Thundersnow12 Posted June 14, 2011 Share Posted June 14, 2011 wont write much since I'm about to go to work but this is off the 12z NAM for friday...a good mid-level westerly jet with a strong LLJ with ample intstablity and moisture to work with with small area of locally backed sfc flow creating very high 0-3 EHI numbers of around 10. Link to comment Share on other sites More sharing options...
tornadotony Posted June 14, 2011 Share Posted June 14, 2011 GFS now siding with the Euro for a MONSTER on Monday. Link to comment Share on other sites More sharing options...
Ajdos Posted June 14, 2011 Share Posted June 14, 2011 Bring on the CAP Link to comment Share on other sites More sharing options...
tornadotony Posted June 14, 2011 Share Posted June 14, 2011 Bring on the CAP Yeah except for one minor detail...the NAM verbatim is uncapped at 00z... Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 14, 2011 Share Posted June 14, 2011 Kind of a new prog by the medium range guidance--but the 12Z CMC/Euro are taking the final jet streak day5+ much farther S. Watch out if something like the Euro verifies. That type of ejecting wave that far S with this type of instability would be potentially significant. Link to comment Share on other sites More sharing options...
thewxmann Posted June 14, 2011 Share Posted June 14, 2011 Kind of a new prog by the medium range guidance--but the 12Z CMC/Euro are taking the final jet streak day5+ much farther S. Watch out if something like the Euro verifies. That type of ejecting wave that far S with this type of instability would be potentially significant. I could argue that if the jet streak dives as far south as the 12Z ECM depicts it, it'd pick up an EML that would be too hot to allow for sfc-based initiation, kinda like what happened with that monstrous trough in June 2007 that prompted back-to-back SPC Day 3 MDT's. Already the 0Z ECM progs 20C 850s to extend over most of the eastern 2/3 of the country. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 14, 2011 Share Posted June 14, 2011 I could argue that if the jet streak dives as far south as the 12Z ECM depicts it, it'd pick up an EML that would be too hot to allow for sfc-based initiation, kinda like what happened with that monstrous trough in June 2007 that prompted back-to-back SPC Day 3 MDT's. Already the 0Z ECM progs 20C 850s to extend over most of the eastern 2/3 of the country. Yeah mainly why I mentioned "potential". Getting too detailed here for this time frame, but one thing about the Euro (just looking at the 24 hr plots) is the way the shortwave/jet streak are oriented W-E w.r.t. the high plains. That type of focused height falls could pose problems to even stout EML's.Also those 850s may very well be boundary layer temps--I guess I would have to see soundings. A GFS type solution with weak height falls through the plains of course would be capped. Link to comment Share on other sites More sharing options...
wisconsinwx Posted June 14, 2011 Share Posted June 14, 2011 wont write much since I'm about to go to work but this is off the 12z NAM for friday...a good mid-level westerly jet with a strong LLJ with ample intstablity and moisture to work with with small area of locally backed sfc flow creating very high 0-3 EHI numbers of around 10. Well I was going to say it is appropriate that one of our better chances for severe weather would happen while I'm in Maine, but after noticing these maps were for the Friday-Saturday timeframe, I won't. However, I'm leaving Sunday, and I am pretty sure we'll have some severe weather for the week I'm gone. Link to comment Share on other sites More sharing options...
Chicago Storm Posted June 14, 2011 Share Posted June 14, 2011 I could argue that if the jet streak dives as far south as the 12Z ECM depicts it, it'd pick up an EML that would be too hot to allow for sfc-based initiation, kinda like what happened with that monstrous trough in June 2007 that prompted back-to-back SPC Day 3 MDT's. Already the 0Z ECM progs 20C 850s to extend over most of the eastern 2/3 of the country. 700mb temps of 10C+ all the way up to Lake Superior and Southern Ontario on Monday. 850mb temps are quite warm too as you mention, around 25C in some areas...Chicago being one of those areas. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 14, 2011 Share Posted June 14, 2011 FWIW, looking quickly on AWIPS, the Euro blows up a long line of convection along the dryline/cold front as the trough ejects. Just something to watch in the day 5+ range should something remotely like the ECMWF verify. It is highly dependent upon on the orientation of the height fields aloft and how focused the convergence is. We have 15 degree C 700 temps pushing into MO today, but this isn't early spring either when dewpoints are struggling to get into the 60s and the low level moisture fields are shallow. Link to comment Share on other sites More sharing options...
Chinook Posted June 14, 2011 Share Posted June 14, 2011 Yeah mainly why I mentioned "potential". Getting too detailed here for this time frame, but one thing about the Euro (just looking at the 24 hr plots) is the way the shortwave/jet streak are oriented W-E w.r.t. the high plains. That type of focused height falls could pose problems to even stout EML's.Also those 850s may very well be boundary layer temps--I guess I would have to see soundings. A GFS type solution with weak height falls through the plains of course would be capped. 12z GFS 12z Sunday trough in southern Idaho 12z Monday: low in southwest South Dakota (564dm) 12z Tuesday, low in northeast MN (558dm) 12z Euro 12z Sunday: trough Idaho/Utah 12z Monday: trough/vort max in southwest Colorado (570dm) 12z Tuesday elongated low from Manitoba to South Dakota (570dm) I have generally learned that the medium-range forecasts are not too accurate in June, so medium range forecasting of severe weather is tougher than April/May. South Dakota looks to be a hot spot for bad weather. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 15, 2011 Author Share Posted June 15, 2011 The 0z NAM sure looks interesting in southwest IA on friday but man that damn cap.. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 15, 2011 Author Share Posted June 15, 2011 This was from the 12z NAM but still... Link to comment Share on other sites More sharing options...
natecast Posted June 15, 2011 Share Posted June 15, 2011 Just based upon today 12z GFS, I can honestly say I can't remember seeing such a deep trough this far south into Oklahoma in late June. Need to look at other indicators other than 500MB heights, but this will be interesting to watch. Edited to add: Forgot to mention timeframe, which is Monday, June 20th. Link to comment Share on other sites More sharing options...
hm8 Posted June 15, 2011 Share Posted June 15, 2011 Link to comment Share on other sites More sharing options...
Chinook Posted June 15, 2011 Share Posted June 15, 2011 June 17 (tomorrow) look at the differences between the NAM and the SREF(based off the NAM) in Missouri http://www.emc.ncep.noaa.gov/mmb/namsvrfcst/images/today/sfccape33.gif http://www.spc.noaa.gov/exper/sref/gifs/2011061515/SREF_SFCCAPE_MEDIAN_MXMN__f030.gif Link to comment Share on other sites More sharing options...
OKpowdah Posted June 15, 2011 Share Posted June 15, 2011 Monday and Tuesday of next week look quite intriguing. A trough digging that far south, into 70+ dps would have major implications in the southern Plains Link to comment Share on other sites More sharing options...
hm8 Posted June 15, 2011 Share Posted June 15, 2011 GFS has just been going bonkers with the instability during the Sun-Tuesday period in the OV and GL. Widespread 5000+ CAPE and LI's <-10. Shear is laking however and there is some CIN.... Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 15, 2011 Share Posted June 15, 2011 Monday and Tuesday of next week look quite intriguing. A trough digging that far south, into 70+ dps would have major implications in the southern Plains ECMWF ensemble and GFS are both ejecting a potent wave into the southern plains with this last wave. It does seem they have both tended away from the amplified trough scenario. This verbatim would potentially get ugly. You just don't see shortwaves with that amplitude (but not closed) ejecting through the summer subtropical ridge very often. We will have to see... Link to comment Share on other sites More sharing options...
gusfront Posted June 16, 2011 Share Posted June 16, 2011 JoMo does this look like another bad one next week fo us here in jln ?? tor setup wise ?? Link to comment Share on other sites More sharing options...
JoMo Posted June 16, 2011 Share Posted June 16, 2011 JoMo does this look like another bad one next week fo us here in jln ?? tor setup wise ?? Not sure. The NAM has been struggling with the capping and timing issues lately. NAM wants to bring down an MCS looking thing tomorrow afternoon it looks like but it kind of falls apart just north of us it looks like. Then on Friday I think it is, it looks like it wants to develop some cells across SE Kansas. The more impressive thing is the giant blob on Saturday night it develops across Kansas and drives to the ESE. That thing looks mean with high instability present and shear which may actually be convective feedback. Of course this is all up in the air and the NAM has really been having issues with the cap. Link to comment Share on other sites More sharing options...
OKpowdah Posted June 16, 2011 Share Posted June 16, 2011 From the OKC AFD this morning: (nice wording for an office that doesn't do much long range discussion usually) AT THE SAME TIME...THIS PATTERN ALMOST CERTAINLY SUPPORTS THUNDERSTORM CHANCES. SHORT WAVE RIDGING MOVES THROUGH VERY QUICKLY TODAY...AND WE TRANSITION TO WEST OR SOUTHWEST FLOW OVER THE DRYLINE FROM THIS EVENING ON THROUGH NEXT TUESDAY. MOS GUIDANCE POPS ARE STILL NOT CATCHING ONTO THIS SOMEWHAT UNTIMELY PATTERN OF SPRING-LIKE FLOW MIXED WITH LATE-SUMMER-LIKE HEAT. BUT THE DETERMINISTIC OUTPUT FROM THE NAM AND ECMWF PRODUCE QPF EACH DAY... AND WE HAVE FOLLOWED SUIT. THE THUNDERSTORMS WILL BE HIGH-BASED AND LIKELY PRODUCE DAMAGING WINDS. THIS COULD OCCUR EACH EVENING FOR SEVERAL DAYS IN A ROW. CAP STRENGTH MAY WEAKEN STORMS IN THE OVERNIGHT PERIOD...BUT THIS WOULD ALSO LEAD TO HEAT BURSTS. A MORE WIDESPREAD AND LONGER LIVED SEVERE THUNDERSTORM EVENT COULD OCCUR EARLY NEXT WEEK WHEN THE LONG WAVE UPPER TROUGH BEGINS TO EJECT. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 16, 2011 Share Posted June 16, 2011 Pretty large differences amongst all global guidance by day 4 even with the same general idea in hand. Unfortunately the small differences have rather large impacts on convective potential. The 12Z Euro today remains the most amped up and goes negative tilt by Day 4-5 whereas the weak GFS is positive tilt and sheared out--looks like what happened quite often earlier this spring with positive tilt waves ejecting into the plains. Link to comment Share on other sites More sharing options...
OKpowdah Posted June 16, 2011 Share Posted June 16, 2011 In terms of the severe threat further south over OK, the trough tilts negative too quickly on the Euro, so that it's lifting northeast, with the best dynamics well to the north of OK. A situation closer to the GFS, with a wave component ejecting downstream of the trough, would suppress the base of the trough further south. But that's also dependent on how well in phase the wave components are in the base of the trough. If the whole thing shears out, that's no good either, obviously Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 16, 2011 Share Posted June 16, 2011 In terms of the severe threat further south over OK, the trough tilts negative too quickly on the Euro, so that it's lifting northeast, with the best dynamics well to the north of OK. A situation closer to the GFS, with a wave component ejecting downstream of the trough, would suppress the base of the trough further south. But that's also dependent on how well in phase the wave components are in the base of the trough. If the whole thing shears out, that's no good either, obviously I would have to disagree. Sure it wouldn't be a massive severe outbreak but the potential for another line of very large hailers and damaging winds similar to the last event a couple days ago would be a very possible scenario with the Euro given the placement of the upper ridge axis and the front. Link to comment Share on other sites More sharing options...
OKpowdah Posted June 16, 2011 Share Posted June 16, 2011 I would have to disagree. Sure it wouldn't be a massive severe outbreak but the potential for another line of very large hailers and damaging winds similar to the last event a couple days ago would be a very possible scenario with the Euro given the placement of the upper ridge axis and the front. would be much more difficult to break the cap. Strong SW flow aloft advects an epic eml into into the state, and with less than adequate forcing, we would have some issues. Also, the greatest surface pressure falls would be to the north, so boundary layer winds wouldn't be able to get much easterly component, and then we're stuck with the drier airmass in place, and high LCLs. That can all change if the trough is suppressed further south. Much better forcing mechanism, and an isallobaric wind out of the southeast to advect higher bl dps. Then a solid outbreak really would be in the cards Link to comment Share on other sites More sharing options...
baroclinic_instability Posted June 16, 2011 Share Posted June 16, 2011 would be much more difficult to break the cap. Strong SW flow aloft advects an epic eml into into the state, and with less than adequate forcing, we would have some issues. Also, the greatest surface pressure falls would be to the north, so boundary layer winds wouldn't be able to get much easterly component, and then we're stuck with the drier airmass in place, and high LCLs. That can all change if the trough is suppressed further south. Much better forcing mechanism, and an isallobaric wind out of the southeast to advect higher bl dps. Then a solid outbreak really would be in the cards Well yes if you are looking for tornadoes only, it certainly doesn't look impressive either way. Not sure where the "less than adequate" forcing is coming from though, even displaced to the N the Euro verbatim is more than sufficient for initiation with the very deep boundary layer progged moisture and efficient June heating. With the placement of the subtropical ridge w.r.t. the front, the entire state isn't going to be capped like it would in spring. I am not saying there is going to be a huge outbreak, but there is the potential for a significant severe DMC. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 16, 2011 Share Posted June 16, 2011 The 12z NAM has a pretty strong signal for a large linear MCS late tomorrow/tomorrow evening. It shows a nice 60-70kt H5 jet streak moving through Iowa later tomorrow. Instability looks pretty nice with dews pooling north of 70 over parts of Iowa and the northern half of Illinois. The NAM forecasts over 3000j/kg of cape in these areas. Link to comment Share on other sites More sharing options...
Justin Posted June 16, 2011 Share Posted June 16, 2011 I may run into some great stuff tomorrow evening/night as I'm heading back to the quad cities from Chicago. The set up is a bit scary actually. I think we'll see some high end wind potentially, very heavy rain of course, and who knows wrt tornadoes. The instability and shear looks good so we'll see. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 16, 2011 Share Posted June 16, 2011 I may run into some great stuff tomorrow evening/night as I'm heading back to the quad cities from Chicago. The set up is a bit scary actually. I think we'll see some high end wind potentially, very heavy rain of course, and who knows wrt tornadoes. The instability and shear looks good so we'll see. EHI actually isn't too bad, especially the 3km. Wind fields below H7 aren't all that great, but with strong mid-level support, and pretty high instability things do look interesting. I think we're going to end up seeing an impressive linear MCS evolve with a strong cool pool, and some significant damaging wind potential downstream. With the shear in place a tornado or two looks possible mixed in with the bows and lewps. Link to comment Share on other sites More sharing options...
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