western pacific Super Typhoon Nuri

[Somerset Squall]

Tropical Depression 20W has formed  a couple hundred miles northwest of Yap, and several hundred miles east of the Philippines. 20W has winds of 30kts. The depression already has well defined banding features and increasing convection over the LLCC. Given this satellite presentation, it won't be long before 20W is a tropical storm. Going by JTWC's forecast, it won't be long before 20W is a typhoon either. Shear is low, waters are very warm and outflow is good. This could produce some rapid intensification over the next few days. 20W is expected to head west-northwestwards, then northwest then north-northeastwards as it rounds the southern and western sides of the subtropical ridge loacted to the north. On the north-northeasterly leg of the track, shear could increase, causing some weakening at days 4 and 5.

 

 

 

[Somerset Squall]

20W has become Tropical Storm Nuri, with winds of 35kts. The storm has continued to consolidate in low shear and good upper level outflow. These conditions should persist, allowing for some potentially rapid intensification. The good news is that Nuri is still expected to recurve away from the Philippines.

[Somerset Squall]

As expected, Nuri has rapidly intensified. Winds are now at 55kts. The storm has a well developed central dense overcast, flanked by numerous strong bands. An eye looks like it will emerge soon. Further rapid strengthening is expected.

[Somerset Squall]

Nuri has continued to strengthen and is now a 75kt cat 1 typhoon (SS scale). The typhoon is developing an eye in the circular central dense overcast, flanked by spiral banding features. Further rapid intensification is expected, perhaps even more rapid than the last 24hrs of strengthening. JTWC expect Nuri to reach a peak of 130kts in as little as 36hrs.

[Somerset Squall]

Here comes the eye! Nuri is going to be an absolute beauty by the looks of things:

[Sainsbo]

:O

 

Gonna be a strong one. Nice and symmetrical with very cold cloud tops. And best of all, no threat to land. JTWC predict a peak of 140kts (160mph), but I don't see much stopping it going stronger.

 

Edited November 2, 2014 by Sainsbo

[Somerset Squall]

Winds are increasing rapidly with Nuri. Winds are now at 120kts, cat 4 on the SS scale. This is an increase of 65kts in 24hrs. Cat 5 looks to be imminent.

Edited November 2, 2014 by Somerset Squall

[Somerset Squall]

Winds now up to 130kts, making Nuri a Super Typhoon, the fifth of the season.

[Sainsbo]

ADT giving raw T values of 7.5+ now. It looks like the JTWC might be being slightly conservative with their outlook. http://tropic.ssec.wisc.edu/real-time/storm.php?&basin=westpac&sname=20W&invest=NO&zoom=4&img=1&vars=11111000000000000000&loop=0

 

Still looking fantastic on satellite too.

 

[Somerset Squall]

Nuri has continued to rapidly intensify, and is now a category 5 on the SS scale, with winds of 155kts. This is the 4th cat 5 of the Western Pacific season (including Genevieve). JTWC expect a peak of 170kts, matching Haiyan of last year if it were to occur. Nuri is in an area of very low shear, excellent radial outflow and very warm sea temps, so further intensity gains are not out of the question. What an amazing system!

Luckily, unlike with Haiyan, Nuri should stay away from land:

Edited November 3, 2014 by Somerset Squall

[knocker]

The new GFS

 

Post tropical reintensification of STY #Nuri down to 914 mb would be among strongest observed in past 50 yrs in NPAC

 

pic.twitter.com/eHIdDCUa5y

[knocker]

Suomi NPP VIIRS Infrared image of the eye of Super Typhoon Nuri in the West Pacific Ocean

 

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2014/11/141102_1712z_STY_Nuri_eye.png

[Somerset Squall]

Nuri's peak was 155kts. The typhoon has since weakened to 120kts in increased shear as Nuri is now accelerating northeastwards. Further weakening and extratropical transition will occur soon.

Edited November 4, 2014 by Somerset Squall

[Vorticity0123]

Nuri's peak was 155kts. The typhoon has since weakened to 120kts in increased shear as Nuri is now accelerating northeastwards. Further weakening and extratropical transition will occur soon.

 

 

Quick weakening is continuing, as the intensity of Nuri has come down to 105 kt (according to the JTWC). It looks like the weakening is partially caused by an EWRC (eyewall replacement cycle). In fact, visible satellite imagery shows a small area of intense convection, surrounded by a convective-free zone, and that area is surrounded by a possible second eyewall, which is not completely circular (i.e. it looks more like banding features).

 

Visible satellite loop of Nuri. Note that the image auto-updates itself.

 

For now, it seems that the very small inner eyewall is able to sustain itself, as shown in MIMIC imagery:

 

CIMSS MIMIC imagery of Nuri. Note that the image auto-updates itself.

 

What can be seen is that a very small eyewall (indicated by red/yellow) exists, with a much bigger eyewall encompassing the cyclone at much greater distance. As of 20:00 UTC, the small inner eyewall has not yet dissipated, though. This indicates that Nuri still has a well-organized structure.

 

With strong shear located to the north of Nuri, further weakening is likely, as suggested by the JTWC as well. In fact, the more north Nuri tracks, the further the shear will increase (up to 100 kt over Japan). Therefore, it looks like ET (extratropical transition) will occur very shortly.

 

After the ET, the life of Nuri is not yet over. it seems like a major extratropical storm may arise from this system, as many models are expecting a sub-925 hPa low (!) to develop in the Alaskan Sea as a result of the typhoon. Confidence in that this is going to be a real bomber is quite high for the system.

 

To illustrate this, GFS-charts are used for analysis of the Northern Hemisphere. First, check the chart below:

 

GFS MSLP + 500 hPa heights (12Z, T+48h)

 

Nuri is located just to the east of Japan as a ~985 hPa low. In this stage, Nuri will well be underway to becoming an extratropical system. However, the surprise comes if one looks at the surface pressure charts 2 days later:

 

GFS MSLP + 500 hPa heights (12Z, T+96h)

 

Nuri is in this case located near Alaska(on the top of the map). The minimum pressure associated with ex-Nuri is not even readable from the map! It should be somewhere around 930 hPa. Such explosive cyclogenesis from a tropical cyclone is rarely seen. This system could have some severe impact on Alaska. 

 

More information about this unusual occurrence can be read below:

 

http://dutch.wunderground.com/blog/JeffMasters/comment.html?entrynum=2851

 

Sources:

http://www.ssd.noaa.gov/PS/TROP/floaters/20W/20W_floater.html

http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/warnings/wp2014prog.txt

http://tropic.ssec.wisc.edu/real-time/mimic-tc/2014_20W/webManager/mainpage.html

http://www.nrlmry.navy.mil/tc-bin/tc_home2.cgi?ACTIVES=14-WPAC-20W.NURI,14-EPAC-21E.VANCE,14-IO-91B.INVEST,14-EPAC-95E.INVEST&SIZE=Thumb&PHOT=yes&NAV=tc&ATCF_BASIN=wp&ATCF_YR=2014&ATCF_FILE=/SATPRODUCTS/kauai_data/www/atcf_web/public_html/image_archives/2014/wp202014.14110406.gif&CURRENT_ATCF_FILE=/SATPRODUCTS/kauai_data/www/atcf_web/public_html/image_archives/2014/wp202014.14110406.gif&CURRENT=20141104.2101.mtsat-2.x.ir1km_bw.20WNURI.105kts-944mb-240N-1369E.100pc.jpg&CURRENT_ATCF=wp202014.14110406.gif&ATCF_NAME=wp202014&AGE=Latest&MO=NOV&BASIN=WPAC&STYLE=tables&SUB_PROD=rscat_save&TYPE=ssmi&YEAR=2014&YR=14&STORM_NAME=20W.NURI&ARCHIVE=active&DIR=/SATPRODUCTS/TC/tc14/WPAC/20W.NURI/ir/geo/1km_bw&AREA=pacific/southern_hemisphere&PROD=shear&AID_DIR=/SATPRODUCTS/TC/tc14/WPAC/20W.NURI/shear

http://www.wetterzentrale.de/topkarten/fsavnnh.html

http://dutch.wunderground.com/blog/JeffMasters/comment.html?entrynum=2851

[Somerset Squall]

Nuri is fast becoming extratropical, and JTWC have issued the last advisory as Nuri races northeastwards out of the tropics and into the open waters of the North Pacific.

[knocker]

Bering Sea "bomb" pressure fall every 6-hours: 990, 980, 962, 942, 927 --> 923 mb

Max deepening rate: 63 mb / 24 hrs pic.twitter.com/shTD6OrllQ