Ed Lizard Posted February 23, 2011 Share Posted February 23, 2011 I remember March 1, 2007... Link to comment Share on other sites More sharing options...
Fred Gossage Posted February 24, 2011 Author Share Posted February 24, 2011 The 00Z operational GFS still has the dryline in eastern Texas at 6 pm Sunday... but if you look carefully, between 6 pm and Midnight... the surface low jumps from Wichita, KS to Peoria, IL without any sign of a new low developing further northeast at 6 pm. Then the surface low is in Michigan by 6 am Monday. This overnight and Monday timing of the surface low is more in-line with the faster GFS ensembles and other guidance.... and makes more sense with a flatter ridge and positive tilt trough. Even the 00Z NAM... at 84 hours... while having a deep low in southeastern Colorado at 12Z Sunday.... is developing a new surface low over central Oklahoma. This timing is more in-line with the other global guidance. I think the GFS is having a harder time handling the surface low with the positive tilt trough.... as it almost always does... but the post 6 pm Sunday timing of the surface low is a sign that we are trending faster... toward the GFS ensembles, UKMET, Canadian, etc.... which makes sense given the large scale pattern in place. Link to comment Share on other sites More sharing options...
Hoosier Posted February 24, 2011 Share Posted February 24, 2011 00z Euro looks like it's going to be on the slower side. Link to comment Share on other sites More sharing options...
Fred Gossage Posted February 24, 2011 Author Share Posted February 24, 2011 00z Euro looks like it's going to be on the slower side. And it's ONLY because I've been talking about the faster timing.... Link to comment Share on other sites More sharing options...
BrentO Posted February 24, 2011 Share Posted February 24, 2011 http://www.crh.noaa.gov/pah/?n=webbriefing .......intresting multimedia briefing from PAH talking about the thrusday storm and at the end mentions the weekend storm. Talking about it being stronger then this thrusday storm with more instability. Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 24, 2011 Share Posted February 24, 2011 GFS- the show gets started near/EAst of I-35 in Oklahoma Sunday afternoon and heads East. A little early for forecast skew-Ts, but from this far out, that isn't insgignificant instability on the GFS and impressive helicity. Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 24, 2011 Share Posted February 24, 2011 Seems like, when a few days away, correlating strongest 850 jet and 500 mb flow crossing at an angle is a decent first guess, the stronger the LLJ, the more intense the severe. Looks darn close to being capped IMBY based on 850 temps, but there is directional shear between 500 and 850. I suspect a 132 hour free ECMWF plot would show the Dixie Alley severe just before its peak, but still lots of wind at 144 hours... Back to Sunday, AccuWx PPV shows >500 J/Kg CAPE East of I-35 KS and OK, with a small lollipop over 1500 J/Kg just West of ICT. Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 24, 2011 Share Posted February 24, 2011 I think an isolated svr threat creeps up close to I80. Link to comment Share on other sites More sharing options...
tornadotony Posted February 24, 2011 Share Posted February 24, 2011 I think an isolated svr threat creeps up close to I80. Agreed. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 24, 2011 Share Posted February 24, 2011 I think an isolated svr threat creeps up close to I80. 12z NAM showing that with the warm front coming north, crazy LLJ with alot of WAA. look how large an area there is in the warm sector on sunday with 0-1km SRH >200. Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 24, 2011 Share Posted February 24, 2011 12z NAM showing that with the warm front coming north, crazy LLJ with alot of WAA. look how large an area there is in the warm sector on sunday with 0-1km SRH >200. Given the prolonged and intense southerly flow at 850 well ahead of the main show, i don't see much from stopping the warm front from making a run at this area. Climo wise it's a good bit early, but I'm not ruling it out. Link to comment Share on other sites More sharing options...
Hoosier Posted February 24, 2011 Share Posted February 24, 2011 I think an isolated svr threat creeps up close to I80. I wouldn't rule it out. Despite the snow that will have to be melted, it's very likely that the model surface temps are underdone. Even with the crappy GFS temps, it is showing steep mid level lapse rates and modification of the forecast soundings would suggest more instability than currently shown. Edit: the 12z Euro surface low track would cast some doubt Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 24, 2011 Share Posted February 24, 2011 I wouldn't rule it out. Despite the snow that will have to be melted, it's very likely that the model surface temps are underdone. Even with the crappy GFS temps, it is showing steep mid level lapse rates and modification of the forecast soundings would suggest more instability than currently shown. Edit: the 12z Euro surface low track would cast some doubt Yes it would, i'm skeptical of a low track that far south, given the position of the baroclinic zone will likely be much further north. We'll see i guess. Link to comment Share on other sites More sharing options...
Hoosier Posted February 24, 2011 Share Posted February 24, 2011 Some frightening helicity showing up on the 18z GFS for central Indiana with 0-3 km values in the 800-1000 range at 6z Monday. Link to comment Share on other sites More sharing options...
Kevin Askew Posted February 25, 2011 Share Posted February 25, 2011 Seems to be timing issues - can't believe how fast this thing moves from point A to B - seems unreal. Guess I will dig into it tomorrow - been a long week already. Obviously what happened tonight will put a damper on all of our area meteorologists spirits. Always does - as it should. I sure hope the children are found... we ready to chase again, hopefully backyard but RUC is breaking out storms at Midnight I understand? Link to comment Share on other sites More sharing options...
CUmet Posted February 25, 2011 Share Posted February 25, 2011 Confidence is continuing to grow that a major severe weather outbreak will occur Sunday afternoon into Monday morning. We will almost certainly be dealing with the type of large unstable warm sector characteristic of significant outbreaks. The two main factors responsible for this (high boundary-layer moisture and an elevated mixed layer) have proven to be very insensitive to the various trough-evolution scenarios offered up by the modeling over the past few days. The persistent low-level ridge extending east of Florida has locked in a pattern of moisture advection from the western Carribean. The elevated mixed layer air mass, already formed over the Mexican Plateau, will be advected over the Southern Plains as the trough ejects eastward. There are a couple of conceivable ways that a major outbreak would not result from this setup. One is a massively-amplified trough that goes negative tilt early, which would back the mid-upper level wind vectors severely and lessen the directional shear, leading to a more linear convective mode. If anything, the models have trended towards a more positive-tilt evolution of the trough until Monday morning, however, so this looks quite unlikely. The second way is for the trough to either be 12 hours slower or 12 hours faster than the current model consensus. Under these scenarios, the main event (whether it be Sunday or Monday) would occur with a considerably-smaller warm sector. Given how fast the speed of the trough is, though, a 12 hour difference in a 72-hour consensus forecast, although not impossible, is pretty unlikely. There will undoubtedly be mesoscale features on the day of the event that play a significant role in the ultimate evolution of this severe weather event. But the large-scale, synoptic table has been set very well for a major outbreak IMO. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 25, 2011 Share Posted February 25, 2011 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0200 AM CST FRI FEB 25 2011 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS OZARKS/ARKLATEX TO LOWER-MID MS/TN VALLEY REGIONS... ..SYNOPSIS BROAD SWATH OF QUASI-ZONAL FLOW OVER MOST OF CONUS WILL BE PERTURBED MAINLY BY STG SHORTWAVE TROUGH AND EMBEDDED UPPER LOW EJECTING ENEWD FROM SRN CA/AZ REGION. TIMING UNCERTAINTIES AMONG PROGS...DISCUSSED IN DAY-2 OUTLOOK...CARRY OVER THIS PERIOD AND RESULT IN LATERAL/LONGITUDINAL UNCERTAINTIES IN RESULTING EFFECTS ON LOW-LEVEL MASS/MOISTURE FIELDS. BY 28/00Z...SREF/OPERATIONAL MODEL CONSENSUS...WITH SOME WWD LEAN IN DEFERENCE TO SLOWER ECMWF...FCSTS TROUGH OVER WRN KS...TX PANHANDLE AND SRN NM...WITH PRONOUNCED POSITIVE TILT. SFC LOW SHOULD SHIFT FROM ERN CO SEWD ACROSS SWRN KS DURING DAY...WHILE COMBINED PAC COLD FRONT/DRYLINE MOVES E AT LEAST ACROSS WRN OK AND NW TX BY 28/00Z...AND WARM FRONT LIFTS NWD ACROSS OZARKS AND LOWER OH VALLEY REGION. BY END OF PERIOD...MAIN SFC LOW SHOULD EJECT NEWD ACROSS ERN LM REGION...WITH COLD FRONT SWWD ACROSS ERN AR TO NEAR MID-UPPER TX COAST...AND WARM FRONT LIFTING NEWD OVER OH AND CENTRAL APPALACHIANS. ..OZARKS/ARKLATEX TO LOWER-MID MS/TN VALLEY REGIONS LEFT-EXIT REGION OF SOMEWHAT CYCLONICALLY-CURVED UPPER JET CORE WILL SPREAD ACROSS CENTRAL PLAINS...MO AND IL. ASSOCIATED ASCENT WOULD BECOME JUXTAPOSED WITH NRN FRINGES OF LOW-LEVEL WAA/MOIST ADVECTION REGIME IN SUPPORT OF THUNDER AND SVR POTENTIAL ON BOTH SIDES OF WARM FRONT...WITH HAIL FROM ELEVATED CONVECTION POSSIBLE N OF WARM FRONT. INTENSE WINDS ALOFT AND FAVORABLE DEEP-LAYER SHEAR WILL OVERSPREAD WARM SECTOR THROUGHOUT DAY...BENEATH AND JUST N OF 150-170 KT 250-MB JET AND 60-90 KT 500-MB FLOW. BY CONTRAST...ANTECEDENT CLOUDS/PRECIP MAY RESTRICT MAGNITUDE/EXPANSE OF FAVORABLE DIURNAL SFC HEATING AND BUOYANCY. STILL...EVEN NARROW CORRIDOR OF CLEARING AHEAD OF COLD FRONT/DRYLINE SHOULD STEEPEN LOW-LEVEL LAPSE RATES CONSIDERABLY...AND WEAKEN CINH ENOUGH TO PERMIT DEVELOPMENT OF AT LEAST SCATTERED TSTMS. FOR REASONABLE SFC DEW POINTS 50S F OVER OZARKS TO 60S IN ERN OK...MLCAPE 1000-1500 J/KG MAY BE REACHED...SUFFICIENT FOR ORGANIZED SVR THREAT AMIDST 50-60 KT EFFECTIVE SHEAR. SFC FLOW SHOULD BE MORE BACKED WITH ELY AND NELY EXTENT IN WARM SECTOR...ENLARGING HODOGRAPHS AND OFFERING TORNADO RISK FOR ANY RELATIVELY DISCRETE/SFC-BASED STORMS THAT CAN FORM ALONG OR AHEAD OF MAIN CONVECTIVE BAND. EXPECT MAJORITY OF SVR TO BE DAMAGING WIND...WITH CONVECTION MOVING NEWD ACROSS OZARKS AND SURROUNDING AREAS INTO LOWER OH VALLEY REGION OVERNIGHT. STG-SVR TSTMS ALSO MAY DEVELOP OVERNIGHT OVER PORTIONS MID-SOUTH AND MS/AL REGIONS...AMIDST INCREASES IN BOTH BOUNDARY-LAYER MOISTURE AND DEEP-LAYER SHEAR. ATTM...MAIN UNCERTAINTIES PRECLUDING GREATER OR MORE FOCUSED UNCONDITIONAL PROBABILITIES INVOLVE POSITION/TIMING OF SPECIFIC BOUNDARY FOCI...CONVECTIVE MODES...AND AREAL EXTENT OF FAVORABLE WARM-SECTOR INSTABILITY. Link to comment Share on other sites More sharing options...
B-Rent Posted February 25, 2011 Share Posted February 25, 2011 Some frightening helicity showing up on the 18z GFS for central Indiana with 0-3 km values in the 800-1000 range at 6z Monday. Think we would be able to vaporize this snow by that time? I'm sure you will have a much better go at it than us though. Link to comment Share on other sites More sharing options...
SmokeEater Posted February 25, 2011 Share Posted February 25, 2011 I sure hope the children are found... we ready to chase again, hopefully backyard but RUC is breaking out storms at Midnight I understand? Sadly, they found 3 of the victims shortly after midnight, one being a 5 month old child. The fourth child, 11 years old, is still missing. Link to comment Share on other sites More sharing options...
csnavywx Posted February 25, 2011 Share Posted February 25, 2011 Given the prolonged and intense southerly flow at 850 well ahead of the main show, i don't see much from stopping the warm front from making a run at this area. Climo wise it's a good bit early, but I'm not ruling it out. NAM BUFKITs from 06Z are producing 1000-1500 J/kg of elevated CAPE, even on the north side of the surface warm front, with 50% of that in the hail growth zone. Even if we don't quite pop into the warm sector, that kind of instability will produce some good hailers and quite a bit of lightning. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 25, 2011 Share Posted February 25, 2011 Yes - sad situation and story down here. Obviously everyone is update. Sometimes you do everything that you can possibly do but it still doesn't matter. Frustrating and tragic. It is definitely an unfortunate reminder that the excitement of weather can also be devastating--hence why mets have a job. Definitely a sad story--no mets want to hear of weather related tragedies. Link to comment Share on other sites More sharing options...
Indystorm Posted February 25, 2011 Share Posted February 25, 2011 As I look at parameters from this morning's NAM I would be concerned for an area from Tulsa/Springfield on east into the Ozarks for significant svr Sunday evening and into the night for a first guess. Very sad to learn of the deaths of the Amish children. Link to comment Share on other sites More sharing options...
David Reimer Posted February 25, 2011 Share Posted February 25, 2011 The SREF is looking much more impressive for Sunday then it did for yesterday. Too bad its in the Ozarks Link to comment Share on other sites More sharing options...
David Reimer Posted February 25, 2011 Share Posted February 25, 2011 Its pretty hard to hit that high on the scale during a severe weather setup in May. You can normally hit around 7, but values here are closer to 10. If convection fires in this environment, look out. Link to comment Share on other sites More sharing options...
ukrocks Posted February 25, 2011 Share Posted February 25, 2011 Yes - sad situation and story down here. Obviously everyone is update. Sometimes you do everything that you can possibly do but it still doesn't matter. Frustrating and tragic. Very sad situation. I just hope we don't have more deaths with more heavy rain moving into the region late Sunday. Just absolutely tragic and the story of the day here on campus. Link to comment Share on other sites More sharing options...
JoMo Posted February 25, 2011 Share Posted February 25, 2011 As I look at parameters from this morning's NAM I would be concerned for an area from Tulsa/Springfield on east into the Ozarks for significant svr Sunday evening and into the night for a first guess. Very sad to learn of the deaths of the Amish children. Looks like more of a wind/hail threat at this time. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 25, 2011 Share Posted February 25, 2011 That STP map is nasty...how did you end up fairing chasing yesterday? 12z NAM is keeping the dryline in OK into late sunday night and not moving it very fast from 0z to 6z but the sfc winds look to veer more ahead of the dryline as you go later into the evening but were still 60hrs away so need to get worked up about that. Its puttng up a decent area of MLCAPE >1000 j/kg along and out ahead of the DL and even a small area of 1500 j/kg up in KS near the triple point. This whole area is in an area of strong LL shear with 0-1 SRH over 200 m2/s2 over a wide area...this day is already looking bigger than yesterday. Link to comment Share on other sites More sharing options...
Ed Lizard Posted February 25, 2011 Share Posted February 25, 2011 GFS is predicting capping issues... A small difference in surface temperature would be huge, just glancing at forecast skew-Ts for ICT and TUL... Link to comment Share on other sites More sharing options...
David Reimer Posted February 25, 2011 Share Posted February 25, 2011 That STP map is nasty...how did you end up fairing chasing yesterday? 12z NAM is keeping the dryline in OK into late sunday night and not moving it very fast from 0z to 6z but the sfc winds look to veer more ahead of the dryline as you go later into the evening but were still 60hrs away so need to get worked up about that. Its puttng up a decent area of MLCAPE >1000 j/kg along and out ahead of the DL and even a small area of 1500 j/kg up in KS near the triple point. This whole area is in an area of strong LL shear with 0-1 SRH over 200 m2/s2 over a wide area...this day is already looking bigger than yesterday. I ended up playing in S AR in an effort to stay away from the rainy mess near the warm front Needless to say, I busted. Link to comment Share on other sites More sharing options...
brettjrob Posted February 25, 2011 Share Posted February 25, 2011 The SREF is looking much more impressive for Sunday then it did for yesterday. Too bad its in the Ozarks The SREF always seems to have a progressive bias with systems in this region. Sometimes it's right, but I can think of plenty where it wasn't. May 10 of last year is a prime example -- the SREF kept hitting the tri-state (OK/MO/KS) area hardest in terms of parameters, but ultimately the outbreak was most severe along the I-35 corridor. The 12z NAM certainly suggests the threat would be closer to I-35 on Sunday afternoon and evening. Of course, it still shows low-level flow veering a bit more than I;d like as the afternoon progresses, so I'm not exactly excited just yet. But I do think there's a non-negligible chance of seeing the first legit Plains chase of the season. Of course, even the best-case scenario (near and W of I-35) would probably be something akin to 2009-03-23 where you have several messy supercells in a low-CAPE dryline environment that exhibit impressive low-level mesos but have trouble producing tornadoes of significance due to marginal moisture/LCL's. We shall see. EDIT: Also looks like some cold-core action is possible across C into SW KS. Seems more often than not, that's the best play with these dynamic early spring systems. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.