NJ Strong Wx 2014 Summer Outlook

There has been a lot of speculation about the upcoming summer in determining whether or not the projected El Nino comes to fruition. If it does, it obviously will have a dramatic effect on our weather pattern. I thought the best way to approach this blog was by looking at some real-time observations (sea surface temps and ENSO regions) while also taking a look at what deterministic models have to say. Then we can research past years to find similarities and ultimately make a forecast for our summer. Lets get started...

Focus your attention on the 0-degree latitude line (Equator) when you are looking at the SST Anomaly map. Got that? Good. Now I want you to look at the next image:

The ENSO regions are broken into 4 parts and sit along the "Equatorial Pacific." So if you compare, for instance, ENSO region 1+2 with the SST Anomaly map I posted, you will notice there is quite a bit of warming taking place off the northwestern coast of South America.  In fact, there appears to be normal to above normal anomalies in all the ENSO regions. Of course, in case you did not know, when the Equatorial Pacific is experiencing SST's running consistently above normal, that is an indication that an El Nino could be forming. Specifically, most Climatologist go by Nino region 3.4 to determine La Nina or El Nino by looking at the ONI (Oceanic Nino Index). If the ONI in Nino region 3.4 exceeds +0.5 degree C for 5 straight overlapping seasons, an El Nino will be officially declared. 

The CFS certainly insists that Nino-regions 3 and 3.4 will reach El Nino criteria, not just for this summer, but into winter of 2014-2015. But that outlook will not be out until around Thanksgiving. Lets not get ahead of ourselves. 

Just in case you do not buy into the good ol' CFS model, here is the EURO for ya:

Some of those members are getting the ONI as high as +3-degree C (anomaly). The mean, however, looks to be around +1-degree C (for the summer). 

To what extent has the Equatorial Pacific been warming? It has been warming quite a bit since January 2014. Take a look for yourself.  

January 2014 SST's:

May 2014 SST's:

Look off the west coast of Latin America, wow at the difference!!

So...with all that being said, I think it is safe to assume we are looking at conditions in the Pacific progressing toward an El Nino. And by the looks of it, it has the potential to last through next winter. Whether it reaches "super" status remains to be seen. 

The ENSO is not the only thing we should look at when we are making a seasonal outlook. One important driver in our weather pattern this past winter was the EPO. It has been consistently negative (positive height anomalies in Alaska and northwest Canada) dating back to this past winter. I think it is a good idea to look into how that is progressing, as well as the PDO, which has been in a "cold" phase for what seems like an eternity (since 2010 to be exact). 

The PDO is no longer in a cold phase (hallelujah?) Over the last couple of months, it has made strides to staying in a warm phase, which means SST's off the Pacific coast are running above normal and cooler than normal in the interior North Pacific. 

Like I stated before, the EPO has been running consistently in a negative phase for quite some time, going all the way back into Fall of 2013. For the time being, I am going to go off the assumption that the EPO remains primarily negative during the summer months, especially for June. 

So when we look at past years, we should be looking for summers that dealt with a...

-EPO, +PDO, and a developing El Nino (+ENSO). 

After doing some research of the ESRL database, here is a list of years I came out with: 

1951, 1953, 1957, 1965, 1972, 1982, 1986, 1997, 2004, 2009 

Most of these years featured a -EPO, +PDO, +ENSO summer but some of them are extreme relative to others in terms of the intensity of all three teleconnections. What I did next was look at the SST anomaly maps of those years and see which ones I felt matched up closely to our current SST anomalies over the Pacific Ocean. 

Here is an example of why 1982 is a BAD analog year, in my opinion. 

While there is warming taking place over the Equatorial Pacific, the northern Pacific and northeast Pacific is experiencing below normal temp anomalies, which goes against our current observations of which we concluded is a -EPO and +PDO. Discard 1982! 

I am obviously not going to go through all the years with you, so here are my top 3: 

1957, 1997, 2004

1997 was a pretty extreme year with a raging +PDO and +ENSO. Take a look at its SST anomaly map from May 1997:

It matches closely with our current SST anomaly map (refer back to first image of this blog) when it comes to the areas of above normal and below normal SST's. It does not match intensity wise. 

Aggregating my top 3 years together, this is the temperature departure from normal map I come out with:

Looks a little...cool. I went to go check out the NAO for each of those years out of curiosity and some of those summer months in each of those years did feature a -NAO, a pretty strong one at times. The NAO is a wildcard as always since it could inhibit ridges from progressing too far eastward if there is blocking overhead of our area. 

Meteorological spring months temp. departures from normal indicate that the above map may not be THAT far off. 

March-April 2014

May 2014 (so far)

Is it just me, or do those two maps have similarities to the analogs map I created? The below normal regimes exist in the center of the country and above normal regimes in the west side. The east side is mainly around average with below normal intrusions at times. 

With all that said, here is my official outlook:

Temperatures

The persistence of the -EPO along with the developing +PDO will keep the western U.S. toasty this summer. Unfortunately there are droughts and wild fires damaging property and just making peoples lives miserable out there, so hopefully the pattern undergoes a change by mid-summer. Since I am expecting the western U.S. to be under the influence of ridging, I can see how an area of below normal temps. develop over the Great Lakes into the mid-section of the country. The northeast will see some temperature swings, but should stay around normal with less 90-degree days this year compared to last. 

Precipitation 

A lot of northern stream energy is going to find its way into our area this summer which will promote wetter than normal conditions, especially if blocking takes shape. We have seem some training storms already this spring with a couple of cut-off low's and trough's. There is a good chance this persists through the rest of this month and into June. By the time we get to July / August, we will have to monitor the tropics very closely. I can see a scenario where we are dealing with numerous extra-topical type of storms or developing low pressure systems off the east coast. The west-central U.S. and parts of the western U.S. will continue to bake and stay mainly dry. 

Please keep in mind seasonal outlooks carry a great deal of risk and are hardly 100% accurate. I focus more on trying to get the general "gist" of how things may play out. It has worked out well for me for the most part, so we will see how this one plays out. 

Have a safe and happy summer! 

Thanks for reading,

Francesco Paparatto 

*Please visit the NJ Strong Wx forum at www.njstrongweatherforum.com* 

Cut-Off Rain Storm 3/29 - 3/31

An impressive storm system is going to effect the Tri-State area this weekend into early Monday morning. The set-up in the upper atmosphere (500 mb) supports a long duration rain storm with frequent moderate to heavy rains which increases the flood threat, especially in areas where there is still snow / ice and if you live in a flood prone zone.

Timing:

Start: 12pm-1pm Saturday

End: 5am-7am Monday

This equates to 40+ hours of rain falling which when all is said and done could add up to 4+ inches of rain in some spots of the Northeast. Obviously the rain is not going to be heavy for 40+ hours. In fact, there may even be a brief break in the action before it starts up again. Nonetheless, we are still looking at a washout weekend with a potent coastal storm developing.

The 00z GFS 500 mb map by 2pm tomorrow is beginning to show a phase with the northern and southern stream energies in the atmosphere which will result in a strong surface low developing. By this time, rain is streaming up the coast into the northeast ahead of the surface low with the heaviest falling over Long Island. 

Fast forward into early Sunday morning, and now those energies have completely phased with the H5 trough now closed off. At this time, very heavy rain is falling throughout NY state, the northern tier of PA, NNJ, and NYC into LI. 

By Sunday night, the closed off low deepens with the H5 trough now going negative, prompting the coastal low to slow down and bring training moderate to heavy rainfall over parts of the coast from PA into NJ into NYC. 

What is happening here is we are seeing the effects of Atlantic blocking and what it could do to east coast storms. Throughout this winter, we have been in a relatively zonal flow due to a constant +NAO with only a north-Atlantic ridge trying to help slow the flow down. 

This time, the combination of positive heights into Greenland and eastern Canada have forced this storm to CUT-OFF from the jet stream and almost come to a stall off the coast of NJ. The good news is this will not be some 950 mb bomb of a storm that is bringing hurricane force winds to the area. It is expected to remain on the weak side with the worst of the winds along the immediate coast, where 30-40+ mph gusts can be expected. 

RAIN MAP

Region wide, we are looking at 1.50-2.50 inches of rain for the most part. In further assessment, I can see how red-shaded areas receive possibly more than 3 inches of rain due to the positioning of the stalling low pressure storm off the coast of NJ. Some pieces of guidance support this notion of sending bands of rain over this area which would enhance rainfall totals. Obviously flooding in NNJ near the rivers could be a concern, but I do not believe rivers are in danger of flooding since it has been pretty dry of late. However, that does not mean roads that flood easily will not flood. So please keep that in mind. 

Enjoy this miserable weekend, 

Frank

*Please follow www.njstrongweatherforum.com for the latest information.*

Possible March 25th-26th Coastal Storm

Mother Nature may be trying to end this winter with a big bang in the Northeast region of the U.S. with a possible coastal storm looming for early next week. Of course, a lot of uncertainty exists with the exact track of this storm, but I am confident that a storm will develop. Now it's just trying to figure out if it will be a storm for the fishes or one we will have to worry about, which would bring heavy snowfall and high winds to the area if it took a track close to the coast.

The above graphic is the 500 mb level 12z EURO model around Monday morning. 

One important thing to note with the setup for early next week is the sub-tropical jet stream (STJ) will be an ingredient to the evolution of the storm. A stream of energy will travel through the STJ and feed into the coastal storm. A poleward ridge in the west (+PNA) connecting with the ridge over Alaska (-EPO) will help bring down extremely potent northern stream energy which digs into the eastern U.S. and phases with the STJ energy to form the coastal storm. 

Moving forward with the 12z EURO, it closes off the H5 trough which allows the coastal storm to get pretty close to the coast, bringing moderate snow accumulations to the area. Any closer to the coast, this would be a substantial snowstorm with blizzard-like conditions given its extreme strength and size. 

The one thing working against a possible Nor'easter is the fact that there is no high latitude blocking, or         -NAO. Low heights continue to reign over Greenland which means the flow along the east coast is progressive. If the phase is timed correctly and a High Pressure system positions itself where the EURO currently projects it to be, there will be a storm along the east coast bringing snowfall to the region. That is a big if though and there still remains a lot of uncertainty with how strong the energy coming out of Canada will be, and how much interaction it has with the southern stream energy. 

The GFS and Canadian models also develop the coastal storm. The GFS has it well east of the area coast since it phases the storm much later than the other models. However, if you look above, some of the GEFS individual members show some pretty big hits and the GEFS mean itself brings .50-.75 qpf into the area. This is indicative to me that the GFS OP is playing to its progressive bias and it may eventually catch onto the other models and come further west with the storm over the weekend. 

The purple zone are the areas I feel are in line to see coastal storm impacts come Tuesday of next week. I do think there will be snow, but I am uncertain about how much will fall. Could be a coating to a few inches or it could be much more. Snow will not be the only thing to worry about, though. Coastal flooding and high winds will also be possible impacts. 

The blue zone may also feel coastal storm impacts but the phase will have to occur much sooner than where current guidance has it to be. This is definitely possible still, but with the progressive pattern along the east coast, I could see how only the immediate coast benefits from this storm. If the NAO were negative I would feel differently. 

Nothing is set in stone yet and the models have been pretty horrific of late. Just realize that the potential for a big storm is there early next week with very cold temperatures (much below normal for this time of year). 

Enjoy your weekend and follow along at www.njstrongweatherforum.com for the latest information

Frank

Possible Snowstorm March 12th-13th

There is growing confidence that a possible snowstorm will effect the Northeast U.S. mid next week as the ingredients needed for one to occur are beginning to show consistency on the models. It seems this winter has been relentless with the constant cold and frequent snowfalls. This type of pattern just does not want to let go. Not yet at least.

Most people have already seen this graphic since I posted it on my forum yesterday. The players involved are as follows: 

1. East-based blocking to help lock in the cold air over the northeast with the PV in northeast Canada. 

2. A ridge in the west to help the arctic jet s/w energy dive into the heart of the country and possible phase with polar jet s/w energy. 

3. A strong piece of s/w energy coming down the backside of the PV (polar s/w energy). 

The biggest question is...IF there is a phase...WHERE does it happen? If there is no phase there will not be a big disruptive storm. It would be a weaker storm with lesser impacts. A phase of the various short wave energies in the upper atmosphere would develop a potent storm bringing many impacts of heavy snow, rain, wind, and possible coastal flooding. 

As of now, the two most reliable models are saying YES, there will be a phase which will result in a big storm for mid-week next week!

When we take a look at the 12z EURO model run from today at H5, we can see the important pieces of energy coming together. The energy circled in south-central Canada is the polar jet energy, the one near the 4 corners is the arctic jet energy, and the one over Louisiana is the southern stream energy. There is triple phase potential with this storm (when all 3 pieces merge together and develop a monster storm), but that does NOT look likely right now. 

Guidance suggests that the southern stream energy will escape ahead of the other two northern stream pieces and shear itself out once it approaches the southeast coast. All pieces of guidance are showing this right now, but there does exist the small chance that they're handling the energy wrong. Right now, I am going to agree with guidance and say that we should only be focusing on the Arctic and Polar energies. 

If we take a look at the GFS H5 maps now, we'll see it has the same general idea as the EURO. The one blemish it does is hold back some of that northern stream energy near the Rockies which is why the storm system on the GFS is not as strong as the EURO has it. This is unusual because the EURO has a bias of holding back western energy, and the fact that it is not, tells me the GFS is WRONG in this aspect. You can also see how the GFS keeps the southern stream apart from the northern stream, so the phase only occurs between the Arctic and Polar energies (no triple phase). 

The result is a great looking trough on the east coast going negative and producing a potent Nor'easter bringing heavy snowfall to much of the northeast US, besides the Philly and DC Metro areas. Although the EURO / GFS are in somewhat of an agreement right now with a storm effecting the area next week, I am not sold yet on the track of the storm.

The 3 main global models used in the weather industry each show different tracks for the possible storm next week. A EURO / GFS track would bring plowable snow accumulations to much of the interior northeast including NYC Metro area. The Canadian model, CMC, is still not impressed with the setup and believes there will NOT be a phase (which I talked about earlier in the blog). It keeps the heavier snow accumulations in northern New England instead.

My current thoughts are there will be a widespread snowstorm for much of the northeast next week, but how far south and to the coast does the accumulating snow get? Since the storm is tracking from the Midwest and moving in a general west-east direction due to the Polar Vortex located to the north preventing the storm from cutting, even after it phases, it should bring a swatch of heavy snow to much of PA and NY state into New England. Those are the areas I think right now are in a prime spot to expect a snowstorm next week. The areas of uncertainty is along I-95 from DC to NYC (Boston will be cold enough to support all snow). If the PV trends further south, the track of the storm will also be further south and more cold air gets into coastal areas to keep precipitation in the form of snow. A likely scenario I see playing out is for the coastal areas to start as rain and gradually change to snow as the storm deepens and track off the coast, changing the direction of the winds. It is VERY possible that the changeover occurs quickly and much of the storm falls as snow and not rain for coastal areas too depending on the timing of the phase and location of the PV. 

We'll see how this plays out! Please follow the www.njstrongweatherforum.com to get the latest infromation on the storm. 

And for those wondering, winter will continue into the third week of March. But we are all warriors by now, aren't we? 

Have a great weekend

Francesco Paparatto 

March Roaring In Like A Lion - Northeast Snowstorm Early Next Week

The winter that never ends continues into March with a large snowstorm taking aim on our area once again. After taking a closer look at data this afternoon and getting a better understanding of how this storm will develop, I can confidently say another plow-able snowstorm will impact the northeast Sunday into Tuesday morning (March 2nd-4th). The worst of the storm is expected to occur throughout the day on Monday. 

One of the driving mechanisms bringing back the arctic air and the stormy weather is the MJO. This phenomena monitors convective storms that form around the world and is divided into eight phases. Phases 8-1-2 in the month of March, which is the current and foreseeable state of the MJO, bring colder than normal and stormy weather to the eastern U.S. This is one of the reasons why the drought-stricken state of California is finally able to see rain over the next few weeks. 

The MJO is not the only signal jump starting our winter pattern. The EPO, as has been the case most of this winter, is back in a negative state and trending even further negative (near -4 value) by this weekend. This means blocking in the eastern Pacific, including Alaska and western Canada has formed. Additionally, the AO is also negative which does not surprise me given the extreme negative state of the EPO and the arctic air mass we are currently dealing with and will still have to deal with for the next 10 days. 

Lets take a look at the players on the field and see how this storm is coming together. As I have already mentioned, we have blocking over Alaska and western Canada due to the -EPO. There is confluence caressing the U.S.-Canadian boarder with strong vorticity over the Great Lakes (will take a look at this later). Our southern short wave, which is progged to be on the weak side hence the flat-looking eastern trough, is in the southeast. One of the most important players, the Polar Vortex, will situate itself somewhere just east of the Hudson Bay in southeastern Canada. The question is...where does the baroclinic zone set-up? Areas north of this boundary will see precip. fall in the form of snow while areas south of it see rain. Areas located along the boundary could see freezing rain / sleet. Also notice near Greenland I say, "No Blocking?" Technically, this is true. However, there is blocking on the other side of the globe that has prevented the PV's this season from escaping northeastward which in turn would allow the southeast ridge to amplify over our area. 

It is called Scandinavian blocking (sorry for the typo in the graphic). Positive heights over Scandinavia, or a   -SCA, have helped force our PV's this winter to sink south into the lower latitudes of the globe and promote much below normal temperature departures. This feature is going to help keep the PV situated over southeast Canada for the storm early next week, though there is room for it to trend north-northeast if it wanted to. 

What are the implications of that? 

Here is the upper air anomaly graphic from the 00z EURO run last night:

The PV was modeled weaker last night than the 12z run today which allowed eastern heights to extend further north, allowing the gradient to get pretty far north as well. This is why the 00z EURO run last night showed significantly less snowfall for the I-95 cities compared to today's run. 

You can see on today's run the PV is stronger and heights are suppressed a bit more. It may not seem like it at a quick glance, but take a closer look and you will see this minor difference changes the projected track of the storm drastically. 

Another ingredient we have to consider is the vort energy located over the Great Lakes, as well as the strained out H5 energy along the east coast. Right now, the southern s/w energy is projected to be weak. But if the vort over the Great Lakes intensifies further, it could force the southern s/w to trend stronger as well which could raise QPF amounts across the board. Right now, .75-1.00 of QPF is projected to fall Sunday-Tuesday, but I could see how this gets up to 1.25+ in a widespread location. This would mean snowfall accumulations, with ratios, of 16 inches or more in some spots. 

The jet streak over Maine is also expected to be impressive Monday morning, which is when the heaviest snow is expected to move into the area. 160+ kts. could really fuel this storm some more as we try and get a better idea of where the best lift at the 700mb level develops. Area JUST north of the gradient area likely to see the heaviest snow rates (but probably not the best ratios). This is why when all is said and done, everyone should receive significant snowfall from this storm. 

The one thing we have to watch which is certainly plausible is the Polar Vortex continues to trend stronger on the models and begins to force this storm to our south, while also shearing it apart (less QPF). The GFS has remained the most consistent and has not showed such a solution, but the EURO / CMC runs today could be interpreted that way (the EURO because it took a big jump from its 00z run). 

As of now, this is the area I see getting hit the hardest with snow early next week. This is more of a EURO ENS / GFS blend with some instinctive feeling. One of the trends this winter have been for storms to make a last minute push back to the north and west, which is why Philly has seen a very nice season in terms of snowfall. Central Park, NY is only 18.5 inches away from breaking their all-time single season snowfall record and this storm could get them VERY close to that record if everything aligns itself perfectly. I also feel the lack of blocking over Greenland could bring the PV slightly further north than where the EURO / GGEM currently have it which is another reason why I like the GFS / EURO ENS solutions. 

A first call snow map will be released tomorrow afternoon around 6pm. Please follow the www.njstrongweatherforum.com for continuous coverage of this storm with the latest information!

Thanks for reading, 

Francesco Paparatto

Setting The Stage: Godzilla Snowstorm February 13th

Toward the end of my previous blog, I briefly mentioned that the period around Valentine's Day will be the next one to watch for a potential snowstorm due to the potent STJ energy entering the SW CONUS. Here we stand a few days later, tracking a major east coast storm to impact millions of people across the eastern seaboard. Although specifics of the storm for our area such as snow amounts, exact track, and timing are not set in stone yet, we should look at upper level maps and seasonal trends to try and help steer us in the right direction.

The above is the 12z EURO model run at the 500 mb level. By looking at the vort maps, we are able to see that the EURO closed off the H5 vort over central North Carolina. This model is the only model to close off H5 this early which is why it is taking a storm track right along the coast. Heights rise ahead of it and the storm tightens / strengthens much quicker. The region starts as snow, then changes to rain, to end as snow. 

In comparison, the 12z GGEM (Canadian) model does not close off H5 at the time the EURO does, but the energy at the base of the trough is much stronger which still raises heights off our coast to promote a storm track tucked in west from the benchmark. In fact, the GGEM really explodes this storm system and brings crazy amounts of both snow and rain to the area. Of the three global's, the GGEM is the strongest one. 

The GFS also does not close of H5 as early as the EURO model. However, this model has struggled greatly with the synoptics of this storm because it has been shearing energy from the west side of the trough which strings out the low level center a bit. The mid-levels fall apart and the surface maps begin to make no sense with a 980 mb low off the coast with not much precip. to show for it.  The GFS has made strides to the other models, but at this point, I think it should be disregarded until it straightens itself out. Heights are also flatter along the east coast compared to the GGEM/EURO which is why the GFS tracks this storm right on or just east of the benchmark. 

A common theme you will find in all of these models is that it does warm temperatures up enough to change snow to rain for some locations, including NYC Metro. This is where the forecast becomes tricky. 

Here is another look at the 12z GFS model. One thing you will notice is that there are two areas of High Pressure surrounding the northwest and southwest quadrants of our coastal storm. The first one is north of Maine, which could help provide us with cold air to prevent snow from changing to rain. The second is along the Gulf coast. The third piece we should pay attention to is the potent clipper in the Great Lakes region. One of the many things I am keeping an eye on is if those two anomalies are providing too much subsidence for our coastal storm to really deepen and bring moderate to heavy banding over our area. Vertical velocity at H7 (frontogenesis) is not going to be impressive if those two pieces are there to disrupt the evolution of our coastal storm and preventing it from amplifying. This could be one of the reasons why the GFS has a funky look to it and I definitely think it should be monitored. 

Another important factor to look at is to see where the 700 mb and the 850 mb low's close off. The Canadian model, for example, vertically stacks each of these low's inside the BM which is another reason why it outputs such an extreme scenario. 

For example, 

12z GGEM 700 mb

12z GGEM 850 mb

One other factor I am considering when trying to forecast this storm is the seasonal trend. We are now in mid-February and have a good idea of how the storms this season have behaved. None of them had a storm track inside of the benchmark. Most of them remain south and east of the benchmark and brought the heaviest precip. amounts along I-95 and points east. I'm only mentioning this because the GFS / NAM models are not sold on the idea of having a storm track hugging the coast. I can see why with the lack of blocking (-NAO) and areas of confluence to the west of the storm why those tracks could be justified. 

How all these factors evolve will determine how this storm plays out along the NYC Metro area. Consistency is there that a long duration event is likely to begin early Thursday morning and continue into Friday morning, possibly a 24-hour + storm. It is certainly possible Blizzard criteria is met and watches / warnings are issued for the area, but that will not be realized until the factors I mentioned above are known. 

Here is an example on the extreme side of what winds at the surface could look like for our area. This is from the latest 18z NAM:

With all that being said, here is my 1st call snow map with this storm system likely to be changed again tomorrow. But I wanted to put this out there so everyone can get an idea of how I view this storm panning out. I do think the GGEM/EURO are a little too far west right now. While they have been consistent, we cannot ignore the consistency of the GFS/NAM either. The UKIE was also a little more east today at 12z compared to its 00z run. A lot depends on when exactly H5 closes off. I think it will happen along the coast of NC or SE VA, not interior Mid-Atlantic like the EURO shows. 

My current thinking feels the models tonight into tomorrow will begin a trend with this storm system a little further east. I think a track right along the benchmark is fair to say at this time because of some of the factors I mentioned throughout this blog post. If the western most track comes to fruition, the heaviest totals will have to be pushed further west and lower amounts will occur along the immediate coast due to mixing. At this time, I do not see that scenario panning out but this is a high volatility forecast. 

Temperatures Thursday morning, the time the storm is expected to start, are only in the low to mid teens across much of the area. Couple that with a possible High to the north and evaporational cooling from our current snow pack, I think models also have a good chance of trending colder with this storm once the dynamics are realized. There is a lot to digest here. Extremely complex set-up. 

Thanks for reading, 

Francesco Paparatto 

*Please visit the www.njstrongweatherforum.com forum for continuous discussions about this impending storm*

What Happened To The 3-Foot Blizzard February 9th-10th?

Sometime last week rumors began to fly that a monster blizzard will impact the northeast this weekend. Since that social media uproar, I have been asked repeatedly what my thoughts are and whether or not I think it has merit. In this blog, I will give you my point of view on the manner by diagnosing the overall pattern. As we all know, it is the pattern that brings us storms, not the models themselves (if so, I would take the DGEX any day of the week, twice on Sunday). 

Remember two mornings ago when we woke up to find the 06z GFS model show this?

A 980mb low off the coast of NJ bringing blizzard conditions and dropping 1 to 2 feet of snow in the area. Soon after, the models suddenly lost that idea and trended to a much weaker one. The reason for this was because they have changed the way the upper level pattern comes together for the upcoming weekend. 

Here is the same 06z GFS run from that morning now looking at the 500mb vorticity map. You can see the beautiful trough in the center of the country working its way eastward as it attempts to close off, with a nice +PNA ridge spike in the western US and a nicely placed 50/50 block south of Greenland. This particular run of the GFS phased both the northern and southern stream energies way back in the western U.S. as they were both coming ashore. The confluence over the northern tier of the country is preventing the phased-out storm from cutting north, so it has no choice but to reach our coastline. 

Now, the upper level maps look different. But not by much! 

Here is the 12z EURO height anomaly map at h5. The overall pattern is actually conducive for storm development along the east coast. There is our everlasting -EPO ridge providing Pacific blocking, the 50/50 block near Greenland that I referenced from the 06z GFS map, and a block (AGAIN) in the Bering Strait. I say "AGAIN" because this block was also there for our January 21st storm last month and it helped force a phase along the east coast to develop the storm. The ONLY thing missing from this map that was existent on the 06z GFS map is the +PNA ridge in the west US. It is much more flatter on the EURO (and every other model now). 

1. The western ridge helps dig the western energy on its eastern flank and helps in amplifying the trough on the east. 

2. The 50/50 block near Greenland as well as the Atlantic ridge will help hold everything downstream in place to try and get this storm to form. If a storm does develop, it would be a slow mover due to the traffic of storm in eastern Canada (something we have not really seen so far this year). 

3. The piece of the Polar Vortex over the Hudson will prevent a cutter and help usher in the cold air mass. 

4. The Bering Strait block is showing up, and I think in the end it could benefit us once again like it has before this season. 

5. The -EPO has been there since the get-go, bringing down arctic air masses and intense short waves. This time, it could possibly help kick that northern stream energy into the CONUS and also help in ushering in the cold.  

Looking deeper into the 12z EURO vort maps, we will examine the micro version of the overall pattern. By Thursday night, both energies associated with developing this potential storm are coming ashore from the Pacific Ocean. You can see I have both circled in the image above. There is a piece of our PV over the Hudson Bay, confluence from coast-to-coast, and the 50/50 block. 

SO, as I bluntly state at the bottom of that image:

ALL THE PIECES ARE THERE

The big storm idea may have disappeared, but the setup has remained the SAME. 

Advancing to Saturday morning, you can see both pieces of energy are well far apart. The Sub-Tropical Jet stream short wave has zipped ahead of the Polar energy, and the overall look of the image is flat. The trough is obviously not as pronounced and the western ridge is non-existent (remember the 06z GFS phased both those pieces of energy together and it had a western ridge). One thing I question is immobile Polar energy and why it just sits there. It could be because of the lack of ridging, but I would still expect it to track into the CONUS. 

Continuing on into Sunday morning, we are left with a very elongated look of the short wave energies since that Polar energy continues to remain stationary over the Pacific NW. An inverted trough develops from the southern stream energy and there is some phasing from the confluence which enables light snow to overspread the area. 

The 12z Canadian model also looks similar to the EURO in respect to the short wave energies and the confluence in the CONUS. You can see the phase is not that far from happening, but we need a pulse from our west to help bring down that northern stream energy out of the Polar Jet and phase it into the STJ. 

My Thoughts:

1. Regardless of how latest guidance is playing out the storm, nothing has changed with the players involved to bring a large storm system together. 

2. The energy is still out in the Pacific and proper sampling will not take place until 06/12z model runs FRIDAY MORNING. 

3. That lead vort (southern stream energy) needs to slow down to allow the northern stream energy to catch up (even if it's not the Polar jet energy, maybe we can get a piece of the confluence to phase into it instead).

4. I want to see the ridge in the west come back (+PNA) because I think that's important for an amplified trough in the east. 

5. The Bering Strait block is important because usually blocking is under-modeled and if it turns out to be stronger, it could force a phase. 

6. I sincerely believe we will see a moderate snow event (at least) Sunday into Monday. I feel like the models are going through their usual games. The pieces are there and I think enough of them will come together to bring us something substantial. Will it be the full blown 2-3 foot blizzard? Probably not, but I can see another 6"-12" type of event on the table with the potential for something greater. 

To be honest, the models clearly show the storm off the coast since that southern stream energy is strong to begin with. What we are looking for is a trend back to the west. The fact that they did not even totally lose the storm is encouraging in itself. You can not expect these models to show run after run of MECS/HECS's along the coast. Of course they're going to run into inconsistency. Right now, they're showing widespread 2-4 inch type of snow amounts. I think by Friday, once the energy is sampled, we will have a MUCH better idea. 

Valentine's Day Storm?

I'm not just bringing this up to save my ass just in case the storm this weekend does not come to fruition. Guidance is showing a lot of short waves entering the US next week, including another potent STJ energy. Hey, somethings gotta give, right? What I want to mention briefly here is we are losing our -EPO (not sure yet whether this is permanent or temporary), but we may be heading into a -NAO period. The Stratosphere has warmed and I think (hope) we have reached our lag period and the Atlantic begins to re-invent itself from what we have seen thus far. In conjunction with the -NAO, we could also be looking at a +PNA. The two together could bring us formidable storms and I think that could be in the cards mid to late next week! If this does turn out to be the case, you can be sure I'll make everyone aware of it. 

Have a great day! 

Francesco Paparatto 

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