Monday: Welcome to Winter, Tracking Weekend Storm Hype

Good morning. I say welcome to winter because our pattern change is now noticeably underway.We had our first real cold weekend of the winter and there is going to be a lot more were that came from over the next several weeks.

Today I will be focusing on a potential storm threat for this weekend. There has been alot of hype on the internet and the weather bot apps (as I call them) have been showing heavy snowfall. Is any of this true? 

At this time at storm is coming this weekend, but I am skeptical if there is enough cold air ahead of it to bring snow down to the I-95 corridor and south. From what I am seeing, the interior may be favored with the setup. 

I will explain below...

We will start this week with fairly seasonable weather with highs in the mid to upper 30's. The story starts with a light to moderate low pressure system that sweeps through the area Thursday night into Friday...

With this system, a few inches of snow will fall in New England and potentially as far south as NNJ and PA.

This is an important storm system for our weekend threat as depending on how this develops has a lot to do with how much cold air is available ahead of the weekend storm...

Above is the cold air in the wake of Friday's system. Notice it is draped over the Mid-Atlantic with a low pressure center developing just to the Northeast of Texas. How established this cold air is is key to where this low pressure center to the Northeast of texas tracks. 

The low or storm will want to form and track along the natural boundry of warm and cold arctic air seen below...

The question is however, where does this boundary set up. It is more to the NW , SE? That determines where the winter precip is and were the rain is. The cool thing here is to the west of this boundary there is true bitterly cold arctic air in the single digits! That would mean who ever sees snow its is a cold powdery snowstorm. My favorite type!

Looking further up in the atmosphere here are the major players on the field to develop the weekend storm to ride along where ever this boundary sets up...

Notice how we have a lot of energy on the field from the pacific and true arctic (north pole) energy and air potentially combining with it. One of the bigger factors that will determine how these two circles interact will be how much blocking or high pressure forms near Greenland which  does have a lot to do with how that moderate storm on Friday behaves. See how this is all connected?

The stronger Friday's storm is, the more cold air it pulls in which as I mentioned sets up that boundary or front for the storm to ride along.

On the other extreme end, if the cold air arrives ahead of the pacific energy then we get a suppressed storm out to sea. So as always guys this is never easy.

So lets get to what may happen here.

The American and to a certain extent the European model are bullish on a major snow event for just NW of I-95 into New England Sat night into Sunday...

You can see the low riding that boundary up the coast.

Now the Canadian shows what happens if that boundary is not established properly...

More rain due to storm cutting more west. I don't think this extreme occurs but I do think the solution lies in the middle based on this setup.

Due to the fact there is no major blocking to lock the cold cold air in ahead of the storm, here is the impact zone I would expect based on analogs or historical setups that looked similar...

The hotter the color the more likely for snow. Translation, at this time the focus is more NW of I-95 and big cities.

More to come on this.

Friday Update: Light Snow for Most Sunday Morning (South)

Good morning. Confidence is now very high regarding Sunday's light snow event for most. There will be a sharp cutoff in seeing any snow to the north so do not get excited if you live anywhere north of CNJ. The most accumulating snow will be in the Delmarva region with this.

No need to make an updated map as this isn't a big enough event to take the effort to do that (I have a day job too). This model printout makes sense to me below..

For the most part expect up to an inch in SNJ and up to a few inches to the south and west of SNJ with this. Most of the snow falls early Sunday morning. 

This storm if you even want to call it that is then over by the mid morning.

This did not amplify how I thought it could earlier in the week. That has been the tune of this winter so far.

In terms of the long range, the data looks great for a major pattern change that is actually starting now. However, there is data and there is reality. The reality is if we do not see a notable snow event before the end of January the winter is a bust in my opinion. No that doesn't mean it can't snow a lot if February, it probably will. We may even see an active march. However, based on my winter forecast January needs to be an active month. Only a big storm can save the day. That is not out of the question given the upcoming cold and stormy pattern but I am not going to lie is has been a frustrating winter.

Lets see what happens. 

Thursday Storm Update: Details Becoming More Clear

Good morning. We are now 3 days away from our potential snow event for some folks which means its time to try to nail out some details. Overall this storm looks to effect our southern zones and just breach by our northern areas.When it is all said and done a moderate snowfall is possible for areas in the Baltimore/Washington and south Jersey regions. To the north there will likely be a cut off.  

The timing of this is Sunday to Monday morning. There looks to be an initial wave of light snow Sunday morning then some more moderate snow for the southern zones Sunday night. I will be ironing out this detail in the next several days.

Here is my preliminary impact map. This will be updated and filled in with more details in the coming days as I gain more forecast confidence. For now its my best estimate of where impacts will be...

I took a middle ground with this map. There are scenarios were I can see this shifting north or south (Which would produce a very light non event).

Lets now take a quick look at the forecast details.

Models are now starting to come into more agreement on a low pressure system that passes to the south of the region...

When I took a look at this setup earlier in the weak it really gave a strong signal for a storm and many factors I liked to see were on the field. Here was my original image...

Good ridge out west, vortex over eastern Canada, energy diving down into the country. All big precursors to a storm. 

Where the wrench got thrown in is with that vortex in eastern Canada being too much of a good thing. It stubbornly drifts too far south which causes the developing storm to sheer off.

For example, by Friday this setup looks great...

Ridge out west, alot of energy looking like its going to consolidate and form a storm...

At this time frame it looks like the big one is approaching. However, due to that vortex drifting too far south, it starts to sheer off the storm, a result of High pressure that is too strong....

Looking above you can see snow is cut off to the north due to too much high pressure. Think of the storm development as being squashed.

The jet stream shows this best with a big area of confluence or air coming together too far south over southern New England (Seen in red)...

So this prevents the big storm from forming and walloping the eastern seaboard.

However, it is not over yet. After an initial wave of light snow that breaks up Sunday morning. Round two is were most of the snow should fall in my target zones. In fact, there till is a chance that we can see further development of a round 2 wave effecting areas more north.

Here is what I mean...

Looking above you see energy in the jet stream and its 4 run trend from the GFS model. This is valid for late Sunday night. Notice how the trend is to sharpen the energy a little and pull it back west. 

This is resulting in a stronger surface low developing Sunday afternoon/night after the initial batch of sheered off snow Sunday morning...

This is the trend we need to watch closely next 2 days. If this energy continues to sharpen further, it would mean the storm is even closer to the coast than I think and this turns from a moderate to a heavy event. It also would mean areas to the north see more snow.

I try to always look were things might go not where they are. 

So thats it for now. There will be frequent updates to come. 

Wednesday Update: Weekend Storm Threat Still Uncertain

Good morning. As the song normally goes we still do not have much more clarity on this weekends storm threat. Today has always been my benchmark day per my previous posts and videos. That means I will be making a preliminary call on this tomorrow morning regarding if how and where this storm will impact folks. 

As of now models are more south compared to my thinking...

Notice the low pressure slides to our south. The reason this is south on the models is due to the upper level energy getting more strung out due to the western ridge not being amplified enough...

The result is the energy to the east of the ridge being too flat. We need to see if the models handle this differently. Any sharpening of that ridge moves this storm north. Given we are 4 days out that is certainly possible. It is usually in this period that we see of this goes boom or bust. 

I think by tonight model runs we will have a better idea of how all this energy is handled. This should give me enough information to make an initial call on this tomorrow. 

For now, I am keeping the moderate chance of a storm for Sunday.

Stay tuned. 

Tuesday Evening Update: Taking a Look at Weekend Storm Potential

Video below discusses my updated thoughts for Sunday's storm threat. As always, nothing set in stone but I think we got a shot here. Enjoy, more tomorrow. 

Monday: Pattern Change on Track, Snow this Weekend?

Good morning. Everything I laid out in my prior post regarding the pattern change so far is playing out as expected. Long range models are now showing a flip towards a sustainable winter pattern within 10 days.  This pattern then has the potential to last well into February. Winter is coming!

In addition to this, we also now have to watch later this weekend for a potential storm. As always, details are unclear but there will be cold air in place and some signals suggest snow on Sunday. I have upgraded my Winter Outlook index to a moderate threat for this period. I will be discussing this more below.

Staring off, this week will feature more seasonable weather for most of us and much needed snow returning to the mts of New England...

Notice how tomorrow morning some snow/ice is showing up for NNJ. Be careful as roads can be slick for tomorrows commute.

The focus however is New England and the mtns continue to see snow as we progress through the week...

When it is all said and done I expect around a foot to fall for the central and northern ski area peaks by the end of the week.

Then we turn to the weekend. This departing low pressure system that will cause the snow in New England is a key feature...

When I see a vortex of low pressure develop in this region, it is a signal to me that there is a mechanism to lock in cold air along the east as seen below with cold high pressure...

The consequence of this is to favor a better chance at snow for any storm that wants to develop behind it. Of course for a storm we need other factors to come into play. Those factors are on the field, it just is a matter of if they come together...

Looking above I labeled a few areas. The vortex of NE Canada to lock in the cold air and aid in blocking the jet stream. Two pieces of energy that need to come together and a western ridge.

Just because these factors are on the field it does not guarantee a storm, but it certainty increases the chances as those two pieces of energy are more favorable to come together in a setup like this. 

The models are all over the place. The GFS has a snowstorm Sunday..

The European is flatter and out to sea...

Its ensemble system is more west...

Bottom Line: Nothing is set in stone but we have enough evidence to monitor a potential winter storm for later this weekend. By Wednesday we should have a better handle on some of the key details I discussed. Stay tuned!

Wednesday Pattern Update: Not Giving Up

Good morning and Happy New Year! I know by now everyone must be giving up on winter. After all, why not. It has been a mild and snowless December with frequent rain. As the calendar strikes January 1st there seems to be no break in this pattern. Naturally, the normal conclusion would be winter is over. 

However, I cannot make that conclusion at this time. No, its not because I just love the cold and snow and am biased, but its because the data I am looking at will not let me. Sure, when it is all said and one I can be wrong and this mild pattern holds for most of the season but I really do not think that will happen based on a few main things going on.

At this time,  think we have 10-15 more days left of this mild pattern then things flip by mid-January to cold and stormy. If by then nothing does change then yes you will see me throw in the towel. But until then I am going down with the ship on this if it does not occur.

The main factors I am looking at are:

• A major stratospheric warming and polar vortex split that has just occurred
• Thunderstorms in the tropics projected to move into a more favorable place for colder air on the east coast
• My seasonal analogs

Staring off, we just have begun to see a split of the polar vortex way up in the atmosphere. To keep things simple, the polar vortex is a semi permanent area of low pressure that sits over the north pole in the winter time. When it is strong the cold air tends to stay locked to the north. When it weakens due to warm air breaking it up, it tends to result in that cold air funneling south to the lower latitudes. This process does not happen over night and usually happens 2.5-3 weeks after a warming and or split occurs.

At this time a split just occurred. Notice how the vortex has split into 3 regions...

Remember this is way up in the atmosphere so it will take time to work its way down to the lower levels and have an impact on our weather. However, the implication of this can be major. Based on where the vortex as split it favors seeing very cold air develop over the regions I circled and high pressure over the region in red which is the north pole. When you get high pressure over the north pole it causes cold air to drill south. Something not to ignore for sure

Secondly, we have our thunderstorm pattern in the pacific (MJO pattern) projected to move into a more favorable region. This is very tough to predict by models, but based on where they are placing these thunderstorms it should produce a pattern like this based on historical cases...

Thirdly, we have my January forecast per my winter forecast analogs...

So there is my logic but what do the long range models say?

In the short term our mild pattern continues with pacific air moving in due to low pressure off the west coast south of Alaska...

Based on the three factors I laid out above, this circled region should flip to high pressure which will block off pacific air in 10 to 15 days.

The GFS model starts to show that...

The Canadian model is similar but the European is not showing this...

So there is the chance I am wrong here. But again I can not just look at one model and ignore those other factors.

We now are going to have to wait to see how this plays out. Like I said, if by mid-Jan nothing is happening I will be the first to throw in the towel. Right now, at least I laid out my case why I still refuse to do so.

More to come.