CIMSS TPARC Support Blog

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:

As of 12Z, JTWC has analyzed Jangmi at 17.7N 127.9E.

It is moving  310 DEGREES AT 12 KTS with an intensity of 095 kts and gusts of 115 kts.

The satcon image below shows Jangmi’s steady intensification:

The animated IR image with overlayed AMVs and analyzed divergence is shown below:

It shows a very well developed upper-level pattern with strong outflow to the north and south. The analyzed divergence is quite strong. This is a very healthy storm.

The attached MIMIC animation shows a very complex and changing eyewall structure:

The 200 hPa streamlines shown below shows the general synoptic set up dominating Jangmi:

Jangmi’s outflow is enhanced by the upper-level low to its east along with the anticyclone above it. The intensity forecast has increased since yesterday: it’s forecast to intensify to 120 kts by 00Z on the 28th and then weaken quickly after that, mostly likely due to Taiwanese interaction.

The consensus track from yesterday, put Jangmi by 12Z at 16.3N 129.1E, a bit to the south and east of it’s current position (17.7N 127.9E). It’s steering is predominantly driven by a subtropical ridge to it’s north, particularly as the upper level trough from the westerlies moves eastward. As this ridge builds, Jangmi is expected to have a more westerly track.

By 00Z on the 29th, ECMWF and NOGAPS bring Janmi directly over Taiwan. The Met Office model is a bit more progressive, moving Jangmi across Taiwan about 12 hours earlier. It is no longer south of the other models as it was previously. The GFS is similar to the Met Office, although it slows Jangmi down a bit after the Taiwanese landfall. None of the models are showing signs of recurvature.

As of 06Z on the 25th, Jangmi was upgraded to a Typhoon.

JTWC’s 12Z analysis:Position: near 14.5N 131.4E

Movement: 275 DEGREES AT 11 KTS

Intensity: max sustained winds - 070 KT, GUSTS 085 KT

The 11:30 Z ADT has analyzed its intensity at 57 knots with its CDO. The most recent satcon analysis was at 20Z on the 24th, with an intensity of 56 knots.

Attached below is an animated IR image with upper-level AMVs and analyzed divergence:

It’s got fairly healthy divergence aloft and reasonable outflow to its northeast and southwest. Outflow is somewhat restricted to the north. There are hints of dry air to the north and northeast, possible due to an upper-level low.

The MIMIC animation below shows the development of an eye over most of Jangmi’s eastern side:

The 12Z AMSU-B image, shown here (courtesy of NRL) does imply a fully closed eye:

The quikscatt 09Z analysis has a fully developed low level circulation around Jangmi. It is a healthy storm. It’s under reasonably low shear (about 10kts) but still surrounded by high shear to the east and south.

And what’s in it’s future:

JTWC has it intensifying to 115 kts by 12Z on the 27th and maintaining that intensity through the 28th. As it approaches Taiwan it is forecasted to weaken.

Its track is being influenced by the subtropical ridge to its west and north, driving Jangmi to the west more than previously forecasted. The T-PARC consensus forecast had predicted it to be at: 15.3N 132.2E. It’s current position is to the south and west of this forecast.

The models are again reasonably consistent with each other bringing Jangmi in some form across Taiwan, but their timing and placement are slightly different. The ECMWF and NOGAPS have it striking Taiwan at about 12Z on the 28th. The Met Office model by that time has it south of Taiwan, but west of the other models. The GFS is a bit to the east of other models, but closer in latitude ot the EC and NOGAPS. They seem to be moving a bit more slowly, in general, today than previous model runs, but not by much.

From JTWC as of 1200 Hagupit is near 19.5N 120.9E, moving 280 degrees at 11 KTS. It’s at 100 kt gusts to 125 kts. The satcon intensity estimate is attached below:

08Z Satcon analysis on September 22nd, 2008 for Typhoon Hagupit.

As you can see Hagupit has been intensifying steadily over the past few days. The ADT seems to be above the JTWC, possibly due to the well developed eye and structure. When the next AMSU pass comes through, perhaps SATCON will catch up. Unfortunately, there will no aircraft penetration for this storm due to some mechanical problems. Perhaps some of the surface obs and buoys will give some clues.

The attached MIMIC animation shows how the convection has been organizing over the past few days as Hagupit moved north past the Phillipeans:

Mimic animation showing Hagupit's recent intensification

Hagupit is in a region of low shear and reasonable outflow to the west. It is forecasted to weaken slightly before landfall (about 00Z on the 24th) as seen in the JTWC forecast graphic.

The attached IR image and upper-level AMVs shown below show the strong, but focused outflow to the west:

According to JTWC, the strong ridge to Hagupit’s north has restricted some northerly outflow. One can’t see a strong anti-cyclone over or just outside of the storm.

The models are in fairly good agreement with the track, bringing it just south of Hong Kong by about 00Z on the 24th. There is a little variation: NOGAPS is a bit to the east of the suite of other models.

It’s under fairly weak shear now. JTWC is expecting the shear to increase slightly, thus causing its slight weakening before landfall.

As of 00Z on the 19th, Sinlaku was upgraded once again to a Typhoon by JTWC. Then, by 12Z on the 19th it was downgraded to a tropical storm

This Mimic animation shows Sinlaku’s eyewall development with convection building to it’s south, and then subsequent weakening:

MIMIC animation of Sinlaku from 12Z on the 18th to 12Z on the 19th. Notice how convection develops on its southwest side as it intensifies.

Sinlaku is still under the duel effects of shear and strong upper-level outflow from the midlatitude westerlies. Both the divergence and shear plots are attached below:

IR MTSAT Image, upper-level AMVs and analyzed divergence. Valid 13Z on September 19th, 2008

MTSAT IR Image and upper-level shear. Valid 13Z September 19th, 2008.

Again, Sinlaku’s motion is aligned fairly well along the shear axis, perhaps limiting it’s negative impact on its intensity somewhat. The enhanced outflow from the upper-levels and relatively high SSTs are competing with the shear. The shear will likely win out and Sinlaku will weaken.

Satcon shows the weakening as well, with the ADT producing much lower intensities than previous satcon analyses:

Satcon for Sinlaku. The ADT is currently producing weaker estimates than previous satcon estimates.

Yesterday and today the P-3 and C-130 will focus on Sinlaku and try and capture it’s ET. This is first time that extra-tropical transition has been captured by recon in the west pacific.

What about the forecast?

They will be the focus of subsequent blogs.

Sinlaku is still churning away. It was briefly upgraded to a Typhoon at 00Z on the 18th, then downgraded back to a Tropical Cyclone.  According to JTWC, as of 12Z on the 18th, it was located near 31.0N 131.5E, moving 060 degrees at 09 kts. They analyze it at 55 kts with gusts to 70 kts.

Attached below is the standard IR/AMV/divergence plot valid 13Z on September 18th:

Although Sinlaku has continued outflow to the northeast, it’s flow is very well contained on the west side as it gets caught up in the midlatitude westerlies. The shear over Sinlaku, shown below, is very strong from the west:

The satcon analysis below shows Sinlaku’s recent intensity trend:

You can see the brief peak in intensity from JTWC (black curve) and the slight upward trend from SATCON and the ADT. Reading their prognostic reasoning, it appears JTWC re-intensified the storm based on recon data from TPARC.

Sinlaku may have re-intensified partially because its center has remained over water. This may allow it to maintain its tropical characteristics a bit longer than if it had passed over land.

As it begins ET, we will focus a bit on the tilt of its vortex. Currently, its low level center is a bit displaced to the southwest from the maximum convection as seen in the attached 85 GhZ and divergence plot:

The displacement isn’t huge, but the center (shown by the hurricane symbol, and the slightly circular pattern in the microwave image) is slightly over from the more intense microwave images and the divergence maximum. As ET happens, we’d expect more a vortex title. We’ll explore other ways to show this.

In the short term, the models are fairly consistent in bringing Sinlaku just south of the Japanese islands. There are some slight differences in terms of time and storm size, but the broad picture is fairly similar.

After Sinlaku leaves Japan, the models take a few different tacks with it’s track. The Met Office model and NOGAPS both bring Sinlaku up fairly far north and intensifying it, threathening the Aleutian Islands.

The ECMWF model merges Sinlaku with another midlatitude system, eventually moving toward Alaska.

The GFS takes a middle path: bringing Sinlaku up the Aleutians, but at a slower pace, and with less intensity than the Met Office.

It’s quite easy to see how uncertainties at this stage of forecasting can easily affect long-range forecasting downstream on the US coast.

And the phase diagrams? The GFS diagram begins to develop an assymetric core by the 19th, but does not really become cold core until the 24th of September!

The NOGAPS is faster: generating the assymetric core right away with Sinlaku becoming cold core just before the 20th.

The Met Office model diagram keeps it warm core throughout the shown forecast period.

How will Sinlaku interact with the midlatitute jets and outflow? When will it become extratropical? How strong will it get? These are questions that will need further investigation.

According to JTWC, at 12Z, September, 16, 2008, Sinlaku is near 27.2N 124.6E with winds at 045 kt and gusts at 55 kts.

Attached is an IR image with AMVs and analyzed divergence:

Valid 14Z, September 16th, 2008.

Sinlaku is highly sheared at the moment. The wind diverges some aloft, and you can see a weak anticyclonic flow to Sinlaku’s northeast. The 0947 Quickscatt winds are still showing Sinlaku’s closed circulation at the surface.

Also, the latest SSMI pass (shown below) shows an intense convective center, but that center is displaced from the divergence maximum aloft.

85 GHZ SSMI image and upper-level analyzed divergence.

This is another sign of a system affected by shear. Also, as Sinlaku has been nearly stationary for so long, it has upwelled lower SSTs to the surface, lessening its own fuel. Sinlaku is  currently centered under a region of relatively low shear (10-15 kts), but surrounded by strong shear to its north.

JTWC has it intensifying only slightly before it makes landfall near Japan. All of the primary models have Sinlaku striking Japan, but the details vary a bit by model.

The NOGAPS has it striking Japan just after 00Z on the 18th.

The GFS model has a much smaller storm. It brings Sinlaku farther south and east than the NOGAPS, and doesn’t hit Japan as directly mostly because it doesn’t make Sinlaku quite as large.

The ECMWF model is similar to the GFS although it seems to be a bit slower with Sinlaku’s progression to Japan.

The UK Met Office model seems to forecast Sinlaku at the same size as the NOGAPS (probably due to bogusing) but has timing similar to the GFS and the ECMWF model.

It’s interesting to see the NOGAPS being the fastest mover with Sinlaku, as that’s been contrary to the previous performance with these models.

And what about ET:

Bob Hart’s ET phase diagrams from the 06Z run of the GFS model is shown below:

Sinlaku's phase diagram from the 06Z September 16th run of the GFS. Courtesy of Dr. Bob Hart (FSU) and Dr. Jenni Evans (PSU)

From this diagram and model analysis, Sinlaku still has a symmetric structure until about 12Z on the 18th. It does not really a develop cold core until the 20th. The Met Office model keeps it fairly warm-cored throughout the forecast time shown. The NOGAPS analysis is a little bit slower in bringing ET than the GFS.

The P-3 and C-130 are both scheduled to fly Sinlaku on the 17th. The P-3 will take off at 20Z on the 16th and return to Japan at 06Z on the 17th and fly box patterns, investigating the pre-warm front region of Sinlaku. The C-130 will fly the same schedule, but will only ferry to Japan for future investigations.

The DLR falcon will investigate Sinlaku’s outflow, flying from the 22Z on the 16th through 07Z on the 17th.

Perhaps they can capture some pre-extratropical conditions that will be valuable for understanding ET.

Sinlaku has started recurving away from the China coast, toward Japan. As of 12Z on September, 15th, Sinlaku was centered at 27N, 122.6 according to JTWC. It was moving 055 degrees at 7 kts with max sustained winds of 65 knots (gusts to 80).

Attached is the IR image and upper-level AMVs along with the JTWC forecast track:

Sinlaku’s outflow is still fairly strong, but you can see the storm’s assymetry. It’s under strong shear from the subtropical jet, although the jet probably is helping to increase it’s outflow.

Sinlaku’s track is driven primarily by a subtropical ridge to it’s east. The primary questions will be the timing when and where it strikes Japan, and when it goes under extra-tropical transition.

The EC model has a southern-Japan landfall by just after 12Z on the 18th, and it brings Sinlaku across the southern coast of the islands.

The Met Office model is actually fairly similar with timing, but seems to have a more coherent vortex analyzed.

The NOGAP model is particularly slow with Sinlaku, bringing it to Japan by 00Z on the 20th. It also brings it much farther north than the other models.

The GFS is the quickest model, bringing Sinlaku to Japan by just after 00Z on the 18th. It brings Sinlaku across the middle of the islands.

The timing/track of these storms can be very sensitive to upper level winds. A case like this may be useful for investigating the impact of AMVs, although there are no Rapid-Scan AMVs at this time.

The timing will also impact the TPARC flight missions in terms of timing. The timing of ET will also be crucial to their missions. It will be worth investigating that in future posts.

As of 12Zm September 12th, JTWC has Sinlaku near 23.7N 123.6E. It was moving 310 degrees at 5 kts

with max sustained winds of 100 kts and gusts of 125.

IR image, upper-level AMVs and JTWC track for Typhoon Sinlaku. Valid 13Z, September 12, 2008.

The above image shows Sinlaku’s solid outflow, reasonably well defined and large eye, and slightly assymetric circulation. Dry air to Sinlaku’s west may be hindering it’s outflow to that direction. It is still under fairly low shear, although there are some 20kt shear zones in the northern edges of Sinlaku.

The forecast:

The models are still uncertain about when/if Sinlaku will recurve.

The NOGAPS model that had been the least progressive, is still mostly moving Sinlaku to the northwest. By the end of the forecast cycle, however, there is a hint of Sinlaku moving northeast. It is no longer bringing Sinlaku back down across Taiwan.

The GFS forecast brings the recurvature at T+72 hours (00Z on the 15th) and then brings a slightly weakened Sinlaku into Japan by 00Z on the 17th.

The ECMWF model, which has far been the most progressive in the recurvature, is a bit to the east and north of the GFS in it’s track across Taiwan. Then, it begins the recurvature a little bit earlier, turning it to the east by 12Z on the 14th. It then bring it across the east coast of Japan: a bit to the east of the GFS.

The Met Office Global model once again sits in between the NOGAPS camp and the EC/GFS camp. It slowly moves Sinlaku up across Taiwan and then into China, but begins the recurvature much earlier than the NOGAPS by +96 (00Z on the 16th). It then moves Sinlaku much more slowly to the northeast barely bringing Sinlaku across the China coast by +120 (00Z on the 17th).

These models seem to vary when they interact with the mid-latitude westerlies. When does the ridge to the north of Sinlaku break down? Examining how observations influence the model and its subsequent track will be of interest.