• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Pattern Marvelous March

The MJO propagation still appears favorable over the next couple of weeks:

diagram_40days_forecast_GEFSBC_member.gif
ECMF_phase_51m_small.gif

Both the GEFS and the EPS continue to show a solid -EPO and a trough in the central and eventually the eastern US, although they vary somewhat in the details. The D9 GEFS shows the block oriented in such a way that the flow backs around it toward the west and eventually the trough retrogrades and connects to the trough out in the Pacific, destroying the pattern.

GEFS.png

The EPS is oriented more so that the flow is out of the north, producing a better, probably longer lasting favorable pattern (although I can't see past D10 right now):

EPS.png

The STJ remains alive and active as you can see by the D10 24 hour total GEFS precip map:

GEFSprecip.png

Temps at 850 are below normal across much of the country. This propagates eastward down the line. GEFS:

GEFS216850.png
GEFS240850.png

EPS:

EPS216850.png
EPS240850.png

At D9, the GEFS mean 2m temp profile looks like this:

GEFS2m.png

It trends colder for the next few days. I don't have one for the EPS, but I assume it has a similar, and probably slightly colder progression. I would not put a lot of stock in model D9 2m temp progs, but the point is, it will likely be below normal. The STJ will remain active. High pressure will continue to build in and track across the country. That is about as good as we can ask for at this point.

The daily SOI contrib is -27. The EPS is still split on the typhoon recurve. The GFS is all in on it. The NAO and AO continue to look like garbage on the GEFS, so if it's right, we'll have to take a -EPO neutral/slightly +PNA and make the best of it. I don't have visibility into the EPS past 240, but given the MJO progs, we have about 2 more weeks, unless a big -NAO suddenly shows up.
 
GaWx said:
The 6Z GFS is not backing away from strong SE cold with a hard freeze at ATL on 3/2. However, some recent FV3 runs oddly enough have backed away. The 6Z FV3 has no freeze at ATL til 3/6. And as earlier mentioned, the 6Z GEFS was the least cold of at least the last 4 in the SE. I hope these are not valid warning signals that the GFS and other models will back away later. For now I remain optimistic that early March will not back away from SE cold with the coldest early March wx in the SE in many years though am far from betting the ranch on this.
Click to expand...

Flippity flop goes the GFS. Whereas the 6Z has a hard freeze at ATL 3/2, the 12Z has about 30 warmer (50s low) on 3/2 and NO freeze the entire run. Now watch the 12Z GEFS come back colder.
 
GaWx said:
Flippity flop goes the GFS. Whereas the 6Z has a hard freeze at ATL 3/2, the 12Z has about 30 warmer (50s low) on 3/2 and NO freeze the entire run. Now watch the 12Z GEFS come back colder.
Click to expand...

Yeah if there is no ensemble support, it’s not even worth a thought


Sent from my iPhone using Tapatalk
 
GaWx said:
Flippity flop goes the GFS. Whereas the 6Z has a hard freeze at ATL 3/2, the 12Z has about 30 warmer (50s low) on 3/2 and NO freeze the entire run. Now watch the 12Z GEFS come back colder.
Click to expand...

And what do you know, the 12Z GEFS did come in much colder than the warmer 6Z and even a net slightly colder than the 0Z with a freeze at ATL on 3/3.
 
If we’re going to get a Miller A it’s going to have to
be on the heels of another system. Need a big system to dive down and leave the 540 line on the Florida panhandle with a big gulf low forming as it slowly pulls out. I just don’t see a scenario where we can track one in from long range this year. Been a terrible pattern and I feel like we’re stuck. I’m a firm believer in blocking. I think it’s most needed in trashtastic winters such as this one
 
Jimmy Hypocracy said:
That’s where my money would be as well. This winter just wants to put down front end ice and rain. Not sure a Miller A is in the cards this year tbh
Click to expand...

The -EPO/- to neutral PNA driven patterns of late seem to be most supportive of Miller Bs. It's what I was talking about yesterday. For a Miller A, you need the storm track suppressed...not one that favors a track up or just west of the Apps. That kind of track leads to a transfer when you get damming, which has been prevalent lately. You either need a decent PNA ridge or a strong -NAO to keep the storm track south. We keep seeing a muted PNA response in the pattern, which tempers my hope for a true southern slider or Miller A snowstorm. My expectation continues to be a Miller B, front-end snow to ice to possibly rain deal in the 9-13 day window.
 
Myfrotho704_ said:
Tbh I’m honestly betting an a miller b/CAD event, I might be completely wrong but eh
Click to expand...

Late in the season, the wavelengths and deceleration of the background wind as meridional temperature gradient progressively dampens can make up for it but it's simply far more difficult to get a nice Miller A cyclone to turn up the coast and the parent trough to amplify when your flow is extremely confluent over the Lakes as it often is when you have a big -EPO/+TNH and the north Atlantic jet is stronger than normal which advects the cyclonic vorticity associated with said trough more rapidly out to sea, forcing the surface cyclone to follow suit.

A Miller B/CAD event or an elongated anafront/overrunning event is favored when high-latitude North Pacific/Alaskan block is the most anomalous feature in the Northern hemisphere as we've seen time & time again the last several years.

Not surprisingly, both the Mar 2-4 1960 & Mar 25-26 1971 storms I mentioned earlier were of this type throughout most of their duration, although Mar 1971 evolved into a coastal cyclone late potentially due to the very short wavelengths/slower bgd flow in late March but that case is still more consistent w/ overrunning/miller B vs miller A.
 
Brick Tamland said:
I'm guessing the Euro didn't have anything.
Click to expand...

Yep, nothing except a monster +PNA, huge PV diving down and a shortwave south. It’s too far south and the PV might be a little strong but this is our chance right here

0a9abea5c396f136fa022564c08332a1.jpg

a515afabca92d1411af221b3c77c183b.jpg

b6bf0a537ffec736f87dc7b07d91efab.jpg


So close to something epic for N.C. at least. The EPS should be fun.

Sent from my iPhone using Tapatalk
 
Jon said:
Yep, nothing except a monster +PNA, huge PV diving down and a shortwave south. It’s too far south and the PV might be a little strong but this is our chance right here

0a9abea5c396f136fa022564c08332a1.jpg

b6bf0a537ffec736f87dc7b07d91efab.jpg



Sent from my iPhone using Tapatalk
Click to expand...

I thought it looked ominous too, about what you would want at day 8-9.
 
PV lobe on this Euro run drops down over the lakes at day 9 with an epic cold shot incoming. I don't really have anything negative to say at all about the general pattern w/ a monster ridge over Alaska and the NW Territories that's migrating towards the Baffin Bay in the extended (certainly not the normal retrogressive -EPO pathway). It's just gonna come down to timing of the waves wrt whether any threats show up on the models over the coming few weeks and we really won't know how legitimate any of them are until we get inside about day 6-7.
 
No SE winter storm on the entire 12Z Euro run, but it is colder at the end as the prior posts implied and ATL gets a freeze on 3/3. Also, though it is largely useless since I'm talking about a 240 hour map on an operational, but had there been days 11-12, we might have seen a winter storm parts of the SE, especially TN/NC, as a very cold high likely would have traversed the Ohio Valley with moisture in TX day 10 coming eastward as H5 became moist/WSW, but this is all just hypothetical/educated guess/just for entertainment since we're talking extrapolating on day 10 of an operational.
 
Webberweather53 said:
PV lobe on this Euro run drops down over the lakes at day 9 with an epic cold shot incoming. I don't really have anything negative to say at all about the general pattern w/ a monster ridge over Alaska and the NW Territories that's migrating towards the Baffin Bay in the extended (certainly not the normal retrogressive -EPO pathway). It's just gonna come down to timing of the waves wrt whether any threats show up on the models over the coming few weeks and we really won't know how legitimate any of them are until we get inside about day 6-7.
Click to expand...
Generally speaking we’re going to have the recipe to produce the coldest pattern possible with arctic and Siberian airmasses being continuously dumped into North America and the US. It’s the kind of pattern that would be capable of producing legitimate snow and ice well beyond our favored climo window for snow deep into mid-late March much less at the beginning of the month
 
Yep, good posts above. The GFS and Euro differ pretty substantially with what they do with the block after it forms, initially. The Euro solution is much more favorable and would have the best chance of resulting in a SE storm with much colder air available. It would also likely provide multiple chances over a longer time frame.

GFS.jpg
Euro.jpg

You can see that the GFS eventually moves the block north (and weakens it in later frames). The Euro is more east and thus more suppressive downstream. It's a much more favorable pattern, and I'm glad it's the Euro that's showing it.
 
Webberweather53 said:
Generally speaking we’re going to have the recipe to produce the coldest pattern possible with arctic and Siberian airmasses being continuously dumped into North America and the US. It’s the kind of pattern that would be capable of producing legitimate snow and ice well beyond our favored climo window for snow deep into mid-late March much less at the beginning of the month
Click to expand...
So it sounds like you're saying the entire month of March is going to be frigid. Is there any sign that spring may arrive by April ? I know everyone else wants snow but I am ready for spring.
 
SoutheastRidge said:
So it sounds like you're saying the entire month of March is going to be frigid. Is there any sign that spring may arrive by April ? I know everyone else wants snow but I am ready for spring.
Click to expand...

He said the entire month of March will be frigid?
 
Rain Cold said:
Yep, good posts above. The GFS and Euro differ pretty substantially with what they do with the block after it forms, initially. The Euro solution is much more favorable and would have the best chance of resulting in a SE storm with much colder air available. It would also likely provide multiple chances over a longer time frame.

View attachment 16173
View attachment 16174

You can see that the GFS eventually moves the block north (and weakens it in later frames). The Euro is more east and thus more suppressive downstream. It's a much more favorable pattern, and I'm glad it's the Euro that's showing it.
Click to expand...

Yes, the Euro has not been as favorable this winter with showing good patterns versus the GFS and FV3, but the GFS and FV3 have been wrong and the Euro has been right. Hopefully, the Euro is right now when it is showing a more favorable pattern for winter storms.
 
GaWx said:
No SE winter storm on the entire 12Z Euro run, but it is colder at the end as the prior posts implied and ATL gets a freeze on 3/3. Also, though it is largely useless since I'm talking about a 240 hour map on an operational, but had there been days 11-12, we might have seen a winter storm parts of the SE, especially TN/NC, as a very cold high likely would have traversed the Ohio Valley with moisture in TX day 10 coming eastward as H5 became moist/WSW, but this is all just hypothetical/educated guess/just for entertainment since we're talking extrapolating on day 10 of an operational.
Click to expand...

And now we have an answer of sorts thanks to the 12Z EPS, which largely matches the 12Z Euro at 240: indeed there is a snow threat to mainly TN/NC and maybe also a IP/ZR threat in the CAD region of NC/SC/GA some time within 3/3-5 thanks to a Miller A or B as H5 flow becomes moist WSW overrunning cold air below. Based on the mean, it does appear some members have a Miller A,
 
The Pacific is just relentless this year. +PNA has zero staying power. Wave after wave hitting the west coast. Story of the season
 
I think there is pretty good agreement right now on a possible system of interest in the March 2-5 period. The Fv3 has one (no surprise), the Euro is close to something and GEFS/EPS members have been showing some interest in this time as well. The blocking looks pretty solid too and if it verifies close to what is being modeled we may have a shot. Here's the main models of interest.

Fv3

1550780439384.png

The GFS has a storm at this same time as well but with a different 5h look.
1550780487647.png

The GEFS has a solid signal too.
1550780572403.png

Finally the EPS also has a weak low moving off the coast.
1550780592923.png
 
Here are some pics from the 12Z EPS showing the 3/3-5 wintry threat to mainly NC/TN and IP/ZR threat to NC/SC/GA CAD areas:

1. Look at all of this qpf: 0.50-0.75" for many, which is wet for an ensemble mean so far out and implies Miller A or B from GOM:
ECM_12Z0221precip.png

2. Here are the 850s/sfc. 850's imply snow threat mainly TN/NC north of 0C line; sfc implies CAD ZR/IP

ECM_12Z0221sfc850precip.png

3. SE closeup of mean implies some member have Miller A that crossed FL before this map's time:

ECM_12Z0221sfcSEcloseup.png
 
You must log in or register to reply here.
Back
Top