cyclone77 Posted April 8, 2011 Share Posted April 8, 2011 I think the one thing that would keep them from issuing the day 3 moderate is the unknown exact timing of the surface front/dryline. Some pretty big differences just between the GFS and NAM alone. They may just broad brush a wide region with a hatched high-end slight for now until timing becomes more clear. Otherwise it's looking pretty likely that a widespread severe weather episode is likely for that period. Link to comment Share on other sites More sharing options...
B-Rent Posted April 8, 2011 Share Posted April 8, 2011 6/7/07 was the only MDT that ended up being a HIGH day 1, if I recall correctly. (I feel like I'm missing one though.) I think at least 5 or 6 Day 3 MDT's have been issued... Sounds like something Hoosier can research and add to his blog. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 8, 2011 Share Posted April 8, 2011 I'm not really relying on it, just commenting. But you can't tell me that the VV charts don't take on a more linear look between 00z-06z Monday. I really don't. Given the wind profiles and late/intense rapid height falls and late cap erosion/fracture and what will likely be even greater instability it would likely be a line of discretely initiating supercells. It looks linear in the VV's--but even if you look at GFS qpf you can see it isn't simulating a squall line. Link to comment Share on other sites More sharing options...
B-Rent Posted April 8, 2011 Share Posted April 8, 2011 I think the one thing that would keep them from issuing the day 3 moderate is the unknown exact timing of the surface front/dryline. Some pretty big differences just between the GFS and NAM alone. They may just broad brush a wide region with a hatched high-end slight for now until timing becomes more clear. Otherwise it's looking pretty likely that a widespread severe weather episode is likely for that period. Doesn't a hatch lend to a MDT on day 3? http://www.spc.noaa.gov/misc/SPC_probotlk_info.html Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 8, 2011 Author Share Posted April 8, 2011 6/7/07 was the only MDT that ended up being a HIGH day 1, if I recall correctly. (I feel like I'm missing one though.) I think at least 5 or 6 Day 3 MDT's have been issued... That one busted nicely lol Link to comment Share on other sites More sharing options...
Hoosier Posted April 8, 2011 Share Posted April 8, 2011 Sounds like something Hoosier can research and add to his blog. Speaking of which, I threw up a post about nocturnal April tornadoes and I'm working on one for this event right now. Link to comment Share on other sites More sharing options...
thewxmann Posted April 8, 2011 Share Posted April 8, 2011 Sounds like something Hoosier can research and add to his blog. If Hoosier's gonna add it to his blog, I will assist in the research: Off the top of my head, 6/10/05, 6/6/07, 6/7/07, 10/18/07, and 5/13/09 were Day 3 MDT's. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 8, 2011 Share Posted April 8, 2011 Doesn't a hatch lend to a MDT on day 3? http://www.spc.noaa....botlk_info.html Yep, you're right. Woops. Link to comment Share on other sites More sharing options...
Hoosier Posted April 8, 2011 Share Posted April 8, 2011 I really don't. Given the wind profiles and late/intense rapid height falls and late cap erosion/fracture and what will likely be even greater instability it would likely be a line of discretely initiating supercells. It looks linear in the VV's--but even if you look at GFS qpf you can see it isn't simulating a squall line. Mode (particularly how long things remain discrete) is anybody's guess right now and like usual we probably won't know for sure until it's happening. Link to comment Share on other sites More sharing options...
CUmet Posted April 8, 2011 Share Posted April 8, 2011 I'm not really relying on it, just commenting. But you can't tell me that the VV charts don't take on a more linear look between 00z-06z Monday. I agree with baroclinic_instability that you can't really look at the model output VVs and determine convective mode from that. I've seen plenty of times when the VVs "looked linear", but the shear profiles were obviously supportive for discrete supercells. In this particular case, it might be pretty linear, given that the directional shear is pretty borderline, but it's tough to tell. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 8, 2011 Share Posted April 8, 2011 Mode (particularly how long things remain discrete) is anybody's guess right now and like usual we probably won't know for sure until it's happening. I dont know about that--I don't think saying it is anybody's guess is necessarily true. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 8, 2011 Share Posted April 8, 2011 I dont know about that--I don't think saying it is anybody's guess is necessarily true. That said--it was an analysis of the GFS itself. The late cap fracture/erosion would suggest a more discrete nature to convective initiation in the GFS through a large portion of the MS valley. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 8, 2011 Author Share Posted April 8, 2011 sunday evening Link to comment Share on other sites More sharing options...
B-Rent Posted April 8, 2011 Share Posted April 8, 2011 Yep, you're right. Woops. Maybe. Somethines the hatch is significantly bigger than the MDT. So I don't know. I don't try to decipher it. Link to comment Share on other sites More sharing options...
Hoosier Posted April 8, 2011 Share Posted April 8, 2011 I agree with baroclinic_instability that you can't really look at the model output VVs and determine convective mode from that. I've seen plenty of times when the VVs "looked linear", but the shear profiles were obviously supportive for discrete supercells. In this particular case, it might be pretty linear, given that the directional shear is pretty borderline, but it's tough to tell. Fair enough. At this point I am leaning toward more of a QLCS by the time it gets here but I'd love for the knowledgeable folks to keep chiming in. Link to comment Share on other sites More sharing options...
Justin Posted April 8, 2011 Share Posted April 8, 2011 Going to be a busy weekend, concur with the other met's here. I don't know if the tornado threat will evolve much past an area around the initiation zone, but the more discrete these storms stay would certainly lend to lingering that threat. And any little boundaries lifting north from the late Saturday Night stuff will lend to potential of some locally backed winds Sunday perhaps over IL/WI. There is going to be tremendous instability so these things will just explode once they go. Damaging wind threat I think may end up being the real story with this set up. Link to comment Share on other sites More sharing options...
turtlehurricane Posted April 8, 2011 Share Posted April 8, 2011 Holy ****, this looks serious. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 8, 2011 Author Share Posted April 8, 2011 I'm going to guess SPC goes with a 30% hatched with the Day 2. Link to comment Share on other sites More sharing options...
B-Rent Posted April 8, 2011 Share Posted April 8, 2011 SLGT out today from I-70 to the KY/TN border. Link to comment Share on other sites More sharing options...
Stebo Posted April 8, 2011 Share Posted April 8, 2011 Holy ****, this looks serious. Better find a parking garage for the Mustang. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 8, 2011 Share Posted April 8, 2011 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1227 AM CDT FRI APR 08 2011 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE OH/TN VALLEY INTO SRN MO... ...MID MS/OH/TN VALLEY REGION... ASIDE FROM A PSEUDO-STATIONARY FRONTAL ZONE DRAPED ACROSS THE OH VALLEY INTO MO...A RATHER NONDESCRIPT LARGE SCALE PATTERN WILL BE SITUATED ACROSS THE REGION FRIDAY WITH WEAK HEIGHT RISES EXPECTED THROUGH THE PERIOD. WEAK LARGE SCALE FORCING THROUGH THE AFTERNOON HOURS WILL ENSURE THE SIGNIFICANCE OF THE AFOREMENTIONED SFC BOUNDARY IN REGARDS TO ORGANIZED THUNDERSTORM DEVELOPMENT. LATEST MODEL GUIDANCE SUGGEST STRONG BOUNDARY LAYER HEATING WILL BE NOTED ACROSS SRN IL INTO NRN KY/SRN OH. THIS SHOULD ENHANCE THE PROSPECT FOR CONVECTIVE DEVELOPMENT WITHIN STRONGLY SHEARED ENVIRONMENT FAVORABLE FOR SUSTAINED ROTATING UPDRAFTS. FORECAST SOUNDINGS FAVOR SUPERCELL DEVELOPMENT EARLY IN THE CONVECTIVE CYCLE AND THIS SEEMS REASONABLE GIVEN THE WEAK FORCING. WITH TIME STORM MERGERS AND CONVECTIVE INTERFERENCE COULD LEAD TO STORM CLUSTERS AS MEAN WIND VECTOR DRIVES TSTMS SEWD AT ROUGHLY 30KT. FOR THIS REASON IT APPEARS THERE WILL BE A THREAT FOR LARGE HAIL...DAMAGING WINDS AND PERHAPS EVEN A FEW TORNADOES AS BOUNDARY LAYER MOISTURE AND RH VALUES WILL HAVE RISEN SIGNIFICANTLY BY THIS TIME. FARTHER WEST ACROSS MO...IT/S NOT ENTIRELY CLEAR HOW MUCH DIURNAL ACTIVITY WILL DEVELOP ALONG THE FRONT AS LOW LEVEL CONVERGENCE WILL BE ESPECIALLY WEAK ACROSS THIS REGION. HOWEVER...LLJ SHOULD INCREASE MARKEDLY NEAR SUNSET INTO THE EVENING HOURS. STRONG WARM ADVECTION ACROSS THIS REGION WILL LIKELY FORCE A BOUT OF SEVERE THUNDERSTORMS AFTER DARK THAT WILL EVOLVE WITHIN A VERY UNSTABLE ENVIRONMENT CHARACTERIZED BY STEEP LAPSE RATES AND MUCAPE APPROACHING 2000-3000 J/KG. LARGE HAIL IS CERTAINLY POSSIBLE IF ACTIVITY CAN BECOME SUSTAINED BENEATH THE LLJ ACROSS THIS REGION. ...TX/OK... STRONG DIURNAL HEATING WILL ONCE AGAIN BE NOTED ACROSS THE SRN PLAINS...ESPECIALLY ALONG/WEST OF THE DRYLINE. UNCAPPED THERMALS NEAR THE DRYLINE WILL LIKELY STRUGGLE TO SUSTAIN THEMSELVES WITHIN A RIDGY MID LEVEL ENVIRONMENT. HOWEVER...SIGNIFICANT MOISTENING WITHIN THE BOUNDARY LAYER AND WEAK LOW LEVEL CONVERGENCE MAY RESULT IN ONE OR TWO SEVERE THUNDERSTORMS NEAR 09/00Z. IF STORMS MANAGE TO INITIATE LARGE HAIL AND DAMAGING WINDS COULD OCCUR. THIS ACTIVITY SHOULD DISSIPATE WITHIN A FEW HOURS AS BOUNDARY LAYER COOLS. ...GULF STATES... EARLY EVENING WV IMAGERY SUGGESTS A WEAK UPPER VORT/SHORTWAVE TROUGH IS EJECTING NEWD ACROSS MEXICO INTO DEEP SOUTH TX. THIS FEATURE MAY NOT BE HANDLED WELL WITHIN BROADER HEIGHT RISES THAT SHOULD OVERSPREAD THE SRN STATES LATER TODAY. AS A RESULT...WEAK ASCENT MAY ENHANCE THE PROSPECT FOR ISOLATED THUNDERSTORMS ALONG THE ERN PLUME OF STEEPER LAPSE RATES...ESPECIALLY ACROSS AL INTO GA. IF SO...STRONG SHEAR AND SUBSTANTIALLY MORE MOIST/UNSTABLE AIRMASS WILL BE IN PLACE FOR POSSIBLE SEVERE. WILL MAINTAIN LOW PROBS FOR WIND/HAIL PRIMARILY DUE TO THE SUBTLE SHORTWAVE AND WEAK FORCING. HOWEVER IF IT APPEARS A MORE ORGANIZED CONVECTIVE SCENARIO WILL UNFOLD THEN A SLIGHT RISK MAY BE REQUIRED. ..DARROW/HURLBUT.. 04/08/2011 Link to comment Share on other sites More sharing options...
Stebo Posted April 8, 2011 Share Posted April 8, 2011 I'm going to guess SPC goes with a 30% hatched with the Day 2. Yeah that would be my guess right now until they get 12z data that could sway them one way or another. Link to comment Share on other sites More sharing options...
tornadotony Posted April 8, 2011 Share Posted April 8, 2011 A serious increase in instability in northern IL this run...some places had near 1000 j/kg of CAPE on the 12z NAM and now its showing near 3500 j/kg on this run and actually all the CIN erased but no precip breaks out either INVOF the warm front or on the dryline. That's because there is either no VA (GFS) or AVA (NAM) across N IL Saturday. No lift. Link to comment Share on other sites More sharing options...
turtlehurricane Posted April 8, 2011 Share Posted April 8, 2011 Better find a parking garage for the Mustang. Already had to a few days ago, huge hail storm! Link to comment Share on other sites More sharing options...
earthlight Posted April 8, 2011 Share Posted April 8, 2011 629 ACUS02 KWNS 080542 SWODY2 SPC AC 080541 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1241 AM CDT FRI APR 08 2011 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS...CNTRL PLAINS AND UPPER MIDWEST... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE OH VALLEY...SRN APPALACHIAN MTNS AND CAROLINAS... ..SRN AND CNTRL PLAINS/UPPER MIDWEST AN UPPER-LEVEL TROUGH OVER THE INTERMOUNTAIN WEST IS FORECAST TO MOVE INTO THE FOUR CORNERS REGION SATURDAY. WELL AHEAD OF THE SYSTEM...A LOW-LEVEL JET WILL STRENGTHEN IN THE SCNTRL STATES. THIS WILL HELP TO ESTABLISH A BROAD MOIST AXIS ACROSS THE GREAT PLAINS AND MS VALLEY WHERE MODERATE INSTABILITY APPEARS LIKELY TO DEVELOP SATURDAY AFTERNOON. AS A WELL-DEVELOPED MID-LEVEL JET MOVES OUT INTO THE CNTRL PLAINS...THUNDERSTORMS APPEAR MOST LIKELY TO DEVELOP IN THE EXIT REGION OF THE JET ACROSS THE MID-MO VALLEY SATURDAY AFTERNOON SPREADING NEWD ACROSS THE UPPER MIDWEST SATURDAY EVENING. THUNDERSTORMS ALSO MAY DEVELOP SWD ALONG A DRYLINE SATURDAY EVENING FROM CNTRL KS INTO WRN OK AND NW TX. THE MID-LEVEL JET SHOULD RESULT IN A STRONGLY SHEARED ENVIRONMENT ACROSS MOST OF THE GREAT PLAINS AND UPPER MIDWEST MAKING CONDITIONS FAVORABLE FOR SEVERE THUNDERSTORMS. AN ENHANCED SEVERE THREAT MAY DEVELOP FROM NE KS NNEWD ACROSS ERN NEB...IA AND SRN MN WHERE CONVECTIVE COVERAGE IS EXPECTED TO BE GREATER SATURDAY EVENING. A FEW TORNADOES...LARGE HAIL AND WIND DAMAGE WILL BE POSSIBLE WITH THE MORE ORGANIZED CELLS. THE SHEAR ENVIRONMENT SHOULD SUPPORT SUPERCELL DEVELOPMENT ESPECIALLY IN AREAS WITH THE STRONGEST INSTABILITY AND AN ISOLATED VERY LARGE HAIL THREAT MAY DEVELOP FROM ERN NEB NEWD INTO SW WI. THE SEVERE THREAT ALONG THE DRYLINE SHOULD BE INCREASINGLY ISOLATED WITH SWD EXTENT BUT HAIL AND WIND DAMAGE WILL ALSO BE POSSIBLE THERE. ..OH VALLEY/SRN APPALACHIAN MTNS/CAROLINAS AN UPPER-LEVEL RIDGE IS FORECAST TO BE IN PLACE ACROSS THE ERN STATES SATURDAY WITH NWLY FLOW LOCATED FROM THE SRN APPALACHIAN MTNS SEWD ACROSS THE CAROLINAS. MODERATE INSTABILITY SHOULD EXIST FROM THE OH VALLEY SEWD INTO THE CAROLINAS WHERE SCATTERED THUNDERSTORMS SHOULD INITIATE AROUND MIDDAY SATURDAY. FORECAST SOUNDINGS SATURDAY AFTERNOON ALONG THIS CORRIDOR SHOW MODERATE TO STRONG DEEP LAYER SHEAR PROFILES WITH SOME DIRECTIONAL SHEAR SUGGESTS CONDITIONS WILL BE FAVORABLE FOR SEVERE STORMS. SFC DEWPOINTS IN THE MID TO UPPER 60S F AND STEEP LOW-LEVEL LAPSE EVIDENT ON FORECAST SOUNDINGS WOULD BE SUFFICIENT FOR A WIND DAMAGE THREAT. IF SUPERCELLS CAN ORGANIZE...THEN AN ISOLATED TORNADO THREAT AND HAIL THREAT WILL ALSO BE POSSIBLE. ..BROYLES.. 04/08/2011 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 8, 2011 Author Share Posted April 8, 2011 That's because there is either no VA (GFS) or AVA (NAM) across N IL Saturday. No lift. Nope. If only.. Link to comment Share on other sites More sharing options...
Stebo Posted April 8, 2011 Share Posted April 8, 2011 Already had to a few days ago, huge hail storm! Ahh yes, I mentioned bout that storm and your car back in the other thread. Link to comment Share on other sites More sharing options...
Stebo Posted April 8, 2011 Share Posted April 8, 2011 Nam is going insane with elevated parameters overnight Saturday night. Almost 3000 J/kg of elevated instability, sure there is an inversion, but that is some big time hail potential. With excellent shear too. Some very good severe parameters there (showalter/sweat/TT) Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 8, 2011 Author Share Posted April 8, 2011 How did you beat all of us? lol Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 8, 2011 Share Posted April 8, 2011 That's because there is either no VA (GFS) or AVA (NAM) across N IL Saturday. No lift. Synoptic scale ascent is only a small part of it though. And since I like to argue synoptics (I am just messing here), should we be making use of synoptic forcings and the QG Theory of synoptic motion--it should always be differential vorticity advection Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.