Feb 9-11 th time period

As we have been watching these models and observing this time period …the question has been whether or not there is going to be a storm and if so what areas are going to be effected….

We had mentioned that because of the history of the past storm ..how we would not be surprised to see this trend further N & W in the short range at 48 hrs and under.

So lets look at what is been happening….

00z GFS ensemble means

Versus 12 Z means same time period

Interestingly enough the 12 Z means have actually trended more N & W and have the .10-.25 range of QPF now into and almost up to Central NJ and not that far off from Philadelphia.

Lets look at the GGEM now from last night at 60 hrs

Notice how the low pressure is well south of hatteras?

Now lets look at 12 Z at the same time period..

Interestingly enough the GGEM has also shifted N and W with the system and its moisture associated with it. Add on top of that the European Computer Model…at 48 hrs

Now the ECM has also come more west with the system and it brings very light QPF into SNJ & DE.

So all these models have one common theme in order and that common theme is that they have all come more towards the NW with the system & its QPF…

Now..by all means I am not saying that we are going to get a storm out of this system..Most likely scenario is this will slide out to the south and the east but folks in the southern areas perhaps MD into SNJ will have to keep an eye on this system. There could also be more of a trend to the NW.

The reason that I am bringing up this possibility of a more NW trend is because at the present moment the modeling is in 100% agreement with position of the surface low with the 12 Z Nogaps.

We know that the NOGAPS has a notorious south and east bias and majority of times if it is in the same location as the other global guidance it is usually an indicator that the global guidance will correct itself more to the west.

The NOGAPS at 12 Z actually has the precipitation stradding the PA/MD border into CNJ at 42 hrs out.

Keep in mind until today the models had this storm sliding south and east much further to the south then what it is now.

So while a few people were accusing R.W.S of wishcasting that this would come further to the N & W that very thing is actually taking place.

We will continue to monitor this latest system and when it comes closer we will also begin to nowcast this system as well.

Some Nowcasting In reference to Current Storm

As you can see by looking at this image above you can see that the primary low is actually over the WVA/VA border. What this is doing is sending a dry slot right up thru PA which you are beginning to see if looking at radar.

Basically we have very weak reflection of a secondary low while the primary remains west and stronger.

What this means is on the previous map issued the eastern side of the area will be lucky if they see any precipitation turning to snow. From East central PA south and east it will probably end as rain and in the next couple hours. NE PA should be seeing snow now but also it should end within a couple hours. Central and Western PA is seeing snow now and western PA should continue to see snow longer cause they are NW of the primary area of low pressure..

We will watch the moisture to the west over W VA to see if that moves east but current thinking is that should pretty much weaken once the coastal does get going but it will generally not be in enough time for eastern PA the way it looks at the present time.

Keep this in the back of your mind as to how far west this actually has come once again because 2-3 days from now another system will be monitored which is suppose to go south and east of the region…

3:30 AM ..Some precipitation is moving towards the region from the west ..it should be very brief…it should be mainly in the form of rain from E Central PA south but it may change to snow before it tapers off…

Feb 7-8th Final Call

As it has been the general case this latest system looks to be taking a more western track with the primary low currently located on the TN/KY border across the East Central area..

Current steering currents are such that this should take the primary pretty much near the PA/MD border around Western MD. The question from there becomes which way does it then go? If past indications are any judge of future movement the primary should actually proceed NE thru central PA.

Temperatures ahead are on the mild side so all areas will generally start off wet. There is a cold front moving across the region as well. As this cold front moves across this should change wet to white along the western viewing areas but on the eastern side..again it becomes a matter of wintery mix and what QPF is left when the cold front moves thru? So snowfall totals on the eastern side have been lowered…

We will continue to monitor this situation….

Feb 7th and 8th Preliminary Map

High pressure currently in control will start to give way to a low pressure area that is developing over SE TX currently…At the same time there is a low pressure that i just south of Lake Michigan. The low pressure to the south will start to lift off towards the NE while the low pressure south of Lake Michigan will move ENE. Meanwhile another area of low pressure further south in the GOM will also begin to lift off towards the NE and these three areas together will bring our next shot at precipitation to the region. Generally expecting at this point and time about .25-.50 liquid equivalent across majority of the region.

Wintery Mix to perhaps some snow will generally occur along the coast. Further inland …we should be cold enough to be primarily snow but in the beginning depending on the arrival of the precipitation it could start off as a wintery mix as well but then change over to snow relatively quickly. It is these areas where we expect the heaviest snowfall to occur and then further to the NE where the storm should deepen more and the QPF could be slightly heavier. In this region it should also be mainly snow with the highest amounts of 3-6 inches.

This is a preliminary map at this point and time and if things should change..we will certainly update this image before the event would begin.

Timing across the eastern regions mainly looks to be after 6 PM on monday night…

Stay tuned for more information on this system!

Let Me Be Perfectly Clear About Something !

This is in reference to the time period around the 10th of the month and in reference to being called a wish caster. Majority of your storms this winter season have all trended NW within the short term at 48 hrs and under. We see this clearly with the last system where the professionals were calling for snow to begin and changing to ice …while we had stated from the beginning that this would start off as ice and any snow would come in on the backside if there was enough left over QPF. What was the result of this system? It came so far NW that it cut thru western PA and then moved to the ENE from there. No model actually showed this occurring and the closest one was the UKMET.

How about the monday and tuesday storm? I already showed how this was also modeled to be to far to the east in the medium range..

And now the 12 Z GFS at the same time period from today..

Another case of where the models have trended NW in the short term. Why is this? Because they recognized now that the trough was going to be sharper then what it once believed..

Matter of fact the 12 Z GFS is the exact same solution as the 12 Z Nogaps..

Pretty interesting huh?  What about the system before this last one that dropped the ice? The one that dropped basically a foot of snow on the region? Was this also not modeled to far to the east in the medium term?

What happened as we got closer?

We came further west. Matter of fact this was the storm system that ABE was only suppose to get 4,3 inches from and we ended up with 11.6 inches and the professionals had to keep upping the totals and they still ended up well short with the final call. We could actually take this NW trend even further back but then we are talking about a completely different pattern…

The moral of the story is the pattern has been one in such that the models have not picked up on this west trend till the short term ranges..

Now what pattern are we in and when is this pattern expected to change?

The arctic oscillation is currently positive and is expected over the next seven days to drop towards neutral…This generally has been resulting in seasonal temperatures because you do not have a strong negative AO. When you have a strong – AO then you are looking at a stronger push of colder air.

NAO is positive and over the next seven days is going towards neutral. Once again ..there is not a strong negative NAO in place so …usually when you have a strong –AO + NAO in place you are looking at systems potentially suppressed to the south and the east because the cold air just crushes these systems in the southern stream.

What about the PNA?

PNA is neutral and over the next 7 days is trending towards the negative. Remember it is a positive PNA that is responsible for developing a trough along the east coast and ridging out west.

However..we can still get ridging to occur out west if we have a negative EPO. So do we ?

What happens with a negative EPO is two fold. One the stronger it is the more ridging to the west. As you can see when this system would be developing in the GOM ..we actually have a negative EPO of about –2.

The second thing that this does is it creates a SE ridge..

We see this in place at 78 hrs on the 18 Z GFS..

However..by 84 hrs the model literally pushes the SE ridge away with barely a surface reflection of a low at 1016 mbs.

Essentially all models are relatively in agreement that this system is going to stay off to the south and the east. The reasons why?

1. The trough never becomes sharp enough ..so this allows the system to slide south and east.

2. The pattern change AFTER this storm..

Why at this point and time am i staying consistent with my thoughts? 

1. Models tend to under do the Southeast Ridge and break it down to soon. This recent time period is generally the first time we have seen an influence from the SE Ridge.

2. When you have a negative PNA this causes higher heights along the east coast. This could cause a further west track…

3. We have seen multiple times in past weather seasons where the Polar Vortex was modeled to be too strong and too far south or to elongated…in the shorter term this proved to be wrong in the medium term ..not always but often enough to make one think. This is the reason of why the push of cold air is so strong. What happens if that is wrong? Higher heights along the east coast.

4. A negative EPO with a Southeast Ridge would not be penetrated by a weak surface reflection of 1016 when the high pressure is stronger by 10 mbs.

5. Majority of the systems this season have trended back towards the NW when it came to short term range of 48 hrs and under.

Now, one can say that this is wishcasting ..however..the results are clearly documented and shown above and majority of us know what has occurred this season.

So lets see what the professionals are saying …

THE ECMWF SHIFTED IN THIS
DIRECTION LAST EVENING AND THE 12Z CYCLE MAINTAINS THIS SCENARIO.
THEREFORE, THE MODEL CONSENSUS IS FOR NO REAL STORM NOW FOR OUR
AREA THURSDAY. HOWEVER, WE HAVE SEEN SEVERAL TIMES THIS WINTER
THAT AS WE GET CLOSER TO THE EVENT, THE MODEL GUIDANCE COMES BACK
NORTHWESTWARD WITH THE STORM TRACK. WHILE THIS COULD HAPPEN AGAIN
WITH THIS SYSTEM, THERE ARE A FEW THINGS AGAINST IT. FIRST, THE
BROADNESS OF THE UPPER-LEVEL TROUGH AS WE WOULD LIKE TO SEE MORE
SHARPNESS TAKING PLACE AS IT NEARS THE EAST COAST. SECONDLY,
FOLLOWING THIS STORM THERE IS A PATTERN CHANGE FORECAST TO OCCUR.

The above is from MT Holly… It appears to me that they acknowledge what has happened prior and that this could happen again…however..they outline the reasons why the models “could” be on the right direction as well. 

Lets see another agency which is HPC

CONSIDERING MODEL VARIABILITY
OVER SEVERAL SYSTEMS THIS WINTER...GUIDANCE TRENDS ARE NOT SET IN
STONE...BUT DO BECOME HARDER TO REVERSE AS LEAD TIME SHRINKS
TOWARD SHORT RANGE TIME FRAMES.  ACCORDINGLY AND CONSIDERING
CONTINUITY...HPC PROGS REMAIN PRIMARILY DERIVED FROM THE 12Z/05
ECMWF ENSEMBLE MEAN WED/THU...AND A HINT OF THE GFS.  THIS OLDER
ECMWF MEAN TRACKED SYSTEM SWATH SLIGHTLY MORE TO THE LEFT THAN THE
BULK OF NEWER 00/12 UTC MODEL AND ENSEMBLE GUIDANCE AND TRIES TO
INCORPORATE ANY LINGERING POSSIBLE EFFECTS FROM ANY SYSTEM
EJECTING OVER SERN US RIDGING ALOFT.

HPC also acknowledges that things are not set in stone and actually have the system tracking up the coast to the left of model guidance. 

In other words these agencies are looking at the guidance and then taking weather history and climo into consideration and putting out a forecast. While doing this they are saying that a NW trend is indeed possible but not a certainty…

It seems to me that they are saying the same thing as i am as far as the potential for this to come back further to the NW in the short term. There reasoning boils down to past weather ..which some want to say is irrelevant..interestingly enough it has relevance with the professionals.

So..what we are going to do is we are going to continue to monitor the guidance over the next 24-36 hrs and see what changes take place.. In the mean time..we are not going to change our thinking that this could come further NW in the short term. To clarify short term is 36-48 hrs and under. 

Its not like we have not seen this happen recently so its not out of the realms of possibilities of happening again.

Now..what is even more interesting is the same people that accuse me of wishcasting etc and constantly put down the Nogaps etc..do not realize that thus far the NOGAPS has been consistently showing this system to be further to the south and the east..So if this indeed does end up missing the region….well….I think where this is heading is clear .

We will continue to monitor this time period & continue to update this every 24 hrs..

Next up in the next hour is what about Monday and tuesday? 

Folks Its All About The Pattern & Persistence Is Key!

I can not stress enough that if one follows the pattern that is in place then one can generally have an upper hand on what one can expect. Specifics are always going to be a bit more difficult compared to what one can expect when one recognizes and understands the pattern that is and has been in place for some time now.

So we are going to reflect back into what pattern has been in place for sometime now…

The AO is above…one can see that at the present time the AO is positive..expected to head towards neutral but then stay positive…

Whenever you have a positive AO the air mass involved is not supportive of deep cold or arctic air…

North Atlantic Oscillation is positive expected to stay that way in the near to medium term before heading towards neutral. Again when you have a positive NAO cold air is not as abundantly supplied if it were a negative NAO. Neutral NAO would be slightly more favorable cause it would allow colder air that is available to tap to bleed somewhat into the 40 N region.

What about the PNA folks? The PNA is neutral currently and forecasted to head into negative territories. Positive PNA indicates a trough along the east and a ridge along the west. We do not have a positive PNA but rather a neutral PNA. This neutral PNA can be compensated and made up for however by a negative EPO or Eastern Pacific Oscillation. We do have a negative EPO coming into play currently and for this time period ahead in reference to the 9-12th. However..there is also a catch 22 when it comes to a Negative EPO. While a negative EPO can send ridging into Canada and compensate for a neutral negative PNA in creating a trough along the east it also places what is known as a Bermuda High or a SE ridge along or off the SE coast. This is a strong area of high pressure located near bermuda that extends westwards to the coast.

Typically speaking a low pressure area unless it is a very deep area of low pressure can not shove into a Bermuda High or SE Ridge…so the low pressure will take the path of least resistance…Since there is a SE ridge in place (negative EPO) it will not head off to the south and east.

Folks the above explains the current pattern that we are in & also points out what one can expect. Here is a graphic representing what is talked about above:

So now lets look at the latest modeling from 12 Z today..

The above is the GFS/UKMET and GGEM. All three of these models generally take the low well east of the region,

the 12 Z Nogaps also takes the low well south and east of the region and this is pretty much to be expected with the models very progressive bias.

However…all these models essentially end up in approximately the same location as the 12 Z Nogaps or in the general vicinity! The problem is all these models are not recognizing the SE ridge and are taking this into and thru where the SE ridge would actually be do to the teleconnections that are in place.

They are also all showing a much colder air mass then what is representative by the teleconnectors. The ECM is somewhat recognizing things a little better ..

Its starting to realize that the SE ridge is stronger and it is starting to slow the system down and build higher heights along the east coast. It still ends up being quite east at 144 hrs.

Now lets just reflect back on past systems and how in this range they were all modeled to be south and east..and at that time we had more favorable connections but they managed to come back and track further to the NW and in most cases further NW then what models showed and suggested. Lets look at the current surface map for the current system..

This shows a strong primary over Western PA and a coastal beginning to deepen but this coastal is not the primary as the low to the west is deeper then the coastal. This storm as well was originally modeled to be a coastal and a colder solution to cause the region to receive several inches of snow but the pattern always suggested a further west solution. This is why i mentioned yesterday in the chat room that the NWS had this completely backwards and that we would have ice turning to snow if there is enough moisture left as the upper levels cool off. Currently on radar you can see the WAA (warm air advection ) from the southerly flow around the stronger primary causing precipitation all the way into Central New England to fall as either Ice or rain.

So..with recognizing the pattern that is in place we are not going to change our thoughts from a further west solution occurring as we get closer to the event. We feel that there is indeed the potential for a significant winter storm in this time period.We also feel that with the further west solution and the teleconnections in place and pointing the direction that things should transpire that the big cities along the east coast would end up being either a wintery mix or mainly rain.

If this storm does materialize it would be the inland locations that receive the snowfall. How far inland? Way to early to speculate on this at this point and time.

Thought to ponder is everyone has been talking about a pattern change. We do believe a pattern change is indeed coming and this storm will usher this pattern change in…However…when you look at the teleconnections that are currently in place and have been in place for some time…what pattern change would be coming? Though to ponder!

Feb 5 & 6th and Beyond

After a little hiatus beyond our control at Real Wx Services…we are back and looks like we came back into some mass model confusion.

 First things first ..Feb 5-6th . We currently have an area of low pressure developing in the GOM and this area of low pressure should generally move to a position near Hatteras. From there this low pressure should ride up along the eastern seaboard. Meanwhile at the same time there is also a primary low that appears to be over ARK..this is also going to be moving off to the NE and should end up somewhere near the western PA /MD border. Current thinking is that the primary could remain stronger then the coastal low and hence the warmer scenario being shown.

The primary hanging on stronger will cause more warm air advection in the upper levels. Overall the thinking is that this will not be an impressive storm system generally on the light side…

Now next on the list is Monday to Tuesday and the potential for yet another low to move in from the west and a low potentially forming off the coast…

Now this actually has a high pressure in better position to the north and this does appear at least in the upper levels it could be colder then the current system. GFS is similar but it also appears to be about 12 hrs faster then the ECM.

So we have two chances at some wintery precipitation thru tuesday and then the question becomes what happens after that?

We have gone from models showing a large storm that would be along the order of 1-2 feet and most recently we have gone to models showing a more easterly or southeasterly solution.

So what does the pattern actually suggest? And what type of pattern change is forthcoming if any?

The pattern above shows that we have a positive AO. What this implies is that the cold air will not be all that abundant. The NAO is also being shown as positive and maybe heading towards neutral. This also suggests that cold air will be around but also not all that strong. PNA is positive but heading towards negative. What this means is that the trough should still be along the east coast but will not be as deep as what it has been previously. Then in addition to this is the Negative EPO which suggests that a SE ridge or bermuda high should be in place.

Now what does this all mean when it comes to the present modeling?

Lets look at the modeling from 12 Z and 18 Z

We feel that the GFS at this present time is playing right into its bias. That bias is being too fast or progressive and we also feel that it is over doing the extent of the cold air considering the connectors above.

12 Z ECM

Here at 144 hrs we see that the ECM still has the system in the GOM.

Now lets look at another very progressive model with a very well known SE BIAS…

Once again ..I find it pretty amazing that a more progressive biased model is actually slower then the GFS. Now..at 12 Z and 18 Z the NOGAPS takes this system off the coast south and east almost AKA the GFS but timing is slower obviously..

However..they end up in relatively the same spot overall. This is a major red flag that the GFS is not correct in its solution. Now the ECM does bring this system up the coast and brings it fairly close to the coast about 100 miles. It also would be a wintery mix in southern New Jersey  & DE etc with QPF getting about as far west as Central PA. It would generally bring snow to inland locations.

GGEM has a system further to the N but from this point it essentially ends up South and east as well.

The UKMET only goes to 144 hrs

Slightly more progressive then the NOGAPS/ECM/GGEM but one can tell that the GFS is the most progressive of all the models and the flattest solution as well.

Judging from the teleconnections in place I would argue for a solution closer to the ECM at this present time and perhaps even more running along the eastern side of the Appalachians and being an inland runner.

We do not feel that the solutions currently being shown are actually portraying what the teleconnections would be portraying. After all, the next two systems all have a primary heading to the NE to the west and a secondary along the coast. These storms for the most part are also warmer then the storms of the recent past. The teleconnections for this potential storm are going to be no different then what they currently are for the weekend system.

Pattern change? If there is to be a pattern change then we are to see a large type storm system. Almost every pattern change that has occurred has been accompanied by a large storm. At this point and time we feel the pattern change that may be upcoming is more a continuation of a gradient type pattern that we are in. Gradient meaning temperatures from I-95 south and east would be more supportive of mainly rain and or wintery mix while areas further inland would be more typical of snow.

We will continue to monitor all three of these potential systems over the days ahead!