Indystorm Posted February 12, 2011 Share Posted February 12, 2011 Ok, I may go down in flames, but it is within seven days and currently this Sat. both GFS and Ukie are showing an intense low pressure tracking through the upper midwest with a 150 knot 300 mb jet screaming from ne KS to sw WI. Saturday morning data shows dews of 50's progged to make it up to central IL and 500-750 CAPE at present. Obviously this early in the season instability is the big wild card, but with a pattern change to a more normal LaNIna depiction of warmth something may be on the table for us to watch in future model runs this upcoming week. I would think possibly central IL on south and soutwestward may be interesting to watch in this period depending upon how much snow melts and how much surface temps rebound ahead of this system. Link to comment Share on other sites More sharing options...
Hoosier Posted February 12, 2011 Share Posted February 12, 2011 It's an interesting looking system. Quality moisture return looks to be one of the bigger issues at this point. These early season systems usually don't need much instability to work with though so it's something to watch. Link to comment Share on other sites More sharing options...
oldlogin Posted February 12, 2011 Share Posted February 12, 2011 For some reason I can not copy the map... Starting to look somewhat interesting.... http://www.spc.noaa.gov/exper/mref_mars/ Link to comment Share on other sites More sharing options...
Macintosh Posted February 12, 2011 Share Posted February 12, 2011 Ok, I may go down in flames, but it is within seven days and currently this Sat. both GFS and Ukie are showing an intense low pressure tracking through the upper midwest with a 150 knot 300 mb jet screaming from ne KS to sw WI. Saturday morning data shows dews of 50's progged to make it up to central IL and 500-750 CAPE at present. Obviously this early in the season instability is the big wild card, but with a pattern change to a more normal LaNIna depiction of warmth something may be on the table for us to watch in future model runs this upcoming week. I would think possibly central IL on south and soutwestward may be interesting to watch in this period depending upon how much snow melts and how much surface temps rebound ahead of this system. SPC has yet to outlook any areas concerning this possibility. However, you can just look in the forecast grids and see screaming SW surface winds in this time frame. That to me says it all. You've got some sort of dynamics forcing high winds from the southwest. The temps are also looking pretty warm for late winter. Link to comment Share on other sites More sharing options...
Macintosh Posted February 12, 2011 Share Posted February 12, 2011 It's an interesting looking system. Quality moisture return looks to be one of the bigger issues at this point. These early season systems usually don't need much instability to work with though so it's something to watch. Yeah, the moisture is going to be the big issue. I.E., dewpoints. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 12, 2011 Share Posted February 12, 2011 SPC has yet to outlook any areas concerning this possibility. However, you can just look in the forecast grids and see screaming SW surface winds in this time frame. That to me says it all. You've got some sort of dynamics forcing high winds from the southwest. The temps are also looking pretty warm for late winter. no...you need more than that to say it "all". Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 Yeah, the moisture is going to be the big issue. I.E., dewpoints. This might be an event where we end up saying "if only it were a month later." Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 13, 2011 Share Posted February 13, 2011 This might be an event where we end up saying "if only it were a month later." or "if only the sfc low didn't occlude so early" or "if only the sfc winds were backed in the warm sector" lol Link to comment Share on other sites More sharing options...
Indystorm Posted February 13, 2011 Author Share Posted February 13, 2011 This and subsequent storms this season will be interesting to follow as always. I don't know how many times I've said that for svr wx we need low to mid 60's dewpoints with other parameters in place only to be corrected by someone who shows me how svr wx occurred with dews in the 50's or lower. But indeed, quality low level moisture seems to be the key in my book. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 13, 2011 Share Posted February 13, 2011 This and subsequent storms this season will be interesting to follow as always. I don't know how many times I've said that for svr wx we need low to mid 60's dewpoints with other parameters in place only to be corrected by someone who shows me how svr wx occurred with dews in the 50's or lower. But indeed, quality low level moisture seems to be the key in my book. or the photogenic tornado that occured last March in OK in a 54/46 environment. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 or "if only the sfc low didn't occlude so early" or "if only the sfc winds were backed in the warm sector" lol I'm really not even thinking about the veered surface winds...and actually, in this case, it might not kill the setup with mid level winds almost due westerly. My biggest concern is definitely moisture availability, and I could easily see that killing it or substantially reducing the threat area. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 13, 2011 Share Posted February 13, 2011 I'm really not even thinking about the veered surface winds...and actually, in this case, it might not kill the setup with mid level winds almost due westerly. My biggest concern is definitely moisture availability, and I could easily see that killing it or substantially reducing the threat area. H5 winds were SW last I checked. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 H5 winds were SW last I checked. Let's compromise and call it WSW. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 I'm not saying that the occlusion/veered surface winds should be ignored, but look at this sounding for LAF. Veered surface winds and it's still spitting out helicity near 600. Flow is very strong at all levels. It's probably safe to assume that the GFS isn't going to handle the temperature profile correctly, but there's still the moisture question (not only surface dewpoints but also how deep it will be). Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 13, 2011 Share Posted February 13, 2011 I'm not saying that the occlusion/veered surface winds should be ignored, but look at this sounding for LAF. Veered surface winds and it's still spitting out helicity near 600. Flow is very strong at all levels. It's probably safe to assume that the GFS isn't going to handle the temperature profile correctly, but there's still the moisture question (not only surface dewpoints but also how deep it will be). yep pretty impressive speed shear. I would agree moisture is going to be the big problem. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 00z GFS has a 130 kt jet max at 500 mb valid 00z Saturday. Link to comment Share on other sites More sharing options...
Stebo Posted February 13, 2011 Share Posted February 13, 2011 One thing to watch though with this, is that the climatology in the models will tend to under do the temperatures and dew points. Also this is the type of potential where 500 J/kg will be enough to get things going. I'd certainly keep an eye on things. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 One thing to watch though with this, is that the climatology in the models will tend to under do the temperatures and dew points. Also this is the type of potential where 500 J/kg will be enough to get things going. I'd certainly keep an eye on things. I can't think of more than a few outbreaks that had 500 mb winds close to that, but they were March/April events. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 Here's the 130 kts I mentioned...southern Wisconsin... Link to comment Share on other sites More sharing options...
Stebo Posted February 13, 2011 Share Posted February 13, 2011 I can't think of more than a few outbreaks that had 500 mb winds close to that, but they were March/April events. Yeah, the one thing though is, we would need some instability, 500-1000 J/kg, because winds that strong would tear apart storms before they go up because weak buoyancy. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 Yeah, the one thing though is, we would need some instability, 500-1000 J/kg, because winds that strong would tear apart storms before they go up because weak buoyancy. Buoyancy would help. The model surface temps are likely going to be underdone in this type of regime. I guess I'm less sure about the moisture but it's possible. Link to comment Share on other sites More sharing options...
Stebo Posted February 13, 2011 Share Posted February 13, 2011 Buoyancy would help. The model surface temps are likely going to be underdone in this type of regime. I guess I'm less sure about the moisture but it's possible. Yeah I think this is a wait and see kind of deal. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 Yeah I think this is a wait and see kind of deal. I'm never gonna ignore a setup with 130 knots but there are certainly some possible negating factors as we've been discussing. Link to comment Share on other sites More sharing options...
Stebo Posted February 13, 2011 Share Posted February 13, 2011 I'm never gonna ignore a setup with 130 knots but there are certainly some possible negating factors as we've been discussing. Oh of course not, when you see something like that any time of year a bell should go off. Link to comment Share on other sites More sharing options...
cmichweather Posted February 13, 2011 Share Posted February 13, 2011 Instability will be the key, we'll have to see how clouded over the warm sector is. This is a straight line threat all the way, unless this trends way southeast and a further phase it'll be a chance for many of you to see some straight line wind and small hail. Link to comment Share on other sites More sharing options...
Hoosier Posted February 13, 2011 Share Posted February 13, 2011 Instability will be the key, we'll have to see how clouded over the warm sector is. This is a straight line threat all the way, unless this trends way southeast and a further phase it'll be a chance for many of you to see some straight line wind and small hail. I don't think this is a typical huge squall line if it pans out like this. There is a distinct lack of strong linear forcing being depicted which is reflected in the rather meager qpf fields. Link to comment Share on other sites More sharing options...
cmichweather Posted February 13, 2011 Share Posted February 13, 2011 I don't think this is a typical huge squall line if it pans out like this. There is a distinct lack of strong linear forcing being depicted which is reflected in the rather meager qpf fields. oh ya no this won't be a long lived squall line most likely a line of heavy rain with embedded thunderstorms and the threat for strong winds or small hail, i doubt instability is ever realized, especially since the strongest forcing from the storm will be the further north you go. I think the only potential is in the iowa,ill areas if i had to choose. I think this won't go above a see text for spc. Just to clarify not a big event for anyone really unless you're talking blizzard conditions for you know who.... Link to comment Share on other sites More sharing options...
nzucker Posted February 13, 2011 Share Posted February 13, 2011 oh ya no this won't be a long lived squall line most likely a line of heavy rain with embedded thunderstorms and the threat for strong winds or small hail, i doubt instability is ever realized, especially since the strongest forcing from the storm will be the further north you go. I think the only potential is in the iowa,ill areas if i had to choose. I think this won't go above a see text for spc. Just to clarify not a big event for anyone really unless you're talking blizzard conditions for you know who.... Do you think the GFS is underdoing the QPF in the cold sector of the system? Considering the low is dropping to 990mb, should we have a more defined deformation zone with blizzard conditions, perhaps over the Dakotas, or are the mid-levels too disorganized for this? Link to comment Share on other sites More sharing options...
Stebo Posted February 13, 2011 Share Posted February 13, 2011 Do you think the GFS is underdoing the QPF in the cold sector of the system? Considering the low is dropping to 990mb, should we have a more defined deformation zone with blizzard conditions, perhaps over the Dakotas, or are the mid-levels too disorganized for this? I think its underdoing the QPF in general, the flow prior to the system will be out of the gulf. Link to comment Share on other sites More sharing options...
cmichweather Posted February 13, 2011 Share Posted February 13, 2011 Do you think the GFS is underdoing the QPF in the cold sector of the system? Considering the low is dropping to 990mb, should we have a more defined deformation zone with blizzard conditions, perhaps over the Dakotas, or are the mid-levels too disorganized for this? It really depends on the return flow from the gulf and if i could check i'd love to look at projected frontogensis, along with csi, also I'm not sure what the storm relative flow will be like but i would have to think we could develop a fairly substantial CCB, I'm not sure that the return flow will be all that strong but we should see a weak trowal like feature that'll be strengthening as it moves west. I think the further east you go the better you do but this is probably a .5'-.75 for the dakotas and possible an inch into the upper MN region. I do think the gfs is a bit low based on what i've seen from the ecmwf but banded precip shouldn't be epic based on what i'm seeing as of right now. Link to comment Share on other sites More sharing options...
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