CIMSS TPARC Support Blog

TCS049 is a potential flight target for today. If they flew, the P3 would fly from 21Z on the 2nd - 05Z on the 3rd.

The animation shown below gives some sense of its structure:

It has some decent convection to the north and moderate upper level divergence.  You can see signs of anticyclonic outflow to the northeast of the storm. You can also see a fairly strong TUTT low to the storm’s northeast limiting its development.

What about a low level center? The attached image shows the quikscatt analysis and available surface obs:

You can see a cyclonic circulation on its northeast side, but there is no sign of westerly winds on the east side.

And the shear?

The image above, valid at 11:30 Z on Oct. 2, 2008 shows the shear surrounding TCS049. You can see the southerly shear from the associated TUTT cell to its northwest and the ridge to its east. The shear is currently preventing significant development.

And for its future?

The EC model is the only one that really does something with this system. It sort of splits, with one system moving north and quickly recurving and a second , weaker system moving westward towards the Phillipeans.

Both of those happen in the long term though. It does not seem to be a system with a bright future.

Links:

ECMWF,Met Office,NOGAPS,GFS

On 06Z on the 25th of Septebember, Jangmi was named a Typhoon. 48 hours later: by 06Z on the 27th, Jangmi was a Super Typhoon with reported 135 knot winds, according to the working best track on the Unisys website. Jangmi intensified very quickly. By  00Z on the 29th Jangmi had weakened to a Tropical Storm. It continues to weaken.

Attached is the SATCON intensity plot for the storm:

SATCON shows Jangmi’s clear intensification and weakening. What is also shows is the very successful performance of the satellite-intensity techniques. The SATCON (and corresponding ADT and AMSU) are very close to the best track. The C-130 recon , however, had also reported nearly 140 kt winds, implying an even better performance for the algorithms that will have to be analyzed post-storm.

The MIMIC animation from 00Z on the 26th - 00Z on the 27th linked here shows Jangmi’s intensification and organization. The animation shown here from 00Z on the 27th - 00Z on the 28th shows its annular status as it holds its intensity for nearly 24 hours and begins to weaken.

The animation below shows the strong analyzed divergence, anticyclonic outflow from the upper-level AMVs, and clear, well-defined eye near the Jangmi’s peak intensity:

Jangmi quickly began to weaken after it neared cooler Sinlaku and Hagupit cooled waters and crossed Taiwan. Its current status and future track will be the subject of a future blog post.

Here is the MIMIC animation showing this intensification (as of 18Z it had 120 kts).

Here is the IR animation. You can see the very strong outflow and clear eye:

TCS048 has been trying to develop over the past few days. Attached are the upper-level AMV divergence plots and the shear plots over the disturbance:

The divergence plot shows some organization and two weak centers of divergence over the distrubance. The AMVs don’t show much of a sign of any coherent, anticyclonic outflow.

The shear plot:

Shows 15-20 kts of northerly shear over the center, with stronger shear toward its edges. A fairly strong TUTT low lies to its northeast, potentially hindering its development.  The surface and ship observations show no sign of a closed circulation, particularly on the southern side. Quikscatt/ASCAT passes aren’t available.

So what are the models doing with this storm?

Only the ECMWF and NOGAPS (no real surprise there) develop this sytem to any degree. And although the EC develops a rather large system, by the end of its run, it is not particularly strong. The GFS develops it a little at first, but by 00Z on the 30th it has begun to dissapate. The Met Office model develops the system to a medium sized but fairly weak disturbance.

The ECMWF seems to be weakening the upper-level northeasterly winds slightly, perhaps allowing for this system to develop. The GFS, on the other hand, has strong upper-level easterlies over the disturbance.

The EC model has been pretty solid for this experiment. It is still the one to watch.

The models are amazingly consistent on Jangmi’s forecast over the next few days. Out to 120 hours they all put Jangmi over Taiwan (with a few minor details).

Links:

ECMWF

Met Office

NOGAPS

GFS

Attached is an animation of Jangmi with its outflow plotted above:

A current C-130 flight observed a maximum wind speed of 55 kts. Satcon (as of 16Z) analyzes the intensity at 53 kts.

As of 12Z on the 24th, 19W was analyzed near 12.6N 136.3E according to JTWC. It is moving 295 degrees at 10 kts with max sustained winds at 045 kts and gusts to 55 kts. The current Satcon (as of 07Z) analyzes its intensity at 46 kts. The 12:30Z ADT gives an intensity of 47 kts.

The attached IR/upper level AMV and analyzed divergence plot shows the organized circulation, well defined outflow and divergence:

The attached MIMIC animation shows some of the convection organizing to its south as it is trying to develop an eyewall:

The shear over the center is still pretty low (around 5kts) although the surrounding shear is still fairly large (nearly 30 to 40 kts to the southwest).

So what about the future? JTWC has it intensifying by 10 kts every 12 hours or so, with intensities of 120 kts by 12Z on the 19th.

In terms of track, the models are in reasonable agreement, bringing 19W to the northwest close to Taiwan by 00Z on the 29th. JTWC has it to the southeast of Taiwan at that time: closer to the Met Office and NOGAPS solution. The GFS and ECMWF have it much closer to Taiwan.

Over the long term, the ECMWF brings 19W into the Chinese mainland as it moves westward. It also develops TCS048 over the long term, bringing along a similar track as 19W. It’s done fairly well with these genesis cases, so it is worth watching.

The ECMWF ensemble probability predicts strong vorticity along its deterministic track to be quite likely. It is a little less certain over the long range.

Links:

ECMWF, Met Office, NOGAPS, GFS 850 hpa vorticity.

ECMWF 850 vorticity probabilities.

The following two images suggest that TCS047 has sustained winds near 25 kts:

Surface observations and IR Image for TCS047. The ship VNVR is reporting a wind speed of 25kts

Quikscat Analysis and IR images for TCS047. The analysis shows a clear surface circulation

The divergence is fairly strong over some of the larger convective areas, although it hasn’t yet developed an anticyclonic flow aloft:

Although the shear is strong around the storm, it has weakened a great deal over the storm center:

What is driving this development? Well, TCS047 has been under the influence of a weak upper-level low to its north. In the attached animation of upper-level AMVs you can see the weak low travel slowly northwest, perhaps allowing TCS047 better outflow and development. In this animation, 47 is at about 10N 140E:

22SEP2008-upperwinds_anim.gif

And what about the model forecasts:

In terms of track, the models are remarkably similar, even through 120 hours.

The GFS and ECMWF bring this, by then, well developed storm just to the east of Taiwan.

The Met Office model and the NOGAPS bring it farther south, with the Met Office model a bit to the west.

All of the major models have some form of intensification.

What’s going on in the upper-levels?

The ECMWF 200 hPa forecast quickly (00Z on the 25th) erodes the upper level low and develops anticylonic flow over TCS047 as it tracks northwestward, steered by an upper level anticyclone to the west. It eventually stalls it out as this ridge moves out to the east. Hopefully this will remain around long enough for some interesting flights.

TCS047 is the next TCS invest of interest.

Attached is the 12Z IR image, Scatt data and surface observations available nearby:

IR Image, surface, ship, buoy reports, Scatt data and low-level AMVs for potentially developing system TCS047.

TCS047 is not very well developed or organized. Most of the surface winds above are easterly, although there are hints of southwest winds from the scatt images and a few ship reports.

Although there is some weak divergence aloft and a low level vorticity center. It’s just to the south of an upper low, and that may be causing the shear surrounding the invest. The shear is fairly weak over the invest center, but it is quite strong to the west and north.

See the attached divergence image, and vorticity/shear image:

Upper level divergence and AMVS (top) and deep shear and low-level vorticity (bottom). AMVs and analyses are valid 16Z on 22 September. The IR images are valid at 11 Z.

Of course the big question is when and if this system will develop.

The Met Office model weakens it through 00Z on the 24th and then slowly strengthens it, moving it to the northwest at about 18N 130E by 00Z on the 27th.

The ECMWF model analyzes the storm fairly well. It’s 12 hour forecast matches pretty well with the cloud pattern seen above. It develops this storm over the next few hours and begins to recurve it by around 12Z on the 26nd. By the end of the forecast period: October 02, the ECMWF has a very sheared system located to the south of Japan.

The GFS doesn’t really develop it at all past the short term. As it moves it north and west it kills it off, merging it with some other convective elements up near the Phillipeans. The 12Z run seems to be developing it a bit more actually.  The convection seems a bit more organized. Is this a trend?

It seems there are some differences in the long term shear. See the 00z run here and the 12z shear/850 vorticity here. Look at the forecasts at 00Z on the 26th. The 12Z has a more organized system that is farther to the west than the 00Z run. It’s also under an area of lower shear. Perhaps this is encouraging it’s development.

The NOGAPS that never made it a disturbance it didn’t like, develops it steadily throughout the forecast period and brings it up east of the Phillipeans by 00Z on the 28th.

Taking a quick look at the upper levels in the two models as shown here implies that the 12Z forecaster has a weaker upper level jet, perhaps contributing to the weaker easterly flow.

Attached is an IR animation for TCS043:

Taking a look at a two day animation (focus on TCS043 at about 15N 142E) you can see dirunal variation, as TCS043 strengthens around 12Z (22:00 Guam time) and weakens around 00Z (10 am Guam time). The short animation above is from 10Z - 15Z: near the convective maximum.

At this point, however, shear is the primary factor influencing TCS043:

The above plots show the shear (top) and divergence (bottom) over TCS043. The shear is consitently pushing the convection south. You can see this with the IR images, and with the location of maximum divergence. It’s unlikely to develop while under such strong shear.

The models are in two camps with this invest. The NOGAPS and GFS model have TCS043 developing and then recurving around (NOGAPS) and past (GFS) 140 E longitude. The 12Z ECWMF still has TCS043 moving west and interacting with the monsoon near the Philippians. Unlike the previous run, this run suggest hints of recurvature towards the end of the forecast period. The Met Office model, always the most reluctant developer, brings TCS043 westward and has a weaker interaction with that Phillipean convection.

The key to the recurve/no recurve difference seems to stem from a trough coming off of the China coast from the 20th-21st. The models with a deeper trough seem to be recurving the storm. The models without it seem to allow TCS043 to progress westward. We’ll have to keep an eye on this track difference in future runs.

TCS 043 has been developing over the last few hours. The attached IR animation shows some of the growing convection. Again, part of this development may be diurnally supported.

IR animation of TCS043. Animation through 16Z, September 16th, 2008.

TCS043 has healthy upper-level divergence and some anticyclonic outflow to the south and west as shown in the image below:

MTSAT IR-image with upper-level AMVs and analyzed divergence. Valid 16Z September, 16th, 2008.

TCS043 has a fairly strong upper-level low to its east. It’s in a very narrow shear minimum, with 20kt shear to it’s west and east. That might limit its current development.

How about surface circulation? There is no current quikscatt analysis, but previous ones have shown a surface circulation. The proximity to Guam, however,  gives us some surface observations to look at, as shown below:

Surface obs, buoys, and ship reports near TCS043. Valid 16Z on September, 16th, 2008.

It looks like, from here, that there are signs of a surface circulation. A few of the reports are showing 15-20 kt winds around the outside of TCS043.

As for the models:

NOGAPS continues its bullish trend by developing this system quickly and recurving it around to the northeast.

The GFS develops a weaker, but slightly larger system, and also recurves the system around to the north and east by the end of the forecast period.

The ECMWF merges this system with TCS045 to the east of the Phillipeans (by about 12Z on the 19th). It strengthens this merged system and brings it across the South China Sea.

The Met Office model, which has seemed  the most conservative with development, doesn’t really develop this system.

TCS043 may be a future recon flight, and has had a previous recon flight.