brooklynwx99

looks like the GEFS actually increased the confluent flow over the NE, this is great to see the vort itself is stronger as well. confluence will almost always exert itself more than a shortwave, so a mixture of both would still result in a more favorable track the majority of the time

EPS is absolutely gorgeous

the OP runs are on the far western edge of their respective ensemble means, I’m not particularly worried about a far W track, especially given the initial confluence over Canada it’s a possibility, but not a major concern IMO the mid levels are amazing though, that’s really all that matters at this range. almost a classic look, the GEPS has a closed contour at 500mb over the TN Valley!

the OP runs are on the far western edge of their respective ensemble means, I’m not particularly worried about a far W track, especially given the initial confluence over Canada it’s a possibility, but not a major concern IMO the 500mb look is amazing though, that’s what matters most at this range

GEFS looks great broad 500mb trough over the TN Valley and some confluent flow downstream thanks to the SE Canada ULL NS energy getting picked up consistently as well

very difficult to draw it up much better than this broad 500mb trough over the TN valley, confluence over the NE and phasing imminent pretty classic look

It looks like we are finally entering an extremely favorable pattern starting around the 14-16th. The Pacific jet retraction will take place during that time, and the +PNA/-EPO will be able to strengthen and remain stable thanks to a semi-permanent Aleutian ULL: This pattern is pretty much a complete 180 from what we saw for most of December, as there is cross-polar flow established that continues throughout much, if not all of the month. This pattern is highly reminiscent of the 2013-15 winters, where there were extreme arctic outbreaks as well as increased storminess to go along with it. Now, this pattern is certainly not one that you'd normally see in a Nina, and here's why: Note the negative height anomalies in the S US along with the split flow W of S CA. This signals that the STJ will be open for business, which is rare in -ENSO winters where the northern stream is dominant and the STJ is often nowhere to be found. The main reason, at least to me, as to why this pattern is so potent is because of the split flow. There will be highly amplified shortwaves rolling S off of the western ridging that will be able to phase with cutoff lows and other pieces of energy from the southern stream. This is accomplished by the W ridging being a bit more poleward than usual: it allows for significant cross-polar flow, but it also keeps the STJ open. This is often how we get our largest storms. There is also an immense cold supply here, as our air will be sourced from Siberia. Hints of transient -NAO blocking have also been showing up on the OP runs, and there's some on the ENS means as well. Transient blocks are really all you need when it comes to large storms, as we've seen in the past. Overall, this is just a loaded pattern and I would honestly be quite surprised if there isn't a MECS (or two!) between the 15th and the end of the month. Our next threat is around the 15th, and there's already a lot of phasing potential there. We will likely have to wait until after the 20th for the pattern to mature a bit, but a KU is certainly on the table.

It looks like we are finally entering an extremely favorable pattern starting around the 14-16th. The Pacific jet retraction will take place during that time, and the +PNA/-EPO will be able to strengthen and remain stable thanks to a semi-permanent Aleutian ULL: This pattern is pretty much a complete 180 from what we saw for most of December, as there is cross-polar flow established that continues throughout much, if not all of the month. This pattern is highly reminiscent of the 2013-15 winters, where there were extreme arctic outbreaks as well as increased storminess to go along with it. Now, this pattern is certainly not one that you'd normally see in a Nina, and here's why: Note the negative height anomalies in the S US along with the split flow W of S CA. This signals that the STJ will be open for business, which is rare in -ENSO winters where the northern stream is dominant and the STJ is often nowhere to be found. The main reason, at least to me, as to why this pattern is so potent is because of the split flow. There will be highly amplified shortwaves rolling S off of the western ridging that will be able to phase with cutoff lows and other pieces of energy from the southern stream. This is accomplished by the W ridging being a bit more poleward than usual: it allows for significant cross-polar flow, but it also keeps the STJ open. This is often how we get our largest storms. There is also an immense cold supply here, as our air will be sourced from Siberia. Hints of transient -NAO blocking have also been showing up on the OP runs, and there's some on the ENS means as well. Transient blocks are really all you need when it comes to large storms, as we've seen in the past. Overall, this is just a loaded pattern and I would honestly be quite surprised if there isn't a MECS (or two!) between the 15th and the end of the month. Our next threat is around the 15th, and there's already a lot of phasing potential there. We will likely have to wait until after the 20th for the pattern to mature a bit, but a KU is certainly on the table.

It looks like we are finally entering an extremely favorable pattern starting around the 14-16th. The Pacific jet retraction will take place during that time, and the +PNA/-EPO will be able to strengthen and remain stable thanks to a semi-permanent Aleutian ULL: This pattern is pretty much a complete 180 from what we saw for most of December, as there is cross-polar flow established that continues throughout much, if not all of the month. This pattern is highly reminiscent of the 2013-15 winters, where there were extreme arctic outbreaks as well as increased storminess to go along with it. Now, this pattern is certainly not one that you'd normally see in a Nina, and here's why: Note the negative height anomalies in the S US along with the split flow W of S CA. This signals that the STJ will be open for business, which is rare in -ENSO winters where the northern stream is dominant and the STJ is often nowhere to be found. The main reason, at least to me, as to why this pattern is so potent is because of the split flow. There will be highly amplified shortwaves rolling S off of the western ridging that will be able to phase with cutoff lows and other pieces of energy from the southern stream. This is accomplished by the W ridging being a bit more poleward than usual: it allows for significant cross-polar flow, but it also keeps the STJ open. This is often how we get our largest storms. There is also an immense cold supply here, as our air will be sourced from Siberia. Hints of transient -NAO blocking have also been showing up on the OP runs, and there's some on the ENS means as well. Transient blocks are really all you need when it comes to large storms, as we've seen in the past. Overall, this is just a loaded pattern and I would honestly be quite surprised if there isn't a MECS (or two!) between the 15th and the end of the month. Our next threat is around the 15th, and there's already a lot of phasing potential there. We will likely have to wait until after the 20th for the pattern to mature a bit, but a KU is certainly on the table.

holy crap

the 12z GFS looks a bit better at 500mb! more buckling of the trough with appreciably higher heights over NJ. much more PVA into the region overall I was not expecting a positive shift at 12z here, so this is great to see. the GFS really isn't backing down here as it improved in all facets

the NAM made a huge shift at 500mb, namely in the positive interaction of the NS rather than a negative confluent push, as we had seen a couple of days ago the initial vort is more amped, which is great, but the NS is now helping to turn heights in a more southerly direction. look at the wind bards S of LI: almost due S from WSW last run. this drastically changes the angle of the PVA

the NAM made a huge shift at 500mb, namely in the positive interaction of the NS rather than a negative confluent push, as we had seen a couple of days ago the initial vort is more amped, which is great, but the NS is now helping to turn heights in a more southerly direction. look at the wind bards S of LI: almost due S from WSW last run. this drastically changes the angle of the PVA

wow, this is much more robust. closed contour at 500mb as well as higher heights over NJ

NAM is way more amped through 25

Monday's system just got more interesting with the significant amplified shift from the GEFS a couple more ticks like this and we're in business

wow, this is an amazing look. strong vort diving S of the region with great jet support

overall, this event is certainly a "thread the needle" type storm, but things still look interesting given today's trend of a stronger, slower SS vort with less NS interaction. a GFS-like solution can't be discarded at this juncture it looks like the American models are doing a decent job with this, as the ECMWF and RGEM took some steps towards the GFS/NAM. the 18z ECMWF made a nice shift towards a more favorable solution: of course, this remains rather unlikely, but I think it's worth looking to see if the 00z runs continue this trend

overall, this event is certainly a "thread the needle" type storm, but things still look interesting given today's trend of a stronger, slower SS vort with less NS interaction. a GFS-like solution cannot be discarded at this juncture it looks like the American models are doing a decent job with this, as the ECMWF and RGEM took some steps towards the GFS/NAM. the 18z ECMWF made a nice shift towards a more favorable solution: of course, this remains rather unlikely, but I think it's worth looking to see if the 00z runs continue this trend

yeah... this system is pretty intriguing if that southern stream energy can separate enough. if so, it would be able to amplify and become something like the 00z GFS, which is a gorgeous solution at 500mb. cold air would not be a problem given a good source region in Canada and a rapidly developing SLP the ECMWF made a step towards holding the SS energy back, which is the main thing to look for here imo the GEFS is also more in favor of greater stream separation as well as a more amplified southern stream... these both bode well for this event more amplified ridging out west as well, this likely helps the SS gain amplitude

My original disagreement with those posts was that, at the time of my post, the -PNA was not nearly at the strength that it was. Therefore, I was claiming that the 3 SD ridge over Greenland would overpower the -PNA, which happens an overwhelming majority of the time. However, we ended up getting 510dam heights over Seattle, which is something that nobody could predict more than a few days in advance, let alone more than 10 days. I did anticipate the -PNA, but there was no way that anybody could see its record breaking nature at that lead time, which is what fully overwhelmed the pattern. Look, LR forecasting is hard, and I did not want to derail my intuition based on the slight possibility that an unprecedented event would occur. It would be just as bad if I said there would be a blizzard over the metro if there was a mean trough over the E US at 180 hours. Everyone makes mistakes though, the weather humbles everyone.

Unfortunately, although the anomalous -NAO/-EPO couplet did develop, it is impossible to overcome a record breaking -PNA. If the PNA was negative but not completely unprecedented (which is what I wrongly predicted), then this month would’ve turned out much differently. Nobody could’ve have seen the PNA being that overpowering, as it was literally a historical event, and there was no indication that an event of such magnitude would unfold. A “normal” -PNA would have been easily overcome by the -NAO, not a -3 sigma trough. So yes, there was a complete pattern change, but we got very unlucky and I’d be lying if I said I wasn’t a bit frustrated about it.

The GEFS and EPS have a gorgeous pattern evolution towards the end of their runs... this is thanks to the extension of the Pacific jet in the medium-long range: This jet extension is thanks in part to the +EAMT that is forecasted to develop in the short range: So, overall, it looks like there is some forcing that may be able to shake up this pattern. The jet extension will allow for the anomalous Aleutian ridge to build poleward and kick the mean trough out of the Pac NW and into the N Plains. This, in turn will allow for cold air to bleed into the E US: It's nice to see the changes to the Pacific jet, as those kinds of shifts on modeling are usually representative of a large shift in the pattern and not a temporary blip. It's great to see the blocking signal still holding strong as well, as the 50/50 ULL and -NAO remain prominent features throughout the runs. As long as the mean position of the trough changes to anywhere east of where it is now, that would be a massive improvement. The patterns on the end of the runs would be quite cold and stormy with the Pacific becoming much more favorable with the cold dumping into the midsection of the country. Now, of course, this could be a head fake, but I really don't believe so. The MJO is taking its time propagating through the Pacific, and Phase 7 forcing is more favorable in January anyway, so I don't see it as an issue. The +EAMT is also forecast to begin very soon, and the changes to the jet over the Pacific aren't very far out either. The forcing mechanisms that might help shake things up are in a tangible range. Overall, I would like to see these changes continue into the weekend. The Jan 2 period is intriguing, as there could be some TPV influence in Canada and some SS wave trying to cut underneath. That's really all you can say at this range. However, it's nice that we're getting some chances, and we have that possible threat as well as the small WAA push in a couple days that's worth keeping an eye on for some light snow.

The GEFS and EPS have a gorgeous pattern evolution towards the end of their runs... this is thanks to the extension of the Pacific jet in the medium-long range: This jet extension is thanks in part to the +EAMT that is forecasted to develop in the short range: So, overall, it looks like there is some forcing that may be able to shake up this pattern. The jet extension will allow for the anomalous Aleutian ridge to build poleward and kick the mean trough out of the Pac NW and into the N Plains. This, in turn will allow for cold air to bleed into the E US. It's nice to see the changes to the Pacific jet, as those kinds of shifts on modeling are usually representative of a large shift in the pattern and not a temporary blip. It's great to see the blocking signal still holding strong as well, as the 50/50 ULL and -NAO remain prominent features throughout the runs. As long as the mean position of the trough changes to anywhere east of where it is now, that would be a massive improvement. The patterns on the end of the runs would be quite cold and stormy with the Pacific becoming much more favorable with the cold dumping into the midsection of the country. Now, of course, this could be a head fake, but I really don't believe so. The MJO is taking its time propagating through the Pacific, and Phase 7 forcing is more favorable in January anyway, so I don't see it as an issue. The +EAMT is also forecast to begin very soon, and the changes to the jet over the Pacific aren't very far out either. The forcing mechanisms that might help shake things up are in a tangible range. Overall, I would like to see these changes continue into the weekend. The Jan 2 period is intriguing, as there could be some TPV influence in Canada and some SS wave trying to cut underneath. That's really all you can say at this range. However, it's nice that we're getting some chances.

The GEFS and EPS have a gorgeous pattern evolution towards the end of their runs... this is thanks to the extension of the Pacific jet in the medium-long range: This jet extension is thanks in part to the +EAMT that is forecasted to develop in the short range: So, overall, it looks like there is some forcing that may be able to shake up this pattern. The jet extension will allow for the anomalous Aleutian ridge to build poleward and kick the mean trough out of the Pac NW and into the N Plains. This, in turn will allow for cold air to bleed into the E US: It's nice to see the changes to the Pacific jet, as those kinds of shifts on modeling are usually representative of a large shift in the pattern and not a temporary blip. It's great to see the blocking signal still holding strong as well, as the 50/50 ULL and -NAO remain prominent features throughout the runs. As long as the mean position of the trough changes to anywhere east of where it is now, that would be a massive improvement. The patterns on the end of the runs would be quite cold and stormy with the Pacific becoming much more favorable with the cold dumping into the midsection of the country. Now, of course, this could be a head fake, but I really don't believe so. The MJO is taking its time propagating through the Pacific, and Phase 7 forcing is more favorable in January anyway, so I don't see it as an issue. The +EAMT is also forecast to begin very soon, and the changes to the jet over the Pacific aren't very far out either. The forcing mechanisms that might help shake things up are in a tangible range. Overall, I would like to see these changes continue into the weekend. The Jan 2 period is intriguing, as there could be some TPV influence in Canada and some SS wave trying to cut underneath. That's really all you can say at this range. However, it's nice that we're getting some chances, and we have that possible threat as well as the small WAA push in a couple days that's worth keeping an eye on for some light snow.