MAweatherboy1's Blog

Invest 99L May Slowly Develop

By: MAweatherboy1, 10:09 PM GMT on July 30, 2012

The tropics have come to life in the last couple days. Very briefly I should mention that a very large, strengthening typhoon, Saola, is bearing down on the island nation on Taiwan and has the potential to casue life threatening floods and mudslides. The JTWC says the system has maximum sustained winds of 55kts. I do not claim to know better than the experts, but this is absolutely ridiculous as Figure 1 shows Saola is almost certainly a typhoon.

Figure 1: Tropical Storm Saola.

Also in the West Pacifc, Tropical Storm Damrey is heading for a brush with southern Japan and an eventual landfall in northern China, with flooding being the main threat from this weak system currently only packing winds of 40mph.

99L May Develop
For the first time in a while, we are tracking an area of interest in the Atlantic with a real chance to develop. This area, Invest 99L, is located approximately 900 miles SW of the Cape Verde Islands, and is moving steadily westward at 10-15mph. 99L has changed little in organization today, with recent satellite images showing perhaps a slight improvement. This should be the general trend for the next 2 days or so. 99L is located in a low wind shear environment and in a fairly moist environment, with most of the Saharan Air Layer to the north of the system. However, this position, while keeping 99L out of the SAL, is also providing it with its biggest problem: Like most systems within 10 degrees of the equator (99L is at 9 degrees N), the system will struggle to get the spin necessary to develop. Despite this, however, many models do indicate gradual development. The National Hurricane Center gives 99L a 20% chance of developing in the next 48 hours. I agree with this percentage, but think that there is a higher chance than that, maybe 50-60%, of it developing at any point in its lifespan. Should development occur, track and intensity are very uncertain right now. Long term intensity will likely depend on track. At least in the short term, there is high confidence in a continued W to WNW motion, bringing the system near the Lesser Antilles. It should be gradually organizing during this time, and could arrive in the Antilles as something between a tropical depression and moderate tropical storm. Beyond that, however, track is highly uncertain. Here's the model breakdown:
GFS: Continued western track into Caribbean, slowly strengthens but then dissipates once it gets into the Caribbean. It should be noted that the 12z GFS backed off on its intensity forecast, which hurts my confidence on this system developing at all. We will have to see if this trend continues.
GFS ensembles: Several of them take the system north of the Caribbean and strengthen it significantly, making it a hurricane with landfall on the East Coast or a track out to sea.
ECMWF: Has shown no or very little development consistently, not uncommon for this model before development. If it catches on then confidence on something forming will go way up.
CMC: Has been taking a northerly track and strengthening the storm more, indicating possible East Coast impacts.
UKMET: Has not shown much development but has shown anything that does develop heading west into the Caribbean.
The key will be how fast the system develops. A stronger system is more likely to take the northerly track, while a weaker system would take the southerly track. It's too hard to speculate very much on this right now since we don't have a developed system yet. The same goes for intensity. The SHIPS model makes 99L a hurricane, but it almost always forecasts strengthening of any invest that forms, so I wouldn't put much faith in this. The bottom line is that everybody should be watching this, whether they are in the Caribbean or anywhere on the US coastline as very little is certain about this system right now.

Figure 2: Invest 99L

I will be working at the Blue Hill Observatory from 7:30-2:30 for the next three days so I will only be on later in the afternoon for these days. Don't miss me too much.
Thanks for reading!

Two West Pacific Storms

By: MAweatherboy1, 10:21 PM GMT on July 29, 2012

The West Pacific remains active tonight, as two tropical cyclones are churning in the waters of this basin. The stronger of the two is Tropical Storm Saola. Saola is currently located about 425 nautical miles SSE of Taipei, Taiwan, and is moving NW at about 7kts according to the latest advisory from the Joint Typhoon Warning Center. It currently has maximum sustained winds of 55kts, or about 65mph.

Forecast for Saola
Saola is in a very moist environment and over warm waters and in an environment of fairly light shear. Because of this, continued strengthening is forecast. The JTWC intensity forecasts have progressively become more aggressive, and they now forecast a peak intensity of 100kts (115mph), making Saola a Category 3 hurricane on the Saffir Simpson Scale. After this, weakening is forecast as Saola will likely interact with the mountainous island nation of Taiwan. It will also move into less favorable atmospheric conditions. My personal intensity forecast is a bit less aggressive than that of the JTWC, as I think the system will peak around 90-95kts due to an increase in shear just before the forecasted peak intensity near Taiwan.

Figure 1: Tropical Storm Saola.

The JTWC has been consistently moving the forecast track farther right than the first advisory showed, as the new track indicated Saola may only graze the northern part of the island, while earlier forecasts indicated a strike near the center of the country. Saola is being steered NW to NNW by a subtropical ridge, and this motion should continue for much of the storm's life. Several of the models are in good agreement on the track towards northern Taiwan, so that is where I think the storm will go. A less likely scenario is depicted by the GFS and NOGAPS, as they favor a track farther to the east. This is likely because they are showing Saola interacting with Tropical Storm Damrey. This is unlikely, however, so this scenario can be mostly ruled out. After its brush with Taiwan a weakening Saola will likely track NW into China.

Figure 2: Official JTWC forecast track for Saola.

Saola has the potential to cause significant problems on Taiwan. One unique aspect of this system is its massive size. This will of course allow it to deposit a lot of rain on any areas it targets, so flooding and flash flooding will be a big concern. Mudslides will also be a big threat since Taiwan is very mountainous. Storm surge will also be a threat since a big system like Saola can push a lot of water in front of it. Everyone there should closely monitor the situation in the coming days as a lot can change.

Damrey Slowly Organizing
Also in the West Pacific, Tropical Storm Damrey has been slowly getting its act together today. As of the latest JTWC warning, Damrey is located about 200 nautical miles ENE of Iwo-To, Japan, and is moving WSW at 4kts. Maximum 1 minute sustained winds are estimated at 40kts (45mph) by the JTWC.

Forecast for Damrey
Damrey is in an environment that is marginally conducive for additional strengthening. Figure 3 shows a good deal of dry air surrounding the system.

Figure 3: Water vapor image of Damrey.

Conditions are not expected to become extremely favorable, but the JTWC does forecast slow but steady strengthening with a peak of 55kts (65mph) in about 3 days. I, however, am skeptical of much strengthening at all, as the systems satellite presentation has not improved and, if anything, has gotten worse today. I will forecast only slight strengthening to 45 or 50kts. Damrey's WSW motion should stop soon, and it should begin a more WNW to NW motion as the subtropical ridge becomes the main steering factor. It will begin to accelerate some in about 3 days and make landfall in China in about 4 days. The main threat will be flooding rains.

Watching the Atlantic
While it is fairly calm now and has been much of this month, all eyes will likely fall on the Atlantic in a few days. A tropical wave is being developed by multiple models, most notably the GFS and CMC. While model consistency has been a problem, it is beginning to improve, so there is a real chance we will see development within the next week. Right now it doesn't look like a major storm, but anything is possible with these waves. Track is also uncertain, but I would like to be more confident that we will actually see development before I speculate more on this potential storm.

Thank you for reading, and have a great week!

Tropical Storm Saola Forms, Targets Taiwan

By: MAweatherboy1, 1:12 PM GMT on July 28, 2012

After a few days of quiet in the wake of Typhoon Guchol, the tropics have come alive again, and once again the action is in the West Pacific. The Joint Typhoon Warning Center is issuing advisories on newly named Tropical Storm Saola. As of the latest JTWC advisory, Saola is located approximately 265 nautical miles east of Manila, Philippines. It is moving WNW at about 14mph. Saola currently has maximum 1 minute sustained winds of 35kts, or roughly 40mph, making it a minimal tropical storm. The disturbance that developed into Saola has already produced flooding rains in the Philippines.

Forecast for Saola
Saola is in a very moist environment and over very warm waters, both important factors in determining how much, if any, a storm can strengthen. The other main factor is wind shear. Saola is currently in an environment of fairly light shear. Its track, however, will take it into an environment of more moderate shear, so the main question for intensity will be how it handles this shear. The JTWC forecasts steady strengthening to a peak of 75kts before landfall on Taiwan. One thing that could help Saola is its very large size. This will likely help prevent shear from seriously disrupting the system. I generally agree with the JTWC intensity forecast. If anything I would forecast a slightly higher peak intensity, possibly 80-85kts, due to the possibility that it takes advantage of its current favorable environment to strengthen more in the short term than forecast. However, as we have seen with large storms in the past, they sometimes struggle to bring their winds up due to their large circulations, so a lower than forecasted peak is also possible, though less likely.

Figure 1: Tropical Storm Saola.

Figure 2: West Pacific shear and shear tendency.

The track forecast is very difficult as models are in poor agreement. A ridge is steering the system in a generally WNW to NW direction. Some models, most notably the ECMWF, favor a stronger ridge that would drive Saola further west, while others, including the GFS, show an abrupt right turn in the near future. The JTWC thinks these models may be showing an interaction with a potential developing storm (Invest 95W) to its northeast. This solution seems unlikely however, so the JTWC has opted for a steady NW track that brings Saola into Taiwan in 4-5 days.

Figure 3: Official JTWC forecast track, showing a large cone of uncertainty.

If the intensity forecast holds then Saola would come into Taiwan as a Category 1 typhoon. Heavy rains and especially dangerous mudslides on the mountainous island will be the main threats if it comes in that direction, with gusty winds and storm surge lesser threats. After landfall in Taiwan Saola is likely to turn more WNW instead of NW, bringing it into China about 2 days after landfall in Taiwan. It would likely weaken some over Taiwan and possibly restrengthen slightly after reemerging over water before landfall. This is all subject to change, however, as the JTWC acknowledges that this is a low confidence forecast.

Another disturbance in the West Pacific, Invest 95E, is being watched for development. It is struggling with shear as its center is fully exposed. However, the JTWC still thinks this system will develop soon as they have issued a Tropical Cyclone Formation Alert for it, meaning it is likely to develop in the next 24 hours. I will write an update should this system form. The Atlantic and East Pacific are both quiet with no areas currently being watched for development. Waves continue to roll off the African coast, and some models, including the GFS and NOGAPS, have shown some weak development. Any significant development is unlikely, however, due to unfavorable conditions in the Tropical Atlantic and Caribbean. Multiple models have shown the potential for East Pacific development in the next 10 days, particularly the ECMWF, so I think it is likely we'll see Gilma by August 5th.

Figure 4: Invest 95W

Thank you for reading, and enjoy your weekend!

Disturbance Near Florida; 90E Organizing; Vicente Strengthens

By: MAweatherboy1, 9:11 PM GMT on July 22, 2012

The tropics have sprung to life over the past couple days. The most interesting feature close to home is an area of disturbed weather not far southeast of the south coast of Florida. This area is being given a 10% chance of development in the next 48 hours by the National Hurricane Center. It is moving northwest at about 15mph. Here are some pros and cons for this disturbance:
Pros: Warm waters, moist environment, and it already has confirmed winds of at least tropical depression force
Cons: It is in an area of high surface pressures, none of the models have picked up on it, and it has quite a bit of land around it.

Any development of this system will hinge on what happens in the next 12 hours. We are heading into DMIN, so it will be more difficult for the system to maintain itself. However, if it survives this and can organize further overnight, it may have a chance of becoming Ernesto tomorrow morning. This is not particularly likely, however, so I give the system only a 30% chance of development. This is higher than the latest NHC update, but I still don't see development of this system. Regardless of development, impacts will be the same: Heavy rains and gusty winds for Florida.

90E Organizing
In the East Pacific, Invest 90E has continued to organize today and is now being given an 80% chance of development in the next 48 hours. The system is currently in the open waters of the Pacific, far from the coast of Mexico. 90E is in fairly favorable conditions, and several models are picking up on it, so I give it a 90% development chance. Before it hits cooler waters in 5 days or so, 90E should strengthen some, probably peaking as a moderate to strong tropical storm, due to the low shear and warm waters in its path. 90E should not threaten land as it will move WNW, taking it further away from the Mexican coast. 90E should dissipate before reaching Hawaii.

Figure 1: Invest 90E.

Vicente Strengthens
In the West Pacific, Tropical Storm Vicente has continued to slowly but steadily organize. It is moving very slowly WSW over the South China Sea with maximum sustained winds of 50mph. The official forecast from the Joint Typhoon Warning Center has come into my line of thinking from the other night forecasting a minimal typhoon. As the official track shows, Vicente should soon stop its WSW motion and head WNW.

Figure 2: Official forecast track for Vicente.

Despite this, the main threat will certainly still be heavy, flooding rains from the slow moving storm as well as mudslides as it heads for an eventual landfall in northern Vietnam 3 days or so from now. Vicente should speed up some from its current 3 knot crawl, but it will still have time to dump up to a foot of rain in Vietnam.

Elsewhere, tropical development is unlikely for the next 2-4 days.

Thank you for reading, and enjoy your week!

Tropical Depression 9W Forms

By: MAweatherboy1, 9:42 PM GMT on July 20, 2012

After a brief few days which saw the Earth void of any tropical cyclones, a new tropical depression has formed in the West Pacific. The disturbance that became this depression has been tracked for days and overall the Joint Typhoon Warning Center (JTWC) has done a good job in predicting the system's development. Advisories were initiated on the system, dubbed TD 9W, this afternoon. As of the first advisory on the system, 9W is located about 220 nautical miles north of Manila, Philippines. It is moving west at about 14 knots. 9W currently has maximum sustained winds of just 25 knots (30mph), so it is barely a tropical cyclone right now.

Forecast for 9W
9W is currently very disorganized. The center has struggled to consolidate and has been difficult to locate on satellite imagery. In addition, 9W is very tangled up in the Philippines, making it difficult for it to strengthen. It is also under moderate wind shear from the east, so much of its convection is on its west side. Because of this shear and the land interaction, major strengthening is not anticipated during the next 24 hours. Beyond that time, however, 9W will enter into the warm waters of the South China Sea, where shear is lower and the air is very moist. This will allow 9W to strengthen, and the JTWC forecasts a peak intensity of 55kts (65mph), making 9W a moderate to strong tropical storm. I am a little more aggressive in my intensity forecast as I think 9W will take advantage of these favorable conditions and peak as a minimal typhoon with winds of 65kts (75mph) in about 4 days. The track forecast is fairly simple, but is complicated some by low confidence in the center location and the very real possibility that the center could reform over the next 24 hours. However, 9W should track generally to the west or WNW for most of the forecast period under the influence of a building subtropical ridge. This track will have 9W skirt the southwest portion of China before eventually making landfall in Vietnam in about 5 days, after which it will quickly weaken and dissipate. The main threat will be heavy, flooding rainfall and dangerous mudslides, with damaging winds and storm surge lesser threats.

Figure 1: Official JTWC forecast track of 9W.

Figure 2: The disorganized Tropical Depression 9W.

Quiet Elsewhere
The Atlantic and East Pacific are very quiet right now, with no areas being watched for development in either basin. Conditions in the Atlantic, Caribbean, and Gulf are mostly unfavorable except for warm waters, so any development through early August is unlikely. It's difficult and usually quite foolish to speculate beyond then, but right now I still feel pretty confident in about 12 named storms, though that may need to be adjusted downwards a bit if conditions remain unfavorable. El Nino appears to be progressing on or slightly behind schedule, but it still appears it will be here for the peak of the season, though a strong El Nino is very unlikely.

Lastly, as I wrote about a week or so ago, I will be going on vacation to Vermont starting tomorrow. I'll still be around but not as much and I probably won't have time for any full blogs. Luckily, unlike when Dr. Masters goes on vacation, the tropics should be very quiet while I'm gone. Thank you for reading and have a great weekend!

Figure 3: The Von Trapp Family Lodge in Stowe, VT, where I will be staying this week. You're jealous :)

Tropics Quieting; A Day at Blue Hill

By: MAweatherboy1, 1:22 AM GMT on July 18, 2012

The tropics are falling quiet tonight. Fabio is dissipating over the chilly East Pacific waters. In the West Pacific, Tropical Storm Khanun is a mid strength storm that is likely near or past its peak intensity as it begins to move into cooler waters. It will make landfall Friday in the drought stricken country of North Korea, so it will hopefully provide at least a little relief.

Figure 1: Tropical Storm Khanun. Image credit.

The Atlantic is currently quiet, as the area of disturbed weather dubbed Invest 91L earlier today was likely a mistake by the HPC. Development over the next 2 weeks is unlikely as it appears any lows that form off an East Coast trough split early next week will be non-tropical. As of the 8PM TWO from the NHC, a disturbance in the East Pacific has been given a 10% chance of development in the next 48 hours and may be declared an invest tomorrow.

A Day at Blue Hill
As I've mentioned before on the blog, I am working at the Blue Hill Meteorological Observatory in Milton, Massachusetts part time this summer. This is a summary of what we/I do there. I typically arrive around 7:30 in the morning. I am not the chief observer; The chief observer arrives earlier, closer to 7:00 AM. One tricky thing that takes some getting used to is that everything at the Observatory is done in Eastern Standard Time. We don't use daylight savings. So 7:00 is really 6:00, etc. Blue Hill is a climate center, not a forecast center. We take readings and examine data, but we don't actually forecast. We take three major readings per day. The first and most extensive occurs at 8:00 AM EDT. At 7:50, we (the chief observer, myself, and anyone else working that day) go to the top of the Observatory to take cloud cover and visibility readings. Our maximum possible visibility is 90 miles. We can see all the way to New Hampshire when that happens! Today, however, was very hazy so visibility was only about 20-25 miles, which is quite low. We have several landmarks that we use to determine how far we can see. After this, we go to the instrument enclosure just outside the Observatory building and take 4 main readings: A dry bulb (current) temperature, a wet bulb (thermometer with a wick that we wet on it) temperature, a minimum temperature from overnight, and a maximum temperature from the previous day. We then go back inside and enter all the data into our computer system. One of my main jobs is to annotate the daily wind charts; there are three of them. One has wind speed and direction on it, one has only speed on it, and one has miles of air to pass the Observatory on it. The charts I did today were for the previous day (Monday). We had 189 miles of air pass the Observatory, the average wind speed was a very low 8.3mph, the fastest mile of air was 17mph, and the peak gust was a meager 23mph. At 9:00 EDT, we take the temperature again, and replace a chart called a hydrothermagraph that shows temperature and humidity. If necessary we also replace the ombroscope chart. The ombroscope is basically just a blank chart that we color in washable marker. If it rains the marker washes off so we have a record of when it rained! Simple but brilliant. At 11 AM EDT we take another set of readings just like we do at 8 AM. At noon we replace our sun card. The sun card is just a unique paper material with time stamps on it that we place underneath a large glass ball. Sunlight beating on the glass ball reflects onto the paper and burns it, giving us a record of when it was sunny. Finally at 2PM EDT we take the final daily set of readings just like what we do at 8 and 11AM. We have multiple automated system that monitor conditions when an observer is not present. There are other projects that go on when we aren't taking readings. Sometimes there are tour groups that myself or others working there show around the Observatory. Or if there's nothing else to do we generally work on maintenance projects (we're in the process of repainting our main instruments shelter) or weather related projects mostly consisting of putting data into computers. See the pictures below for more details.

Our sunshine recorder.

The main building.

Many of our anemometers.

Our chief observer, Mr. Robert Skilling (nicest guy ever). He's worked there for over 50 years. At the top left are the mercurial barometers, including the oldest one in North America, which has been in use almost as long as the Observatory has recorded. We are in our 127th consecutive year of observing. At the far right and extending off the screen are the wind charts.

Another view from inside the observer's room.

Thank you very much for readings. Feel free to ask me questions/ give feedback. I kept it kind of concise but if you want me to give some more details I'd be happy to. You can also explore our website. Enjoy your night!

Fabio Weakening; Khanun Slowly Organizing

By: MAweatherboy1, 10:49 PM GMT on July 16, 2012

Due to drier air and cooler waters than it has experienced through its lifespan, Fabio weakened to a tropical storm today. As of the National Hurricane Center's 5PM advisory, Fabio has maximum sustained winds of 70mph and a minimum central pressure of 992mb, making it a high end tropical storm. Fabio's anticipated turn northward has begun, as it is now moving NNW at 9mph according to the NHC. Fabio is not currently threatening any land areas as it remains about 700 miles WSW of the tip of Baja California.

Forecast for Fabio
Fabio has been moving WNW, but now is being pulled north due to a weakness in the subtropical ridge which has been steering it. Fabio should continue to turn further to the right, going due north by tomorrow and then turning more NNE. The intensity forecast is fairly simple. Fabio is entering into increasingly drier air as well as water temperatures far below what is needed to support a tropical cyclone. Thus, steady weakening is forecast and the NHC says Fabio will be post tropical by Wednesday evening, which I agree with. Convection has occasionally flared up today, but the eye has disappeared and any convective flareups should quickly die down.

Figure 1: Tropical Storm Fabio. Image credit.

Tropical Storm Khanun Forms
In the West Pacific, Tropical Storm Khanun formed earlier today. According to the Joint Typhoon Warning Center, Khanun has maximum sustained winds of 35kts (40mph), making it a minimal tropical storm. It is moving WNW at about 17mph and is located about 275 nautical miles east of Kadena Air Base, Okinawa as of the latest JTWC warning.

Forecast for Khanun
Khanun is not in an ideal environment for strengthening, but marginal strengthening is possible for the next 24 hours. The JTWC forecast a peak of 45kts (50mph). I think a slightly weaker storm is likely, probably about 40kts (45mph). Khanun is being steered by the subtropical ridge, and should continue on its WNW motion for another 12-24 hours before turning more NW and eventually due north. The forecast path has shifted west some since yesterday but still shows Khanun making landfall in southwestern South Korea. Khanun will be weakening rapidly by then however due to much cooler waters. Hopefully it can hang on long enough to provide the Korean peninsula with some much needed rain as that area is suffering through its worst drought in 100 years. Unfortunately, the weakening and accelerating Khanun will likely do very little to help.

Figure 2: Tropical Storm Khanun. Image credit.

With Fabio and Khanun both expected to be gone within a couple days, it appears we are heading into a slow period for the tropics. Some models, most notably the GFS, are showing possible Atlantic development off the East Coast in 5-7 days from a trough split. My thinking hasn't changed much on this, and I continue to give it about a 30-40% chance of producing a tropical cyclone.

Thanks for reading, and enjoy your night!

Fabio Peaks; TD 8W forms; Watching the Atlantic Next Week

By: MAweatherboy1, 10:27 PM GMT on July 15, 2012

The only named tropical cyclone on Earth this evening is Hurricane Fabio in the East Pacific. As of the National Hurricane Center's 5PM advisory, Fabio is currently located 660 miles SW of the tip of Baja California. It is moving WNW at 10mph. Fabio attained a peak intensity of 105mph yesterday and held that intensity through last night and most of today. Fabio has started to slowly weaken, however, and as of the 5PM advisory its maximum sustained winds have decreased to 100mph, with a minimum central pressure of 974mb.

Forecast for Fabio
Fabio is currently being steered by the subtropical ridge. A trough currently over the Northwest US will continue moving southeast and allow Fabio to turn further to the right. It should be moving due north by early Tuesday as the forecast track suggests.

Figure 1: Official NHC forecast track for Fabio

The intensity forecast is also fairly straightforward. Fabio is currently in an environment of fairly low shear and moderately dry air. It is steadily moving into cooler waters. Because shear is low and it is not in an extremely dry airmass, weakening should be gradual at first, for about the next 12-24 hours. After that, however, Fabio will move into much cooler waters and drier air as it turns north, so weakening should become more rapid by late tomorrow. If you were to extrapolate Fabio's projected path it would take it into northern Baja California, but Fabio should be dissipated well before it gets there. The NHC forecasts Fabio to become post-tropical by Wednesday evening, which I agree with.

Figure 2: Visible image of Hurricane Fabio. Its cloud filled eye indicates weakening. Image credit.

Also in the East Pacific, former Hurricane Emilia dissipated today and is now a weakening remnant low as it moves into the Central Pacific Hurricane Center's area of responsibility. Any redevelopment of Emilia is not expected as it is in very hostile conditions.

New Tropical Depression in the West Pacific
For the first time in a while, there is a tropical cyclone in the West Pacific Ocean tonight, Tropical Depression 8W. 8W is currently located about 630 nautical miles ESE of Kadena Air Base, Okinawa, according to the latest advisory from the Joint Typhoon Warning Center. It is moving WNW at about 14 knots. 8W is in a moderate shear environment. There is a lot of dry air to its northeast but more moist air to the west, the direction it is moving. It is also over warm waters right now. The intensity forecast is tricky because besides some shear, 8W will be moving into a favorable environment. However, right now it looks very poor as Figure 3 shows.

Figure 3: Tropical Depression 8W. Image credit.

8W has been unable to organize a good cloud and outflow pattern, likely because of the dry air to its northeast. The tricky part of the forecast is determining whether or not it will shake off this dry air, wrap convection around itself, and strengthen. The official JTWC forecasts brings 8W to a peak of 40 knots, which is likely a compromise between two possible scenarios.
1. 8W shakes off the dry air quickly and uses the more moist air in its path and warm waters to become a strong tropical storm.
2. 8W fails to organize due to shear and dry air and dissipates quickly or remains a weak tropical depression.

I think the second scenario is the more likely of the two, but just to be safe I will forecast a peak of 40mph, making it a minimal tropical storm.
The track forecast is easier. 8W is being steered by the subtropical ridge, and should continue tracking northwest for most of its lifespan. As it starts to arrive in cooler waters and weaken, it will begin to turn north. As the official track shows, this should result in 8W making landfall in South Korea as a weakening or dissipating system.

Figure 4: Official JTWC track for 8W.

Watching the Atlantic Next Week
Multiple models, including the GFS, are forecasting the potential for trough split development off the East Coast in about a week. Shear is lower than normal off the East Coast, so anything that attempts to form will have some chance. I give this potential East Coast development about a 30-40% chance of happening, a bit higher than I was thinking last night. Also in the Atlantic, a train of tropical waves continues to roll off of Africa. Conditions in the Central and Eastern Atlantic are not currently conducive for development however, so none of the waves will develop.

Thank you for reading, and have a great week!

Emilia Dissipating; Fabio Strengthening

By: MAweatherboy1, 12:28 AM GMT on July 15, 2012

As July nears its midpoint we continue to see all of the globe's tropical cyclone activity focused on the East Pacific basin. There are currently two active cyclones in the East Pac, one of which is Tropical Storm Emilia. Emilia is currently located about 1600 miles WSW of the tip of Baja California according to the National Hurricane Center's 5PM EDT advisory. She is moving west at 15mph. According to the 5PM advisory Emilia has maximum sustained winds of 50mph and a minimum central pressure of 997mb.

Forecast for Emilia
There's not too much to say at this point. Emilia is a very small, weak, shallow system being influenced by nothing more than standard Pacific trade winds blowing from east to west, so she should continue to move in this direction for her remaining lifespan, as the official forecast track in Figure 1 shows.

Figure 1: Official forecast track for Emilia.

As far as intensity, there's not much to say for that either. Emilia is embedded in a very dry environment and over cool sea surface temperatures.

Figure 2: Water vapor image of Emilia.

Figure 2 shows tiny Emilia completely surrounded by dry, stable air. The NHC is forecasting her to dissipate in about 36 hours. I, however, think she will be declared post tropical tomorrow based on the fact that her low level center is now exposed, with the few remaining thunderstorms to the east of the center. Regardless, Emilia is no threat to land as even if she did maintain intensity she would pass south of Hawaii. Emilia should move into the Central Pacific Hurricane Center's area of responsibility tomorrow, if she survives that long.

Fabio Strengthens
Also in the East Pacific, Hurricane Fabio has strengthened today. According to the National Hurricane Center's special 8PM EDT advisory, Fabio is located nearly 600 miles SW of the tip of Baja California. It is moving WNW at 9mph. According to the 8PM advisory, Fabio has maximum sustained winds of 105ph and a minimum central pressure of 972mb, making it a Category 2 hurricane on the Saffir Simpson Scale.

Forecast for Fabio
Fabio is under the influence of the subtropical ridge, which has been forcing it in a W to WNW direction for most of its lifespan. However, a trough will soon move in from the northwest, allowing Fabio to escape through a break in the ridge. It should turn NW and eventually N.

Figure 3: Official forecast track for Fabio.

As far as intensity, Fabio is probably nearing its peak. Shear is expected to stay low to moderate, but Fabio will soon be moving into cooler waters and drier air, which will weaken it. The NHC intensity forecasts calls for Fabio to begin weakening immediately, but I think it will hold its current intensity or strengthen slightly in the short term based on its current healthy appearance.

Figure 4: Hurricane Fabio.

It should be noted that T numbers are currently at 5.6, 5.8, and 5.8, which would mean Fabio is a major hurricane. However, T numbers seem to have been running high all day so while it is possible Fabio is slightly stronger than currently shown, it is likely just short of major hurricane intensity. Fabio should weaken slowly at first, for the next 24-36 hours, as it gradually moves into less favorable conditions. After this, more rapid weakening should begin as Fabio turns north and really hits the cooler waters. Some models, including the GFS, show Fabio moving on a course that brings it towards southern California or northern Baja California, however it will be dissipated by the time it gets this far, if it does indeed go in this direction.

An area of disturbed weather is being watched for development in the West Pacific. It is being given a medium chance of development in the next 24 hours by the Joint Typhoon Warning Center. Looking ahead in the Atlantic, the only chance of development in the next 10 days appears to be from a potential trough split off the US East Coast in about a week. I think there's a 20-30% chance we see development out of this. Finally, looking ahead in the East Pac, it appears the storm train out there will take a breather after Fabio dissipates, but models have continued to show more development in this basin over the next 2 weeks. It is looking more and more likely that we will reach the 20 storms mark in the East Pac this year.
Finally, a couple of personal notes.
1. I gained a lot of respect for forecaster Roberts from the NHC last night. He wrote the NHC's 11PM EDT advisory last night and forecasted a peak intensity of 110mph, above what most guidance was showing. Very rarely will anyone from the NHC stick their neck out and make a gutsy call like this, but he did, and he turned out to be right even when other forecasters overturned his predictions at later advisories, so kudos to him.
2. Next Saturday I'll be leaving with my family for our annual summer trip to the ski town of Stowe, Vermont. While there's no skiing in the summer, it's still a beautiful place up there year round and I always look forward to the trip. Luckily it looks like the tropics will be pretty quiet while I'm up there since I won't have much time for blogging.

Thank you for reading, and enjoy the rest of your weekend!

Emilia Weakening; Fabio Strengthening

By: MAweatherboy1, 12:09 AM GMT on July 13, 2012

As has been the case for a while now, the East Pacific is the focus of tropical activity tonight. There are currently two active cyclones in this basin, one of which is Hurricane Emilia. Emilia is currently located about 1000 miles WSW of Baja California according to the National Hurricane Center. It is moving west at about 12mph. As of the 5PM advisory from the NHC, Emilia has maximum sustained winds of 105mph and a minimum central pressure of 965mb. This intensity makes it a Category 2 hurricane on the Saffir Simpson Scale.

Forecast for Emilia
Emilia is currently in a fairly dry environment, as Figure 1 shows.

Figure 1: Water vapor image of Emilia.

In addition to the drier air, Emilia is also struggling with the cooler sea surface temperatures it has moved into over the past day or so. The NHC is forecasting Emilia to weaken below hurricane status in a little over a day, and to become a remnant low in 4 days. Emilia looks very poor right now. However, powerful storms like her take time to spin down and often maintain tropical storm force winds when it really doesn't look like they have them. So while it seems to make sense to forecast a quicker demise of Emilia than what the NHC is projecting based on her current poor appearance, I actually agree with their timeline. Regardless, Emilia poses no threat to any land areas.

Figure 2: Wind history of Emilia, showing her general WNW path.

Fabio Strengthening, but Little Threat to Land
Meanwhile, the East Pacific's sixth storm of the season formed this morning, Tropical Storm Fabio. After maintaining a solid satellite appearance yesterday, Invest 98E was declared a tropical depression late last night and strengthened into Fabio this morning. Strengthening has continued, and Fabio currently has maximum sustained winds of 50mph and a minimum central pressure of 1000mb. It is currently located over 600 miles S of Baja California, and is moving towards the WNW at 10mph.

Forecast for Fabio
Fabio is currently in an environment of low shear, under 10kts. This is forecast to increase over the next day to near 20kts according to the SHIPS intensity model. However, Fabio is in a moist environment and over waters warm enough to allow for further strengthening. The NHC is forecasting Fabio to reach a peak intensity of 80mph in about 2 days, before it begins to weaken over cooler waters and more stable air.

Figure 3: Tropical Storm Fabio

Figure 3 shows Fabio has a fairly well defined cloud pattern, and is probably continuing to gradually strengthen right now. Probabilities for rapid intensification are fairly low as Fabio is not over the same very favorable conditions Emilia had. However, I think a peak of 85-90mph is likely, slightly more than what the NHC is thinking, based on the moist environment and warm waters Fabio is in. If it has a problem with the increasing shear it may not make hurricane status at all. The track forecast is fairly straightforward. Over the next 2-3 days Fabio should continue a steady WNW motion. However in about 4 days Fabio will enter into a break in the ridge that is steering it now, turning on a more NNW path. While this will bring it closer to Baja California, it will not recurve into the peninsula, and even if it did head in that direction, it would be dissipating or dissipated by the time it got there.

Figure 4: Official track forecast for Fabio.

I've been working at the Blue Hill Observatory again this week and helped prepare the daily discussions for yesterday and today, which can be found here for Wednesday and here for today.

Thank you for reading, and have a great rest of the week!

Daniel Spinning Down; Emilia Spinning Up

By: MAweatherboy1, 11:54 PM GMT on July 08, 2012

The East Pacific continues to be the focus of tropical activity tonight, with two storms churning through its waters. The more powerful of the two right now is hurricane Daniel. Daniel currently has winds of 105mph and a pressure of 970mb according to the National Hurricane Center's 5PM update. It is located over 1100 miles SW of the tip of Baja California and is continuing to move west at 14mph according to the NHC. For the last day Daniel has defied his intensity forecasts, as he strengthened into a major hurricane late last night despite moving into cooler waters and drier air.

Figure 1: Water vapor image of Hurricane Daniel.

These harsh conditions have begun to get the upper hand on Daniel however as he has weakened slightly. Still, he remains a powerful, but small, Category 2 hurricane. As Figure 1 shows, Daniel is fending off the mass of dry air quite well. However, it will soon begin to weaken faster because of the cool water temperatures, and this will help to allow the dry air to get more sucked into the system. Based on its healthy appearance right now, Daniel should maintain its intensity or weaken slowly for the next 12-24 hours. However once the dry air finds a way in, which should be in no more than a day's time, it will kill Daniel fast due to his small size. I think a dissipation in 3-4 days is likely, which is a faster time period than what the NHC is thinking, as they call for dissipation in 5 days. Regardless, Daniel poses no threat to land as it would miss Hawaii well to the south even if it did make it that far, which it won't.

Emilia Intensifying
Tropical Storm Emilia is the other East Pac system this evening, and it has intensified at a steadily quick pace today. According to the National Hurricane Center's 5PM advisory, Emilia has maximum sustained winds of 65mph and a pressure of 997mb. It is located over 800 miles south of the tip of Baja California and is moving WNW at 15mph. The good news with Emilia is that, like Daniel, it poses no threat to land. This is a good thing because it looks like Emilia is going to turn into a monster.

Figure 2: Tropical Storm Emilia

Figure 2, as well as other satellite instruments, show Emilia is attempting to form an eye and is likely near hurricane intensity. Emilia is in a moist, very low shear environment and over extremely warm waters, the perfect recipe for rapid intensification which may be happening as I type. The official NHC forecast brings Emilia to a peak intensity of 120mph in 2-3 days time. After this it will begin to encounter higher shear, cooler waters, and drier air, so it will begin to weaken. Because it is almost certain Emilia will undergo rapid intensification, if it is not already doing so, my forecast is more aggressive, as I think Emilia will become a Cat 4 hurricane and peak around 145-150mph. There is an outside chance Emilia could become a Category 5 storm. Regardless, it certainly will be a beautiful storm to watch.

Quiet Elsewhere
The rest of the tropics worldwide, including the Atlantic, are quiet tonight. I'm still expecting a chance for African development in about 2 weeks.

Thank you for reading, and have a great week!

Daniel Peaking; 5E Likely to Intensify

By: MAweatherboy1, 10:30 PM GMT on July 07, 2012

The action is definitely in the East Pacific this evening. The strongest storm out there right now is Hurricane Daniel. Daniel currently has winds of 90mph and a pressure of 977mb as of the National Hurricane Centers 5:00PM advisory today. Daniel remains in a relatively low shear environment. However it's path will soon bring it into much cooler waters as well as a significant area of dry air, as seen in Figure 1.

Figure 1: Water vapor image of Daniel.

As Figure 1 shows, dry air is already infiltrating the west side of the storm, so it won't be long before weakening begins. My thinking is similar to the NHC official forecast, calling for Daniel to be peaking right now and begin weakening soon. However due to the dry air and much cooler waters I anticipate Daniel to be dissipated in 4 days rather than 5 as the official forecast shows.

Figure 2: Official forecast track of Daniel.

As far as track for it's remaining lifespan, Daniel should continue in a generally westward direction until dissipation. This track brings it well south of the Hawaiian islands. However, even if it were to take aim at the islands, it would be too weak to provide any impacts.

TD 5E Likely to Become Hurricane Emilia
After being declared an invest only yesterday morning, Invest 97E organized quickly today to become the fifth tropical depression of what is proving to be a very active East Pacific hurricane season. TD 5E currently has maximum winds of 35mph and a pressure of 1005mb according to the National Hurricane Center. It is moving to the WNW at about 15mph. TD 5E is located well south of Mexico and is forecast to continue moving parallel or slightly away from the coast, as the official forecast track in Figure 3 shows.

Figure 3: Official forecast track of TD 5E.

Like Daniel, 5E will only be a threat to shipping interests as no land areas will be impacted. Daniel is in an environment that is very favorable for significant intensification. It is in an area with almost no wind shear, limited dry air, and extremely warm waters. The SHIPS intensity model is predicting an extremely high, 67% chance of rapid intensification. I think RI is almost a certainty for 5E as it has nothing stopping it from becoming a powerful hurricane. After about 5 days time 5E will begin to encounter cooler waters and drier air, which will begin to weaken it. The NHC is forecasting a peak intensity of 100mph. While even this is above the majority of model guidance, I think 5E will become a major hurricane thanks to rapid intensification and probably peak at about 120mph in about 4 days.

Figure 4: Tropical Depression 5E.

Quiet in the Atlantic
The Atlantic basin is very quiet right now with no invests nor any areas being watched for potential development. This should continue for at least another 2 weeks since the Atlantic will not have the MJO, which greatly aids in early season development. However, based on some signals I've seen from several of the recent GFS runs, I think development will be possible off the African coast in 15 days or so. The GFS has hinted at some vigorous waves off the African coast at that time, and while it is a long way out the GFS has been fairly good long range this season. Certainly no guarantees at this point, but it's something to keep an eye on. The three images below are from the three most recent GFS runs, showing low pressure in an area I think should be watched around 15 days time.

Thank you for reading, and enjoy the rest of your weekend!

Daniel and 97E in the East Pacific

By: MAweatherboy1, 9:25 PM GMT on July 06, 2012

As has been the case since the dissipation of Debby, the Atlantic is very quiet this evening, with no active cyclones nor any areas being watched for possible development. The East Pacific is a different story, however. Tropical Storm Daniel is currently located about 650 miles SW of the southern tip of Baja California. Maximum sustained winds of Daniel are at 70mph, and it's minimum central pressure is 993mb. Daniel is moving west at 12mph according to the National Hurricane Center.

Forecast For Daniel

Figure 1: Official forecast path of Daniel

The official NHC forecast track, shown in Figure 1, as well as the majority of model guidance, takes Daniel in a generally W/WNW direction throughout the forecast period. A continued movement in this direction would bring Daniel close to Hawaii. However, Daniel will not make it nearly that far.

Figure 2: Water vapor image of Daniel.

As Figure 2 shows, a wall of dry air lies in the path of Daniel. Combined with much cooler sea surface temperatures along Daniel's path, he will dissipate well before he can threaten Hawaii. The official NHC forecast brings Daniel to hurricane status soon and has him peak at 80mph while keeping him a hurricane through Sunday morning. The forecast then dissipates him on Wednesday. My forecast is much different. Daniel has been looking pretty ragged all day, and he is really starting to push into that dry air. I think he has probably already peaked or is nearing peak. I think he will most likely maintain this intensity, or perhaps briefly attain hurricane status, through tomorrow afternoon, but begin rapid weakening by tomorrow night or Sunday morning as he encounters very hostile conditions. I am predicting a complete dissipation by Tuesday afternoon.

97E Should Become Emilia
Invest 97E formed in the East Pacific this morning.

Figure 3: Invest 97E

As Figure 3 shows, 97E is large, broad, and disorganized. It is being given a 50% chance of development in the next 48 hours by the NHC. I put these odds a bit higher at 60% due to the favorable conditions 97E is in. It is very likely 97E will develop at some point, and once it does indications are that it will strengthen as it is in a moist, fairly low shear environment and over extremely warm water. To me, this seems like a perfect setup for rapid intensification. While still very early in the forecast process, I am expecting 97E to peak as a Cat 2 storm, though this could be too low if significant rapid intensification occurs. The good news with 97E is that it is expected to move in a WNW/NW direction, keeping it well offshore. High surf along the coast and dangerous rip currents will be the only threats. We have plenty of time to watch this system, so stay tuned for any changes.

Thank you as always for reading, and have a great weekend!

Random Thoughts

By: MAweatherboy1, 11:13 PM GMT on July 03, 2012

The tropics are quiet tonight, at least in the Atlantic, and have been for a little while and will be for at least a little while, so this blog is dedicated mostly to whatever I'm thinking about right now. First I want to give my opinion on the merger of Weather Underground and The Weather Channel Companies. I don't think it's the worst thing that could happen to WU, but if given the option to undo the merger, I would. TWC is without question the most recognizable name in the world of weather broadcasting. For the first 10-12 years of my life I was addicted to it. However the fact is that TWC is nowhere close to as good as it used to be. From the addition of weather clown Al Roker to the implementing of "TWC Social", it's turned into nothing more than a ratings game for them; Providing a good, thorough forecast no longer matters. WU on the other hand is online; There aren't really any ratings it needs to get. It provides a ton of great tools and is much more serious in its approach to weather, which is the way it should be. I sincerely hope that WU is able to maintain its identity in this process, and maybe even get a few more tools with the backing of TWC. I certainly wish Dr. Masters and the whole staff at WU the best as they get everything straightened out in the next couple months.

It's truly amazing the wild weather we've seen in the past month. The heat has been incredible. Not so much up here in Mass; We were below normal for June actually, but everywhere else. I especially feel for all those without power due to the amazing derecho that swept through the country from Chicago to Washington DC. Living without power in that heat must be unbearable. Even living without power for a few days after Irene in the 80 degree weather was tough for me, so I can't imagine what they are going through.

I also can't imagine what the residents whose homes are being threatened by the Colorado wildfires are going through. The destruction those fires have caused is simply amazing. I feel very lucky to live in an area where fire isn't a big concern. The uncertainty of whether your home is still standing or burned to the ground must be the most helpless feeling in the world.

I'm still thinking around 12 named storms for this year. We'll see one in July I bet and then August into early September will be the make or break point this year. Remember, it only takes one regardless.

Finally, happy birthday America! 236 years and still the best country on Earth.

At some point tomorrow, pause to remember the thousands of brave men and women who have fought and continue to fight to preserve the freedom we have, especially those who have given their lives for our country. As the son of an ex Navy member, I have a great appreciation for the dedication of all who serve our country.

Thank you for reading, and I hope you have a great 4th of July!

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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About MAweatherboy1

Average 20 year old weather nerd. Plymouth State University Meteorology, Class of 2018. NOAA Hollings scholar. Summer 2016 intern at NWS Boston.