Winter 2021/2022 February Thread

[Carvers Gap]

If this west TN/Arkansas/ sw Mizzou ice storm is still showing up tomorrow AM, might be worth a thread.  That was a nasty 18z GFS run...

[Carvers Gap]

This is the 18z RGEM and 18z GFS.

 

 

[Carvers Gap]

Winter Storm Watches have been hoisted for portions of Arkansas and west TN.  @Mr. Kevin, are you under a WSW?

[Holston_River_Rambler]

Also, one of my favorite products, the Hyrdological Outlook! 

Hydrologic Outlook
National Weather Service Louisville KY
456 PM EST Mon Jan 31 2022

...Widespread Heavy Precipitation Expected Wednesday-Thursday
Night...

A large scale weather system is expected to impact southern Indiana
and central Kentucky later this week. Initially our area will be on
the warm side of this system were heavy rainfall is expected. Given
that our soils are fairly moist from recent snow melt, some flooding
issues and eventual river flooding will be possible later this week.

Rain is expected to develop across the region late Tuesday night and
become more widespread during the day on Wednesday. A brief lull in
the precipitation is possible Wednesday night before a second round
of heavier precipitation moves into the region on Thursday. Colder
air will arrive in parts of southern Indiana by Thursday morning
changing this rain over to a mix of freezing rain, sleet, and some
snow before the change over works south through central Kentucky
later in the day. The precipitation ends early Friday morning.

Rainfall amounts of 2.75 to 3.5 inches are expected across the
region with isolated higher amounts. This amount of rainfall is
expected to create excessive runoff which will result in localized
flooding in some areas. Sharp rises on area creeks and streams are
expected and some rivers across the region may go into flood by the
end of the week and into the weekend.

[Carvers Gap]

6z GFS run had a ton of wintry looks in it.  The 0z Euro has a light wintry event on Sunday for the eastern Valley.

[Holston_River_Rambler]

Going to be interesting to see where the North Pac ridge sets up in the long range.

If you like wintry weather, this works:

 

This doesn't:

Even though they may not look too different at first glance, 6z GFS (top) has a big overrunning event lined up at the surface for us, the 0z (bottom) has it over Iowa. It is waaaayyyy out there so neither scenario could happen. But I think it is pretty much a given that we get an EPO ridge somewhere after 10 days. 6z has it in a good location, 0z doesn't. We're in a Nina and despite what the RMMs say I think the actual MJO pulse that went through 8//1/2 earlier in January, is in low amplitude phase 3/4 right now. Some of that is being offset (why we have the COD) by convection flare ups all over the place and a TC heading towards Madagascar, but with all that in mind I suspect that the EPO ridge in the long range will end up being more over the Aleutians than AK and Yukon area. The models have shown that ridge setting up in an ideal location in the long range many times in the past few years and it adjusts west based on the reality of tropical forcing. Now that hasn't always been the case this year, we've actually had good tropical forcing recently, so hopefully I'm wrong. At least the SOI stopped rising overnight (dropped from +27 to +21). Honestly I'm kind of leaning for the model progression in February to get worse before it gets better. In other words I think we see good looks in the long range deteriorate as we get closer to verification, but I think by maybe the third week through late month we get back into phase 7 heading back toward 8 and the opposite may start to happen. The models give us a "close the blinds" look, but by Feb week 4/ March week 1, the pattern starts to verify better. 

One thing that could help us is SST mixing from the Tonga eruption. 7 day cooling over the MJO 5/6 and (I hate to say it, 7 too) areas:

but notice that even with that cooling it is still warmer than average in some of those areas, lol:

I think those SSTs may be a little bit of a wild card though, as the MJO pulse moves east. 

[Daniel Boone]

8 minutes ago, Holston_River_Rambler said:

Going to be interesting to see where the North Pac ridge sets up in the long range.

If you like wintry weather, this works:

 

This doesn't:

Even though they may not look too different at first glance, 6z GFS (top) has a big overrunning event lined up at the surface for us, the 0z (bottom) has it over Iowa. It is waaaayyyy out there so neither scenario could happen. But I think it is pretty much a given that we get an EPO ridge somewhere after 10 days. 6z has it in a good location, 0z doesn't. We're in a Nina and despite what the RMMs say I think the actual MJO pulse that went through 8//1/2 earlier in January, is in low amplitude phase 3/4 right now. Some of that is being offset (why we have the COD) by convection flare ups all over the place and a TC heading towards Madagascar, but with all that in mind I suspect that the EPO ridge in the long range will end up being more over the Aleutians than AK and Yukon area. The models have shown that ridge setting up in an ideal location in the long range many times in the past few years and it adjusts west based on the reality of tropical forcing. Now that hasn't always been the case this year, we've actually had good tropical forcing recently, so hopefully I'm wrong. At least the SOI stopped rising overnight (dropped from +27 to +21). Honestly I'm kind of leaning for the model progression in February to get worse before it gets better. In other words I think we see good looks in the long range deteriorate as we get closer to verification, but I think by maybe the third week through late month we get back into phase 7 heading back toward 8 and the opposite may start to happen. The models give us a "close the blinds" look, but by Feb week 4/ March week 1, the pattern starts to verify better. 

One thing that could help us is SST mixing from the Tonga eruption. 7 day cooling over the MJO 5/6 and (I hate to say it, 7 too) areas:

but notice that even with that cooling it is still warmer than average in some of those areas, lol:

I think those SSTs may be a little bit of a wild card though, as the MJO pulse moves east. 

I think ur right irt the MJO. The 500 mb pattern sure is looking like that 3 to 4 transition.

    If so, odds of the Feb. 72 and 75 similar playout are off the Table. 

    Maybe an '84 Feb/March variation. Not good in the great Valley . Points West did o.k. . There was a March event that produced Thundersnow and a significant Snowfall 2000ft and above in the Eastern Forum Area.

      

[Carvers Gap]

Ensembles look good, which when past d10 this winter, have been very reliable.  There are some warm-ups between extended cold shots.  Operational models are going to be all over the place as we get closer to spring.   Eventually we are just going to get to spring!  LOL.  Looks to me like we are going to end-up with a positively tilted trough over the mid-section of the US and the eastern US.  That is over-running city for whoever is north of that cold from.  I need to go back and look at 14-15, but pretty sure that was similar except it was more northern stream stuff.  This weekend will be storm one of that setup.  I think the pattern, absent a strong MJO signal, is going to simply repeat what it has been doing.  With the lag that accompanies the MJO, we may well scoot by most of the month in this pattern.  For eastern folks, we need a strong cutter to drive the boundary southeastward or a 50/50 low to pop.  Either way, we continue to see winter produce across the forum.  Will be interesting to see how far southeast the boundary is pushed for the TR/FR system.    Then, we have the sneaky system Sunday that could be nuisance variety, but interesting.

[Carvers Gap]

It is really important to look at the surface when looking at the LR, especially with a trough which is positively tilted.  The 500mb maps will not tell the entire story.  LR modeling continues to keep this region in the ice box for the next 2-3 weeks.  We have more cold air than we have had during previous winters over NA.  I suspect an at times cold, normal precip, and wintry pattern for some in the forum area through the first 2/3 of Feb.  I could be wrong...and I will always preface a monthly forecast with that last statement.  

[Carvers Gap]

Here are the 0z EPS(left) and 0z GEFS(right) for d10-15 in the LR.  That is a great look for a snowstorm.  The 6z GEFS looks a bit better as it has just a hint of a SER(prevents suppression of storm systems).

 

[Daniel Boone]

Thanks for the uplifting posts Carvers. You made valid points as did Holston.   Hopefully, ur right irt the MJO. 

    There was a time I'd been completely delved n2 and saturated with the current data but, not anymore as my health prevents it. Terrible to seldom feel like doing things you enjoy.

   If it weren't for you guy's on here I'd be lost anymore.    Those of you that aren't Mets, u r as good as and even better than many. It's a shame most in the Field r not as you all.

[Carvers Gap]

12z GFS...and there it is.

[Kentucky]

3 minutes ago, Carvers Gap said:

12z GFS...and there it is.

[brewman22001]

3 hours ago, Daniel Boone said:

Thanks for the uplifting posts Carvers. You made valid points as did Holston.   Hopefully, ur right irt the MJO. 

    There was a time I'd been completely delved n2 and saturated with the current data but, not anymore as my health prevents it. Terrible to seldom feel like doing things you enjoy.

   If it weren't for you guy's on here I'd be lost anymore.    Those of you that aren't Mets, u r as good as and even better than many. It's a shame most in the Field r not as you all.

Absolutely 100% agree!!  These folks on here are my go to!!

[Math/Met]

3 hours ago, Daniel Boone said:

Thanks for the uplifting posts Carvers. You made valid points as did Holston.   Hopefully, ur right irt the MJO. 

    There was a time I'd been completely delved n2 and saturated with the current data but, not anymore as my health prevents it. Terrible to seldom feel like doing things you enjoy.

   If it weren't for you guy's on here I'd be lost anymore.    Those of you that aren't Mets, u r as good as and even better than many. It's a shame most in the Field r not as you all.

This Tennessee Valley forum does a great job with these discussions. I intentionally stay away from the long range stuff personally, because I really don’t think I could add much to what’s already posted here. Obviously Jeff is an expert in long range forecasting, but the rest of you do a great job as well.

I told someone a few days ago. The collective knowledge of all the microclimates and historical data on this subforum is really remarkable too.

[Carvers Gap]

18 minutes ago, Kentucky said:

Great look, now we just need to see it get some support.  Just looking at the configuration of the 500 pattern after this brief warm-up(warm-up for some....for others it is ice), supports a storm lifting almost due north out of the GOM.  Now where the launch pad for that storm will be(genesis thereof...) is the million dollar question.  The GFS is likely correcting towards other modeling.  So, it is entirely possible the 18z run will be suppressed further due to that correction.  That said, there have been some operationals which are taking a slightly inland track, but are weaker.  This run pops a stronger slp.  The synoptics are there for a storm to press northward.  I would guess this storm will possibly originate somewhere between Mobile and say Ocala.  For us that difference in origin is hammer time or a whiff.  

[Carvers Gap]

12z GFS....And there is another low right behind it.  

[nrgjeff]

Classic Valley warm nose, lol! Ice storm Piedmont. You know, I'll take rain over ice any time. Maybe Chattanooga isn't so bad.

[Carvers Gap]

The 12z CMC is going to try the same thing.  It has that little 500mb vortex (much weaker) pushing north of the stalled front along the GOM.  Whether it amounts to anything...not sure on the Canadian run.

[Carvers Gap]

The thing I am noticing is a buckle(some might call it a weak SER or even just a seasonal upward curve of the jet along the coast) right after that system comes through which causes the ice storm.  The front moves slowly enough that it drags its heals in the GOM.  That allows another wave to form and head northward.  The GFS has a tendency to be amped, and this could be right in the wheelhouse of its own bias, but we'll see.   Anyway, if something forms underneath that buckle, it is going to try to gain some latitude.

[Vol4Life]

27 minutes ago, Carvers Gap said:

12z GFS...and there it is.

Great look for the Tri-Cities...warm nose issues for the Valley from Morristown south.  Really would like to get a good snow for all of East TN.  Been so close this year...

[Carvers Gap]

The CMC sends an ensuing hp a little further south(after the ice storm) and suppresses that buckle which forces that slp out to sea.  Just can't tell if the GFS is moving to the CMC and this 12z GFS run is just a snapshot of its transition to a solution much further SE...OR if it has something.  It really has wanted to put something into play during that time frame.

[nrgjeff]

We need to do these boundaries in spring. When's the next chance of severe weather? Thursday sweet (adopted) home Alabama! 

Oh I forgot in spring the boundary hangs up south and we remain stable. In winter it surges north and we remain rain. This is the Way.

[Carvers Gap]

3 minutes ago, Vol4Life said:

Great look for the Tri-Cities...warm nose issues for the Valley from Morristown south.  Really would like to get a good snow for all of East TN.  Been so close this year...

There is a piece of energy trailing that weekend system.  Looks like there are two tightly spaced chances with SLPs passing to our south.  Gotta get that slp south of here which those two looks do.

Now the CMC does have the second look as well.  The CMC is more progressive and washed out, and it may indeed be right.  The GFS amping things makes me slightly distrustful.  That said, is has been placing SLPs and systems in the right spot...just giving them too much juice in the process.

[Vol4Life]

2 minutes ago, nrgjeff said:

We need to do these boundaries in spring. When's the next chance of severe weather? Thursday sweet (adopted) home Alabama! 

Oh I forgot in spring the boundary hangs up south and we remain stable. In winter it surges north and we remain rain. This is the Way.

At least you gave up on winter on 1/31...lol!

[Carvers Gap]

5 minutes ago, Vol4Life said:

Great look for the Tri-Cities...warm nose issues for the Valley from Morristown south.  Really would like to get a good snow for all of East TN.  Been so close this year...

I addition to that second system which slides by just after, there is a parade of northern stream energy as well which would likely result in some northwest flow/clipper type events.  We want the GFS to be right about where it is placing the battle zone which is slightly to our south.  As Jeff notes, it will likely come back north some.  February rarely has prolonged suppression issues(speaking of the pattern and not this weekend's system).

[Kentucky]

37 minutes ago, Carvers Gap said:

Great look, now we just need to see it get some support.  Just looking at the configuration of the 500 pattern after this brief warm-up(warm-up for some....for others it is ice), supports a storm lifting almost due north out of the GOM.  Now where the launch pad for that storm will be(genesis thereof...) is the million dollar question.  The GFS is likely correcting towards other modeling.  So, it is entirely possible the 18z run will be suppressed further due to that correction.  That said, there have been some operationals which are taking a slightly inland track, but are weaker.  This run pops a stronger slp.  The synoptics are there for a storm to press northward.  I would guess this storm will possibly originate somewhere between Mobile and say Ocala.  For us that difference in origin is hammer time or a whiff.  

yeah, would really like to see some model support other the GFS. 

[Holston_River_Rambler]

I really like that day 12+ overrunning set up. Would love to see something like that happen. Hopefully the GFS is having one of its lucid long range moments at 6z and 12z today! 

[Holston_River_Rambler]

Also the Feb 5 - 6 deal, if that doesn't happen that's just cruel torture for the some of the I-95 Mid Atlantic folks. 

[Carvers Gap]

18z GFS trends SE but still has the storm this weekend.  It would not surprise me to see this trend off the board.  What I do like is the clipper fest behind it.  That is very 14-15ish.   Would be a nice way to end the season.