LouWX Posted April 16, 2013 Share Posted April 16, 2013 Mid level lapse rates are very marginal that's the first issue. Second is how the models handle the surface temps after dark. I haven't yet modified a sounding but would think that 250-750 units are possible ahead of the line higher west in IL. With the extreme shear present this will either be just enough or the updrafts will get knocked over. The forcing should help with this. Link to comment Share on other sites More sharing options...
Hoosier Posted April 16, 2013 Share Posted April 16, 2013 Thursday setup looks pretty decent and has moderate risk potential imo if the uncertainties break favorably. I think the ceiling is higher with this one compared to April 10. Link to comment Share on other sites More sharing options...
Gilbertfly Posted April 16, 2013 Share Posted April 16, 2013 new D2 inlcudes LOT in the slight Link to comment Share on other sites More sharing options...
snowlover2 Posted April 16, 2013 Share Posted April 16, 2013 Might get a watch here. MESOSCALE DISCUSSION 0483 NWS STORM PREDICTION CENTER NORMAN OK 1256 PM CDT TUE APR 16 2013 AREAS AFFECTED...MUCH OF SRN OH/SERN IND/NERN KY/PART OF WRN WV CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 161756Z - 161930Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...POTENTIAL EXISTS FOR TSTMS MOVING EWD INTO AND/OR DEVELOPING ACROSS THE MIDDLE-UPPER OH VALLEY THIS AFTERNOON WILL INTENSIFY AND BECOME SEVERE. WW ISSUANCE IS POSSIBLE BY MID-LATE AFTERNOON WITH DAMAGING WINDS AND HAIL BEING THE PRIMARY THREATS. DISCUSSION...TRENDS IN LATE MORNING-EARLY AFTERNOON SURFACE ANALYSES ACROSS THE OH VALLEY SHOWED A COLD FRONT ADVANCING EWD INTO NORTH CENTRAL TO WEST CENTRAL OH...AND FAR SWRN IND. THE TRAILING PORTION OF THIS BOUNDARY HAD REMAINED GENERALLY QUASI-STATIONARY FROM FAR SRN IL THROUGH NWRN AR AND SOUTH CENTRAL OK. OBJECTIVE ANALYSES INDICATED DESTABILIZATION UNDERWAY ACROSS THE WARM SECTOR WHICH EXTENDED INTO THE MIDDLE AND UPPER PORTIONS OF THE OH VALLEY WITH SURFACE DEWPOINTS INTO THE LOWER 60S BENEATH THE ERN EXTENT OF THE STEEPER MIDLEVEL LAPSE RATES /7-7.5 C PER KM/. DESPITE GRADUAL HEIGHT RISES AND SOME MIDLEVEL WARMING...FURTHER LOW LEVEL MOISTENING SHOULD PROVE SUFFICIENT IN SUPPORTING A MODERATELY UNSTABLE ENVIRONMENT ACROSS MOST OF THE DISCUSSION AREA BY PEAK HEATING FOR STORMS TO BECOME SURFACE BASED. MEANWHILE...A CLUSTER OF PERSISTENT TSTMS UPSTREAM OVER CENTRAL IND...CENTRAL IL TO FAR EAST CENTRAL MO IS LOCATED N OF THE SURFACE FRONT AND LIKELY ROOTED AROUND 850 MB PER RECENT RAP SOUNDINGS. THIS ACTIVITY APPEARS TO BE SUPPORTED BY LOW LEVEL WAA AND ASCENT ATTENDANT TO A SUBTLE MIDLEVEL IMPULSE. TRENDS IN THE HRRR THIS MORNING AND THE 12Z 4 KM WRF-NSSL...DESPITE TIMING DIFFERENCES IN THE LATTER MODEL...SUGGEST THE IND/IL STORMS COULD DEVELOP A COLD POOL AS THIS ACTIVITY REACHES SERN IND INTO SRN OH. ALTHOUGH LOW LEVEL WINDS ARE WEAKENING IN THE DISCUSSION AREA...50 KT WLY MIDLEVEL WINDS WILL MAINTAIN SUFFICIENT BULK SHEAR FOR STORMS TO BECOME ORGANIZED WITH ACTIVITY EVENTUALLY TRACKING TOWARD THE ESE PRODUCING A THREAT FOR PRIMARILY DAMAGING WINDS AND HAIL. Link to comment Share on other sites More sharing options...
snowlover2 Posted April 16, 2013 Share Posted April 16, 2013 New t-storm watch here until 11pm. Link to comment Share on other sites More sharing options...
wxhstn74 Posted April 16, 2013 Share Posted April 16, 2013 Periods of Strong to Severe Storms Possible Thursday Into Friday! Link to comment Share on other sites More sharing options...
Buckeye05 Posted April 16, 2013 Share Posted April 16, 2013 Just got a burst of dime-size hail at my location . Link to comment Share on other sites More sharing options...
Chinook Posted April 16, 2013 Share Posted April 16, 2013 New t-storm watch here until 11pm. Looks like large hail is starting to pop in Cincinnati and Columbus. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 16, 2013 Share Posted April 16, 2013 Might need a TW for Henryville, IN. Link to comment Share on other sites More sharing options...
Indystorm Posted April 16, 2013 Share Posted April 16, 2013 I do think concern is growing for Thursday into Friday for those in IN/KY/MI based on recent model trends of the GFS. It was in the low 80's today with 65 dews from Evansville over to Louisville. Kinematics with this system look to be strong and it wouldn't take much to get that warm front northward. As always insolation and instability issues are there but the potential for the first real svr outbreak in the heartland seems to be there unless messy convection or stratus foul things up. Link to comment Share on other sites More sharing options...
andyhb Posted April 16, 2013 Share Posted April 16, 2013 The 12z GFS has some very beefy 0-3 km CAPE values on Thursday. Link to comment Share on other sites More sharing options...
frostfern Posted April 16, 2013 Share Posted April 16, 2013 The GFS has more CAPE now. There's always the stupid Lake MI hole making it look less impressive but I think the GFS overdoes that. With such strong wind fields the warm air should glide right over top the lake stratus layer without cooling much at all. The only real issue is the entire column will be pretty moist with a tall-skinny tropical looking CAPE by then. There could be too much precip coverage to allow strong discrete supercells. With that much shear squall lines can produce tornadoes too though so you can't completely rule it out. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 17, 2013 Share Posted April 17, 2013 From a chasing standpoint, I'm actually more interested in the warm front in central IL tomorrow. Looks very similar to last Wednesday, only with better parameters. Agree that Thursday's even looks significant, but a massive QLCS isn't really all that chase-able. Link to comment Share on other sites More sharing options...
Stebo Posted April 17, 2013 Share Posted April 17, 2013 From a chasing standpoint, I'm actually more interested in the warm front in central IL tomorrow. Looks very similar to last Wednesday, only with better parameters. Agree that Thursday's even looks significant, but a massive QLCS isn't really all that chase-able. It is, but you usually get one shot before you get swamped by the line and then have to play catch up. Link to comment Share on other sites More sharing options...
frostfern Posted April 17, 2013 Share Posted April 17, 2013 It is, but you usually get one shot before you get swamped by the line and then have to play catch up. I've never had success trying to punch back through a line from the back. Either run into a traffic jam or have to slow way down to avoid hydroplaning. Most of the "chasing" I've tried to do in Michigan was more like trying to position myself for a nice shelf view and then hunker down. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 17, 2013 Share Posted April 17, 2013 Probably gonna fail again, but we'll be out chasing Thu somewhere down in central or southern IL. I've been extremely busy all day and night and haven't had a chance to look at anything yet, but from the sounds of it everything still looks decent. Link to comment Share on other sites More sharing options...
Stebo Posted April 17, 2013 Share Posted April 17, 2013 Probably gonna fail again, but we'll be out chasing Thu somewhere down in central or southern IL. I've been extremely busy all day and night and haven't had a chance to look at anything yet, but from the sounds of it everything still looks decent. I am thinking I will also be out and about on Thursday probably somewhere in MI if things continue to look the way they are right now. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 17, 2013 Share Posted April 17, 2013 I am thinking I will also be out and about on Thursday probably somewhere in MI if things continue to look the way they are right now. Good luck. After my 2012 and the dismal chase last Sunday I'm having a hard time being optimistic. Need a slump breaker. Link to comment Share on other sites More sharing options...
Indystorm Posted April 17, 2013 Share Posted April 17, 2013 Good luck. After my 2012 and the dismal chase last Sunday I'm having a hard time being optimistic. Need a slump breaker. I'm thinking that this chase will be much more productive than Sunday's. Link to comment Share on other sites More sharing options...
Brewers Posted April 17, 2013 Share Posted April 17, 2013 Thinking of heading towards Peoria or Champaign on Thursday, although the potential for heavy rain is concerning. Link to comment Share on other sites More sharing options...
Hoosier Posted April 17, 2013 Share Posted April 17, 2013 From a chasing standpoint, I'm actually more interested in the warm front in central IL tomorrow. Looks very similar to last Wednesday, only with better parameters. Agree that Thursday's even looks significant, but a massive QLCS isn't really all that chase-able. A QLCS looks kinda inevitable but I'm wondering if there may be an opportunity for some discrete activity before that happens. Capping looks weak in the warm sector. Link to comment Share on other sites More sharing options...
andyhb Posted April 17, 2013 Share Posted April 17, 2013 Tony posted this over at C/W for Thursday, great stuff here. Farther north, a sleeper play tomorrow is the warm front across NE MO and central IL. Weak-mdt instability will be in place along the front, along with large, looping hodographs. After dark, the NAM and GFS show slight sfc stabilization, but with 50kt winds at 925mb, I would not rule out a tornado threat continuing during the overnight hours, and, depending on the progress of the warm front, maybe even approaching Chicago by 09z or so. A hail threat seems like a foregone conclusion. Then comes the fun on Thursday. This is going to be a very complex scenario that may result in some areas seeing a prolonged, multiple-round significant severe weather episode. The NAM, GFS, and Euro are actually in pretty good agreement about the evolution of convective activity on Thursday. After clearing out the original convection from IL/IN around 12z, another round of convection develops near the MS River and moves across nrn IL, nrn IN, and srn MI between about 15z to the west and 21z to the east. Ahead of that convection, CAPE exceeds 1000J/kg+ and 0-1km SRH of 200-300 m^2/s^2, with 0-6km shear of 45-60kt suggests that, at a minimum, semi-discrete supercell structures with a strong tornado threat are possible, even with this round of convection, despite the timing. And if that weren't enough, the GFS, Euro, and NAM recover the atmosphere immediately behind that round of convection and provide and environment for a significant QLCS with a wind and tornado threat to develop along the cold front around 21z and push across IL and IN. Farther south, the QLCS will continue down the front into AR and eventually push east across TN, KY, MS, and AL through the overnight hours Thursday night/Friday morning. There is some indication that more discrete convection could form ahead of the front giving an lack of capping over the warm sector. Once again, with the amount of boundary layer humidity and the strength of the low-level wind fields, wind and tornadoes will be possible with the QLCS, with that threat lasting overnight across the OH and TN Valleys. Link to comment Share on other sites More sharing options...
hm8 Posted April 17, 2013 Share Posted April 17, 2013 Damn @ tony's post there. Didn't think S. MI was so much in play. If only I didn't have a damn exam Friday morning... Link to comment Share on other sites More sharing options...
Harry Perry Posted April 17, 2013 Share Posted April 17, 2013 If this keeps up I could see the SPC bringing a moderate risk into much of the area... Could get pretty nasty from Alma-south. Link to comment Share on other sites More sharing options...
Stebo Posted April 17, 2013 Share Posted April 17, 2013 Damn @ tony's post there. Didn't think S. MI was so much in play. If only I didn't have a damn exam Friday morning... Study in the car while chasing Link to comment Share on other sites More sharing options...
andyhb Posted April 17, 2013 Share Posted April 17, 2013 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1216 AM CDT WED APR 17 2013 VALID 181200Z - 191200Z ..THERE IS A SLGT RISK OF SVR TSTMS FROM ERN TX TO LOWER MI ..ERN TX TO LOWER MI STRONG MID LEVEL JET CORE WILL EXIT THE BASE OF UPPER TROUGH OVER NM RACING NEWD INTO THE MID MS VALLEY AND INTENSIFY IN EXCESS OF 100KT OVER MO/IA BY 19/00Z. THIS ACCELERATING JET STREAK WILL SHARPEN THE PROGRESSIVE COLD FRONT WHICH IS EXPECTED TO BE THE PRIMARY FOCUS FOR DEEP CONVECTION THROUGH THE PERIOD. LATE DAY1 TSTMS WILL ORGANIZE INTO AN EXTENSIVE SQUALL LINE ALONG THE COLD FRONT WITH MCS EXPECTED TO EXTEND FROM NRN IL...SWWD ACROSS MO INTO NERN TX AT SUNRISE. LATEST NAM SUGGESTS THE MOST SIGNIFICANT BOUNDARY LAYER HEATING WILL OCCUR AHEAD OF THE FRONT NORTH OF I-20 WHERE SFC-3KM LAPSE RATES WILL STEEPEN IN EXCESS OF 7 C/KM. BOUNDARY LAYER THERMALS SHOULD SUPPORT ROBUST UPDRAFTS WITHIN AN ENVIRONMENT YIELDING SBCAPE ON THE ORDER OF 1500 J/KG. FORECAST SHEAR PROFILES ARE QUITE STRONG ALONG THE COLD FRONT WITH IMPRESSIVE FLOW JUST OFF THE SURFACE NORTH OF THE OH RIVER. LATEST THINKING IS EARLY MORNING SQUALL LINE WILL REMAIN ORGANIZED AS IT SURGES EWD. THERE IS REASON TO BELIEVE BOW-TYPE STRUCTURES COULD EVOLVE ALONG THE SQUALL LINE GIVEN THE FAVORABLE SHEAR...IN ADDITION TO EMBEDDED SUPERCELLS THAT COULD PRODUCE ISOLATED TORNADOES. IF MODELS CONTINUE TO DEPICT SUFFICIENT BUOYANCY THERE MAY BE AN ENHANCED RISK OF AN EXTENSIVE DAMAGING WIND EVENT WITH THIS ELONGATED CONVECTIVE COMPLEX. WILL MAINTAIN 30 PERCENT SEVERE PROBS BUT THERE IS SOME CONCERN THIS MAY NEED TO BE UPGRADED IN LATER OUTLOOKS. ..DARROW.. 04/17/2013 Link to comment Share on other sites More sharing options...
hm8 Posted April 17, 2013 Share Posted April 17, 2013 Study in the car while chasing no can do....I get wicked nauseated whenever I do read or anything but look out the window in a moving car It's fine...there will be more opportunities (though I'll be so crazy busy this summer who knows?) Link to comment Share on other sites More sharing options...
A-L-E-K Posted April 17, 2013 Share Posted April 17, 2013 Link to comment Share on other sites More sharing options...
Gilbertfly Posted April 17, 2013 Share Posted April 17, 2013 watch out now per that MCD Link to comment Share on other sites More sharing options...
nwohweather Posted April 17, 2013 Share Posted April 17, 2013 If discrete stuff starts to build I am flying for that border. Don't mind driving a little west Link to comment Share on other sites More sharing options...
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