Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

February/March 2021 - Frigid or Flop? Pattern/Longterm Forecast Thread.


John1122
 Share

Recommended Posts

For eastern folks, I do have at least give mild attention to this 12z CMC look for Tuesday.  The slp(as is) is likely too weak.  However, if that strengthens even a little...that is not benign for the eastern valley IMHO.  That is different from what we have seen recently.  Modeling has trending towards this inland runner during the past few runs.  The para has a similar look but runs a shadow up through the eastern valley which is no good.  If the CMC consolidates, that is good.  Might just be a hiccup, but the RGEM was pretty much there as well at 84.

1055539838_ScreenShot2021-02-12at12_22_39PM.png.8afc09c66fc5f54dea703b6e40411c48.png

  • Like 3
Link to comment
Share on other sites

The 18z RGEM is tracking an areas of weak slp from the Panhandle of FL through the Carolina Piedmont with seemingly little energy transfer.  Back side of the slp switches to light snow in ETN.  It is on the eastern envelope of storm tracks not implausible.  The EPS at 12z moved several of its slp member tracks into the same vicinity as the RGEM.

  • Like 3
Link to comment
Share on other sites

Not calling for a storm IMBY yet, but I think the jury is still out on how this SLP system develops on Tuesday.  Here are the comparison runs for the 12z EPS 90 and 96 time frames compared to 6z.  Notice the shift south and east.  New is on the left.  There has been a trend towards moving this area of weak slp to our SE and reducing or eliminating energy coming west of the Apps.  May or may not hold, but that is the trend on some modeling.  Notice that at 6z many SLPs went through E TN and into WVA.  At 12z, many went from central Georgia and into the Carolina Piedmont.

81186466_ScreenShot2021-02-12at4_43_58PM.png.d5299e5654b886933cb17be35d9959b5.png

237761863_ScreenShot2021-02-12at4_44_09PM.png.6ec1ee3765ba3972b24f7ec50b25645e.png

  • Like 3
Link to comment
Share on other sites

18z GFS SLP location is east of the Apps.  Not sure how much more east it can actually trend.  At some point, it trends back west - I think.  However, the ensemble does hint that a mixed bag IMBY is not out of the possibility on Tuesday.  Not gumming up the middle/west TN storm thread with this though.  LOL.

451169854_ScreenShot2021-02-12at7_23_16PM.png.e537d041297bf826f0f0a00ac6891a1c.png

  • Like 3
Link to comment
Share on other sites

Looks like the NAO tries to refire after d10.  The Euro MJO continues to forecast a move into the COD - dives out of 7, head fakes to 8, moves to 6, and then moves back to colder phases.  Larry Cosgrove who has done a fantastic job this winter hinted that he thinks we may see the current pattern repeat again during March.  The MJO is hinting at that as well.  He also has stated that when we break to spring that it will be quite abrupt.  He is calling for a scorcher of a summer as well.   March can hold a surprise or two.  If the NAO re-fires that is a good thing for March...we don’t want that index negative for summer as all.

  • Like 2
Link to comment
Share on other sites

Long Range Ideas and Short/Mid-Range Commentary:

Here are the 0z EPS NAO and the 6z GEFS NAO forecasts from earlier today.  All three current global ensembles are depicting the NAO to re-fire around the 25th.   This does signal an at least temporary eastern ridge after this week(as the pattern waits for a -NAO reload), and then the potential exists for a return to a colder pattern towards the end of February and/or the beginning of March(likeliest is early March).  This has been the pattern this winter.  We see cold, we get a few weeks break, and then it returns.  Would not surprise me if the cold returns one last time relative to March norms.  I hate to quote Cosgrove without his permission, so I will simply state that he thinks the relaxation of the pattern during late February is simply the pattern recharging for one more cold shot similar to what we have now but maybe excluding the Deep South.  I would note that when the NAO changes phases to negative (or leaves negative) that is when we might see another round of storms.  I could be wrong, but would be very surprised if winter is over.  I think we see a relaxation coming up very similar to what we saw in January(just shorter) and then maybe one last bout of winter. 

 I think the -NAO has more than proven its value this winter as western(and hopefully middle as well!) subforum areas of the TN Valley Region are possibly about to experience one of the great winter patterns of recent memory for this subforum and for their local.  If the NWS verifies for Memphis this week, this pattern could well be the best winter pattern for them during the past two decades.  Their temps are not forecast to rise above freezing until next Saturday!   They are modeled to have two winter storms.  Just because the NAO does not deliver IMBY, does not mean it is not a signifiant pattern driver for winter weather for this region - even on its own.  It is also worth noting that this maturing of the trough occurred right at the end of the current negative phase of the NAO.  That is worth remembering if the NAO goes negative once again (if LR modeling is correct) later this month.  As a final caveat, the NAO is a tricky animal to forecast...so keep that in mind when looking at LR forecasts showing it re-firing.  I think it likely, but not a certainty. I am also adding the EMON from the 11th.  The Euro MJO looks nearly identical today.  Notice the dive back to cooler phases after the jaunt towards six.  For posterity(and for future reference regarding the NAO), I am attaching the Memphis forecast for the week. They are simultaneously under a wind child advisory and winter storm warning with yet another winter storm modeled for mid-week.  Also, it is worth noting that the MJO is at mid-amplitude phase 7(nearly 6).  The NAO has overcome warm phases of the MJO as well.  

Lastly, I think this forum has done a great job with pattern recognition this winter.  That doesn't mean we nail every storm, but I think folks have done a great job of weighing the possibilities "for" and "against" winter weather.  Hopefully, after the warm up set to unfold after 6-7 days, we see one more bout of winter.  Good luck(meaning lots of snow and not as much ice) to those in middle and western forum areas this week!!!  

Addendum note: Some modeling is also hinting that the EPO may go briefly negative right as the NAO block potentially reforms later this month and early March.

166211603_ScreenShot2021-02-14at8_57_41AM.png.e9cc3349f2a6922645c592d12282db6a.png

1190095894_ScreenShot2021-02-14at8_58_23AM.png.00e1d07572ff4fbb18f3d1ebdb176a42.png

 

36402240_ScreenShot2021-02-14at9_01_37AM.png.ad9cfd9e470c6bd28347ec3fecfc0f2c.png

622501329_ScreenShot2021-02-14at9_16_07AM.thumb.png.8634597706bf6ceae40094bacfd56db4.png

  • Like 3
Link to comment
Share on other sites

One other thing to watch in the LR, the Euro and GFS again both set a really nice boundary just after d8.  To me that is a little bit early.  However, maybe we get one more system to run an east/west boundary prior to a brief warm-up to end the month and more winter later during the first week of March.  Seems like two years ago, we hit 80 during February here at TRI.  LOL.  

  • Like 1
Link to comment
Share on other sites

5 hours ago, CG2 said:

Long Range Ideas and Short/Mid-Range Commentary:

Here are the 0z EPS NAO and the 6z GEFS NAO forecasts from earlier today.  All three current global ensembles are depicting the NAO to re-fire around the 25th.   This does signal an at least temporary eastern ridge after this week(as the pattern waits for a -NAO reload), and then the potential exists for a return to a colder pattern towards the end of February and/or the beginning of March(likeliest is early March).  This has been the pattern this winter.  We see cold, we get a few weeks break, and then it returns.  Would not surprise me if the cold returns one last time relative to March norms.  I hate to quote Cosgrove without his permission, so I will simply state that he thinks the relaxation of the pattern during late February is simply the pattern recharging for one more cold shot similar to what we have now but maybe excluding the Deep South.  I would note that when the NAO changes phases to negative (or leaves negative) that is when we might see another round of storms.  I could be wrong, but would be very surprised if winter is over.  I think we see a relaxation coming up very similar to what we saw in January(just shorter) and then maybe one last bout of winter. 

 I think the -NAO has more than proven its value this winter as western(and hopefully middle as well!) subforum areas of the TN Valley Region are possibly about to experience one of the great winter patterns of recent memory for this subforum and for their local.  If the NWS verifies for Memphis this week, this pattern could well be the best winter pattern for them during the past two decades.  Their temps are not forecast to rise above freezing until next Saturday!   They are modeled to have two winter storms.  Just because the NAO does not deliver IMBY, does not mean it is not a signifiant pattern driver for winter weather for this region - even on its own.  It is also worth noting that this maturing of the trough occurred right at the end of the current negative phase of the NAO.  That is worth remembering if the NAO goes negative once again (if LR modeling is correct) later this month.  As a final caveat, the NAO is a tricky animal to forecast...so keep that in mind when looking at LR forecasts showing it re-firing.  I think it likely, but not a certainty. I am also adding the EMON from the 11th.  The Euro MJO looks nearly identical today.  Notice the dive back to cooler phases after the jaunt towards six.  For posterity(and for future reference regarding the NAO), I am attaching the Memphis forecast for the week. They are simultaneously under a wind child advisory and winter storm warning with yet another winter storm modeled for mid-week.  Also, it is worth noting that the MJO is at mid-amplitude phase 7(nearly 6).  The NAO has overcome warm phases of the MJO as well.  

Lastly, I think this forum has done a great job with pattern recognition this winter.  That doesn't mean we nail every storm, but I think folks have done a great job of weighing the possibilities "for" and "against" winter weather.  Hopefully, after the warm up set to unfold after 6-7 days, we see one more bout of winter.  Good luck(meaning lots of snow and not as much ice) to those in middle and western forum areas this week!!!  

Addendum note: Some modeling is also hinting that the EPO may go briefly negative right as the NAO block potentially reforms later this month and early March.

166211603_ScreenShot2021-02-14at8_57_41AM.png.e9cc3349f2a6922645c592d12282db6a.png

1190095894_ScreenShot2021-02-14at8_58_23AM.png.00e1d07572ff4fbb18f3d1ebdb176a42.png

 

36402240_ScreenShot2021-02-14at9_01_37AM.png.ad9cfd9e470c6bd28347ec3fecfc0f2c.png

622501329_ScreenShot2021-02-14at9_16_07AM.thumb.png.8634597706bf6ceae40094bacfd56db4.png

This is a great breakdown Carver!!!  I appreciate you going into detail on this stuff.  

  • Like 1
Link to comment
Share on other sites

  • Mr Bob unpinned this topic

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...