Latest run of the European Computer Model guidance which just came out at 2:30 pm est..confirms our thoughts on 93 L .
Considering this model has done the best with this system and has been the best model with short term development this one will bear watching .
The above is a water vapor image of Tropical Storm Gert. Tropical storm gert is a smaller then your average Tropical Cyclone. The reality of it is a very compact sized tropical system. And as we stated from the get go with this system it would continue to feel the effect of dry air. This dry air , when a system is as compact as Gert will combine with even light vertical shear and help to slow down the intensification process!
We feel that GERT has reached its peak in intensity. Over the next 24 hours GERT will begin to move over cooler waters as it moves North-Northeast and this should begin a weakening process.
Now the above image is 93 L. If you remember we were the ones who said that 93 L was not going to develop with in 48 hours when NHC had the system up to 40% for developing.
We also were following the ECM guidance which kept this system weak and on a westward path. It should be evident by what is happening with 93 L that the ECM was indeed correct in not developing this and keeping it weak on that westward path.
Looking at the environment around the system we can see that there is dry air off to the west of the system which is the direction this is moving. However..that dry air is also moving west. Shear is only around 5-10 knots across the system & the system has decent convergence and divergence in its favor.
Our current thinking is that this should continue to move off to the west for the time being and could develop to a tropical cyclone with in the next 72 hrs. Likely to become a threat to the Yucatan area .
So within the next 48 hours we will go with a 40% chance of development..however we think better likely hood would be between 48-72 hrs out.
We are looking at two different systems in the image above. The system at the top is Tropical Depression #7. This is the system that in the update yesterday we stated “we would not be surprised to see this upgraded to a tropical depression” in the next 24 hrs..if it could shake off the dry air. Well as of 11 PM within that 24 hrs it has occurred.
Now if you been reading comments along the side of the blog ..they are coming from an accu weather forum member who is 15. He stated that dry air is 200 miles from an invest center and stating that is “ ridiculous” and yet we see the following from the NHC discussion on this depression:
“
.AS WELL AS
ADVECTING UPPER-LEVEL DRY AIR INTO THE DEPRESSION. IN ADDITION...
A LARGE PLUME OF AFRICAN DUST AND ASSOCIATED DRY AIR ARE
APPROACHING THE DEPRESSION FROM THE EAST. “
Does that sound like 200 miles to you? No not at all..I was also told that my forecast was a complete bust..well I said within 24 hrs..I would not be surprised to see it upgraded to a depression…folks it was in about 12 hrs or less. It was given a 50% chance because of the dry air on all sides.
We only update the tropics once a day because we have other responsibilities..so if something happens during the time frame when we are not able to be at the pc because of supporting a family etc ..we are not going to be able to update and say its now at 70% or 80 % etc . However, for someone to call something a busted forecast when it happened with in the time frame stated…is well flat out not correct.
Any forecaster knows that you can not give something a greater then 50% chance of development when you have a lot of dry air around a system…as that dry air gets ingested and causes slow development to occur.
Again NHC says “
THE ABUNDANT DRY AIR AROUND THE SYSTEM SHOULD AT LEAST SLOW
INTENSIFICATION.”
They also think that we should not rely on the ECMWF computer model but yet we see NHC says “
WITH THE FORECAST BEING
A BLEND OF THE ECMWF AND GFDL MODEL FORECASTS”
Folks it is a known weather fact that the ECM model is the better performing model with in 48 hrs.
These statements that are being discussed are coming from a young teenager from accu weather forums. I find it remotely strange that I am not a member of that forum any more and yet some from that forum still feel threatened by the forecasting. Threatened enough that they have to make statements like above that are blatantly false.
Folks we will continue to do what we have been doing and that is providing you with tropical updates every 24 hrs and looking at the environment around these systems as has become expected of us by the followers.
Now moving on… the next issue is 93 L. We mentioned that we felt that only had a 10 % chance of developing in which NHC at one point felt it had a medium chance of developing. We stated that the environment around it was not supportive of that happening.
National Hurricane Center took 93 L down to 0% and since then it has been deactivated so its no longer shown on the map.
So that is just another example of knowing the environment can lead to a more accurate result.
Now the system to the SE of TD 7 is 92 L ..
This is a better look at 92 L..Folks NHC has this at 30% and recon is going into investigate it tomorrow.
In our opinion this already looks better then TD # 7 and feel its quite possible that this is already a Tropical Cyclone..IF this maintains convection as it currently has we would not be surprised to see this upgraded later on today.
The one wildcard is interaction with TD # 7..if this occurs then its possible that both systems may end up cancelling one another out.
We will watch this over the next 12 hrs or so and then resume tomorrow night around midnight…
Stay tuned for more information
These are the recent visible and water vapor shots on 94 L. You can see that 94 L ATM is an exposed naked swirl..however when you put the images in motion it appears as though 94 L is trying to cover the naked swirl up with convection.
If 94 L can overcome the dry air that is surrounding it ..
We would not be surprised to see this get upgraded to a Tropical Depression.We place this at a 50% chance within the next 24 hrs of becoming a tropical cyclone. It’s a matter of will it be able to overcome the dry air that is surrounding it?
This is an early outlook released for Day 2 which would be on Sunday. Normally we do not like to go this far ahead but with a rather tight schedule later today we have decided to do the outlook now.
For the most part across the east it will be a weak cold front that will be moving thru with CAPE in the order of 500 to roughly about 2000-3000. Not very impressive CAPE..we think the greater threat from this will be heavy rain across some of the east on the order of 1 inch plus.
Further to the west: a trough will be in place which will kind of limit convective potential with an a upper level ridge over top..this will more then likely limit any convection to the higher locale IF daytime heating can cause the atmosphere to become unstable enough.
Over all we are not thinking this will be to big of a severe weather day with the main focus being on heavy rains across the east…
Persistent stationary front still resides across the southeast part of the USA..Low pressure is over southern Alabama. This stationary front then goes west to another area of low pressure over Kansas which then runs into an occluded front to a low pressure over Minnesota..with a cold front draped from west to east ..sagging south from a low pressure system in the southern tier of Canada above the Great lakes.
This frontal system out west and the area of low pressure with associated trough will begin to work its way to the east. Meanwhile the stationary front will begin to try and work its way towards the north,,and the cold front attached to the low pressure in Canada will slowly move also towards the south and east.
Shear on the order of 30-40 knots along with decent lift and instability should cause severe thunderstorm potential with the greatest risk being from Illinois/Indiana and points south as the frontal system moves east.
The primary threat appears to be wind damage.. There is some question as to whether or not convection occurring overnight tonight stabalizes the atmosphere…If this convection occurs and does not move out quick enough it would not allow enough daytime heating and destabalization as the trough and frontal system moves east.
Stay tuned in case further information is needed before 8-13-11!
We have a lot to talk about in the tropics today..or do we? That is really a trick question. As you can see the NHC has 4 different invests or areas of interest in the Atlantic. We are going to look at each one and we are going to determine the chances of development with in the next 48 hrs.
First up on the tropical tour of the atlantic is 93 L ..
You can see the latest satellite photo suggests that there is nothing much happening or occurring with 93 L . Yet NHC has this at a 40% chance of developing. Is the environment surrounding this invest showing this to be the case?
As you can see the greatest area of vorticity with this is off to the east of the system which is the exact opposite direction from which this is moving.
Convergence and divergence is definitely lacking over the system. The greater the divergence and convergence the greater the system has a chance to develop.
Shear across the system is 10-20 knots. While this is not detrimental to the system development it will definitely cause it to develop slower. However…dry air appears to be a greater problem for development as this image will show :
Surrounded by dry air on all sides this will cause dry air to be ingested into the developing system and hinder development.
We do not agree with 40% chance of development with this system…rather we put this at 10% chance of developing within the next 48 hrs.
Next up is 92 L on the tropical atlantic update:
Again you can tell pretty much by looking at the water vapor image here. There is not much convection with this system and you can also see that dry air is also going to be a problematic feature..
The above image while it does show some divergence near the system (on the western edge of it) the system is completely lacking in convergence.
You can also see in the above image that there is no area of vorticity near the system which means this is not a vertically stacked system.
NHC places the chance of this developing in the next 48 hrs at 50%. We place this at 10% chance of developing over the next 48 hrs as there are some issues that the system clearly needs to resolve.
Next up is 94 L and we will look at the latest water vapor image…
NHC places this at a 20% chance of developing over the next 48 hrs.
In this systems favor is that it is located in some decent convergence and divergence.
However, slowing down the potential for development will be 10-20 knots of shear across the system. Also another problem the system has to over come is dry air.
As you can see pretty much this invest is also surrounded by dry air on all sides of it.
The vorticity of this is also broad and elongated and tilted as well. The more elongated the system the more difficult to tighten a COC up and develop. So we would actually place the chances of this developing at 10%….
One last system to look at and this system was at a 60% chance of developing at the beginning of this outlook but since has been upgraded to a tropical depression #6.
A couple problems we have with this is that you can clearly see that this is associated with a stationary front.
This image shows that it is associated with a front and even the most recent updated image for 5 PM shows the same thing though labeled a depression..
Now lets let the images speak for themselves
Notice there is no convergence however the divergence is stretched out and elongated and this is because it’s the stationary front..
Vorticity is very broad and elongated. Once again this would be because it is still attached to a front..
The shear is 30-40 knots over the system and even greater amounts north..Again this would be because of the front.
And last but not least the dry air that is in place around the system.
As is clearly obvious by the data above if this should be classified as anything it should be classified as a subtropical system do to its association with the stationary front.
It clearly has not lost all its frontal characteristics..
As for the guidance we will continue to lean upon the ECM for guidance as over the next 48 hrs it still does not show any development of the other three invests..
We will continue to monitor these systems and keep you updated with the latest!
