OUGrad05 Posted April 5, 2015 Share Posted April 5, 2015 Can't get the model data to completely load on my phone Obviously several days out timing is leaving something on the table but that's generally the case this far out. Looks like either Wednesday or Thursday will have some potential. Could definitely split the days as mentioned above but we are about at the point of the year were even systems with blah timing produce some cashable storms and photo opportunities. I don't like okc and ict both under the gun. Lots of people... Will check the models tomorrow when I am at the PC. Link to comment Share on other sites More sharing options...
ZackH Posted April 5, 2015 Share Posted April 5, 2015 Capping is starting to worry me a bit for Wednesday... but most good plains events have some capping concerns. Link to comment Share on other sites More sharing options...
thewxmann Posted April 5, 2015 Share Posted April 5, 2015 Capping is starting to worry me a bit for Wednesday... but most good plains events have some capping concerns. Current positioning of trough is okay regarding capping but could definitely be a concern if the parent system slows down some in subsequent runs. Link to comment Share on other sites More sharing options...
ZackH Posted April 5, 2015 Share Posted April 5, 2015 00z still looking stout... 500s appear a bit stronger... Capping looks like less of an issue and the target may have fallen back west slightly. Surface winds don't really back until 00z but that's okay. Sent from my iPad Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 00z still looking stout... 500s appear a bit stronger... Capping looks like less of an issue and the target may have fallen back west slightly. Surface winds don't really back until 00z but that's okay. Sent from my iPad I'd be really concerned for the OKC metro (perhaps Wichita as well) with the 00z GFS' idea, with the dryline essentially uncapped at 21z with storms firing and then with rapidly strengthening low level shear by 00z as capping strengthens and keeps storms discrete. If we see that dryline positioned west of I-35, trouble is likely in the making. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted April 5, 2015 Share Posted April 5, 2015 I haven't looked closely at the euro, but it looks like it wants to eject the energy out in one piece, much depends on the how the surface reflection transpires, but we could get a major event if the LLJ cooperates. Especially on Thurs April 9th. Link to comment Share on other sites More sharing options...
brettjrob Posted April 5, 2015 Share Posted April 5, 2015 New Euro is crazy, I'd call it something close to everything falling into place to maximize the potential of this trough. Even convects along the DL Tuesday (which I'll believe when it happens, literally). With its solution, it's easy to imagine both Wed and Thu being called "significant" when it's all said and done. I'm still plenty nervous and I think the practical outcome is highly sensitive to somewhat-subtle details, but it's got to be the best an early April system has looked inside of 96-120 h for several years out here. Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 It's not done there either btw, check out 144-192 hrs. Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 New D4-8 outlook, unsurprisingly the only thing preventing them from upgrading to 30% at this juncture for Wed is the uncertainty in storm coverage. Increasingly strong language being used though, no surprise given the general ramp up in solutions since yesterday. DAY 4-8 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK0358 AM CDT SUN APR 05 2015VALID 081200Z - 131200Z...DISCUSSION...APPRECIABLE SPREAD -- EVEN MORE THAN 24 HOURS PRIOR -- IS EVIDENTAMONGST THE MEDIUM-RANGE MODELS THIS FORECAST...WITH THE GFSSHIFTING THE WRN TROUGH INTO THE PLAINS FASTER AND WITH MORE OF APOSITIVE TILT...WHILE THE UKMET AND PARTICULARLY THE ECMWF DEPICT ASLOWER AND MORE NEUTRAL TO NEGATIVE TILT PROGRESSION. AS A RESULTOF THESE DIFFERENCES -- AND THE ASSOCIATED VARIANCES IN SURFACEFEATURE LOCATIONS IN THE DAY 4-5 TIME FRAME...SPECIFICS OF THESEVERE WEATHER FORECAST WITH RESPECT TO TIMING/LOCATION REMAINDIFFICULT TO ASCERTAIN.DESPITE TIMING DIFFERENCES WITH RESPECT TO THE MAIN UPPERLOW/TROUGH...CONFIDENCE HAS INCREASED THIS FORECAST WITH RESPECT TOSEVERE RISK FOR DAY 4 /WED 4-8/ ACROSS CENTRAL AND ERN OK/ERN KS/MO.ALL MODELS INDICATE MID-LEVEL HEIGHT FALLS ACROSS THIS AREA...ANDAT LEAST HINTS OF A SUBTLE/EMBEDDED WAVE CROSSING THE REGION NEARPEAK HEATING. ATTM...EXPECT RESULTING UVV TO BE SUFFICIENT ATOP THEEWD-MIXING DRYLINE TO PERMIT CAP WEAKENING SUFFICIENT TO YIELDISOLATED TO SCATTERED STORM DEVELOPMENT BY LATE AFTERNOON. WITH AVERY MOIST BOUNDARY LAYER AHEAD OF THE DRYLINE TOPPED BY STEEP LAPSERATES...AND A KINEMATIC ENVIRONMENT FEATURING FLOW THAT VEERSSUBSTANTIALLY AND INCREASES STEADILY WITH HEIGHT...SHEAR WILL FAVORLONG-LIVED SUPERCELLS AND ATTENDANT RISK FOR VERY LARGEHAIL...DAMAGING WINDS...AND TORNADOES. GIVEN UNCERTAINTY DUE TOSTORM COVERAGE...WILL MAINTAIN ONLY 15% PROBABILITY AREA ATTM --DESPITE SIGNIFICANT SEVERE WEATHER POTENTIAL WITH ANY STORM THATDOES DEVELOP.THE LIKELIHOOD FOR MORE WIDESPREAD STORMS -- BUT WITH GREATERUNCERTAINTY IN TERMS OF TIMING AND AREA -- EXISTS DAY 5 /THU 4-9/.DEEPENING OF THE SURFACE LOW IN THE KS/NEB/IA VICINITY AND ADVANCEOF A TRAILING COLD FRONT INTO THE CENTRAL/SRN PLAINS WILL FACILITATEA BROAD ZONE OF STORM INITIATION...GIVEN THE MOIST/FAVORABLYUNSTABLE AIRMASS EXPECTED. WITH STRONGER FLOW ALOFT AS COMPARED TODAY 4 GIVEN PROGRESSION OF THE MAIN MID-LEVEL JET STREAK INTO THECENTRAL STATES...SUPERCELL STORMS AND ASSOCIATED RISK FOR VERY LARGEHAIL...DAMAGING WINDS...AND TORNADOES CAN BE EXPECTED.MODELS CONTINUE TO DIVERGE DAY 6 AND BEYOND...AND GIVEN THEINCREASING SPREAD IN SOLUTIONS BETWEEN THEM...LOW CONFIDENCE EXISTSWITH RESPECT TO EVOLUTION OF SEVERE RISK THROUGH THE SECOND HALF OFTHE PERIOD. THUS...LOW PREDICTABILITY PRECLUDES ATTEMPTS TOHIGHLIGHT THREAT AREAS BEYOND DAY 5...GOSS.. 04/05/2015 Link to comment Share on other sites More sharing options...
ZackH Posted April 5, 2015 Share Posted April 5, 2015 We're in the NAM range now, and it is quite impressive to say the least. Diffluent flow over central KS... also under the left exit region of the jet streak... I don't see capping being an issue on Wednesday. While I don't love the NAM at hour 84... its hard not to take notice when it agrees with everything else... I see little that's wrong with the Wednesday setup at this point. Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 I liked the more neutral tilt of the 12z GFS by 00z Thursday. That will only support stronger forcing along the dryline in KS/OK and possibly multiple points of initiation. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 5, 2015 Author Share Posted April 5, 2015 It's down to Wednesday being the only nice looking chase worthy day to me. Gonna try to be out there. Link to comment Share on other sites More sharing options...
nwburbschaser Posted April 5, 2015 Share Posted April 5, 2015 It's down to Wednesday being the only nice looking chase worthy day to me. Gonna try to be out there. I'm not writing Thursday off yet chase wise, but I agree it looks like Wednesday is the day. I'm still holding out hope for something Thursday that would be chase worthy on the way back home if I go for Wednesday. Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 5, 2015 Share Posted April 5, 2015 I'm not writing Thursday off yet chase wise, but I agree it looks like Wednesday is the day. I'm still holding out hope for something Thursday that would be chase worthy on the way back home if I go for Wednesday. I agree too early to kick Thursday do the curb. I think it could definitely be potent in AR. Eastern OK looks possible as well but at this point it would be a lunchtime type event in eastern OK. Not impossible or unheard of but the atmosphere is likely to be worked over from Wednesday. Being this early in April I'm not sure how readily the atmosphere can recover? If it were late afternoon, it would seem to be no problem but a 11am to 1pm? that's early... Link to comment Share on other sites More sharing options...
Jim Marusak Posted April 5, 2015 Share Posted April 5, 2015 is it just me, or am I the only one noticing the inverse troughs on the NAM and GFS near i-29 that mysteriously don't appear at all on the Canadian Global between t+72 and t+96? I'm awaiting the Euro now. I know those would screw up the mix a bit, especially on the moisture flux and dynamics sides. Link to comment Share on other sites More sharing options...
ZackH Posted April 5, 2015 Share Posted April 5, 2015 is it just me, or am I the only one noticing the inverse troughs on the NAM and GFS near i-29 that mysteriously don't appear at all on the Canadian Global between t+72 and t+96? I'm awaiting the Euro now. I know those would screw up the mix a bit, especially on the moisture flux and dynamics sides. I may be referring to a different feature than you... but the only inverted surface trough that I'm seeing is roughly associated with the warm front. Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 Dewpoints already in the 70s on Texas Coast. Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 5, 2015 Share Posted April 5, 2015 Yeah Andy pretty nuts. I was looking at wind profiles etc for the next several days, all out of the south bringing in pretty deep moisture. Feels a lot like an early/mid May setup. Link to comment Share on other sites More sharing options...
Stebo Posted April 5, 2015 Share Posted April 5, 2015 Dewpoints already in the 70s on Texas Coast. That is pretty impressive especially since we are still over 3 days out. Link to comment Share on other sites More sharing options...
Amped Posted April 5, 2015 Share Posted April 5, 2015 The euro looks very impressive on the 12th and 13th. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 5, 2015 Share Posted April 5, 2015 18z NAM looks pretty darn good for Weds but I will say I don't like the weakness the winds above H5. Quite weak at upper levels would lead to believe HP mode but we'll see. I know some have thrown out 4/14/12 and just for reference 250-300mb winds on the 0z raobs that evening at OUN/LMN are around 80-90kts where the NAM is progging 35-40kts. Isolated convective signal at the triple point with great parameters in place. Link to comment Share on other sites More sharing options...
andyhb Posted April 5, 2015 Share Posted April 5, 2015 18z NAM looks pretty darn good for Weds but I will say I don't like the weakness the winds above H5. Quite weak at upper levels would lead to believe HP mode but we'll see. I know some have thrown out 4/14/12 and just for reference 250-300mb winds on the 0z raobs that evening at OUN/LMN are around 80-90kts where the NAM is progging 35-40kts. GFS has significantly stronger flow aloft there with what seems to be a broader left exit region of the subtropical jet. Link to comment Share on other sites More sharing options...
brettjrob Posted April 5, 2015 Share Posted April 5, 2015 18z NAM looks pretty darn good for Weds but I will say I don't like the weakness the winds above H5. Quite weak at upper levels would lead to believe HP mode but we'll see. I know some have thrown out 4/14/12 and just for reference 250-300mb winds on the 0z raobs that evening at OUN/LMN are around 80-90kts where the NAM is progging 35-40kts. This is definitely a concern I share, but these things can be so finicky and hard to nail down. One (crude, optimistic) analog I've been thinking of is 2004-05-29. Several chasers I know chose to stay in OK that day specifically because the jet max was S of I-40, so they feared HP mode up the dryline and closer to the triple point in KS. They were treated to a lovely HP beast that produced a dozen tornadoes across W OK -- approximately none of which were photogenic, and few of which were even visible. Meanwhile, Harper Co. put on the show of the decade for the southern Plains beneath ~60 kt at H25 and ~35 kt at H5. Anecdotal, and probably more the exception than the rule. I'd certainly like to see a greater increase in flow speed with height between H5 and H25. Like that day, though, the best difluence on Wed is N whereas the strongest upper flow is S. Of course, this all assumes the progressive timing of the trough stays on track. I'm as excited as anyone, but I'm trying to keep in perspective that only 48 hours ago, the consensus timing was 12-18 hours slower -- and that oftentimes there's a slowing trend as these systems come ashore. It's fortunate that the ECMWF has been rock solid in initiating along the DL for days now, and that its timing hasn't wavered too much. But obviously, we're not out of the woods yet as far as a heartbreaking cap bust is concerned. Impressed to see another significant southern stream wave on tap for next weekend, as Andy mentioned last night. Pending diurnal timing and adequate recovery of moisture, we might have another shot at something impressive right away... perhaps even over areas of TX that haven't been able to buy favorable synoptic setups for years. Link to comment Share on other sites More sharing options...
RCNYILWX Posted April 5, 2015 Share Posted April 5, 2015 GFS has significantly stronger flow aloft there with what seems to be a broader left exit region of the subtropical jet. 18z GFS continued in that regard, 65-75 kts at h25 over OK at 21z and 00z on Wednesday. Link to comment Share on other sites More sharing options...
kevinbente Posted April 6, 2015 Share Posted April 6, 2015 I agree - Wednesday seems to have the bigger potential over Thursday. Any ideas why analogues are so aggressive for Thursday when instability seems to clearly be lacking, at least on the GFS? Granted, it is only model, but still. Link to comment Share on other sites More sharing options...
thewxmann Posted April 6, 2015 Share Posted April 6, 2015 18z NAM looks pretty darn good for Weds but I will say I don't like the weakness the winds above H5. Quite weak at upper levels would lead to believe HP mode but we'll see. I know some have thrown out 4/14/12 and just for reference 250-300mb winds on the 0z raobs that evening at OUN/LMN are around 80-90kts where the NAM is progging 35-40kts. Isolated convective signal at the triple point with great parameters in place. The good news is that weak winds above H5 is not as much as a deal breaker as high LCLs or VBV wind profiles are. If I recall correctly both Pilger from last year and 6/17/10 were prolific tornado events with fairly weak winds above H5. Link to comment Share on other sites More sharing options...
ZackH Posted April 6, 2015 Share Posted April 6, 2015 The 00z NAM is pretty eye popping verbatim. Link to comment Share on other sites More sharing options...
Jim Marusak Posted April 6, 2015 Share Posted April 6, 2015 I agree - Wednesday seems to have the bigger potential over Thursday. Any ideas why analogues are so aggressive for Thursday when instability seems to clearly be lacking, at least on the GFS? Granted, it is only model, but still. wednesday is looking more like a mesoscale day for sure. but when it comes to thursday, if the models are close on the timing, what you lose in thermodynamic buoyancy you get back in not only shear, but also pure synoptic forcing (frontal lift and a vigorous vortmax resulting from the upper air low synching rather well) which can over-ride most of the mesoscale thermodynamic buoyancy issues. Link to comment Share on other sites More sharing options...
andyhb Posted April 6, 2015 Share Posted April 6, 2015 wednesday is looking more like a mesoscale day for sure. but when it comes to thursday, if the models are close on the timing, what you lose in thermodynamic buoyancy you get back in not only shear, but also pure synoptic forcing (frontal lift and a vigorous vortmax resulting from the upper air low synching rather well) which can over-ride most of the mesoscale thermodynamic buoyancy issues. How so? Everything I'm seeing is indicating that Wednesday will be driven heavily by the synoptic side, particularly the timing of the synoptic scale trough. Link to comment Share on other sites More sharing options...
brettjrob Posted April 6, 2015 Share Posted April 6, 2015 The 00z NAM is pretty eye popping verbatim. There's been a clear and steady slowing trend with the progression of the upper trough, though, from the 12z run this morning to tonight's 00z run. Whether it means anything, being the NAM beyond H+48 and a synoptic-scale feature upstream of the CONUS, is questionable. But I'm nervously keeping an eye on whether that trend occurs with the GFS or Euro. I will say that the lack of explicit QPF on the NAM down the dryline doesn't bother me at this stage, given the BMJ convective scheme is known to struggle in this scenario. If anyone gets nervous about that, just know that it showed a cap bust along the length of the dryline the night before this. Link to comment Share on other sites More sharing options...
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