baroclinic_instability Posted May 21, 2012 Share Posted May 21, 2012 Tuesday shaping up to be a nice chase day across the Northern Plains. GFS was right from a couple days ago...and the warm front will be draped across North Dakota. Lee low becomes mobile late as the 300 hpa jet maxima begins nosing into western Nodak. While GFS dews are likely overdone again...MLCAPE will range from 1500-2500 j/kg with low level SE flow veering around to SW at 50-55 kts, MLLCLs may be a bit high, but should see some impressive supercells likely developing near the triple and propagating along the nose of the LLJ/warm front across eastern Nodak. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 21, 2012 Share Posted May 21, 2012 Can you say holy coupled upper jet. 06z GFS trying to uncork a hybrid COlorado Low Thursday. ECMWF about 12-15 hrs slower...bombing it across Lakes. Either way...GFS/ECMWF still project a High Plains show day 6. Link to comment Share on other sites More sharing options...
brettjrob Posted May 21, 2012 Share Posted May 21, 2012 Saturday is looking up, synoptically, for a central High Plains show on both the GFS and Euro. Trouble is, neither show particularly good moisture in place, which is rather stunning when you consider it's late May and the Plains will have seen about a week of return flow by that time. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 21, 2012 Share Posted May 21, 2012 Saturday is looking up, synoptically, for a central High Plains show on both the GFS and Euro. Trouble is, neither show particularly good moisture in place, which is rather stunning when you consider it's late May and the Plains will have seen about a week of return flow by that time. It isn't bombastic, no doubt, but mid 60s for western NE/Panhandle...which ranges from 3000-4500 feet...isn't bad. Right now...a far more impressive synoptic setup progged by the only two global models worth looking at...it isn't to too shabby compared to two days ago. ECMWF Ensemble is a tick faster and weaker than the EC op...but that isn't surprising. Even ECENS mean would yield something interesting. Link to comment Share on other sites More sharing options...
jpeters3 Posted May 21, 2012 Share Posted May 21, 2012 Tuesday shaping up to be a nice chase day across the Northern Plains. GFS was right from a couple days ago...and the warm front will be draped across North Dakota. Lee low becomes mobile late as the 300 hpa jet maxima begins nosing into western Nodak. While GFS dews are likely overdone again...MLCAPE will range from 1500-2500 j/kg with low level SE flow veering around to SW at 50-55 kts, MLLCLs may be a bit high, but should see some impressive supercells likely developing near the triple and propagating along the nose of the LLJ/warm front across eastern Nodak. I think LCLs are too high for much of anything more than a "marginal" tornado threat, but I would have said the same thing two days ago and we saw an EF-3 tornado in KS. Thermodynamic profiles look pretty similar to the other day, with a bit more deep layer shear and slightly better low-level wind profiles: My concern is that we'll only have a few hour window of time where MLCAPE is uncapped, and storms will undoubtedly become elevated as the nocturnal LLJ kicks in. My hotels and gas are paid for though, so i'm probably going to bring my group up there. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 21, 2012 Share Posted May 21, 2012 I think LCLs are too high for much of anything more than a "marginal" tornado threat, but I would have said the same thing two days ago and we saw an EF-3 tornado in KS. Thermodynamic profiles look pretty similar to the other day, with a bit more deep layer shear and slightly better low-level wind profiles: My concern is that we'll only have a few hour window of time where MLCAPE is uncapped, and storms will undoubtedly become elevated as the nocturnal LLJ kicks in. My hotels and gas are paid for though, so i'm probably going to bring my group up there. In total agreement...I wasn't thinking tors either, but I suck at severe forecasting. I also agree it may be a late show. Latest GFS trying to suggest lee low may become mobile early enough for SB initiation...but it may very well be LLJ/nocturnal induced. Nothing spectacular...but after living up there for so long...you will realize no event up there is a slam dunk. Link to comment Share on other sites More sharing options...
jpeters3 Posted May 21, 2012 Share Posted May 21, 2012 In total agreement...I wasn't thinking tors either, but I suck at severe forecasting. I'm pretty sure most people weren't thinking tornadoes on Saturday - was a bit of a surprise event. Link to comment Share on other sites More sharing options...
brettjrob Posted May 21, 2012 Share Posted May 21, 2012 It isn't bombastic, no doubt, but mid 60s for western NE/Panhandle...which ranges from 3000-4500 feet...isn't bad. Right now...a far more impressive synoptic setup progged by the only two global models worth looking at...it isn't to too shabby compared to two days ago. ECMWF Ensemble is a tick faster and weaker than the EC op...but that isn't surprising. Even ECENS mean would yield something interesting. If we get dew points of 63-65 F in the NE Panhandle coincident with the kinematics and synoptic chart shown by the Euro, you won't hear any complaining from me. My concern was that moisture throughout the southern/central Plains in general looks unseasonably lacking, so we'd be relying on pooling to some extent to get those numbers. From what I can tell, the Euro has the 60 F isodrosotherm all the way out in eastern NE, only bending back to the High Plains right along the warm front in S SD. Way too early to talk about exact numbers and/or locations, but it's safe to say that moisture isn't looking particularly impressive for late May. Most anytime I can recall chasing the central Plains in the late season, there was a reservoir of 65-70+ F dew points back home (OK/TX) at the time. Link to comment Share on other sites More sharing options...
Derek30 Posted May 21, 2012 Share Posted May 21, 2012 Looks like southern Manitoba should be in a good spot for scattered elevated convection tonight through tomorrow night. We'll be in a good spot north of the warm front with a good push of warm air advection and some modest instability. Best chances will be tomorrow night as the LLJ really gets going. Link to comment Share on other sites More sharing options...
Chinook Posted May 21, 2012 Share Posted May 21, 2012 If we get dew points of 63-65 F in the NE Panhandle coincident with the kinematics and synoptic chart shown by the Euro, you won't hear any complaining from me. My concern was that moisture throughout the southern/central Plains in general looks unseasonably lacking, so we'd be relying on pooling to some extent to get those numbers. From what I can tell, the Euro has the 60 F isodrosotherm all the way out in eastern NE, only bending back to the High Plains right along the warm front in S SD. Way too early to talk about exact numbers and/or locations, but it's safe to say that moisture isn't looking particularly impressive for late May. Most anytime I can recall chasing the central Plains in the late season, there was a reservoir of 65-70+ F dew points back home (OK/TX) at the time. Are you talking about the Nebraska Panhandle tomorrow or Wednesday? Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 21, 2012 Share Posted May 21, 2012 If we get dew points of 63-65 F in the NE Panhandle coincident with the kinematics and synoptic chart shown by the Euro, you won't hear any complaining from me. My concern was that moisture throughout the southern/central Plains in general looks unseasonably lacking, so we'd be relying on pooling to some extent to get those numbers. From what I can tell, the Euro has the 60 F isodrosotherm all the way out in eastern NE, only bending back to the High Plains right along the warm front in S SD. Way too early to talk about exact numbers and/or locations, but it's safe to say that moisture isn't looking particularly impressive for late May. Most anytime I can recall chasing the central Plains in the late season, there was a reservoir of 65-70+ F dew points back home (OK/TX) at the time. Yeah I see what you are saying now. The setup itself is dependent upon everything coming together perfectly. Of course the 12z guidance completely backs off a strong lead wave....slows down the second wave as well and builds in the ridge out east a bit. Fun to watch the sensitivity issues w.r.t. that first wave. Link to comment Share on other sites More sharing options...
MnWeatherman Posted May 21, 2012 Share Posted May 21, 2012 30% hatched in North Dakota for tomorrow Link to comment Share on other sites More sharing options...
Derek30 Posted May 21, 2012 Share Posted May 21, 2012 Reed "BACK UP!" Timmer is targeting ND tomorrow in the hatched area. I don't know how the guy doesn't burn out. He was actually up in southern MB for a short time on Friday as well as North Dakota and Minnesota. Link to comment Share on other sites More sharing options...
Buckeye05 Posted May 21, 2012 Share Posted May 21, 2012 Tomorrow looks marginal to me tornado wise. I'm gonna say that moisture issues are gonna be a repetitive negative factor for setups this week. Models have been so persistent with it too. Link to comment Share on other sites More sharing options...
Ian Posted May 21, 2012 Share Posted May 21, 2012 Tomorrow looks marginal to me tornado wise. I'm gonna say that moisture issues are gonna be a repetitive negative factor for setups this week. Models have been so persistent with it too. i could see it still be an issue tomorrow but i'd be more and more surprised as time goes if it remains a big one. Link to comment Share on other sites More sharing options...
Ian Posted May 21, 2012 Share Posted May 21, 2012 18z gfs blowing up that lead vort again on thurs Link to comment Share on other sites More sharing options...
MNstorms Posted May 21, 2012 Author Share Posted May 21, 2012 Thunderstorms looking more and more likely here. Along with heavy rain. Too early to see if severe storms are possible. Link to comment Share on other sites More sharing options...
andyhb Posted May 21, 2012 Share Posted May 21, 2012 18z gfs blowing up that lead vort again on thurs Gotta love a 984 mb sfc low in late May... Link to comment Share on other sites More sharing options...
Ian Posted May 21, 2012 Share Posted May 21, 2012 Gotta love a 984 mb sfc low in late May... selfishly i have to root it on for the eastern target in the midwest. tho it looks like moisture is still pretty limited with the EC low. overall a pretty stellar run into the long range.. at least it looks active. Link to comment Share on other sites More sharing options...
andyhb Posted May 21, 2012 Share Posted May 21, 2012 selfishly i have to root it on for the eastern target in the midwest. tho it looks like moisture is still pretty limited with the EC low. overall a pretty stellar run into the long range.. Yeah, lots of different systems on that run well into the later ranges. Link to comment Share on other sites More sharing options...
Buckeye05 Posted May 21, 2012 Share Posted May 21, 2012 In terms of long range, i'm not gonna get too optimistic just yet with this run. We got so pumped over this current system, only for it to become pretty lackluster as the time approached. I'm gonna wait until I see some really consistent and synoptically evident major setup in the works before I get too exited. Anything short of that has busted big time since mid April. I bet it will look pretty "meh" as we get closer. Link to comment Share on other sites More sharing options...
Buckeye05 Posted May 22, 2012 Share Posted May 22, 2012 However, instability and moisture looking a tad better tomorrow, although maybe too late in the day. Link to comment Share on other sites More sharing options...
andyhb Posted May 22, 2012 Share Posted May 22, 2012 In terms of long range, i'm not gonna get too optimistic just yet with this run. We got so pumped over this current system, only for it to become pretty lackluster as the time approached. I'm gonna wait until I see some really consistent and synoptically evident major setup in the works before I get too exited. Anything short of that has busted big time since mid April. I bet it will look pretty "meh" as we get closer. 2 days ago wasn't a bust in any sense (in fact, it over performed, as did the Medford event on 4/30)...not every event is gonna have your ideal juxtaposition of moisture, shear and other parameters. The main thing has been the rather lack of impressive synoptic systems ejecting in a manner that would be conducive for an event (and subsequent capping problems with the ones that somewhat did). Several days ago we were concerned that we were not going to see anything until perhaps after Memorial Day, and now that at least one model shows a weakness in the ridge for a period with multiple synoptic potentials through the mid/long ranges, I believe that is a cause for (tentative) optimism. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 22, 2012 Share Posted May 22, 2012 TOG definitely west of KAMA Link to comment Share on other sites More sharing options...
andyhb Posted May 22, 2012 Share Posted May 22, 2012 Not sure what the NAM is developing at the end of its run with the second wave, but it looks rather interesting... Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 22, 2012 Share Posted May 22, 2012 I'm sure this will get MPX's attnention. I do not know what is weighted more heavily when calculating EHI numbers, but if it is cape than the EHI could be underdone. I can't show 0-1km shear which is around 25 knts and 0-6 km which shows around 40 knts-55 knts but here is some things that look interesting to me, although cape doesn't appear to get over 2k, near the metro, the other values are there. Cape Helicity EHI This looks to be a pretty narrow threat area, I would like to see broader EHI values for the SPC to issue a slight risk, IMO Link to comment Share on other sites More sharing options...
jpeters3 Posted May 22, 2012 Share Posted May 22, 2012 I do not know what is weighted more heavily when calculating EHI numbers, but if it is cape than the EHI could be underdone. I can't show 0-1km shear which is around 25 knts and 0-6 km which shows around 40 knts-55 knts but here is some things that look interesting to me, although cape doesn't appear to get over 2k, near the metro, the other values are there. Cape EHI is a normalized multiplication of CAPE and SRH, therefore it cannot be "overdone," since it has a numeric definition. It is meant to indicate when the combination of thermodynamic (CAPE) and kinematic (SRH) is optimal for tornadoes. Both of these quantities play a role in the generation of vertical vorticity (updraft rotation) since SRH is indicative of how much vorticity is "available" to updrafts, but strong cape also enhances vertical vorticity by stretching - the less cape, the less vertical stretching and enhancement of SRH that has been tilted into the vertical. Lacking CAPE equates to less intense updraft vertical vorticity than what would otherwise occur with more CAPE. Link to comment Share on other sites More sharing options...
andyhb Posted May 22, 2012 Share Posted May 22, 2012 Ridge and poor ejection really kills the second wave on this run of the GFS...and the pattern turns to crap in the long range as well... Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 22, 2012 Share Posted May 22, 2012 EHI is a normalized multiplication of CAPE and SRH, therefore it cannot be "overdone," since it has a numeric definition. It is meant to indicate when the combination of thermodynamic (CAPE) and kinematic (SRH) is optimal for tornadoes. Both of these quantities play a role in the generation of vertical vorticity (updraft rotation) since SRH is indicative of how much vorticity is "available" to updrafts, but strong cape also enhances vertical vorticity by stretching - the less cape, the less vertical stretching and enhancement of SRH that has been tilted into the vertical. Lacking CAPE equates to less intense updraft vertical vorticity than what would otherwise occur with more CAPE. Thanks for the answer, that was a good explanation, so one more question, if I can. If cape values were around 2000, what would happen to the EHI values, would they grow at a steady pace, or would they grow exponentially? Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 22, 2012 Share Posted May 22, 2012 4 km SPC WRF unloading tomorrow across NODAK. Usually not into just posting this eye candy, but the potential for a good chase day tomorrow (especially for up there) is high as long as it doesn't become a late show. Northern Nodak along the front seems the place to be. Link to comment Share on other sites More sharing options...
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