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February Medium/Long Range Disco Thread 2


WxUSAF

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31 minutes ago, mitchnick said:

Both of those 500mb maps have that persistent ridge over Japan. 

In the macro I agree. But in the micro it wasn't the main problem in that look. The reason a ridge over Japan is a bad is in a typical longeave pattern that places the ridge axis near us more often then not and makes it hard to sustain a trough. That was a sign of our bad winter.  But if we manage to get a trough over us it can and has snowed with a ridge over Japan. 

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19 minutes ago, C.A.P.E. said:

Before someone stomps on me, there is relative cold nearby, and the E Pacific looks pretty decent for a time. But most of the lower heights are west, with general ridging over the east. Not impossible to score something in the first 10 days or so of the month with that look.

Your right it's not that far from decent but it's not a good look and everyone is probably tired of maybe if we're lucky. 

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17 minutes ago, gymengineer said:

Hey, it took until April for IAD to get an inch-er in 72/73 and finally go above average snow for a single month :lol:  Hope can persist for anyone if they want it to.....

We have had several 10" snows in April up here but they aren't the kind of thing you can track. Takes so much to go right including getting death banded to get temps to work. 

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Someone can move this to banter if no other post on this page is less deserving. 

From micro to macro, first we have a bunch of highs and lows off the coast that don't seem to physically exist...

lows and highs.jpg

Then, the latest mesoscale 3km nam NEST (red-tag reminder) shows precipitation displaced from the low inching its way closer to us on Wednesday...

nam3km_ref_frzn_us_42 Feb 13_2017 3km nam.png

and lastly, the MJO ensembles hint at a u-turn back into phase 8 in a couple weeks...

mjo u_turn.gif

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41 minutes ago, psuhoffman said:

We have had several 10" snows in April up here but they aren't the kind of thing you can track. Takes so much to go right including getting death banded to get temps to work. 

Do you remember April 9th, 1996? Pretty much the only short term negative bust for our area that season. It was ok for southern PA and extreme northern MD-- Manchester got 3.5" with the silver-dollar-flake band that was west of the main band associated with the low.

Everyone was in love with the ETA that season based on its performance for the blizzard. So lots of forecasts for the rest of the season were weighted on the ETA's output. For this storm, rapid deepening was depicted overnight just south of our latitude. A WSWarning for 4-8" was issued while TV mets either ran with it or shaved off some (Bob Ryan went with 2-5" for DC Metro). I woke up to temps in the upper 30's and light rain, and I was disappointed to not get one last snow day. We did eventually flip to snow that dusted the ground. But just above our latitude, 6-8" fell in southern coastal NJ (Atlantic City boardwalk covered by snow was a pretty amazing video for April).

Total example of the craziness of a deepening  April low; it was just too late for the DC area. 

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17 minutes ago, BTRWx said:

Then, the latest mesoscale 3km nam NEST (red-tag reminder) shows precipitation displaced from the low inching its way closer to us on Wednesday...

nam3km_ref_frzn_us_42 Feb 13_2017 3km nam.png

 

A definite shift west on the 00z 3km NAM and 00z GFS. 

WKSGb3K.gif

The GFS has been trending faster with the southern low and towards a sharper trough.  I'm not sure how it all plays out, but we might see some cold rain or even a few flakes from this yet.  At least it's something to track.

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On 2/12/2017 at 11:01 PM, psuhoffman said:

This is the kind of thing I do love to get into. Trying to dig in and understand this whole thing.  I've not had time to do all the research and reading on some stuff I would like yet but my initial thoughts are that it's a combination of a whole lot of factors lining up wrong. 

Some of the big ones hurting us most imo are the enso configuration, the qbo, the north PAC sst and the sst off the east coast. 

I don't think enso is as simple as El Niño and La Niña. There is also a huge difference between west and east based enso events.  Data seems to suggest we want west based ninos and east based ninas. Basically regardless of enso state we want warmer water centered over the central equatorial Pacific and cooler waters off South America. That places the tropical forcing where we want it for colder snowier patterns. While the enso signal was weak, never reaching official Nina status, the location of the forcing was all wrong. The coolest waters were in the central PAC and as the Nina weakened the waters warmed even more to the east. So that if anything hurt us more. So while the enso signal was weak whatever forcing it had was detrimental to us. 

The westerly qbo was at record levels. There is an observed correlation between a westerly qbo and a stronger polar vortex and positive AO. So it's hard to ignore the possible effects of a record qbo on the positive AO this year.  I don't want to place too much importance on one thing because the closest qbo analog was 2013/14 but that year we had an anomalous warm pool in the North Pacific that was conducive to a helpful epo. This year we had almost the opposite and a north PAC sst that was hostile to getting much help from the epo or pna combo. The combo of those two factors hurt a lot imo.  

I want to read more on the qbo  I know the disruption of the normal qbo cycle last year really had some alarmed.  I've read it blamed on anything from global warming to the super nino to sst years strat warm event.  I have no idea the cause but it's interesting that we had a disruption in the phase change that brought on a second straight west phase and it went to record levels.

Also the Atlantic sst was conducive to ridging on the east coast.  And the North Atlantic sst wasn't all that great for nao help.  Combine the warmer waters in the eastern equatorial Pacific with the warm waters off the east coast and that's a whole lot of warm signal aimed at us.  

Then there are other factors also lined up wrong.  The whole northern hemisphere is biased warm probably due to a lag from the nino.  At least I hope it's that because it's been a blowtorch for a long time now and if that's the new base state it's going to be difficult to get sustained cold.  There just isn't much around.  There were times the models showed ridging in good spots and temps were still torching all around like one huge ridge everywhere.  Seeing that look a lot bothers me.  We have a hard enough time here without a lack of cold anywhere adding to our troubles  

Finally the northern jet has been screaming along.  Progressive isn't always bad but given all those other factors lined up warm a progressive flow is going to prevent the kind of jet buckling we would need to get cold in here and or amplify a storm under us.  The few times we did have cold the northern jet threw vorts across to help suppress the flow underneath. 

So off the top of my head those are the biggest problems I see. It's not one thing. More a whole lot of contributing factors that all lined up wrong this year. 

I appreciate the feed back.  I just love talking analysis.  I had forgotten in my previous response to Bob Chill that in the SE forum discussion someone had mentioned the raging +QBO. 

Man I am ready for a state-change in winters: three of the last six (11-12, 15-16, and 16-17) have been super-torch for the SE, plus 12-13 which was merely a plain torch, so four out of six crappy or super-crappy winters down here.

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7 hours ago, gymengineer said:

Do you remember April 9th, 1996? Pretty much the only short term negative bust for our area that season. It was ok for southern PA and extreme northern MD-- Manchester got 3.5" with the silver-dollar-flake band that was west of the main band associated with the low.

Everyone was in love with the ETA that season based on its performance for the blizzard. So lots of forecasts for the rest of the season were weighted on the ETA's output. For this storm, rapid deepening was depicted overnight just south of our latitude. A WSWarning for 4-8" was issued while TV mets either ran with it or shaved off some (Bob Ryan went with 2-5" for DC Metro). I woke up to temps in the upper 30's and light rain, and I was disappointed to not get one last snow day. We did eventually flip to snow that dusted the ground. But just above our latitude, 6-8" fell in southern coastal NJ (Atlantic City boardwalk covered by snow was a pretty amazing video for April).

Total example of the craziness of a deepening  April low; it was just too late for the DC area. 

Coastal NJ has had a few big April snows, way more then us despite a lower snow climo overall. My guess is those late season storms bomb out very tight and we're stuck too far west to get into the best deform bands but we're not high enough like WV and western MD to get snow from less intense storms that late. 

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GFS has a nice system skirting us to the south at hour 372.   Yeah, I know...372.

The weird thing is that the GFS shows 2m temperatures rising as the system passes south of us and turns left to go up the baroclinic zone.

I'm guessing that a second system over Detroit is producing warm air advection.   Maybe a front end dump?

Maybe discussing a system at hour 372 is desperation.

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7 minutes ago, winterymix said:

GFS has a nice system skirting us to the south at hour 372.   Yeah, I know...372.

The weird thing is that the GFS shows 2m temperatures rising as the system passes south of us and turns left to go up the baroclinic zone.

I'm guessing that a second system over Detroit is producing warm air advection.   Maybe a front end dump?

Maybe discussing a system at hour 372 is desperation.

6z gefs actually supports something day 12-16. 6 members get snow into DC with several other near misses. Not wasting any more time on that yet. 

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14 hours ago, C.A.P.E. said:

Before someone stomps on me, there is relative cold nearby, and the E Pacific looks pretty decent for a time. But most of the lower heights are west, with general ridging over the east. Not impossible to score something in the first 10 days or so of the month with that look.

Do think it's a workable pattern?

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Just now, North Balti Zen said:

Definitely. Only have to get one thing faster, one thing slower, move a ridge a bit west, move a trough a bit east, find some cold air, and get a bit of luck on top of that and its workable...

Just need a little luck.  We could be looking at March 93.

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1 minute ago, North Balti Zen said:

Definitely. Only have to get one thing faster, one thing slower, move a ridge a bit west, move a trough a bit east, and get a bit of luck on top of that and its workable...

Slow the northern stream down by 10 hours, speed up the southern stream by 18 hours, get the ridge to move 700 miles east to Greenland, have that initial bomb sit just off Newfoundland, pop a little ridge up into Alaska, and establish a ridge bridge and we're golden!

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Just now, mattie g said:

Slow the northern stream down by 10 hours, speed up the southern stream by 18 hours, get the ridge to move 700 miles east to Greenland, have that initial bomb sit just off Newfoundland, pop a little ridge up into Alaska, and establish a ridge bridge and we're golden!

Don't forget to throw in a potent sw in the stj, get a neutral tilt by the Mississippi River, a northern stream sw to phase at the right moment in the space-time continuum, the proper phase of the MJO, a perturbed polar vortex, a trio of highs to the north to form the banana, and maybe, just maybe, we can get a 2-4" event.

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9 hours ago, peribonca said:

Noticeable shift west in 0z gfs. Just look at noon Wednesday... Precip now makes it into DCA 

 

10 hours ago, cae said:

A definite shift west on the 00z 3km NAM and 00z GFS. 

WKSGb3K.gif

The GFS has been trending faster with the southern low and towards a sharper trough.  I'm not sure how it all plays out, but we might see some cold rain or even a few flakes from this yet.  At least it's something to track.

You guys are really still analyzing this?...

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