Somerset Squall

Convection fired over Madi after last posted, saving Madi for another day. However, the dry air and shear has now won, and Madi is now a largely convectionless remnant low. The remnant low will make landfall shortly after the 12 hour mark, but will bring little significant weather. As Coast's post above describes, an interesting track!

Madi peaked at 70kts this morning, but has since collapsed, big style. The convection has vanished rapidly with the cyclone, and winds have fallen to 50kts, which is probably a bit generous considering what's left of Madi. Madi has started the southwest turn towards southern India. Unless convection makes a comeback soon, Madi will become a remnant low. It's amazing how this system looked this morning compared to now! This morning: Now:

Madi weakened to 60kts yesterday but overnight has developed a better defined eye, looks like Madi could well be defying forecasts and overcoming the shear that has affected it over the last 24 hours:

Madi strengthened to 65kts last night and has remained at that intensity since. The storm retains a well established central dense overcast with a cloud obscured eye feature. Madi has been moving at a brisker pace to the north today to the east of a trough over India. This trough is expected to fill and be replaced with a ridge soon, which will block Madi's northward movement and send it southwards or southwestwards eventually. Dry air and increasing shear should begin to affect Madi soon, but I think Madi could strengthen a little more before it does.

06B has continued to strengthen and has been upgraded to a Severe Cyclonic Storm by IMD, named Madi. Madi has winds of 55kts according to JTWC. Madi has been crawling northwards overnight. This slow motion is expected to persist whilst a trough weakens the ridge to the west giving slightly more steering influence to the ridge to the east. Thereafter, the trough should weaken, which will likely grind Madi to a halt yet again as it becomes trapped between the two ridges. Over the next day or so, Madi should remain in an environment conducive for intensification. Shear is low, and waters are warm. Madi has developed a central dense overcast flanked by strong banding, so the storm should reach cat 1 strength on the SS scale soon as an eyewall begins to develop. Thereafter, the slow motion will upwell colder water to the surface, which is forecast to weaken Madi. Shear values are higher to the north, and these higher shear conditions are also likely to affect Madi in a couple days time.

Certainly has a long feeder band stretching to the southwest. Some impressive convection over the LLCC too, which is drenching northeastern Sri Lanka at present. Strengthening is likely for the next few days a shear is low, but upwelling will play a big role in the intensity in the long term if this quasi-stationary motion persists.

Another tropical cyclone has formed in the Bay Of Bengal, will have a fuller update later. From JTWC:

33W has been stripped bare by strong shear overnight, and has degenerted into remnant low. Regeneration is not expected, and the system is no longer expected to become an extratropical storm, and should instead dissipate entirely.

A late season tropical depression has formed in the West Pacific, 369 nautical miles west-northwest of Guam. Winds are estimated to be at 30kts. The depression has some moderately deep convection in the eastern quadrant of the LLC. Shear is increasing over the depression has it recurves northeastwards, and as a result, strengthening will be limited prior to the imminent onset of extratropical transition as 33W runs into cooler waters within the next 24hrs. 33W may briefly become a tropical storm prior to the transition.

In the first half of the month, the whole of the average rain for November fell, but a dry second half means that November comes in above average but not excessively so. January: 95.2mm (above average)February: 43.1mm (below average)March: 55.9mm (average) April: 27.3mm (well below average) May: 57.4mm (above average) June: 28.0mm (well below average) July: 71.7mm (well above average) August: 58.3mm (average) September: 69.9mm (slightly above average) October: 128.5mm (well above average) November: 80.9mm (above average) 2013 so far: 716.2mm (a little above average) Only 8.3mm of rain needs to fall in December to reach average rainfall for the year, a feat I'm sure we will manage easily.

Mmm, maybe not Coast, because the remnant low of Alessia has moved back over water yet again. The low, instead of moving back west towards it's birthplace, has meandered northeast and has moved back over the warm waters of the southern Gulf Of Carpentaria, where convection is increasing once more. JTWC give ex-Alessia a MEDIUM chance of becoming a TC for the third time (within 24hrs).

Lehar is falling apart, fast. Winds are down to 40kts. Dry air and shear are causing the convection associated with Lehar to rapidly dissipate. There won't be much left of Lehar at landfall in the next 24 hours at this rate, which is very good news for India, but not expected.

Alessia has made a third landfall, this time on the southern coast of the Gulf Of Carpentaria. Shear has increased over the system, seperating the convection from the LLCC, which is just inland. BOM have downgraded Alessia back to a low, and JTWC will probably follow suit (they re-upgraded Alessia this morning).Just what will happen to the remnant low is open to question, and is far from certain.

Lehar has further weakened, to 65kts. The convective canopy has shrunk and the LLC has further elongated due to ever increasing shear. Further weakening is expected before landfall, so although rain is still a serious threat to eastern India, Lehar is not quite the beast it was expected to be at landfall.

BOM have re-upgraded Alessia to a tropical cyclone over the southern Gulf Of Carpentaria. Looks well organised this morning:

Looking good though, I wouldn't rule out Alessia becoming a tropical cyclone again during it's visit to the Gulf Of Carpentaria. So many uncertainties regarding track- will be an interesting watch. Alessia, in one form or another, could be around for a while yet!

Lehar strengthened to 75kts earlier, but has weakened back to 70kts. Despite the tremendous area of convection present, the inner core is not well organised, with no signs of an eye. Moderate shear has prevented this cyclone from strengthening further, and JTWC now forecast little intensity change prior to landfall, as good outflow battles moderate shear to provide an environment not ideal for strengthening, but supportive of a storm of Lehar's intensity.

This is an interesting possibility. The remnant low of Alessia has now entered the far west of the Gulf Of Carpentaria, where convection has increased a little over the low. But as the steering pattern continues to reverse, Ex-Alessia will soon be back inland. But it could regenerate down the line when it emerges back over water, funnily enough, near where it formed. If the low remains intact throughout, JTWC would keep the same name/number, as they did with TC30W the other week in the West Pacific and North Indian Ocean, which went a full 9 days before regeneration. I'm not sure what BOM's policy is, though they still are referring to the low as Alessia currently.

Lehar has continued to strengthen, and now has an intensity of 70kts. Moderate shear has prevented rapid intensification, but warm waters and good outflow have allowed a slow intensity gain. Lehar doesn't have a visible eye yet, though the convection in the slightly elongated central dense overcast remains very deep. Rapid strengthening is no longer expected. Despite this, Lehar is still a dangerous cyclone that is set to impact eastern India as a category 2 or 3 on the Saffir-Simpson scale.

Lehar is really drenching the Andaman Islands currently:

05B has been named Lehar by IMD. Winds have increased to 55kts according to JTWC. Lehar has developed a central dense overcast, indicative of a mature system. Lehar should further intensify, as shear continues to lessen, and outflow remains robust.

The fifth tropical tropical cyclone of the 2013 North Indian Ocean season has formed in what has been an active period for this basin. 05B is located southeast of the Andaman Islands and has winds of 30kts. Conditions are highly favourable for strengthening as the cyclone crosses the Bay of Bengal from southeast to northwest towards India on the southern side of ridging over the northern Bay Of Bengal. Shear is low, waters are very warm if not hot in places along track, and outflow is good in all directions. This implies the potential for rapid intensification, and JTWC's estimated peak of 100kts before landfall in Eastern India could end up too low. Landfall is subject to change but Eastern India is most definitely in the firing line.

Alessia is closing in on it's first landfall. The convective canopy has shrunk due to dry air infiltrating Alessia, but the system retains winds of 45kts. As Alessia drags across land, it will weaken before briefly emerging into the Josef Bonaparte Gulf, before a second landfall, south of Darwin. Alessia is then expected to degenerate into a remnant low. The remains could enter the far south of the Gulf Of Carpentaria, but the system is not expected to spend enough time back over water to regenerate.

The second tropical cyclone of the 2013-14 Southern Hemisphere tropical cyclone season has formed, this time in the waters of Northwest Australia (the first was in the South Indian Ocean also, last month, east of Madagascar). The cyclone has winds of 35kts according to JTWC. The low was noted a few days ago just south of Indonesia, and has since dropped south whilst slowly developing. Overnight, the system has become much better organised, with deep convection over the increasingly well defined LLC, and formative banding features taking shape. I expect BOM to name the system soon. The environment ahead seems to favour at least some modest intensification over the next few days. The waters off the NW Australian coast are certainly warm enough, and looking at CIMSS wind shear charts, shear looks fairly low, at least for now, but are higher further north: Track wise, it seems fairly straightforward. An equatrorial ridge seems to be now steering 02S to the east, and this is expected to continue over the next few days, taking 02S north of Kuri Bay, into Kalumburu, into the Josef Bonaparte Gulf before final landfall south of Darwin. Some minor adjustments in track can be expected, but models are in quite good agreement on this scenario.

Slow moving Helen is about to make landfall. Winds have decreased to 35kts. The observed weakening is mainly down to shear, as convection has been sheared to the northeast of the LLCC, leaving it exposed, just off the coast. Helen will make landfall in the next few hours and dissipate quickly over land.