March Pattern and Discussion

[MillerA]

gsp disco

Long term /Monday night through Friday/...

as of 305 PM Friday...confidence continues to increase that a precipitation

event will take place Monday night through Tuesday night. However...uncertainty

remains regarding timing and any wintry precipitation accums. The European model (ecmwf) has

trended toward the GFS regarding timing and track of the weather

system...but remains slower to move it east of the area. While the

Canadian is faster at onset but similar to the GFS at the end. The

GFS is the warmest model...the Canadian is significantly colder

while the European model (ecmwf) is in the middle but trending toward the GFS. The

gefs ensemble mean is very close to the operational GFS...but a tad

slower ending the precipitation Wednesday. Therefore...have trended toward the

GFS regarding all facets of the forecast...but played down the quantitative precipitation forecast

amounts as it is significantly wetter than any guidance.

Therefore...expect precipitation to spread into the mountains after midnight

Monday night...then spread across the County warning forecast area during the day. Guidance

is in good agreement with this and expected partial thicknesses and

forecast soundings. With a significant warm nose developing...precipitation

would be rain...expect across portions of the mountains and I-40 corridor

where freezing rain develops. That said...guidance lows have risen

significantly...so it is possible that any freezing rain would be

more limited in coverage. Precipitation quickly becomes all liquid by noon.

The GFS forecast soundings show weak instability developing during the

afternoon...so isolated ts could develop. As the low moves east of

the area Tuesday night...precipitation slowly moves east of the area with the

European model (ecmwf) and Canadian showing light precipitation changing to snow across NC

and mixing with snow elsewhere. The GFS however...develops

convectively enhanced precipitation with a deformation zone...trowal and

frontogenesis centered on the NC/SC border. Should this develop...

an area of heavy snow would be expected. For now...have kept precipitation

generally light with significant accumulations limited to the NC

mountains end precipitation from SW to NE across the County warning forecast area Wednesday a little slower

than the Ops GFS more in line with the gefs mean. Any lingering

afternoon precipitation would change to rain outside of the mountains with

lingering northwest flow snow over the NC mountains ending Wednesday night.

[Bevo]

I just called you rigid, sharp and aggressive

 

this is no time to assume you a**

 

Well then we're all good because those are not assumptions

[ncwinterwxman]

It confirms my thoughts as well...I really don't see this as a snow threat to central or eastern NC...I really think this is a central VA north to DC storm to be honest...however, it does have room to go the other way, so I am not saying take your eyes off of it as this is the best pattern we have seen all year...we'll see...

To me this is not good, it confirms what Robert seems to be saying, it is moving north.

[dsaur]

I think the main...wait - did you jus...did you just call me fat?

That's not fat, that's power!

  I've got one gfs that has a ULL in Ark. tomorrow for one frame.  Then poof.  My other gfs model I watch is completely different.  How can we trust models when  two versions of the same model are different for the same day   I get more confused as time goes by.  It seems the "look out the window" method is still the most accurate, if not prescient, lol.  T

[packfan98]

One thing I'm noticing on the 18z NAM is the the ridge and trough axis seem to be shifted a bit west, fwiw.

 

EDIT: That could just be a matter of speed, though.

 

The main difference between the GFS and the NAM appears to be the evolution of the trough that is developing this weekend.

 

The GFS really flattens that out by Sunday night/Monday while NAM has a much sharper orientation.

 

Looks like the Blocking is a little stronger and further SW too.

[burgertime]

One thing I'm noticing on the 18z NAM is the the ridge and trough axis seem to be shifted a bit west, fwiw.

 

EDIT: That could just be a matter of speed, though.

 

The main difference between the GFS and the NAM appears to be the evolution of the trough that is developing this weekend.

 

The GFS really flattens that out by Sunday night/Monday while NAM has a much sharper orientation.

 

Boy, I'll tell you what if you put both the 12z and 18z @72 and toggle between the two you see some big differences in the flow. 

[ColdRainsStr8cashhomey]

JMA: Dr. Yes!

 

 

hahaha

 

  is my reaction every time I see a Sweet Brown Cold-Pop of moisture located squarely in the cold-dry sector of the storm

 

truly amazes me

 

the JMA/"Dr. yes" is the king of contradicting itself on placement of features

[burgertime]

This is why it's hard to take the NAM serious in the LR...just look at the diff between 12z and 18z. Note I kept both @72 as 18z had slowed down the progression of energy so I wanted to kind of show how they aligned. 

 

 

[Thrasher Fan]

Pretty cool update from FFC, guess maybe those of us especially north of Atlanta may see a little fun this evening into tomorrow.

 

 

...WINTER WEATHER ADVISORY ISSUED FOR NORTH GEORGIA FROM 10 PM TONIGHT TO 7 PM SATURDAY... .SHORT TERM /TONIGHT THROUGH SUNDAY/... MAIN CONCERN IN THE SHORT TERM IS THE THREAT OF WINTRY PRECIPITATION ACROSS MAINLY NORTH GA TONIGHT AND SATURDAY. LATEST UPPER ANALYSIS AND SATELLITE WV IMAGERY SHOW AN UPPER TROUGH DEEPENING OVER THE MID MS VALLEY REGION. MODELS AGREE THIS DEEPENING PROCESS WILL CONTINUE AS A SERIES OF DISTURBANCES TRAVERSE AROUND THE BASE... AND DRIVING THE SYSTEM EASTWARD... SUPPLYING AMPLE LIFT/FORCING ACROSS THE FORECAST AREA BEGINNING THIS EVENING AND CONTINUING THROUGH AT LEAST MID SATURDAY AFTERNOON. THIS COUPLED DEEPENING LOW-MID LEVEL MOISTURE AND COLD AIR ADVECTION WILL COMBINE TO BRING A THREAT WINTRY PRECIPITATION TO NORTH GA... MAINLY IN THE FORM OF SNOW BEGINNING BY MID-LATE EVENING ACROSS FAR NORTH GA AND SPREADING SOUTHWARD INTO THE ATLANTA METRO AREA BY 5-7 AM SATURDAY MORNING AND POSSIBLY AREAS SOUTHWARD. TEMPERATURE PROFILES FROM BUFR SOUNDING DATA SUGGEST ANY INITIAL LIGHT RAIN THIS EVENING WOULD CHANGE OVER TO SNOW BY 10PM TO MIDNIGHT... AND POSSIBLY BECOME HEAVY ENOUGH TO ALLOW LIGHT ACCUMULATIONS ON GRASSY AND ELEVATED SURFACES AS THE SNOW SPREAD SOUTHWARD TOWARD ATLANTA THROUGH 8 AM SATURDAY.

 

Bring it!!

[burgertime]

Hmm...well the NAM now has picked up on pushing that energy south. @84 it's taking the dive. 

[beanskip]

I love how the NAM comes out SOOOO slowly for the first 36 hours or so, then it just vomits out the last half of the run in a few minutes, as if to say: "This is totally worthless."

This is why it's hard to take the NAM serious in the LR...just look at the diff between 12z and 18z. Note I kept both @72 as 18z had slowed down the progression of energy so I wanted to kind of show how they aligned. 

[Bevo]

That's not fat, that's power!

  I've got one gfs that has a ULL in Ark. tomorrow for one frame.  Then poof.  My other gfs model I watch is completely different.  How can we trust models when  two versions of the same model are different for the same day   I get more confused as time goes by.  It seems the "look out the window" method is still the most accurate, if not prescient, lol.  T

 

Well, earlier today we had two versions of the same model from the same run!  Relax guys - it's a joke.

 

I've resigned to letting this thing ride and picking up on Monday.  If it's still there, we'll know more and have better conclusions so I figure I won't miss much in between.  If it's not there, so be it.  The weather manipulation machine I bought off eBay won't get here from China for another 6 weeks, so that's out of the question...

[packfan98]

Hmm...well the NAM now has picked up on pushing that energy south. @84 it's taking the dive. 

Yeah with that look it would have to go south.  The blocking looks pretty strong.

[burgertime]

I love how the NAM comes out SOOOO slowly for the first 36 hours or so, then it just vomits out the last half of the run in a few minutes, as if to say: "This is totally worthless."

  so true. 

[ColdRainsStr8cashhomey]

This is why it's hard to take the NAM serious in the LR...just look at the diff between 12z and 18z. Note I kept both @72 as 18z had slowed down the progression of energy so I wanted to kind of show how they aligned. 

 

 

 

 

post of the day... do not even bother with this piece of dung until we are within 24-36 hours

[Southern Track]

With that toggle Burger did between the two runs, the block definitely looks stronger on the 18z nam

[Lee_Sidedryslot:-(]

Really new to the board, but want to say really great disco yesterday and today to all, Andy AKA "ColdRainStr8cashhomey" Thanks for droping by this AM and putting things in prespective. I think that help a lot of people stop and take a deep breath, I know it did me. please stop by as much as possible, I know you are a little more busy now at the day job.

 

Really enjoy the pbp Buger / Bean 

 

As for the storm- It's pretty evident this one has the potential to make someone from Upstate SC thru NC to VA and even DC really happy, most likely will, but I also has the potential to make any of those same areas  that's the thing with these ULL's they can and have changed on a dime. Of the models the GFS to me seems to have to least variation in it's runs, even though it still has moved around quite a bit and most likely will until good sampling can be done once the system hits the west coast.

 

Anyway thanks to all for the great read and remember everybody here is here for the same reason we all love the weather, the chase and especially the   

[burgertime]

With that toggle Burger did between the two runs, the block definitely looks stronger on the 18z nam

 

Ha true, but the toggle was to show how pointless it was...that being said typically the GFS will sometimes lean a little towards the NAM...so I want to see what happens. Can't wait to see the DGEX and it's ridiculous map. 

[Southern Track]

Ha true, but the toggle was to show how pointless it was...that being said typically the GFS will sometimes lean a little towards the NAM...so I want to see what happens. Can't wait to see the DGEX and it's ridiculous map.

Ha right! Extended run of the ridiculous.

[ColdRainsStr8cashhomey]

Really new to the board, but want to say really great disco yesterday and today to all, Andy AKA "ColdRainStr8cashhomey" Thanks for droping by this AM and putting things in prespective. I think that help a lot of people stop and take a deep breath, I know it did me. please stop by as much as possible, I know you are a little more busy now at the day job.

 

Really enjoy the pbp Buger / Bean 

 

As for the storm- It's pretty evident this one has the potential to make someone from Upstate SC thru NC to VA and even DC really happy, most likely will, but I also has the potential to make any of those same areas  that's the thing with these ULL's they can and have changed on a dime. Of the models the GFS to me seems to have to least variation in it's runs, even though it still has moved around quite a bit and most likely will until good sampling can be done once the system hits the west coast.

 

Anyway thanks to all for the great read and remember everybody here is here for the same reason we all love the weather, the chase and especially the   

 

 

best name on the board

 

hope you get snow buddy... surely naming yourself lee-side dry slot would put an end to the chance of being dry-slotted in another storm setup

[dsaur]

Well, earlier today we had two versions of the same model from the same run!  Relax guys - it's a joke.

 

I've resigned to letting this thing ride and picking up on Monday.  If it's still there, we'll know more and have better conclusions so I figure I won't miss much in between.  If it's not there, so be it.  The weather manipulation machine I bought off eBay won't get here from China for another 6 weeks, so that's out of the question...

Lok, that's what I'm saying..... the 12z run on two different sites are different, look different, are different for the surface, anyway    Maybe it's a resolution thing.

  Yep, I don't care about next week yet.  That's next week.  I have the Mole Storm tomorrow and that's where the ointment loosens the scab.  If I get snow I'll be able to laugh at Burnsy, and go ya, ya, ya, ya, YA!  Far more satisfying than worrying about a storm that may or may not happen 5 days from now.  And I can't figure the naysayers who say this is the last chance.  No one knows if another triple phaser is out there around the 13th.  The models can't even get the same run to show the same on two different sites, lol.  The future is always open...always I have snow in the forecast for tomorrow...that's all that matters now! But Gfs 1 at 0z says I get more...Gfs 2 at 0z says dry slot.  Go figure   T

[packbacker]

One nice change on the Euro ENS from the 0z to the 12z run is the SLP is not gaining latitude.  The 12z Euro is SE of the OP and it looks to get to Hatteras and heads due east from there, where the 0z run got to Delmarva.  Also, the Euro ENS mean is identical to the GFS ENS mean, WRT to SLP track.

 

 

0z Euro ENS

 

 

 

12z Euro ENS

 

[GaWx]

Pretty cool update from FFC, guess maybe those of us especially north of Atlanta may see a little fun this evening into tomorrow.

 

 

...WINTER WEATHER ADVISORY ISSUED FOR NORTH GEORGIA FROM 10 PM TONIGHT TO 7 PM SATURDAY... .SHORT TERM /TONIGHT THROUGH SUNDAY/... MAIN CONCERN IN THE SHORT TERM IS THE THREAT OF WINTRY PRECIPITATION ACROSS MAINLY NORTH GA TONIGHT AND SATURDAY. LATEST UPPER ANALYSIS AND SATELLITE WV IMAGERY SHOW AN UPPER TROUGH DEEPENING OVER THE MID MS VALLEY REGION. MODELS AGREE THIS DEEPENING PROCESS WILL CONTINUE AS A SERIES OF DISTURBANCES TRAVERSE AROUND THE BASE... AND DRIVING THE SYSTEM EASTWARD... SUPPLYING AMPLE LIFT/FORCING ACROSS THE FORECAST AREA BEGINNING THIS EVENING AND CONTINUING THROUGH AT LEAST MID SATURDAY AFTERNOON. THIS COUPLED DEEPENING LOW-MID LEVEL MOISTURE AND COLD AIR ADVECTION WILL COMBINE TO BRING A THREAT WINTRY PRECIPITATION TO NORTH GA... MAINLY IN THE FORM OF SNOW BEGINNING BY MID-LATE EVENING ACROSS FAR NORTH GA AND SPREADING SOUTHWARD INTO THE ATLANTA METRO AREA BY 5-7 AM SATURDAY MORNING AND POSSIBLY AREAS SOUTHWARD. TEMPERATURE PROFILES FROM BUFR SOUNDING DATA SUGGEST ANY INITIAL LIGHT RAIN THIS EVENING WOULD CHANGE OVER TO SNOW BY 10PM TO MIDNIGHT... AND POSSIBLY BECOME HEAVY ENOUGH TO ALLOW LIGHT ACCUMULATIONS ON GRASSY AND ELEVATED SURFACES AS THE SNOW SPREAD SOUTHWARD TOWARD ATLANTA THROUGH 8 AM SATURDAY.

 

 

Here in Dunwoody (just north of ATL), I'll believe it if/when I see it. I've still yet to see a single flake or pellet this winter despite the several minor events nearby. These NW flow type of events quite often dry up so much that they have a lot of trouble getting all of the way down to here. So, I'm assuming I'll see nothing but I'm hopeful that is wrong and that I see a flurry or two. However, even if some flurries get here, they may come in when I'm sleeping.

[audioguy3107]

Here in Dunwoody (just north of ATL), I'll believe it if/when I see it. I've still yet to see a single flake or pellet this winter despite the several minor events nearby. These NW flow type of events quite often dry up so much that they have a lot of trouble getting all of the way down to here. So, I'm assuming I'll see nothing but I'm hopeful that is wrong and that I see a flurry or two. However, even if some flurries get here, they may come in when I'm sleeping.

 

I completely agree with you, however it is a little easier to keep spirits up this year (even with such a crappy winter) when FFC seems to be much more aggressive with some of their forecasts and outlooks.  Its been discussed a ton in the past, but they've really stepped it up this year with their discussions, graphics, and explanations of past events.  A couple of years ago, I couldn't even imagine this scenario prompting them to put our a WWA, but hey, I appreciate the diligence.   After all an advisory is just an advisory and a watch is what it is called.....a watch.  I completely understand patience when it comes to WSW especially here in the south, but I've often thought that certain situations do warrant watches.  Anyway, here's to seeing a few flakes fly tonight or tomorrow morning  ...unless the silly JMA   is on to something, this may be our last gasp for winter 2013 and its bring on severe season!

[DaculaWeather]

Here in Dunwoody (just north of ATL), I'll believe it if/when I see it. I've still yet to see a single flake or pellet this winter despite the several minor events nearby. These NW flow type of events quite often dry up so much that they have a lot of trouble getting all of the way down to here. So, I'm assuming I'll see nothing but I'm hopeful that is wrong and that I see a flurry or two. However, even if some flurries get here, they may come in when I'm sleeping.

So you're up in our neck of the woods I see! Had to come and see some flakes!

[packbacker]

From HM in the MA thread....

 

~HM~

Just a statement about possible future trends north: usually in coastal storm situations like this when the models trend north in the final days, the 50-50 low/block has already reached its westward point and they begin to dismantle/move out at storm time/just before. A lot of famous blizzards happen at the end of a -NAO cycle for a reason in the Mid Atlantic.

In this case, the modeling retrogrades and then moves the anticyclone southward right up until the storm date. If this is accurate, there will be NO trend north last minute. Also, the scenario has evolved away from having to rely on a phase for you guys to get the snow. Between these two points, I'm now getting pretty excited for you guys. I'll have more in the days ahead of course but I like that the picture is growing less "phase-reliant" ...simple evolution is better than something like 2/8 for the Mid Atlantic.

~HM~

[packbacker]

FWIW, the EPS Control is pretty much like the OP run, maybe a smidge south, it sets up shop right on the NC/VA and than hits a brick wall and actually backs a little SE and than heads due east.  Looks like it clips RDU with 0.1-0.2" of precip, FWIW.

[burgertime]

18z looks a tad south with our northern energy @63 compared to 12z. Also that second peice of energy out west is a little stronger 

[griteater]

From HM in the MA thread....

 

~HM~

Just a statement about possible future trends north: usually in coastal storm situations like this when the models trend north in the final days, the 50-50 low/block has already reached its westward point and they begin to dismantle/move out at storm time/just before. A lot of famous blizzards happen at the end of a -NAO cycle for a reason in the Mid Atlantic.

In this case, the modeling retrogrades and then moves the anticyclone southward right up until the storm date. If this is accurate, there will be NO trend north last minute. Also, the scenario has evolved away from having to rely on a phase for you guys to get the snow. Between these two points, I'm now getting pretty excited for you guys. I'll have more in the days ahead of course but I like that the picture is growing less "phase-reliant" ...simple evolution is better than something like 2/8 for the Mid Atlantic.

~HM~

Good find.  GFS and Euro Ensemble combo puts northern VA & DC in the crosshairs for snow based on the 500mb low track.  I think it's going to be a real stretch to get this far enough south for a noteworthy impact in the Carolinas.  Blocking setup over New England and the amount of western ridging behind our upper low are key.

[GaWx]

So you're up in our neck of the woods I see! Had to come and see some flakes!

 

My being in Dunwoody will probably keep it away lol.