Jump to content
  • Member Statistics

    17,587
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

Extended Range Severe Weather Discussion


Recommended Posts

  • Replies 70
  • Created
  • Last Reply

I am having trouble finding anything wrong with the 00z Euro concerning that second system for a possible outbreak across the south.

GFS is trending stronger, CMC has it, except a bit further north due to a different phasing solution...even the NOGAPS has it, which I rarely look at.

Link to comment
Share on other sites

Posted this over in the SE thread- the 00Z Euro has two potential severe/tornado outbreaks in the South, the second one looks very ominous if this is close to being true. Also has a prolonged snow/ice event in the NE, and a Plains blizzard. March comes in like a lion.....

The day 7 ECMWF event would be potentially significant. CMC at times has also hinted at a more vigorous amplifying trough tracking across the south/southeast (all guidance including GEFS prog a strong height anomaly tracking through day 5-7). One thing is for sure...the plains bomb day 4-5 won't be hauling a deep diving cold front, and the GOM will have plenty of time to recover from the current cold front clearing it out now. It will be moist by day 6 on. ECMWF verbatim wouldn't be pretty for the southeast.

Link to comment
Share on other sites

The day 7 ECMWF event would be potentially significant. CMC at times has also hinted at a more vigorous amplifying trough tracking across the south/southeast (all guidance including GEFS prog a strong height anomaly tracking through day 5-7). One thing is for sure...the plains bomb day 4-5 won't be hauling a deep diving cold front, and the GOM will have plenty of time to recover from the current cold front clearing it out now. It will be moist by day 6 on. ECMWF verbatim wouldn't be pretty for the southeast.

The ensembles are not as potent with the Op a pretty big outlier by Friday and Saturday. There still is a good trough, just not the end-o-the-world scenario of the Op. We shall see.

Link to comment
Share on other sites

The ensembles are not as potent with the Op a pretty big outlier by Friday and Saturday. There still is a good trough, just not the end-o-the-world scenario of the Op. We shall see.

On the other hand, several of the GFS ensemble members are more potent than the GFS OP with their solutions.

Link to comment
Share on other sites

The ensembles are not as potent with the Op a pretty big outlier by Friday and Saturday. There still is a good trough, just not the end-o-the-world scenario of the Op. We shall see.

On the other hand, several of the GFS ensemble members are more potent than the GFS OP with their solutions.

Yeah it isn't a surprise since the 0Z ECMWF was such an extreme solution.

Link to comment
Share on other sites

The guidance, especially the Canadian and GFS, is going to have fun at least for a few more days... trying to figure out exactly how the energy with that second disturbance is supposed to phase together. It seems like the North American models struggle with that more than any other scrap of guidance available on the planet. Still, regardless of the model discrepencies at this stage of the game, the idea of the lead wave ejecting out to the east-northeast... with the upper-flow going zonal between the two systems... and the surface front stalling out just north of the Gulf Coast... then the second piece of energy diving into the Rockies while the high theta-e air builds to the south.... is unsettling. Regardless of the eventual evolution of the second disturbance, the large scale pattern will be favorable for both a prolonged low-level return flow straight out of the Caribbean and for an advection of a large scale elevated mixed layer overtop the developing warm sector for over a day in advance of any potential Dixie Alley risk (the mid-level amplification and low-level trajectories suggest the moisture advection the the boundary layer may "skip" the Plains on Thursday). Those two things alone spell the potential for a wide, significantly unstable warm sector, regardless of the evolution of the upper-level disturbance itself.

Degreed or not degreed, folks that have studied and/or forecasted severe weather for a pretty long period of time will understand this... My "spider senses" are tingling. Sometimes, you just have "that feeling" about a possible storm system. I don't get "that feeling" that often, and rarely do I get it a week in advance.... but based on what I've seen thus far (even with the model solution discrepencies) and general synoptic thinking... I have an uneasy feeling, and a general sense of dread, about this potential system for late next week.

Link to comment
Share on other sites

post-6489-0-04785400-1330165029.gif

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0359 AM CST SAT FEB 25 2012

VALID 281200Z - 041200Z

...DISCUSSION...

WRN CONUS TROUGHING DESCRIBED IN DAY-3 OUTLOOK WILL LEAD TO

STG/DEEP-LAYER CYCLONE TRACKING FROM CENTRAL HIGH PLAINS TO UPPER MS

VALLEY DAY-4/28TH-29TH. MOST CONFIDENT SVR POTENTIAL...INCLUDING

THREAT FOR TORNADOES...IS OVERNIGHT OVER PORTIONS

OZARKS/MID-SOUTH/ARKLATEX REGIONS. STG MID-UPPER WINDS -- I.E.

50-70 KT AT 500 MB -- AND HODOGRAPH-ENLARGING LLJ SHOULD OVERSPREAD

SFC DEW POINTS INCREASING TO 60S F. FARTHER N...PRIND MOISTURE

RETURN WILL BE MEAGER INTO AREA NEAR SFC LOW...ALTHOUGH STRENGTH OF

DEEP-LAYER LIFT AND WIND FIELDS SHOULD BE SUFFICIENT TO SUPPORT AT

LEAST MRGL SVR THREAT WITH ANY SUSTAINED/SFC-BASED CONVECTION THAT

CAN FORM. POTENTIAL OVER CORN BELT APPEARS TOO CONDITIONAL ATTM TO

EXTEND CATEGORICAL AREA THERE.

MIDWEST SYSTEM SHOULD DEAMPLIFY SOMEWHAT AND OUTPACE GULF MOISTURE

RETURN DAY-5/29TH-1ST...THOUGH SVR POTENTIAL IN SRN

APPALACHIANS/PIEDMONT REGION AND CAROLINAS CANNOT BE RULED OUT.

NEXT SUBSTANTIAL MID-UPPER TROUGH SHOULD CROSS CENTRAL/NRN ROCKIES

DAY-6/1ST-2ND...WITH SFC CYCLOGENESIS OVER CENTRAL HIGH PLAINS.

SOME SVR IS POSSIBLE DAYS 6-7/1ST-3RD FROM SRN/CENTRAL PLAINS TOWARD

LOWER OH VALLEY AS SFC CYCLONE EJECTS FROM HIGH PLAINS...HOWEVER

SPREAD IN VARIOUS MREF/OPERATIONAL PROGS IS TOO LARGE TO ASSIGN

CATEGORICAL OUTLOOK ATTM.

..EDWARDS.. 02/25/2012

Link to comment
Share on other sites

The guidance, especially the Canadian and GFS, is going to have fun at least for a few more days... trying to figure out exactly how the energy with that second disturbance is supposed to phase together. It seems like the North American models struggle with that more than any other scrap of guidance available on the planet. Still, regardless of the model discrepencies at this stage of the game, the idea of the lead wave ejecting out to the east-northeast... with the upper-flow going zonal between the two systems... and the surface front stalling out just north of the Gulf Coast... then the second piece of energy diving into the Rockies while the high theta-e air builds to the south.... is unsettling. Regardless of the eventual evolution of the second disturbance, the large scale pattern will be favorable for both a prolonged low-level return flow straight out of the Caribbean and for an advection of a large scale elevated mixed layer overtop the developing warm sector for over a day in advance of any potential Dixie Alley risk (the mid-level amplification and low-level trajectories suggest the moisture advection the the boundary layer may "skip" the Plains on Thursday). Those two things alone spell the potential for a wide, significantly unstable warm sector, regardless of the evolution of the upper-level disturbance itself.

Degreed or not degreed, folks that have studied and/or forecasted severe weather for a pretty long period of time will understand this... My "spider senses" are tingling. Sometimes, you just have "that feeling" about a possible storm system. I don't get "that feeling" that often, and rarely do I get it a week in advance.... but based on what I've seen thus far (even with the model solution discrepancies) and general synoptic thinking... I have an uneasy feeling, and a general sense of dread, about this potential system for late next week.

I would have to agree that the 2nd event has a higher ceiling to it. Some of the GFS ensembles both 00z and 06z go gangbusters with that potential. Certainly will be keeping a watchful eye on it, though can't gloss over the Tuesday/Wednesday potential by any stretch.

Link to comment
Share on other sites

12z Euro really took the late week threat to the gutter, although the CMC still has it with a very large upper trough across the Central CONUS. Remember that the models/ensembles will probably not settle on a solution until this next system moves through, which carries a threat of its own as mentioned. The pattern in between the two storms will be crucial in how the second one develops.

Link to comment
Share on other sites

00z Euro going back to a more dangerous solution than 12z WRT the second system. Honestly what the GFS is putting out appears rather unlikely as a powerful upper jet like the one shown digging into the west coast doesn't just get sheared apart like the GFS shows.

Disclaimer: I am NOT trying to scare anyone with the following graphics by any means, but this comes from talkwx regarding the current Euro solution, Fred and I's jaws have dropped at what the majority of the ensembles/Euro (and even to a lesser extent the CMC) have shown tonight:

comp1.gif

comp2-3.gif

Link to comment
Share on other sites

00z Euro going back to a more dangerous solution than 12z WRT the second system. Honestly what the GFS is putting out appears rather unlikely as a powerful upper jet like the one shown digging into the west coast doesn't just get sheared apart like the GFS shows.

Most of the GFS ensembles would disagree with the OP and are much stronger than the OP some by a significant margin.

Link to comment
Share on other sites

Is that showing a repeat of 4/27 for n al???

There's no way that we can make comparisons to 4/27 at all at this point, I just found that graphic to be telling of the possible threat that we may be facing. I do NOT want this image going around evoking some kind of mass panic. In all honesty, I'm thinking about deleting it just because of that.

Link to comment
Share on other sites

In my mind, what that signals.... is that the placement and track on the 00Z Euro favors a severe weather threat across the same general areas. I can assure you that actual coverage/intensity will not be anything similar, even if we were to somehow end up with a major severe weather outbreak at the end of this coming week.

Link to comment
Share on other sites

00z Euro going back to a more dangerous solution than 12z WRT the second system. Honestly what the GFS is putting out appears rather unlikely as a powerful upper jet like the one shown digging into the west coast doesn't just get sheared apart like the GFS shows.

Disclaimer: I am NOT trying to scare anyone with the following graphics by any means, but this comes from talkwx regarding the current Euro solution, Fred and I's jaws have dropped at what the majority of the ensembles/Euro (and even to a lesser extent the CMC) have shown tonight:

I am sure that scenario as far as track has been shown numerous times before 4/27 and will be shown numerous times from here on out. It's just a track and as significant as it may be-even if it went HIGH RISK, there will hopefully not be another 4/27 in our lifetimes. Hopefully people know that. New Orleans will be hit by more hurricanes but they probably won't be like Katrina for a bit anyway..

Link to comment
Share on other sites

There's no way that we can make comparisons to 4/27 at all at this point, I just found that graphic to be telling of the possible threat that we may be facing. I do NOT want this image going around evoking some kind of mass panic. In all honesty, I'm thinking about deleting it just because of that.

Just a friendly little reminder. We have seen guidance offer some spectacular solutions in the 3-5 day range all year that failed to produce. My suggestion is to see how all this looks in a day or two and remember that the SPC does not issue High Risks lightly and rarely, if ever in the Day 3 time frame or beyond.

Link to comment
Share on other sites

Just a friendly little reminder. We have seen guidance offer some spectacular solutions in the 3-5 day range all year that failed to produce. My suggestion is to see how all this looks in a day or two and remember that the SPC does not issue High Risks lightly and rarely, if ever in the Day 3 time frame or beyond.

I suspect we will have "4/27 syndrome" for a while. But anyone who watched that event closely would remember just how extraordinary the setup was. Shear/instability parameters (EHI, bulk shear, etc) were some of the best we had ever seen. As far as this threat, I would agree with the other posters that it is something to watch. And as you said, model performance in this time range hasn't been very good.

Link to comment
Share on other sites

Friday / Friday night event: 12Z Euro and Ensemble both show large warm sector with dew points to 60 degrees all the way to the OH River... could be serious trouble for OH / TN Valleys and deep south.

Tuesday night and Wednesday AM looks more elevated in the OH Valley off the Euro. Not a lot of frontal convergence farther south in the more favorable air mass.

Link to comment
Share on other sites

Just a friendly little reminder. We have seen guidance offer some spectacular solutions in the 3-5 day range all year that failed to produce. My suggestion is to see how all this looks in a day or two and remember that the SPC does not issue High Risks lightly and rarely, if ever in the Day 3 time frame or beyond.

It isn't even allowed to issue a day 3 high risk :P , but yes I completely understand.

18z GFS just came in a lot stronger.... :yikes:

18z GFS ensembles at 132 hrs, just shift it west for peak heating on Friday and you can see that a lot of those would be nasty:

21lljzb.jpg

Link to comment
Share on other sites

It'll be interesting to see what happens with the trough ahead of the March 2nd event. The ECMWF and GFS have differed substantially regarding this feature, with the former shearing it out and weakening it much more quickly. Such a scenario would mean the front doesn't get quite to the Gulf Coast, resulting in a quicker moisture recovery for a larger area. This would mean a much broader warm sector for the next system instead of the sharp inverted-V shaped warm sector that typically is a limiting factor in early season severe weather events.

Link to comment
Share on other sites

Personally, I think the sfc low is too far north to really have much of an effect on the GoM...

If anything, it might actually have a positive effect and help advect moisture more quickly than it would if it wasn't there.

Also keep in mind that the ST ridge is in a position to advect moisture from the Caribbean, not just the GoM.

Link to comment
Share on other sites

It'll be interesting to see what happens with the trough ahead of the March 2nd event. The ECMWF and GFS have differed substantially regarding this feature, with the former shearing it out and weakening it much more quickly. Such a scenario would mean the front doesn't get quite to the Gulf Coast, resulting in a quicker moisture recovery for a larger area. This would mean a much broader warm sector for the next system instead of the sharp inverted-V shaped warm sector that typically is a limiting factor in early season severe weather events.

Yeah I don't see the 1st system's front even making it to the Gulf Coast (00z GFS has it stopping about midway between I-20 and I-10). The initial trough is too far to the North to penetrate to the Gulf Coast with the front. If anything the first system primes the pump for the 2nd system. 00z GFS shows a very large warm sector across the South on Friday.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...