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Medium Range-Long Range thread

NaoPos

By NaoPos,
in Philadelphia Region

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Yes_Probably_Maybe_No

Yes_Probably_Maybe_No

Posted
Posted

Any thoughts on the AAM transports? Seems to be stuck with mid-latitude +AAM transport locked in since December, which also is seen on the relative AAM plot. I've noticed +AAM tendency shifting poleward on the charts and I suspect much of that is contributed by the Pacific, which could also be the reason for mid-latitude HP that we have been seeing in the 6-10 range of the models. 

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Harbourton

Harbourton

Posted
Posted

Borrowed the idea from NYC METRO but it is getting more interesting!

 

 

UPSTREAM...A DYNAMIC SHORTWAVE IMPULSE WITH LIMITED MOISTURE WILLDROP SEWD THROUGH THE WRN US THU/D3. DIGGING ENERGY WILL FEED MORESHARPLY INTO THE S-CENTRAL US BY FRI TO THE LEE OF A RAPIDLYAMPLIFYING MID-UPPER LEVEL E-CENTRAL PACIFIC TROUGH AND WRN USRIDGE COUPLET DEVELOPING UPSTREAM. THIS LEADS TO QUITE ANAMPLIFIED WRN US RIDGE AND COLD ERN US TROUGH... POSITIVE PNAPATTERN... BY SAT/D5 JUST AS HEIGHT RISES FEED WESTWARD FROMGREENLAND INTO ERN CANADA AT HIGHER LATITUDES. THIS MAY LEAD TOERN US COASTAL LOW POTENTIAL SAT-MON AND HPC MANUAL PROGS SHOWMODERATE DEVELOPMENT BUT THE PATTERN FAVORS OFFSHORE DEVELOPMENT.500MB STANDARDIZED HEIGHT ANOMALIES ARE FCST TO DROP TO -3.5 OR SOCENTERED OVER FLORIDA OVER THE WEEKEND WITH SFC TEMPS 10-15 DEG FBELOW NORMAL. TEMPERATURES IN THE WEST SHOULD BALANCE WITH HIGHSWELL INTO THE 80S IN THE SW DESERTS.
Still offshore but with a little push west?
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Mitchell Gaines

Mitchell Gaines

Posted
Posted

I looked at the chance for a coastal low today with my part of the extended.

A BROAD TROUGH WILL BE IN PLACE OVER THE REGION MONDAY WITH A
PERSISTENT NORTH TO NORTHWEST FLOW. A CONCERN FOR THIS PERIOD IS IF
A COASTAL LOW CAN FORM DUE TO THE INTERACTION OF MID-LEVEL
DISTURBANCES AND FRONTAL BOUNDARIES OFFSHORE. IF A COASTAL LOW DOES
DEVELOP WITH A FAVORABLE TRACK THAT MIGHT CHANGE THE GAME A BIT.
ATTM THE MAJORITY OF GUIDANCE SUGGESTS LOW PRESSURE FORMATION AND A
TRACK OFFSHORE OR NO SYSTEM TO FORM AT ALL.

 

we'll see how that plays out.

 

I think March 7th has a shot but looks similar to events we've already had this winter aka light snow event.

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famartin

famartin

Posted
Posted

I don't think I've busted this bad on a medium range forecast in the last 1.5 years, since I really started working on this stuff. Of course, non-weather work is insane right now, so I don't even have time to figure out why I'm busting so hard.

You're referring to the (non)warm start to March I take it?

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CooL

CooL

Posted
Posted

I don't think I've busted this bad on a medium range forecast in the last 1.5 years, since I really started working on this stuff. Of course, non-weather work is insane right now, so I don't even have time to figure out why I'm busting so hard.

 

You are not alone lol..But now that you see how the early March pattern is shaping up, do you think that most of the month will be cold and/or snowy?

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Ellinwood

Ellinwood

Posted
Posted

High-latitude blocking will be doing its thing over the next 2+ weeks with no sign of it going anywhere at the end of the run on both the GFS and Euro ensembles. Seems to be the dominant signal at this point. PNA starts dropping into negative territory towards the end of the run... hopefully we can get some downstream effects from that and pop the Southeast ridge to change up the pattern over the eastern U.S.

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Mike.Ventrice

Mike.Ventrice

Posted
Posted

I don't think I've busted this bad on a medium range forecast in the last 1.5 years, since I really started working on this stuff. Of course, non-weather work is insane right now, so I don't even have time to figure out why I'm busting so hard.

 

I'm right there with you as for the east. Forcing from tropical convection was alot less than what was originally expected with the past MJO event. Carl Schreck's time longitude (with CFS forecast) really shows this quite well. There has been a good deal of equatorial Rossby wave (westward propagating equatorial waves coupled with convection) activity over the IO and West Pac that superimposed with with this past MJO event. At one point over the IO, the superposition of the convectively suppressed ERW and active MJO yielded an overall weaker MJO-convection signal over the Indian Ocean (phase 2-3), as you know a component that is crucial to modulate the extratropical flow regime.  There were actually positive OLR anomalies within the active MJO phase over the IO at one point! This is something that you can't really predict and just unfortunate how little tropical convection forcing there was with the previous event. You just can't use the MJO as a predictor now and as Ellinwood stated, this is a time where the extratropical response to extratropical weather events is dictating the pattern. Just a headache for medium range mets. 

 

 

cfs.waves.EQ.gif

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HM

HM

Posted
Posted

Quick post, I'm freakin' busy lately...

1. Lower stratospheric ozone pump still fast and furious from the eastern hemisphere into the western hemisphere.

2. Pattern is and will continue to be in a state of retrogression through mid-March at least.

3. Mid-week, next week is of course a threat but I'm worried that it goes the way of the 2/22 event (the block retrogrades into Quebec/Ontario as trough amplifies in the Midwest). Should the block stay further NE, it could trap the Sunday-Monday trough in the NW Atlantic and act to suppress it. We need a hybrid of the two scenarios to pan out for the snowiest outcome.

4. Troughs will continue to dig into the West but the -EPO being signaled makes sense (retrogression / AAM). If the NAO can rejuvenate, then suddenly mid-March becomes the most threatening since 2/8. If the NAO does not bounce back into negative territory, the threats will stay well west of us.

Adios Amigos

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NJwinter23

NJwinter23

Posted
Posted

I'm right there with you as for the east. Forcing from tropical convection was alot less than what was originally expected with the past MJO event. Carl Schreck's time longitude (with CFS forecast) really shows this quite well. There has been a good deal of equatorial Rossby wave (westward propagating equatorial waves coupled with convection) activity over the IO and West Pac that superimposed with with this past MJO event. At one point over the IO, the superposition of the convectively suppressed ERW and active MJO yielded an overall weaker MJO-convection signal over the Indian Ocean (phase 2-3), as you know a component that is crucial to modulate the extratropical flow regime.  There were actually positive OLR anomalies within the active MJO phase over the IO at one point! This is something that you can't really predict and just unfortunate how little tropical convection forcing there was with the previous event. You just can't use the MJO as a predictor now and as Ellinwood stated, this is a time where the extratropical response to extratropical weather events is dictating the pattern. Just a headache for medium range mets. 

 

 

cfs.waves.EQ.gif

 

I noticed that around the time you are mentioning when the +OLR shows up over the central IO while the MJO is passing through, it is in the wake of two twin -OLR anomalies spinning northward and southward in their respective hemispheres. I believe the SH anomaly developed into a cylcone. Isnt this a common occurrence with the passage of the MJO?...Note the image below from Feb 11th in the top left.

 

R5231118.png

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Mike.Ventrice

Mike.Ventrice

Posted
Posted

It does happen time to time, but these occurances may be a reason for forecast busts. Any comments on today's new model guidance? There was a significant warm up over much of the eastern U.S. during 1 to 2 week period. Only thing I can see as a reason is the forecast during the 1 week time frame no longer shows a high-latitude wave breaking event over the North Pacific. This would result in more of a zonal, progressive pattern over the U.S. The GFS actually takes the large-blocking ridge over the Davis Straight and plunges it south over the Great Lakes. MORCH! ahhh

 

I noticed that around the time you are mentioning when the +OLR shows up over the central IO while the MJO is passing through, it is in the wake of two twin -OLR anomalies spinning northward and southward in their respective hemispheres. I believe the SH anomaly developed into a cylcone. Isnt this a common occurrence with the passage of the MJO?...Note the image below from Feb 11th in the top left.

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HM

HM

Posted
Posted

Another -NAO period toward the astronomical spring? Possibility of yet another late-season wet snow before the month is out?

The pattern could remain favorable from that point into early/mid April too for additional coastal storms. Not good news for Sandy-relief efforts.

I'm still thinking we get a taste of summer in latter April with a string of 80s but I know that's not really a ballsy call.

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HM

HM

Posted
Posted

 

Hey, at least I nailed the MJO forecast for late Feb/early Mar. That and a dollar will get you a cup of coffee.

You are one of the best long range forecasters I know and your MJO thoughts have been great this cold season. What kind of adjustments to the temp anomalies did you have to make for the rest of March?

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NJwinter23

NJwinter23

Posted
Posted
All things considering from an MJO standpoint, the temps here in early March outside of the first week may not bust that badly against the MJO state after all. This first week will be colder/mjo bust because of the nao,  but week 2 has trended much warmer in the East from where we stood on the model data last week. I believe a lot of that has to do with the big storm this week becoming the NAO breaker..Recall last week at this time the ensembles showed this Wed threat, but the -nao continuing in the means with what appeared like another possible threat in week 2 to break the pattern. I would have argued the 2nd threat was the potential bigger deal and that is incorrect. Either way you cut it though, Morch is a fail and I agree with the end of March crappy start to spring idea.

 

I'd have to go back and double check, but from what I can remember, these first 2 weeks of March appear like they will play out very similar to how you outlined it a while back HM

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HM

HM

Posted
Posted

 

 

All things considering from an MJO standpoint, the temps here in early March outside of the first week may not bust that badly against the MJO state after all. This first week will be colder/mjo bust because of the nao,  but week 2 has trended much warmer in the East from where we stood on the model data last week. I believe a lot of that has to do with the big storm this week becoming the NAO breaker..Recall last week at this time the ensembles showed this Wed threat, but the -nao continuing in the means with what appeared like another possible threat in week 2 to break the pattern. I would have argued the 2nd threat was the potential bigger deal and that is incorrect. Either way you cut it though, Morch is a fail and I agree with the end of March crappy start to spring idea.

 

I'd have to go back and double check, but from what I can remember, these first 2 weeks of March appear like they will play out very similar to how you outlined it a while back HM

 

Thanks. Yeah it seems good so far; although, I wish was a little more adamant about the snow potential! lol

I just messaged zywts the same thing when we were both talking about DC threats. I told him "maybe something after his 3/1 date" ... gee what a kick in the sack that statement is! lol

Anyway, I'm glad everyone is in agreement about the rest of winter/early spring...ugly!

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snowlurker

snowlurker

Posted
Posted

Quick post, I'm freakin' busy lately...

1. Lower stratospheric ozone pump still fast and furious from the eastern hemisphere into the western hemisphere.

2. Pattern is and will continue to be in a state of retrogression through mid-March at least.

3. Mid-week, next week is of course a threat but I'm worried that it goes the way of the 2/22 event (the block retrogrades into Quebec/Ontario as trough amplifies in the Midwest). Should the block stay further NE, it could trap the Sunday-Monday trough in the NW Atlantic and act to suppress it. We need a hybrid of the two scenarios to pan out for the snowiest outcome.

4. Troughs will continue to dig into the West but the -EPO being signaled makes sense (retrogression / AAM). If the NAO can rejuvenate, then suddenly mid-March becomes the most threatening since 2/8. If the NAO does not bounce back into negative territory, the threats will stay well west of us.

Adios Amigos

 

The CPC D+11 (centered on 3/14) analog composite spat out two KU dates. Except for the most southwest 1/4, the nation looks below normal on Ts and at least the MA looks above normal for precip.

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snowlurker

snowlurker

Posted
Posted

The CPC D+11 (centered on 3/14) analog composite spat out two KU dates. Except for the most southwest 1/4, the nation looks below normal on Ts and at least the MA looks above normal for precip.

For the past few days, the CPC D+11 analog composite has continued to look colder and wetter and keeps spitting out analog dates a day or two before March 18, 1958 and March 2, 1960 - both of which were good snowstorms for this sub-forum.

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