CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 This still looks like a high shear/low CAPE to me. It's interesting that the SREF tstm probs are rather low even in NY state, yet they highlight a small area in ern PA for tornado ingredients. I'm just not sure how unstable it gets. Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 This still looks like a high shear/low CAPE to me. It's interesting that the SREF tstm probs are rather low even in NY state, yet they highlight a small area in ern PA for tornado ingredients. I'm just not sure how unstable it gets. Yeah agreed. That said given the shear and the fact the models do have a solid slug of sfc based instability we could have one nasty squall line and maybe even a sig tor somewhere west of us. Link to comment Share on other sites More sharing options...
earthlight Posted September 7, 2012 Share Posted September 7, 2012 The SPC SREF hasn't been as impressive with it's past few runs with some of the parameters...interesting b/c other models haven't been backing off much. I just hope we can develop just enough Cape so where updrafts aren't being torn apart by strong winds aloft...although with the amount of forcing/lift involved here that could be enough to compensate for lack of stronger Cape. Cloudcover is a pretty big concern for me. The guidance has been indicative of clouds in the warm sector from 9z on with only some hints at breaks. This could be part of the reason why we're seeing the SREF mean adjust downward with instability parameters. Obviously, with the kinematics in place...a decent amount of instability will suffice. So I guess we'll see. Link to comment Share on other sites More sharing options...
earthlight Posted September 7, 2012 Share Posted September 7, 2012 Interestingly most models are indicative of this being pretty unorganized until that one vigorous shortwave hits the trough base and starts ejecting eastward. It's at that point that the high resolution models kick off the rapid development of a line of convection that extends from Eastern PA into NY State. I would think we could see some LEWPs in NE PA and NY State as well. Even the SREF mean has 0-1km helicity of 250 m2/s2 or more throughout much of that area...and values of 200+ extend south along the front. Pretty impressive. Link to comment Share on other sites More sharing options...
CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 Yeah agreed. That said given the shear and the fact the models do have a solid slug of sfc based instability we could have one nasty squall line and maybe even a sig tor somewhere west of us. Yeah I can see a strongly forced squall line with some damage. Maybe a segment with a book end vort or something too? Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 Yeah I can see a strongly forced squall line with some damage. Maybe a segment with a book end vort or something too? Yeah that sounds good to me. If we clear out watch out but this event has potential for sure. Link to comment Share on other sites More sharing options...
Quincy Posted September 7, 2012 Share Posted September 7, 2012 Regardless of cloud-cover and instability, that squall line at night could still pack some strong winds. GRID data showing winds as high as 50kt as low as 900mb and near-surface winds in the range of 30+ knots. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 Cloudcover is a pretty big concern for me. The guidance has been indicative of clouds in the warm sector from 9z on with only some hints at breaks. This could be part of the reason why we're seeing the SREF mean adjust downward with instability parameters. Obviously, with the kinematics in place...a decent amount of instability will suffice. So I guess we'll see. The cloud cover factor tomorrow will be rather interesting. Normally in these types of setups, especially this time of year, we see profiles which are pretty moist and rather saturated. In this case there is a decent amount of dry air above 800mb so while there will be clouds around perhaps we'll be able to get more in the way of breaks than what we typically see? Link to comment Share on other sites More sharing options...
CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 GFS has some sort of shwr activity or even iso tstm coming up from the south in the aftn too. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 Cloudcover is a pretty big concern for me. The guidance has been indicative of clouds in the warm sector from 9z on with only some hints at breaks. This could be part of the reason why we're seeing the SREF mean adjust downward with instability parameters. Obviously, with the kinematics in place...a decent amount of instability will suffice. So I guess we'll see. The cloud cover factor tomorrow will be rather interesting. Normally in these types of setups, especially this time of year, we see profiles which are pretty moist and rather saturated. In this case there is a decent amount of dry air above 800mb so while there will be clouds around perhaps we'll be able to get more in the way of breaks than what we typically see? Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 GFS has some sort of shwr activity or even iso tstm coming up from the south in the aftn too. yeah...although the GFS is a bit more robust with instability than it has been on past runs here. Regardless of the instability we should still see a fairly solid line moving through which will be dynamically driven...I think the instability factor and how much sun we see will apply for any discrete development out ahead of the main line. Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 Mid level temps are awfully warm tomorrow... mid level lapse rates are, not surprisingly, abysmal. That said the NAM does have very strong 0-1km shear, low LCLs, a nasty LLJ, and a fair amount of CAPE in low levels so I suppose some low topped supercells are possible out ahead of the main forced line. Keep in mind with a 50 knot LLJ out of the south we will have the potential for some very gusty winds just through turbulent mixing with SSTs at the climatological peak. I think tomorrow will be a fun day. Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 If we can get convective initiation prior to the main forcing tomorrow (which is possible given very little CIN) we should watch out for rather unimpressive looking cells dropping TORs. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 Mid level temps are awfully warm tomorrow... mid level lapse rates are, not surprisingly, abysmal. That said the NAM does have very strong 0-1km shear, low LCLs, a nasty LLJ, and a fair amount of CAPE in low levels so I suppose some low topped supercells are possible out ahead of the main forced line. Keep in mind with a 50 knot LLJ out of the south we will have the potential for some very gusty winds just through turbulent mixing with SSTs at the climatological peak. I think tomorrow will be a fun day. Yeah the mid-level lapse rates are pretty pathetic, even getting down to as low as 4.5-5 C/KM which is about as bad as it gets. While this certainly be be a factor this should be compensated some by the high sfc dews and strong forcing/lift. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 If we can get convective initiation prior to the main forcing tomorrow (which is possible given very little CIN) we should watch out for rather unimpressive looking cells dropping TORs. llvl shear is going to be ridiculous tomorrow as will helicity...perhaps even moreso than models are showing. Such strong southerly winds channeling through the Valley will get further enhanced...even have to watch for sfc winds being more SE wherever that warm front ends up. Link to comment Share on other sites More sharing options...
CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 Yeah the mid-level lapse rates are pretty pathetic, even getting down to as low as 4.5-5 C/KM which is about as bad as it gets. While this certainly be be a factor this should be compensated some by the high sfc dews and strong forcing/lift. That's kind of why I like areas to the west for the best stuff since the vortmax would help force anything, but I guess you can't write off the shear and some instability here. Better in western areas than here. That early aftn stuff may have some decent cells with it....the stuff ahead of the line. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 Well this blows...this site doesn't have 12z run http://www.nssl.noaa.gov/wrf/ and this site hasn't updated since Wednesday http://www.emc.ncep.noaa.gov/mmb/mpyle/spcprod/12/ Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 That's kind of why I like areas to the west for the best stuff since the vortmax would help force anything, but I guess you can't write off the shear and some instability here. Better in western areas than here. That early aftn stuff may have some decent cells with it....the stuff ahead of the line. Yeah that squall line is going to be nasty to our west tomorrow. I think there is the potential for some really nasty low topped supercells ahead of it. Nothing will be pretty on radar but this to me could be high-end (for this kind of setup) if things fall together just right. Link to comment Share on other sites More sharing options...
weatherwiz Posted September 7, 2012 Author Share Posted September 7, 2012 That's kind of why I like areas to the west for the best stuff since the vortmax would help force anything, but I guess you can't write off the shear and some instability here. Better in western areas than here. That early aftn stuff may have some decent cells with it....the stuff ahead of the line. I wouldn't rule out isolated severe to the coast but I agree in that the best stuff will be off to your west and perhaps even just off to my west. winds are going to be gusty regardless given strong mixing and how strong winds are above the sfc with no inversion. Stuff ahead of the main line is exactly what we need to watch out for, especially if the NAM is correct with it's forecasted instability values. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted September 7, 2012 Share Posted September 7, 2012 GFS has some sort of shwr activity or even iso tstm coming up from the south in the aftn too. Those are probably the TOR's? Link to comment Share on other sites More sharing options...
Damage In Tolland Posted September 7, 2012 Share Posted September 7, 2012 If we can get convective initiation prior to the main forcing tomorrow (which is possible given very little CIN) we should watch out for rather unimpressive looking cells dropping TORs. Didn't we have something like this about a month ago..where we had all those midday storms popping and some showed rotation, but the day as a whole blew dong? Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 Judging by the BUFKIT soundings the GFS has a pretty early fropa on Saturday Link to comment Share on other sites More sharing options...
CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 Hi res models actually fire off storms here today. SPC WRF goes nuts, but wonder if it is too aggressive. Link to comment Share on other sites More sharing options...
andyhb Posted September 7, 2012 Share Posted September 7, 2012 I am quite interested to see the next D2. I'd say they maintain the 30% hatched, maybe with a bit stronger wording. Link to comment Share on other sites More sharing options...
earthlight Posted September 7, 2012 Share Posted September 7, 2012 You can see some of the warm sector debris ahead of the main line on the 12z SPC WRF simulated radar http://www.emc.ncep.noaa.gov/mmb/mpyle/spcprod/12/ Link to comment Share on other sites More sharing options...
CoastalWx Posted September 7, 2012 Share Posted September 7, 2012 That looks reasonable. Strong line with some winds and probably some book end stuff or embedded sups. Link to comment Share on other sites More sharing options...
CT Rain Posted September 7, 2012 Share Posted September 7, 2012 I could see a damaging synoptic wind event tomorrow afternoon if the NAM LLJ verifies lol Link to comment Share on other sites More sharing options...
Cyclone-68 Posted September 7, 2012 Share Posted September 7, 2012 Hopefully something will pop around Brimfield at the antique show to spare me my usual eastern MA severe storm heart break. Link to comment Share on other sites More sharing options...
ineedsnow Posted September 7, 2012 Share Posted September 7, 2012 looks good for today and tomorrow. You can see some of the warm sector debris ahead of the main line on the 12z SPC WRF simulated radar http://www.emc.ncep....yle/spcprod/12/ Link to comment Share on other sites More sharing options...
earthlight Posted September 7, 2012 Share Posted September 7, 2012 LLJ could be an issue with the prefrontal convection and debris...or "crapvection" as some would prefer to call it. SPC WRF illustrates this pretty well. I wonder if some areas could get screwed in that way..where the line then runs into weaker instability and more CIN in the areas that were affected by the debris and quickly becomes elevated and weakens. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.