MAweatherboy1's Blog

Tropics Bursting With Life

By: MAweatherboy1, 9:05 PM GMT on October 11, 2012

Despite the peak of the season being past us, there is a lot of tropical activity in the Atlantic, and the world, this evening. The biggest feature in the Atlantic right now is newly named Tropical Storm Patty. Patty currently has maximum 1 minute sustained winds of 40mph and a minimum central pressure of 1007mb. Patty is currently located 255 miles NE of the central Bahamas and is stationary.

Forecast for Patty
Patty does not have a long life ahead of it. Upper level conditions over Patty right now are marginally favorable, and I would not be surprised to see her strengthen another 5mph or so in the next 12-24 hours. However, beyond 24 hours, the already moderate shear will increase and tear the system up. Dissipation should occur in no less than two days and it may happen before then. Patty is a very interesting system as practically no one, including myself, thought it had any real chance of developing when it was first classified, and even by last night when it had remained organized for a while, the prospects for classification still looked bleak. I am looking forward to Patty's Tropical Cyclone Report after the season ends, which will hopefully shed some light on exactly how she developed and what the NHC was thinking as they tracked her precursor disturbance, 97L.


Figure 1: Tropical Storm Patty.

98L Likely to Develop
Also in the Atlantic, large invest 98L has been slowly but steadily organizing as it approaches the Caribbean. The National Hurricane Center gives 98L a 50% chance of developing in the next 48 hours. I agree with this percentage, but give the system an 80% chance of developing at some point in its life. 98L is currently located near Barbados, and is moving slowly NW. This motion is expected to continue, and 98L will likely brush the NE islands of the Caribbean. It is unlikely to be a strong system as it does this, but it will provide locally heavy rain nonetheless as it is a large disturbance. Beyond this time I am thinking that 98L will strengthen more, and likely recurve well east of the US. It is possible Bermuda could eventually see impacts but it is too early to know for sure right now.


Figure 2: Invest 98L.

97E May Develop
In the East Pacific, an area of disturbed weather, invest 97E, is currently located about 550 miles S of Manzanillo, Mexico. 97E has slowly organized over the past couple days, and it is currently being given a 40% chance of developing in the next 48 hours by the NHC. I put these odds slightly higher at 50%, with a 70% chance 97E develops at some point in its life under fairly favorable upper level conditions. 97E is slowly drifting west, further away from the Mexican coast, so it should not be a threat to land.


Figure 3: Invest 97E.

Prapiroon A Threat To Japan
The main feature in the West Pacific right now is Typhoon Prapiroon. As of the latest advisory from the Joint Typhoon Warning Center, Prapiroon has maximum 1 minute sustained winds of 95kts, making it a high end Category 2 equivalent on the Saffir Simpson Scale. Prapiroon is currently located about 400 nautical miles south of Kadena Air Force Base, Okinawa, and is crawling NNW at 3kts. It is soon forecast to take a hard NE turn, but not accelerate significantly. Then, after about 3 days, it is actually expected to turn back to the north. This is extremely unusual as you almost never see storm recurving to the NE turn back after three days of NE movement. I have been warning for a while that the previous tracks that were showing no movement back north would be too far out to sea and it appears this is the case. It still does not appear a direct hit on Japan will occur. The GFS and Euro have come into pretty good agreement on a track just south of the country, with the GFS moving north some, and the Euro, which a couple times showed a direct hit, moving south some. As far as intensity, Prapiroon is forecast to intensify slightly to 100kts and then level off, with no change for a day or two, then steady weakening to 80kts by 5 days. Prapiroon has been interesting because unlike most West Pacific storms that have become typhoons this year, it didn't get there through rapid intensification. It has intensified at a rather climatological rate. I'd like some more microwave imagery to back this up, but I think the storm will soon enter into an eyewall replacement cycle, which should induce some short term weakening and long term strengthening. My forecast peak intensity of 110kts from a few days ago remains unchanged, and it should be reached in 24-36 hours. Beyond this time I think the official forecast shows too much weakening in later days. There remains a lot of time to watch this one and I'll provide more information as time goes on.


Figure 4: Typhoon Prapiroon. The small, ragged eye seems to indicate an impending EWRC.


Figure 5: Official JTWC track of Prapiroon.

91S Likely to Develop
A very interesting system continues to churn in the south Indian Ocean this evening, Invest 91S. Southern Indian Ocean cyclone season does not officially begin until November 15, but 91S may have other ideas. I'm lazy so I'll just paste in what the JTWC is saying about it:

(1) AN AREA OF CONVECTION HAS PERSISTED NEAR 5.8S 74.4E,
APPROXIMATELY 145 NM NORTHEAST OF DIEGO GARCIA. ANIMATED INFRARED
SATELLITE IMAGERY AND A 111300Z SSMIS SHOW A BROAD LOW LEVEL
CIRCULATION CENTER WITH FLARING DEEP CONVECTION ALONG THE SOUTHERN
AND WESTERN PERIPHERIES. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM
LIES FOUR DEGREES NORTH OF A RIDGE AXIS IN AN AREA OF MODERATE (15-
20 KT) VERTICAL WIND SHEAR AND GOOD POLEWARD OUTFLOW. SEA SURFACE
TEMPERATURES IN THE AREA ARE ESTIMATED TO BE FAVORABLE (>28 DEGREES
CELSIUS). MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO LOW.

I will add that both the GFS and Euro develop the disturbance, and it should continue to move SW for the duration of its life. This brings it in the general direction of northern Madagascar, but it is likely that if it does make it this far it will be in a much weakened state. Still, this will be quite the event if 91S does in fact develop over a month ahead of the scheduled start of the season.


Figure 6: Invest 91S, looking pretty good right now.

Latest Dvorak classifications of the systems I mentioned:

11/1800 UTC 6.1S 72.8E T1.0/1.0 91S -- Southwest Indian
11/1800 UTC 11.1N 104.2W T1.0/1.0 97E -- East Pacific
11/1745 UTC 26.0N 71.9W T3.0/3.0 16L -- Atlantic
11/1745 UTC 12.0N 58.3W TOO WEAK 98L -- Atlantic
11/1501 UTC 19.5N 128.5E T5.0/5.5 PRAPIROON -- West Pacific

Thank you for reading and have a great evening/night!

Two Atlantic Invests; Prapiroon Organizes

By: MAweatherboy1, 11:41 PM GMT on October 08, 2012

We are watching two invests in the Atlantic basin this evening. The first is invest 97L. 97L is a sprawling system, with convection starting in the east central Bahamas and extending a couple hundred miles east. As of now, none of the reliable computer models develop this disturbance, and with upper level winds becoming even less favorable, development is highly unlikely. The National Hurricane Center is currently giving 97L a 10% chance of development in the next 48 hours, and I agree with this. While development is unlikely, enhanced shower and thunderstorm activity is likely for the Bahamas and surrounding areas for the next day or two.


Figure 1: Invest 97L, showing a large but very disorganized cluster of showers and thunderstorms. These should steadily weaken and become more disorganized in the next couple days.

98L May Develop Eventually
The other invest being tracked right now is 98L, which was designated this morning. 98L is currently located about 1500 miles ESE of the Lesser Antilles and is moving WNW at 15-20mph. 98L is definitely the more interesting of the two invests as several models are indicating some development of the system. One of the more aggressive models has been the GFS. As of right now, the National Hurricane Center gives 98L a 10% chance of development in the next 48 hours. I do not foresee any chance development in the next 48 hours, but beyond that things could get interesting. Right now 98L is mostly embedded in the ITCZ, and it is also at a very low latitude. Being stuck in the ITCZ prevents 98L from really gaining its own identity as a system and developing. The low latitude prevents the system from gaining spin and developing. I believe both of these issues will eventually be solved, and it will depend on upper level conditions to determine whether the system develops. It is currently too far out to know specifics, but here are two possible scenarios if development occurs.
1. 98L organizes faster than expected, skirts the northern Caribbean islands, then sharply turns out to sea as it intensifies. The GFS has been showing this solution.
2. 98L is slow to organize but does not dissipate and gets into the Caribbean further south. Beyond here several things could happen, ranging from dissipation due to unfavorable upper level conditions to significant intensification over warm waters with a helpful MJO pulse.
As of right now, I would say there is a 40% chance of no development, a 35% chance of scenario 1, and a 25% chance of scenario 2.


Figure 2: The East Atlantic, with 98L at the bottom left of the image.

West Pacific Remains Active
In the West Pacific, the main feature right now is Tropical Storm Prapiroon. Prapiroon currently has maximum 1 minute sustained winds of 60kts, or about 70mph, according to the Joint Typhoon Warning Center. Prapiroon has been organizing steadily today, but not rapidly. The official JTWC forecast indicates steady strengthening for the next 3 days, with a peak intensity of 100kts, followed by slight weakening on days 4 and 5. I find this intensity forecast to be quite difficult. On the one hand, basically every West Pacific storm over favorable conditions like Prapiroon is has rapidly intensified. On the other hand, microwave imagery is not suggesting any organized eyewall forming, which would indicate only slow strengthening is likely. My thinking is that strengthening will be slow for the next 12-24 hours, followed by a burst of rapid intensification as an eyewall does form. My estimated peak intensity is 110kts, a bit higher than the official forecast. The track forecast is also a challenge. The JTWC is currently hinting at a continued W/WNW motion for the next 2-3 days, followed by a sharp northeast turn out to sea as the ridge steering it breaks down. I think the scenario JTWC is showing is way to far out to sea. I anticipate a slower turn, bringing the system closer to Japan. I don't expect direct impacts, but high surf and rip currents will be a concern. There's plenty of time to watch this one and a lot will change, so stay tuned.


Figure 3: Official JTWC forecast track of Prapiroon.


Figure 4: Latest microwave image of Prapiroon. I do not see any rapidly developing eyewall that would suggest RI is imminent.

Also in the West Pacific, the remnants of Gaemi have essentially dissipated. A few days ago I mentioned there was a slight chance at regeneration in the Bay of Bengal as some GFS runs had suggested, but this will not be the case.

Other
* All other basins, including the East Pacific, are quiet, with no development expected in the next 5 days.
* A severe weather event is possible for the central US towards the end of the week. The Storm Prediction Center has not highlighted any risk areas for this period yet, but that should not come as a surprise as confidence is low this far out. I'll provide more details if necessary in a couple days.
* The chunk of cold weather that brought numerous record low temperatures to the central US over the past couple days is pushing eastward, losing some of its punch as it goes. It will not be long before it pushed out of the country, and as Figure 5 shows warm air is likely to take its place.


Figure 5: Climate Prediction Center 6-10 day temperature outlook, showing the current cold blast leaving and warmer than average temperatures returning for most.
* There was some interesting solar weather last night and this morning. A CME produced by a solar flare a few days ago hit Earth last night and produced a moderate geomagnetic storm. The worst is over but residual minor storming is still possible. We also saw an M2.3 class solar flare produced by a sunspot off the NE limb of the Sun, not yet visible to us. It has fallen quiet since, possible a temporary lull or possibly a sign the spot is beginning to decay. We'll get a much better idea when the spot rotates into view in the next couple days. Another sunspot is hiding off the SE limb and appears to be growing more active as it just produced a C class flare. Again, we'll know more about it when we can actually see it.


Figure 6: The sunspot off the NE limb lights up after producing an M class solar flare.

Thank you for reading, and have a great week!

Tracking the Tropics Worldwide

By: MAweatherboy1, 12:51 AM GMT on October 07, 2012

Believe it or not, there is plenty of action in the tropics right now, as I am watching six separate features scattered all over the world tonight.

Tropical Storm Olivia Forms
After coming together quite quickly yesterday and continuing to organize this morning, Invest 96E was declared Tropical Depression 15E at 11AM today, and after continued organization during the afternoon, it was upgraded to Tropical Storm Olivia at 5PM EDT today. As of the 5PM advisory, Olivia's maximum 1 minute sustained winds are estimated at 45mph, with a minimum central pressure of 1004mb. She is located well offshore of Mexico, about 900 miles SW of Baja California, and is moving west, further away from the coast, at 12mph.

Forecast for Olivia
The official NHC forecast takes Olivia to 65mph in about 36 hours. This is very similar to what I predicted last night, and it still seems reasonable to me. It appears the rather quick consolidation seen earlier in the day with the system has stopped, and the gradual strengthening indicated by the initial forecast through 36 hours should be on track. After this time steady weakening is likely as strong shear, dry air, and cooler waters begin to impact the system. The track forecast is fairly straightforward as it is currently being steered westward by a weakening ridge. This ridge should continue to weaken, causing a turn more to the WNW/NW shortly, followed by a bend back W or even WSW later in the forecast period as the circulation becomes weak and shallow and susceptible to being moved by nothing more than trade winds. My forecast would indicate a more northerly solution as I think the ridge will break down enough to cause a solid NW turn as opposed to a more WNW solution shown by the NHC. Regardless, Olivia will never be a threat to land.


Figure 1: Tropical Storm Olivia.


Figure 2: Official NHC forecast for Olivia.

Invest 97L Unlikely to Develop
An area of disturbed weather persisted a couple hundred miles east of the Bahamas this morning and was designated Invest 97L. As of their latest (8PM EDT) Tropical Weather Outlook, the NHC is giving 97L a 10% chance of development in the next 48 hours. 97L is in an area of unfavorable conditions, with shear being the biggest issue, and I do not believe this system will develop as I give it a near 0% chance of development in the net 48 hours. Regardless of development, increased shower and thunderstorm activity is likely in the eastern Bahamas for the next couple days.


Figure 3: Invest 97L. The system is struggling, and there has been a significant decrease in deep convection in the past several hours.

Invest 90S Will Not Develop
We had a somewhat interesting event occur a couple days ago as the Southern Hemisphere's first invest of the season, 90S, was born. It looked decent at times over the past couple days but is currently dissipating and will not develop. Still, this is definitely a sign that times are changing, as the Atlantic's season winds down.


Figure 4: Invest 90S this morning. The clockwise circulation is evident, as opposed to the counterclockwise circulation Northern Hemisphere storms display.

Gaemi May Attempt to Regenerate
In the West Pacific, Tropical Storm Gaemi was declared dissipated earlier today by the Joint Typhoon Warning Center after making landfall in Vietnam. I have not heard of any significant damage out of the area, though their were worries that heavy rains could damage the coffee crop. While it is now just a remnant low crossing over southeast Asia, Gaemi may not be done quite yet. The GFS is indicating what's left of Gaemi emerging over the Bay of Bengal in about 2 days. Some runs have shown the remnants attempting to redevelop, and today's 18z run actually showed the most significant redevelopment yet. Because Gaemi is such a weak circulation, however, I am not ready to buy this yet, as I think it is more likely the remnant low will dissipate over land or become too disorganized to redevelop when it emerges over water.


Figure 5: The remnants of Gaemi.

93B Unlikely to Develop
Sticking with the Bay of Bengal theme, the first invest in quite a while has formed in the Bay, invest 93B. 93B is currently weak and disorganized, and it does not have much time over water to develop, and none of the major global models show development of the disturbance. The JTWC has not mentioned 93B on its Indian Ocean tropical weather outlook.


Figure 6: Invest 93B.

99W Could Become A Powerful Typhoon
The final stop on our worldwide tour tonight is in the open waters of the West Pacific, Invest 99W. This disturbance has been tracked for several days, and the JTWC currently has a Tropical Cyclone Formation Alert issued for it, meaning there is a high chance it will develop into a tropical cyclone in the next 24 hours. Its current satellite appearance is fairly impressive for an invest, and advisories could be initiated by JTWC at any time. Steady organization is likely for the next 4 days, as indicated by the GFS and ECMWF models. After this time these same models indicate the potential for more rapid strengthening as conditions will be very conducive for development. I don't foresee this becoming a Cat 5 monster like Sanba or Jelawat, but a Cat 3 is definitely within the realm of possibility. Regarding track, 99W should follow a typical pattern of a recurving West Pacific storm. The question will be how close will the system get to Japan? As of right now most indications are it will pass south/east of the country in 8-10 days, but we will have a much better idea of the exact track in a couple days when models have a more well defined system to track.


Figure 7: Invest 99W, which is likely nearing tropical depression status.

Still Watching the Caribbean Long Range
As I mentioned last night, the GFS was showing tropical development in the Caribbean in the longer range. The GFS runs today have been rather unenthusiastic about development, but we see models flip flop like this all the time, and with the MJO returning and climatology favoring the Caribbean at this time of year, it's still possible we could be dealing with something in two weeks or so.

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

Atlantic Falls Silent, But Watching the Caribbean Long Range

By: MAweatherboy1, 12:00 AM GMT on October 06, 2012

For the first time since August 14, the Atlantic basin is quiet tonight, as weak and short lived Tropical Storm Oscar became post tropical as of today's 11AM advisory from the National Hurricane Center. Oscar's remnants will continue to rapidly accelerate NE, and will not harm any land areas.

Invest 96E May Develop
A new invest, 96E, developed in the East Pacific today. This disturbance is located about 700 miles SSW of Baja California. 96E came together quite rapidly today, even forcing the NHC to issue a special Tropical Weather Outlook earlier. In this outlook they have the system a 30% chance of development in the next 48 hours. The regularly scheduled 8PM TWO brought the odds up to 50%. I do think this system will develop, and based on its current organization I give it a 60% chance of developing in the next 48 hours. 96E will not have a particularly long time in favorable conditions, so nothing more than a 65mph tropical storm seems likely to me. 96E is already well offshore and is continuing to move west, so it will not be a threat to land.


Figure 1: Invest 96E. Overall, the cloud pattern is quite well organized for an invest, but dry air is clearly present to the north.

A Weak Gaemi Nears Landfall, Flooding and Mudslides a Concern
Things have remained active in the West Pacific, and tonight Tropical Storm Gaemi is making landfall in Vietnam. Gaemi has been a rather interesting system to track. A few days ago it organized rather nicely, and the Joint Typhoon Warning Center increased its intensity forecast accordingly to call for the system to become a typhoon. However, the system was very suddenly hit with a blast of shear that exposed the circulation and forced the convection west of the center. The storm never recovered, and is limping into landfall as a minimal tropical storm with 40mph winds. As of the latest advisory from the JTWC, it is located about 350 nautical miles ESE of Hue, Vietnam, and moving west at 14kts. The center of Gaemi should make landfall in Vietnam tomorrow, but due to shear, the convection is already moving ashore. As usual when tropical systems impact Vietnam, there will be a threat for flash flooding and mudslides. However, since the storm is weak, and is moving at a fairly good clip, impacts should not be too severe.


Figure 2: The Sun is up on Gaemi. The thunderstorms have somewhat moved back over the center, but it remains on the eastern edge of the convection.

There are three additional invests in the West Pacific right now, but none of any immediate threat.

Watching The Caribbean Long Range
With the beginning of October comes the end of the Atlantic's Cape Verde season. We won't be looking to the African coast for development until next summer. Now our attention turns closer to home. The last two runs of the GFS model have each shown fairly significant development towards the end of their runs in the Caribbean. There are a few reasons these runs may have some credibility. One is that climatology favors development in this area at this time of year. Another is that around this time the MJO should return to the Atlantic, allowing for increased moisture in the Caribbean that can help to allow development. As of right now, we can do nothing more than speculate, as it is very much up in the air on getting anything in the 12-15 day period as the GFS has started to suggest. However, a couple of things I think we could see if something decides to form:
1. A track mostly away from the US. With a constant barrage of troughs moving across the US, it appears unlikely that anything that forms in the Caribbean will make a run at the Gulf Coast. At this point I think if anything forms it will take anything in between a track like Wilma's, which hooked across Florida, and Lenny, which moved due east in the Caribbean.
2. Potential For Rapid/Significant Intensification. Right now, if conditions in the Caribbean come together to allow for development, there is a real chance we could see something fairly powerful form. The MJO should help stop any dry air issues, and if shear relaxes enough, the extremely high heat content in the Caribbean waters seem primed to allow for a fairly powerful storm. The last two GFS runs reflect this thinking. Again, this is very speculative and hinges on some initial spark forming first.


Figure 3: 12z GFS at 384 hours, with a hurricane moving through the Caribbean.


Figure 4: 18z GFS, 384 hours, with a hurricane pounding Jamaica.

Whatever happens, we'll be keeping our eyes on it. Thank you for reading, and have a great long weekend!

Nadine Losing Steam; West Pacific Remains Active

By: MAweatherboy1, 10:46 PM GMT on October 01, 2012

After a nearly three weak long reign as the only active cyclone in the Atlantic basin, Tropical Storm Nadine is weakening this evening. As of the latest advisory from the National Hurricane Center, Nadine's maximum 1 minute sustained winds are down to 65mph and its minimum central pressure is 995mb. Nadine is still meandering out there, currently on a southward drift at about 5mph. It is located about 710 miles W of the Azores.

Forecast for Nadine
After one final burst of restrengthening yesterday, Nadine's appearance began to deteriorate last night and through the day today as it moved over cooler waters and less favorable conditions. While the last three weeks have taught us not to count Nadine out, she is likely on a permanent weakening trend this time as sea surface temperatures under her will remain cool and shear will increase further ahead of a trough. As the trough approaches, the weakening Nadine will begin to move towards the east and accelerate rapidly in a day or so as it becomes post tropical by the end of the week. Right now it appears that the storm should stay west of the Azores, but the western islands are in the cone of uncertainty so they need to keep an eye on Nadine. By the time she gets close enough to affect the Azores she will likely be post tropical or nearly post tropical, so I do not see the need for tropical storm watches at this point.


Figure 1: Official NHC forecast track of Nadine.

Maliksi Organizing, But Will Not Affect Land
The West Pacific remains very active right now with two active storms. The first one is Tropical Storm Maliksi, located about 360 nautical miles SSE of Iwo-To, Japan, according to the latest advisory from the Joint Typhoon Warning Center. According to their latest advisory, Maliksi has maximum 1 minute sustained winds of 35kts, making it a minimal tropical storm. Dvorak T numbers support a higher intensity of 45-50kts, however, and based on its satellite appearance this seems to be a more appropriate intensity. The storm is moving NNW at 11kts. Maliksi is expected to steadily, but not rapidly, strengthen under fairly favorable conditions, and the forecast peak intensity in 2 days is 70kts, which would make it a category 1 equivalent on the Saffir Simpson Scale. Because I feel the currently listed intensity is too low, I am a little more aggressive on my forecast peak intensity, as a peak of around 80kts seems more reasonable. Regarding track, Maliksi should be a fairly typical recurving storm. It is currently being steered by a subtropical ridge, but an approaching trough will act to erode this ridge and turn Maliksi NE out to sea, very similar to what happens when Atlantic storms recurve. As of right now it appears Maliksi should pass safely south and east of Japan as it accelerates NE with high surf and rip currents being the only concerns.


Figure 2: Tropical Storm Maliksi. The very deep convection is a common characteristic of West Pacific storms, and the cyclone is likely intensifying right now.


Figure 3: Official JTWC forecast track of Maliksi, indicating a recurve well before it can threaten Japan.

Gaemi A Threat to Vietnam
Also in the West Pacific, this time in the South China Sea, newly named tropical storm Gaemi is churning. Gaemi currently has maximum 1 minute sustained winds of 35kts according to the JTWC, making it a minimal tropical storm. Like Maliski, its intensity may be a bit higher than what is officially listed. Gaemi has been showing very little motion recently, and will likely move little for the next day or two, with just a little southward drifting likely. During this time it should slowly intensify, and the forecast peak intensity from JTWC is 55kts in about 3 days. Tropical systems rarely intensify significantly in the South China Sea, and I think 55kts, is probably a fair bet for a peak intensity. After its southward drift, Gaemi is expected to accelerate west and make landfall as a tropical storm in Vietnam in 4-5 days. Due to the current weak steering currents Gaemi is in now, confidence is rather low on the extended track as if the system does not go south for the next day or two changes in the track may be required. The biggest impacts for Vietnam will definitely be floods and mudslides, as that country has a long history of destructive floods brought by often relatively weak tropical cyclones. One advantage they have this time is that Gaemi should be moving rather fast as it passes through the country. Still, the situation bears watching.


Figure 4: Tropical Storm Gaemi. As opposed to the deep convectioned Maliksi, I think Gaemi actually bares a resemblance to Atlantic and East Pacific storms.


Figure 5: Official JTWC forecast track of Gaemi.

Follow Up On Last Night's Post
If you read my post last night, you'll remember I was talking about some interesting solar weather events yesterday. I was discussing the potential of geomagnetic storming last night, and indeed, we did reach brief periods of major storming last night. Refer to last night's entry for the whole story.


Figure 6: The Kp index hit 7 last night, meaning we were experiencing a major geomagnetic storm.

Thanks for reading, and have a great night!

Fun on the Sun

By: MAweatherboy1, 12:26 AM GMT on October 01, 2012

Dr. Master's blog is pretty busy with 96L this evening, so I didn't want to throw all this information on there. We've had two interesting solar weather events occurring today. The first is the result of a coronal mass ejection (CME) that left the Sun a couple days ago in association with a relatively mild C class solar flare. What the eruption lacked in strength, however, it made up with launching the blast directly at a planet. An initial shock arrived this morning, but effects were negligible. However, a secondary shock has recently arrived, and this looks to be the main event. There are two main ways to tell this has happened. One is that there has been a relatively significant increase in solar wind, though it is still not at a level that suggests major geomagnetic storming is arriving. The other is that the Bz component of the interplanetary magnetic field (IMF) has become tilted sharply negative, which is almost always a precursor to geomagnetic storming. NOAA's Space Weather Prediction Center (SWPC) is forecasting minor geomagnetic storming to occur tonight into tomorrow morning. For the past couple days, they had been predicting moderate geomagnetic storming, and I think it is possible/likely that we will at least briefly reach moderate storming levels at the height of the event. With geomagnetic storming always comes the possibilities of seeing auroras further south than usual, however this event will likely be somewhat drowned out by a bright full moon. Still, those at high latitude should be on the lookout late tonight. A map is posted below to give you a better idea.

Sunspot 1583 Rapidly Grows
The other interesting event today has occurred on the actual surface of the Sun. For the past few days, most of the sunspots on the Sun have been relatively small and quiet. To become "active" sunspots need to develop complex, twisted magnetic fields that harbor energy for powerful explosions. Today, one of the sunspots crossing the Earth facing side of the Sun underwent the sunspot equivalent of rapid intensification, growing rapidly and gaining a more complicated magnetic field that can produce more powerful solar flares. Indeed, we have seen an almost continuous onslaught of C and M class flares throughout the day as this region grows. Sunspots are constantly changing- growing, shrinking, moving, and changing in magnetic complexity. But rapid fluctuations like this are rare, and it has been am exciting event to watch. Unfortunately, the show has been somewhat marred by the fact that 1583 is quickly rotating over the Sun's western limb and out of the view of Earth. This means that we will have a very limited ability to monitor its growth as it transits the far side of the Sun. One way to tell if a sunspot is active on the farside is to watch for CMEs to leave the Sun traveling away from Earth, which would indicate the spot is actively flaring. However, we still have no way of actually getting a detailed look at the spot. Sunspots generally take about 2 weeks to go around the backside and come back into Earth view, so by the time it is back in view 1583 will likely be gone or in an advanced state of decay. Still, it's been a lot of fun to watch today, and as we head for solar maximum next year we may get to see more events like this unfold.

Graphics!!

Figure 1: X ray chart. All of the notable jumps in the line represent solar flares, and they are all being produced by 1583. This will constantly update but as it stands now I count 6 C class flares and an M class flare in the past couple hours.


Figure 2: Aurora map for tonight. Like the CME's and geomagnetic storms that produce them, this phenomenon is almost impossible to predict. But if you're in the green shaded area, it's worth a shot to take a look outside tonight. You may get a colorful surprise.


Figure 3: The Earth facing side of the Sun. The back edge of fast growing 1583 is just barely visible now as it rotates over the western limb, leaving only small (relatively speaking) and magnetically simple sunspots in its wake. X ray detectors will soon stop picking up on activity from the region.


Figure 4: Aurora in Norway early this morning.

Solarham.com, an excellent source of info on all things Sun related.

NOAA's Space Weather Prediction Center.

Thank you for reading. Feedback would be appreciated as I've never done a blog like this before. I hope you have a great week!


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.