Ocean storm to bring light rain to the coast Monday

Another example of the volatility in weather forecasting will unfold early next week. Yesterday, there was good agreement that the ocean storm that we had been monitoring was going to go out to sea. Now the models ore more divided with the Euro taking it farther to the east while the GFS brings it closer to the coast. I chose a track more on the Euro side of things but I brought in a light band of rain as the CMC suggests. The CMC track is closest to where I think it will track. The GFS brings in a band of heavy rain and puts the low in the Gulf of Maine. I do not thinks this is the right idea as the upper level trough thought to help turn the storm to the west likely will not be as strong as the GFS predicts. However, the GFS has been more or less consistent form run to run on this system so that scenario cannot be discounted.

IPCC climate report- The Intergovernmental Panel on Climate Change (IPCC) which is a group of top scientists and policymakers that convene every 5-6 years and produce a 3,000+ page report on climate change. They do this over a period of about a year and the first part of the 2013-2014 report came out early this morning. One key fact it pointed out is that there is a 95% chance humans are causing climate change. Dr. Jeff Masters has a great post summarizing this stage of the report. I encourage everyone, particularly those skeptical of climate change, to look at this article. It’s very informative and sheds light on some of the potential impacts that our energy consumption has on the planet and on civilization.


Monday storm to head out to sea

The first disappointment (or victory) of nor’easter season has come. The storm slated to come up the East Coast looks to be heading out to sea. All the models are on board with that solution or one like it so that is what the forecast calls for with reasonably high confidence. Expect a beautiful weekend with temps in the 70’s region-wide. Sunny over the weekend with a few clouds Monday. Storm free for the next 7 days it looks like.


Ending this week quiet, starting the next active

The end of this week will be more of the same across New England. Cool days and cold nights are on tap with sunny skies dominating region-wide. All eyes shift to next week for the potential of an oceanic storm.

Thursday: Sunny and cool. Less windy with temps in the 60’s for highs and the 40’s for lows.
Friday: More of the same. Great way to end the week-sunny and cool.
Saturday: Milder with highs near 70 across Maine and mid 70’s across the rest of New England Sunny.
Sunday: 70’s With late day clouds on the increase.
Monday: Big storm? Or sunny? Uncertainties abound here but I will continue to watch the potential for a powerful ocean storm.

I will have more on the storm potential if it looks more likely…

24 hours- Gabrielle came and went

Since my last post, TD 7 intensified into TS Gabrielle and then the LLC got separated from the MLC and has since weakened into a TD. I expect it to dissipate tonight. In other weather news, invest 99L in the Bay of Campeche is slowly organizing however I doubt there will be much in the way of development because the system will hit Mexico in the morning. A tropical wave in the Central Atlantic, the remnants of 98L has been highlighted in the NHC’s tropical weather outlook as a potential threat to develop.

TWO 9-5-13

This is the NHC’s tropical weather outlook. The yellow circle to the NE of Gabrielle is a strong tropical wave that has been sucking the energy from Gabrielle.

I’ll have another quick update tomorrow with a much more detailed post over the weekend.


TD 7 forms out of 97L in the northeast Caribbean

97L has improved everything substantially in the past hour or 2 and has earned the distinguished title of Tropical depression 7. I will outline the forecast below.


This shows TD 7. Notice the clear spiral bands, the convection near the center, and a more symmetrical shape. Also notice the good outflow on all sides.


The NHC track projection for TD 7 (07L). I expect this to be highly accurate however, there is another scenario drawn up by a credible model: the GFS. This model has the storm moving NNW then stalling and moving due W. This is possible and here’s why. The factor that might allow for a track to the NNE/N/NNW is a break in the ridge of high pressure that steers any storms to the west. When there is a weakness in this ridge, storms are sucked into it like a vacuum. This is what the NHC is calling for. However, some models forecast that this gap will close before the storm sneaks through. Like a gate closing in a spy movie while the spy rolls under at the last second. So we’ll just have to wait and see. I have little confidence it will impact the US with more than a solid swell.

Land areas that could be affected: Puerto Rico, Hispaniola (Dominican Republic, Haiti), Bermuda, Maritime Canada. This list will be updated as the track projection changes. This is just my idea of where the storm will go and who it might affect. For decision making refer to the NHC.

My next update on the storm will be around the same time tomorrow.


Quick update on the tropics

Our main disturbance 97L has improved its looks with more symmetrical and has developed a more concentrated LLC. With regard to other disturbances, 98L near Africa has faded due to an unusually large burst of dry air from the Saharan desert. Meanwhile over near the Yucatan, thunderstorm activity has increased marginally in association with a tropical wave currently over land. This disturbance is expected to move over the far southern reaches of the Gulf of Mexico in the next day or 2. There is a slight chance of development over this area. This will be somewhat like that happened to Franklin if it develops.



This image shows how 97L has built a small amount more in terms of convection. Also, its convection has become more organized. the red lines indicate spiral bands that could be forming. The black circle indicates where a LLC might be.


The SAL has removed a good part of its heavy thunderstorms so the chances of development have significantly diminished.


The AOI is over land so development is postponed until tomorrow at the earliest. I do not expect any development as the models have their doubts and its not particularly well organized.

This is basically what has changed over the day today.

My next update will be in the next few days.


Big changes in the topics overnight

Overnight, much happened in the tropical Atlantic. Our disturbance 97L consolidated it’s multi-centered low level structure into 1 main low level circulation (LLC). However, it lost most of it’s convection. We also have 2 more invests and one more AOI on top of that.

By the numbers:

3 invests (97L, 98L, and 99E)

2 day probability of formation into TD/5 day probability of formation into a TD (in%)

97L: NHC 20/50
ME 30/50

98L: NHC 10/20
ME 20/30

99E: NHC 20/80
ME 30/80

AOI 1: NHC 10/30
ME 0/20

KIKO: 35 mph 1005mb

TWO 9-2-13

Atlantic tropical weather outlook.

TWO 9-2-13 EPAC

Eastern Pacific tropical weather outlook.



Overnight the diurnal minimum, the time of day when the sun’s energy is the least really took its toll on 97L. The storm lost most of its heavy thunderstorm activity as shown by satellite imagery.


This image shows 97L and a new tropical wave that has been moving across the Atlantic for the past few days. 97L has been moving very, very slowly over the past day or so and this new wave is now overtaking it. What this will do is bring much needed moisture and lift to the storm which will likely enhance thunderstorm activity. Notice the burst of convection near Barbados. This is near where the LLC is located. This is a sign the storm is strengthening. However, it still has a long way to go before it attains TD or TS status.


In this graphic, I’ve highlighted the LLC and the new tropical wave approaching the system. Notice that the majority of the convection on this map is associated with the new tropical wave. This tropical wave will likely reinvigorate 97L with more moisture and atmospheric lift which helps to create thunderstorm updrafts.


This map shows how little 97L has in the way of thunderstorms and how much energy the new wave might put into 97L. It also shows indications of a healthy outflow pattern. You can tell because of the wispy looking clouds to the north of the center. This shows that cool, dry air is being vented out of the storm which is important for development.

In this graphic I’ve highlighted the center in black and the approaching tropical wave in red. Notice how in the top 2 images the area near the center looks like it contains healthy thunderstorms. Now look at the bottom 2 and notice how that area is devoid of any real convection. What you’re seeing in the top 2 images is just cirrus clouds left over from old convection.

The forecast for 97L



This map shows the tracks proposed by the various hurricane models.
Here’s my take:
The only way this system can go to the NW is if a trough off the east coast (responsible for the rainy Labor Day) pulls it to the north. However, for this to occur, the system must extend its circulation higher into the atmosphere. Due to the dry air present at the middle levels of the atmosphere, I don’t have confidence that it will be able to strengthen enough to get affected much by the trough. I expect it to continue on its track to the WNW and affect Hispaniola Wednesday with heavy rain being the primary threat. After that, I expect it to continue WNW over the Bahamas on Thursday. This is when development is most likely.



This map shows the intensity forecast proposed by the various hurricane models.
Here’s my take:
I expect that for the next 24 hours, it will be struggling to figure itself out. In a day or so, the new tropical wave will complete merging with 97L and that is when it will have more of a chance to develop. However, I do not expect development until AFTER its passage over Hispaniola if it makes one. That is because the mountainous terrain that is the dominant feature of Hispaniola acts to disrupt the circulation of tropical cyclone not to mention robbing them of their heat energy. Therefore, it is when the storm is in the Bahamas late this week and into next weekend that development should occur. However, IF the storm takes a track due west which is also a possibility, then development should occur around 72 hours out when it is over the Western Caribbean. If this were to be the case, I would expect that it would reach weak TS strength before hitting the Yucatan. If it enters the Bay of Campeche, a strong TS is possible.

One funny thing I found while looking at the models was this


This is the CMC model forecast for 168 hours out (7 days). It shows 97L as a powerful extra-tropical cyclone. It then goes on to slam Canada. Do not worry however, this scenario is HIGHLY unlikely to happen. It just goes to show how models can not always be fully relied upon and that sometimes, they just entertain us weather geeks more that anything else.


A tropical wave moved off the coast of Africa yesterday and overnight it has acquired a sufficient amount of convection for it to be designated 98L by the NHC.


This is a satellite image of 98L. Notice how much more thunderstorm activity it has vs 97L.

This graphic shows the center in black and a developing spiral band in red. This could be important in aiding the development of this system as these spiral bands tend to act as a conveyor belt bringing warm moist air into the storm from afar. Notice the wispy cirrus clouds to the NW of the center this indicates a healthy outflow pattern which will also aid in development.

The forecast for 98L



This map shows what the models think of the track of 98L. Notice that since 98L is much better organized than 97L, models forecast a sharper northward turn.
My take:
I think 98L will develop fairly quickly resulting in a tug northward. It may affect the Cape Verde islands with rain and wind in the upcoming days as it tracks near or over the islands. It’s a much more straightforward forecast here thankfully and there are not many scenarios to talk about.



This map shows what the models have to say about the intensity of 98L.
My take:
I think that the models are spot on here. I expect to see development within the next 48 hours with the system reaching weak TS strength by 72 or 84 hours out. After that, the system will move over cooler waters and dissipate. NOt much variation in outcomes here either.


This system is not an invest yet so the amount of data is limited. There is a tropical wave off of the southern Yucatan peninsula that has started to fire up some convection today. However, development will be little to none in the next 48 hours.


This map shows AOI 1, a disorganized tropical wave with little chance of development in the next couple of days. Where we have to watch it is when it moves into the Bay of Campeche. This area is notorious for spinning up tropical cyclones rather quickly because of the topography of the area.

The forecast for AOI 1

Given this storm does not have invest classification yet, the hurricane models are not able to weigh in on the forecast. But I will look at the regular models and outline what they have to say below.
GFS: Open wave heading due westward.
CMC: open wave heading due westward.
NAVGEM: Stationary TD in the Bay of Campeche.

My take: I am going towards the GFS/CMC scenario. I just dont see any factors going for it. It’s poorly organized and I highly doubt it will be able to develop into anything.

There is a tropical wave off of Central America in the Eastern Pacific ocean. It has plenty of convection and will not have too much of a problem developing in the next few days.


This is a satellite image that shows the abundance of convection associated with 99E. As I said, It has little to worry about in terms of development.


In this graphic, I’ve highlighted the center in black and a developing spiral band in red. The storm has good outflow channels in all directions and plenty of convection which is well organized. Now all it has to do is organize an LLC and it will become the 12th depression of the Eastern Pacific hurricane season.

The forecast for 99E



This map shows what the hurricane models think of the storm’s track.
My take
I think that the hurricane models have it nailed here. Monsoonal flow that is bringing flooding to the Southwestern US will likely suck 99E to the north like it did to KIKO a few days ago. I expect the only impacts on land will be widespread rain across northwestern Mexico and the southwestern US.



This map shows what the hurricane models think of the intensity of 99E in the coming days.
My take
I expect the models to be a slight bit conservative here. I think a strong CAT 1 is certainly possible here. This area has spawned some very intense tropical cyclones over the years and the disturbance is very well organized.

Tropical depression KIKO is dying and in another couple of hours will be nothing more than a low level swirl. Therefore, there is not much to say about KIKO.


Tropical depression KIKO in the Eastern Pacific.

In other weather news…
A cold front is moving through the eastern US bringing heavy rains to the region. Expect clearing tomorrow afternoon. Until then, beware of flooding as this system has a lot of moisture associated with it.
In the western Pacific tropical storm TORAJI is expected to hit Japan in a few days bringing heavy rains and high winds to the country.


This map shows the expected track and intensity of TORAJI.

Next update will be in the next 2 days.


Reliably hype-free weather info for Western Maine and New Hampshire from amateur forecaster Jack Sillin

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