few strong. Yeah I would have to agree here, the highest threat will be widespread wind damage with tornadoes being the second significant threat. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 18, 2011 Share Posted April 18, 2011 As SPC stated, impressive moisture return from the CRP sounding this evening. Here it is compared with FWD (in orange). Not only is the surface moisture return impressive, but as has been stated in this thread, the depth (through 850 mb) is as well. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 18, 2011 Share Posted April 18, 2011 Another point SPC brought up that I noticed as well is the placement of upper forcing relative to the instability. Below is the 00z GFS run 0-4km thetae and jet winds. Notice that the core of the strongest winds remains on the cool side of the surface boundary (hence initiation being tied to that boundary). Compare those images to the day of the eastern Oklahoma outbreak, which had the core of strongest winds aloft punching directly over the warm sector. Link to comment Share on other sites More sharing options...
BrentO Posted April 18, 2011 Share Posted April 18, 2011 I'm gonna sound like a total noob here but oh well, so what does that mean for Tues? ^^^^^^ Link to comment Share on other sites More sharing options...
OceanStWx Posted April 18, 2011 Share Posted April 18, 2011 I'm gonna sound like a total noob here but oh well, so what does that mean for Tues? ^^^^^^ Pretty much confirming some of the analysis already in this thread. The warm sector will remain capped until surface boundary impinges on the instability and initiates convection along it. Initially supercells will be supported, but owing to the fact that the forcing will be along a cold front with upper level flow parallel to the boundary, upscale growth into linear segments is favored. An isolated tornadic threat will continue with the line after that due the large low level shear, and near the triple point/warm front any semi-discrete structure will have a chance to produce as well. Link to comment Share on other sites More sharing options...
csnavywx Posted April 18, 2011 Share Posted April 18, 2011 Pretty much confirming some of the analysis already in this thread. The warm sector will remain capped until surface boundary impinges on the instability and initiates convection along it. Initially supercells will be supported, but owing to the fact that the forcing will be along a cold front with upper level flow parallel to the boundary, upscale growth into linear segments is favored. An isolated tornadic threat will continue with the line after that due the large low level shear, and near the triple point/warm front any semi-discrete structure will have a chance to produce as well. Winds are actually maxed closer to 700mb with weaker winds aloft at 500 and 300. There's a pretty pronounced and well defined jet streak at the 700mb and 850 levels, producing a very non-classical look to the wind profiles. Since we're dealing with what looks to be a wind max near or just below the LND, I'd have to think that we'd have to look near the nose of that streak to find where the cap breach is most likely at first. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 18, 2011 Share Posted April 18, 2011 12z NAM is impressive with lapse rates and parameters tomorrow over southern MO into IN. If supercells or a supercell can form in eastern MO into Illinois then the potential is certainly there for a strong tornado. Soundings show winds backing tomorrow evening over the KPAH region. Low is a bit further south and east than some other runs. Moderate risk seems well placed - question will be storm mode. Squall line is a given - question remains on discreet cells. The CAP is very impressive tomorrow over the region. Weakens late in the day and evening. Though SPC might put a slight over us for some hailers tonight. Link to comment Share on other sites More sharing options...
BrentO Posted April 18, 2011 Share Posted April 18, 2011 CAP doesn't appear as strong over IN and KY at 21z : Cinh But still pretty stout over central IL southwest in the STL area. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 The RGEM breaks the cap as early as 19z in northeast Missouri. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 18, 2011 Share Posted April 18, 2011 South of Springfield on 12z GFS. Looks pretty nice up through H7. Definitely good enough to get me out the door. Link to comment Share on other sites More sharing options...
hooralph Posted April 18, 2011 Share Posted April 18, 2011 I will be in Indy tomorrow through Wednesday. My first big midwest Severe outbreak! Link to comment Share on other sites More sharing options...
snowlord81 Posted April 18, 2011 Share Posted April 18, 2011 This may be a dumb question to alot of you but could someone explain what a hodograph is? I've got the skew-t's down, I just always see the hodo and cant quite interept what its showing. Thanks! Link to comment Share on other sites More sharing options...
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