September Pattern Update

September Pattern Update
Summer weather is essentially over and a thing of the past other then perhaps eeking out one more day of warmer weather which would be today. Signs of fall weather on the way and perhaps some very chilly air arriving right on time at the start of the fall season around the 22nd of this month.

Lets look at the PNA to start this off..

As one can see when looking at the chart above the PNA is very positive. When the PNA is positive such as it is this is usually pretty indicative of troughiness being somewhere in the continental USA. One thing at this time that I am not seeing happening is the substantiated drop from such a positive PNA to the opposite side of the spectrum in neutral to negative at the end of the period.

The reason for not believing it is that the EPO is expected to be pretty much negative at the occurrence of the dropping of the PNA. When the EPO goes negative that means that high pressure will generally sit itself off the West coast or along the west coast and cause the Jet stream to lift into Canada and then dive back down into the USA carving a trough out along the east coast. This is exactly what we see occurring in the 00z ECM last night as high pressure causes that ridge to form (-EPO) and this would allow the PNA to stay quite positive with an impressive trough along the east coast. Hence the reason why i do not believe that the PNA is going to drop to neutral to negative.
Both the 00z ECM & operational 12 Z GFS from today support the indexes teleconnecting the way I think they should go..
During this time period the NAO is expected to remain somewhat positive to a neutral position..

So essentially over the next week we should be expecting to see seasonal to slightly below seasonal but there after look for a more below normal regime when it comes to the temperatures. Also look for the potential of wet weather and coastal storm scenarios to possibly effect the region. This pattern that we have now gone back into with the start of mid month (right on time as well) is the pattern to watch for thruout the winter season. I will be making a post in the winter thread sometime this afternoon..

Sept 4th Early Morning Thoughts on ERIKA

The much anticipated weakening of ERIKA has occurred. For the past 48 hours been referencing that ERIKA would weaken to a Tropical Depression and that had occurred. While I was not anticipating weakening to a remnant low...I have also been emphatic on ERIKA not dissipating. Now to clarify, what I mean by dissipating, is losing complete structure that she no longer becomes trackable. In other words I never felt that ERIKA would just vanish! Perhaps that is a better word then dissipate. As you can see from the above image..this is the first image of ERIKA after the satellite eclipse. Once again..ERIKA with the overnight period has pulsated back into a better condition then previous satellite images before the eclipse. This is a cycle with pulsating type storms. We have seen this repeated day in and day out and everytime she has done this she has relocated her center.
I have been referencing in all my discussions where the best convergence is located and how I been thinking that this is where the center is going to either relocate or move towards. And when you look at the best convergence you can see once again that the area where the blowup is occurring is exactly where that best convergence is located.

So, the convection is occurring in the best potential area and is causing ERIKA to actually reorganize. This area is also only in 5-10 knots of shear in the mid level which also aids in reorganizing.

The only problem that ERIKA is facing right now is the shear in the upper levels. The shear in the upper levels is 20-30 knots around where she is trying to reorganize and relocate.

So, essentially, the sooner that ERIKA gets out of the CARRIBEAN, the sooner she will start to head towards a better surrounding conducive to potentially regain Tropical Depression status. As you can see off to her NW the shear is much lighter once N of Hispanola.
What about the guidance? Well, previously the GGEM all but essentially caused ERIKA to vanish. The ECM..essentially does not really develop ERIKA any further and keeps her more or less as an open wave. The GFS redevelops ERIKA by pulling the old LLC back to the MLC that was off to the NE of the old LLC and then moves that on a WNW basis to the north of the islands. The NOGAPS..also focuses on a the same type of development method as the GFS. While the GFS redevelops ERIKA and moves her WNW to north of the BAHAMAS and then NW to N out into the central atlantic to get stalled for quite some time before moving NE out to sea completely. The NOGAPS which uses the same developmental idea as the GFS..brings ERIKA closer to the east coast and actually brings a landfall of a pretty potent system into the SNE area. In particular around Long Island. The GFDL & HWRF also ramp this system up and take it on a track similar to the Navy Nogaps.
At this point and time..intensity level is not really a concern considering that we are out in the future between 100-200 hours. The track is also going to be shifting around on guidance.
The question becomes can Erika actually redevelop? The answer in my opinion is yes! Heres why! ERIKA at this point is a remnant low. Even if ERIKA were to go across Hispanola..she would be going across as a REMNANT LOW. A remnant low going across the island would not be the same as a CAT 2/3 going across the island and having its core ripped out. As a remnant low you are already without your core. However, the remnant low potentially will skirt either across PR or in between PR and Hispanola and then move WNW to the north of Hispanola. If that track of the remnant low of ERIKA prevails...then ERIKA will be heading into a better environment for redeveloping. If ERIKA stays in the CARRIBEAN sea..under hostile conditions it will mean vanishing. Until ERIKA gets out of the CARRIBEAN sea she will continue to go thru the pulsation cycles that have become quite familiar.
Now what happens once she is out of the CARRIBEAN sea, assuming she survives the shear and dry air that she is battling? What type of synoptic setting are we looking at? Lets look at the GFS above.

I have labeled certain things here at 78 hours out. I have pointed out where the ridging is, high pressures making that ridging and also where the troughs are as well as where the remnants of ERIKA are. Remember this is at 78 hrs and ERIKA is weak. And the ridging only gets stronger from this point on. While I think the GFS is correct in its redevelopment of ERIKA.. I have some major issues with what the GFS is showing here in regards to the synoptics and ERIKA. ERIKA on the GFS is a weak storm. With ridging that strong in place...ERIKA IMO would not be able to even move to the North and if she were able to due to a weakness in that ridge..the GFS is forecasting that ridge to close that weakness with ERIKA already in the atlantic. This would mean the ridge would be pressing to the east and ERIKA is strong enough to resist that pressing and just stall in the atlantic? I do not think that is a likely scenario. However, the most important thing about the GFS run and essentially all guidance agrees on this is that there is going to be strong ridging from the CAR into the NE. If this synoptic set up is correct and ERIKA does redevelop..she is not going to penetrate that ridge unless she was a stronger system like CAT 1 or above. A thought to keep in the back of your mind.

So the more likely scenario with that type of ridging in place would be for ERIKA to move WNW out of the CARRIBEAN sea ...pass to the north of the island of Hispanola..and then to continue WNW till she is north of the BAHAMAS. It is at this time that potential intensification can happen. Then from there i think ERIKA would continue WNW to NW and potentially impact the SE coast.

The other scenario is that ERIKA completely vanishes and dissipates that she is no longer trackable due to never getting out of the CARRIBEAN sea.

And the final scenario is that ERIKAs remnants just remain a remnant low and never redeveop into anything greater and become nothing but a big rain maker across the Southeast.

All three of these options are viable. All three of these options have potential to happen!
However...until ERIKA completely vanishes...any one of these scenarios can occur. At this point and time, I am thinking that ERIKA will redevelop once north of the islands and in the better atmosphere. Shes a pulsater!

September 4th Weather Discussion

September 4th Weather Discussion
Pleasant Weather On Tap!
The Daily high temperatures for KABE For Sept 1-3 were 74,77,80 degrees

Today is going to be a mostly sunny day across the region..with the exception of SNE around the CC area where skies will be partly cloudy with an outside chances of showers. Otherwise weather across the area will be pleasant and a great day to be outdoors.Temperatures have rebounded from what they were. From SC Pa points northeast temperatures will be in the lower to middle 80s. Interior regions will be in the 70s. To the south of PA temperatures will also be in the lower to mid 80s.Pretty much a quiet stretch of weather right now! Lets enjoy it while we can!

September 3rd Thoughts on Erika

September 3rd Early Morning Thoughts as of 4 AM. 
Lets look at a little history of Tropical Cyclone ERIKA. Originally all the models were showing ERIKA to take a sharp right curve. This sharp right curve was expected to take ERIKA out to sea and pose no threat to land. ERIKA was forecasted to move to the north of the Leeward Islands as well as NHC. History with ERIKA shows that this has not happened. Instead, ERIKA went across the islands and headed in a SW direction which was also not modeled to occur. So,once again ERIKA has defied the models and the pro mets. ERIKA has baffled the minds of many! Moving on to some of the more recent guidance...as recent as September 2nd..models were either dissipating ERIKA or they were taking her across PR...but more importantly they were taking her across Hispanola. Remember this point, we will come back to it.
Just as recently as yesterday evening..it appeared that there was a possible center relocation going on with the best convergence lying to the north of the islands. Convection was indeed blowing up in that location which made the most sense at the time due to where the best convergence was. As of the writing of this..the latest coordinates are not out. So we will wait to see whether that idea had any "sustained" merit or we could look at where the best convergence is as of 06 Z. So for the purpose of this discussion and my map I have used RECONS most recent center location of 16.6 N and 62.5 W.
This location actually makes the most sense when you look at where the greater covergence now is. This means that convection is blowing up over the center. So that convergence shifted south which means that the center more then likely is not going to relocate to the north. Now does this imply that ERIKA is going to move over Hispanola? Well before I attempt to answer that lets look at wind shear involved with ERIKA.

The first image is the current wind shear as of 0600. As one can see the wind shear has actually decreased around ERIKA. So her atmosphere is not quite as hostile as it was. The shear has been essentially been moving in tandem with ERIKA.

Looking at the mid level sheer it is only around 10 Knots. So generally conditions have improved somewhat for ERIKA. 
Perhaps the most important aspect that has occurred in the early morning hours here with ERIKA is that she has actually begun to move off to the WNW. Its important for ERIKA to get out of the CARRIBEAN region as the combination of shear/substinance will more then likely cause ERIKA to dissipate. 
Now, remember earlier that I said about the guidance from September 2nd...majority of models were either dissipating ERIKA and taking her across Hispanola? Well, most recent guidance is suggesting that a track to the north of the islands of Hispanola is now possible. This is important, not only does it show that the models have been essentially clueless with the system..but if that were to occur then the chances of ERIKA either maintaining minimal TS or maintaining TD status would go up as she takes her journey towards a better surrounding to the N of the Bahamas. Basically all "guidance" today shows this happening. The GFS/NAM/NoGAPs/GFDL/ most of the dynamical models/HWRF (to a lesser extent) all show this now occurring. The ECM keeps this as a weak open wave..well currently as of this writing ERIKA was still a tropical cyclone (TS) which already means that the ECM is in error. And not surprising as we are still 100+ hours out and not in its best time range. The GGEM appears to either take the system as an open wave towards the GOM or causes it to dissipate. So basically that puts the GGEM off on the wrong foot as well when it comes to comparing to the other recent guidance.
So what should happen here with ERIKA? ERIKA should maintain status of a tropical cyclone. There is the potential that she will be downgraded to a TD. However, as steering currents show she should continue to move off to the WNW with an increase in speed. This should take her close to if not over PR..but then skirt the island of Hispanola with her center of circulation remaining off shore. This will make any effect on the C.O.C minimal. Then as ERIKA moves WNW she should start to move off to the NW. With the synoptic setup of a huge CAR extended into the NE..I still do not think a trip up the east coast is likely...unless the NOGAPS idea..or HWRF idea were to occur. I think that once ERIKA were to get to the BAHAMAS ..conditions will become more favorable for potential intensifying back to TS if she loses that status by being downgraded. That is scenario #1 and the one that I think is the most likely to occur at this point and time.
Scenario #2 is dissipation as ERIKA would move to the west into a more hostile surrounding ..or move over the island of Hispanola and dissipate due to being a weak storm! 
So in summary what to look for so theres no surprises.
1. Potential to be downgraded to a Depression.
2. Potential track to the North of Hispanola or over Hispanola depending on scenario outcome.
3. Potential to intenisfy down the road or dissipate (again dependant on #2)
With that all in mind here is my latest forecast track for ERIKA...

September 2nd 12 Z Erika thoughts...

Current thoughts on Tropical Storm Erika, as of 3 PM EST on September 2nd. Its not a surprise that ERIKA is currently located at 16.2 N and 61.1 west. It is also not a surprise that ERIKA is weakening at this point and time. ERIKA has been fighting off to the best of her abilities the dry air in her surroundings. At times it gets the better of her and she weakens. However...when diurnal max comes around she strengthens back up. Currently she is close to the islands. This is important to remember. Close land interaction can also be responsible for the weakening that we are seeing at this time with ERIKA. 
12 Z guidance from the ECM to the GFS.(basically dissipates) .to the NAM, including the GGEM all dissipate this system. On the other side of the spectrum, the GFDL/HWRF maintain the systems strength (some weakening evident on the GFDL) and then restrengthen ERIKA. Meanwhile the NOGAPS from 12 shows quite the potent system riding up the eastern seaboard.
First lets look at what is currently happening to ERIKA. Lets look at the shear.
This will update shortly for the 18 Z, however since this is currently the only available it will reference whats happening. To the NW side and to the southeast side of ERIKA there is 20 to 30 knots of shear. However, i do not think the shear is as much an issue ,as ERIKA has been dealing with dry air. The slowing down of the system also could be a component of the weakening. So right now ERIKA is a minimal TS..perhaps bordering on a depression..which i mentioned was a possibility of happening at around 5 Am and i still will stick with that potential happening.

Now lets turn to the steering currents. Again, they are pretty much showing that a west to west northwest track should continue. A weaker system will be subjected to follow the lower level steering currents.
I think its important not to pay to much attention to the tracks that the models are currently showing. Rather, I think its more important to pay attention to the synoptic setup that is going to be in place. Sometimes a forecaster will have to put the models aside and focus more on the synoptic setup. Lets think back to several days ago. What were the models showing at that time? The models from the global to the dynamical to the hurricane models were all showing a sharp right turn or a recurve. How close were they to being correct? What model actually showed the southern extent of this system where it currently is? The models have been trying to play catchup to ERIKA, as ERIKA has been defying all the models and basically the professional mets thoughts. Its very important at this point and time when following ERIKA to pay more attention to satellite and steering currents and synoptic patterns and teleconnections.
So what does the synoptic pattern look like? All guidance and I emphasize the word guidance, is suggesting that there is going to be a strong central atlantic ridge attached to a ridge of high pressure over the Northeast. The guidance has suggested that the weakness that was origininally being showed was nothing more then convective feedback. With such a ridge in place a weaker system is going to have a hard time penetrating that type of ridge in place. So where does ERIKA go?
The two scenarios that I am looking at right now are below.
Scenario # 1. Erika continues to maintain her strength at either a TD or minimal TS and heads W and then WNW towards Florida. Once north of the Bahamas...extremely warm waters could potentially cause ERIKA to reintensify. Potentially putting FL in the bullseye! I do not see this making a trek up the east coast, UNLESS, the intensification process is like the NOGAPS, and at that point ERIKA would be able to just plow thru that ridging. At this time, i think that is too extreme.
Scenario #2 is that ERIKA keeps moving off to the West and enters the Carribean. If this were to happen ERIKA could potentially dissipate. 
These are the only two scenarios that I can see happening at this point and time and i would suggest that both scenarios are indeed possible. For now, the map above is what i am sticking with. Stay tuned for further updates. 

September 2nd Early Morning Thoughts on ERIKA

Early Morning thoughts as of 3:30 AM, september 2, 2009.
ERIKA was born officially today with NHC at 4:30 PM this afternoon when they reran the 18 Z model data at 20Z due to the classification. In my personal opinion, if they would have sent recon in on the 31st of Aug , Monday..I think they would have found out that this was a Tropical Depression already. The call for this from the start has been slowly intensifying and basically ERIKA has been behaving quite well in that manner. Perhaps, in some other way she has not, but i will get to that further down in the discussion. As of 2 AM ERIKA was located at 17.0°N 58.7°W...ERIKA went from 50 MPH @ 5 PM to 60 mph @ 8 AM. Since that time ERIKA has become somewhat less organized and I think that could be due to potentially the wind shear that is on the northern side of the system of 20-30 knots.
Looking at the latest guidance...pretty much all guidance tonight with the exception of the 00z NAVY NOGAPS has shifted this to the west. The NOGAPS does ride up along the eastern seaboard but ends up recurving and I think this change comes about because it is actually showing a quite potent ERIKA. All the other guidance from the 00z GGEM, 00z GFDL, 00Z HWRF,00z ECM have shifted to the west. In some cases like the ECM it was quite a considerable shift. 
Why the shift? The shift can be explained for quite a few reasons. First off the trough that the GFS and ECM was showing in prior runs..is no longer a valid idea. And to be perfectly honest, with the ECM ensemble means it never was a valid idea. So in the case of the ECM, tonights 00z operational has started to move in the direction of its ensemble in regards to the synoptic setup! The 00z GFS also realized this as well and now has very little weakness in the ridging as it builds it from the Central Atlantic into the NE. This also lies in harmony with the prior consistent runs of the ECM ensemble means. Aside from the ECM ensemble means the only model that was showing this before any other model was the GGEM. The model that HPC labeled as an outlier. The problem is when the GGEM is holding hands with the ECM ensemble means, it quicly becomes more credible.
The GGEM as far as the global models has also been consistently showing a southern solution. Matter of fact as of tonights 00z GGEM it actually takes it over the islands. Current satellite depiction would show that ERIKA is further south then most other global guidance has ERIKA located. Matter of fact ERIKA is getting quite close to the islands considering NHC cone at 5 PM had her spotted pretty much northeast of the islands.
Remember,in the beginning of the discussion I mentioned about her misbehaving in some other way. This would be in regards to the movement of the system. Current 2 AM coordinates were...17.0°N 58.7°W. This is important because 11 PM coordinates were 17.5N 57.6W ..So what this has done is it shows that there was indeed a SW movement with ERIKA which was observed earlier in the evening on the 1st via satellite. 
So whats going on here? What is causing ERIKA to move to the SW? Helping factor #1 is the wind shear that ERIKA is experiencing has caused her to weaken. 11 PM pressure was 1004 mbs and 2 AM was 1008. That was a 4 mb rise. Remember a weaker storm will be more prone to follow the lower level steering currents. So lets look at them..
The steering currents actually show why this went SW earlier in the evening and that is because the flow is actually WSW and because of being a weaker system will be more prone to follow that current. So this is the reason in my opinion why she is getting closer to the islands and why she is further SW then 11 PM.
Intensity level once again is going to be the most difficult with this system to forecast. If ERIKA does indeed pass over the islands there is a chance that the land interaction could weaken her more. However, these are relatively small islands, so the effect could be minimal. If it were to pass north of the islands then there would be no effect on ERIKA because of no interaction. 
I still think we have to lay three scenarios on the table. Scenario # 1 is to continue to head off to the W or WNW and then eventually NW and potentially make landfall on the east coast. 
Scenario #2 is that ERIKA could potentially continue on the WSW and then west tracking and go across the Bahamas and end up going into the GOM, which then depending on whether or not ERIKA can survive the shear and dry air, could become a potential threat somewhere along the USA GOM region. Scenario # 3 which I think needs to be laid out on the table is still the possibility of dissipation. The 00z NAM actually never develops this system and it dissipates. 
Out of all the three scenarios that I have laid out...My current thinking is that scenario #1 is the one that has the most potential at this point and time of happening because of the reasons laid out above! So with all the above..I see at this point and time no reason to change my track that was made while ERIKA was an invest and it is at the top of this post. Stay tuned for further updates.

September 1st Early Morning Thoughts on Invest 94 L

An absolutely beautiful image at 7:15 UTC. Latest early morning thoughts on Invest 94 L as of 3:33 AM EST, tuesday september 1st.

First let me start off by saying that i disagree with NHC up to this point and time for not classifying this as at least a tropical depression. According to two sources wunderground being one,and the recon tropical atlantic site being the other...both have wind speeds that would make this a depression. Wunderground shows 35 MPH and so does the recon center. Now i know that people may disagree with me on this issue and that is fine but the people that are in the Leeward Islands, Antilles and Pr at this point and time are probably under the impression that this is just a Tropical wave because it has yet to be classified. Those winds support a Tropical Depression and 4 miles away from a minimal Tropical Storm. It really does not matter how the winds are derived..the fact of the matter is that they are there and they are observed. I would be very surprised if this does not get classified in about an hour from now...
Looking at the latest guidance...00z GFDL has woken up out of its slumber and is now finally starting to develop ERIKA 2 be. This is probably because the GFS is also starting to come around,but IMO still not there. Dynamical models are all pretty much taking the southern route. 00z NAM has also come in further to the south of its 12 Z run. 00z NOGAPS is probably the model that takes ERIKA the furthest south at this point and time. The 00z GGEM which was showing a recurve on its two prior runs is now no longer showing this recurve but a storm riding up the east coast and impacting the SE. The ECM 00z has actually moved this more to the NW then its prior 12 Z run. I believe that this is highly attributed to it opening the wave up at hrs 192 and amplifying the trough across SE Canada that then picks up invest 94 L and keeps her out to sea. I highly believe that the ECM is the outlier at this point and time for three reasons.
#1. The 00z ECM keeps the wave weak. This is important because if the wave is actually weaker then its going to be subjected to the lower level steering currents and with its more southern latitude...it would keep to a further south track then what the 00z ECM is applying.
#2. The teleconnections do not support a amplifying trough. At this point and time the NAO is positive and then trends to neutral..PNA is positive and trends to neutral while the EPO remains neutral. This does not spell an amplifying trough across SE Canada into the Northeast as it is implying on tonights run.
#3. Though I have not seen the ECM ensemble means for tonights 00z ECM run..it would be completely out of sync with its ensemble means for the past 6 days. I think the ECM is also having trouble with this because it is a weaker invest at this point and time (though slowly developing)
Lets move on to shear. At this present time there is about 5-10 knots around the center of the storm with shear increasing somewhat to its North. As has been the case thru out most the day..the ULL that has been positioned to the North of invest 94. While this has slowed development..it has not weakened the system as evident by winds increasing and pressure dropping. Instead its been acting as a ventilator for invest 94 L and has been allowing it to "breathe"

Steering currents. As you can see the steering currents continue on a track to take invest 94 L off to the wnw. From 11 PM to 2 AM ..the gain has been .6 N and 1.6 West. Again this shows that a weaker system will be subject to those steering currents and we are gaining more westward progression then we are northwards with the system current as of 2 AM at 16 N and 55.9 west. So its just about at 56 W currently and is still 4 degrees south of 20 N.
So what should happen with Invest 94 L? The first thing that should happen is 94 L should be classified and I think there is a high chance that it might just jump to a Tropical Storm. I have no doubt that invest 94 L is going to become a named storm. I also think due to the steering currents that Invest 94 L will continue to move off to the WNW. 
I think that ERIKA has the potential to become an east coast threat. I think that a track closer to the east coast is more of a likely scenario then a track out to sea. Why? Most models indicate a strong ridge extending onto the east coast. Perhaps the only model that does not is the 00z ECM, but like i said, its ensembles (12 Z) tell a different story and I also provided reasons why i think its an outlier. Due to its southern extent of origin and history, being more south then Danny was, weaker then Bill was...and the former making landfall at Marthas Vineyard while the latter passes 150 miles SE of CC..this factor puts it at a greater chance to avoid the weakness in the ridge and then allow the ridge to build in back over top as majority of the guidance shows. With all the above in mind ...Here is latest track expected.. above...

Stay tuned for further updates...