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MATMO Approaches Taiwan Coast as Atlantic TD#2 continues Westward

By: Dr. Jeff Masters, 3:42 PM GMT on July 22, 2014

(By Steve Gregory - Substituting for Dr. Masters who is on Vacation.)

Latest SAT and Radar imagery shows Typhoon MATMO approaching the Taiwanese east coast and is currently about 65 NM S-SE of Taipei. With a NW movement at 16 Kts, MATMO should hit the east coast within the next hour or so. Radar indicates strong convective bands have been impacting the Island for the last 4-6 hours.



Fig 1: IR imagery clearly shows MATMO has gotten much better organized since yesterday, but with so little time left for higher level winds to work their way to the surface, MAX winds are almost certainly still under true, CAT 2 intensity.

Imagery has also depicted a partial but distinct eye feature for the last 8 hours, with very good outflow to the north and south of the storm. This, combined with Dvorak estimates of over 80Kts, and JMA estimates of a central pressure near 965mb means MATMO should still be able to hit the coast near CAT 2 intensity.

Although conditions are still quite favorable for further intensification, interaction with Taiwan’s mountainous terrain, and effects of friction with the China mainland even as the storm traverses the Taiwan Strait, MATMO should weaken rapidly once it makes landfall and will almost certainly make its second and final landfall on the SE coast of China in 24 hrs at Tropical storm intensity. As the storm makes landfall on mainland China, it will turn northward in response to an approaching long wave TROF followed by acceleration towards the N-NE on THU as it transitions rapidly to a non-tropical Low.



Fig 2: Radar depiction from Taiwan shows a reasonably well-defined eye, with convective banding already over the central portion of Taiwan. The strongest convection appears to be in the S-SW quadrant which corresponds with the overall ‘history’ of this cyclone in which the strongest convection has generally been in the southern semi-circle.




TROPICAL DEPRESSION #2 OVER CENTRAL ATLANTIC

Very small Tropical Depression #2 is located near 12.5N / 47.8W or about 700NM east of the CARIB, moving westward (285ᵒ) at 16Kts. With the system embedded in deep easterlies, and convection remaining relatively weak, this trajectory should continue for the next 48-72 hrs.



Fig 3: TD#2 remains quite small, with a general 'circulation' diameter estimated at about 200NM (This estimate is based on VIS and microwave imagery shown in Fig 4 below.)

Despite relatively low wind shear (approximately near 10Kts), there has been very little change in the overall size and structure of TD#2 during the last 24 hours. In addition, the small cyclone will soon begin encountering significantly drier air, and as the system approaches the eastern CARIB Thursday, it is expected to encounter stronger wind shear which is likely (though not with 100% certainty) to prevent any significant intensification despite warmer SST’s that will support stronger convection. In addition, the shear may be strong enough to cause the system to open up into a wave.



Fig 4: The 85Ghz microwave image continues to support a closed low or mid-Level circulation which has been more difficult to locate on VIS or IR imagery than it was yesterday.

The large scale global models still cannot resolve/initialize this small system, but the specialized Tropical Cyclone models, initialized at 12Z, forecast the storm to continue tracking towards the CARIB, reaching the eastern CARIB late on Thursday. Interestingly, a few of the dynamical models show a slow intensification of the system to Tropical Storm intensity – though the most reliable models, and the Official NHC forecast, call for dissipation in 48-60 hours





Fig 5 & 6: The Early 12Z cycle model runs are generally a bit more aggressive in developing TD#2 into a Tropical Storm compared to yesterday's runs – but the most reliable dynamic models continue to forecast dissipation and admittedly have a high probability of verifying.



Fig 7: The official NHC Track forecast is in excellent agreement with the model consensus, but calls for dissipation prior to the system reaching the CARIB.

ELSEWHERE in the Atlantic, there are 2 Tropical Waves over the far eastern Tropical Atlantic that have brought along more ‘moisture laden air’ (versus dry, Saharan air). In addition, there are now several somewhat stronger appearing Tropical waves upstream over Africa (only 2 are shown in Fig 9) that will reach the Atlantic later this week and early next week, with one of these systems having a significantly higher potential for development next week.



Fig 8: Aside from TD#2, only 2 significant Tropical Waves are present over the eastern most Atlantic, and they are entangled in the African Monsoonal TROF and/or ITCZ.



Fig 9: Tropical Waves over Africa have become somewhat stronger over the past week, with the easternmost one in the above image showing a mid-level 'turning' on imagery loops.

In the meantime, however, no new tropical cyclone formation is expected during the remainder of the week.

The next update will be Wednesday afternoon unless conditions in the Atlantic warrant an earlier posting.

Steve Gregory

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

1001. VR46L
NATURE'S ROADBLOCK TO HURRICANE PREDICTION
Experiment shows how small-scale variability can thwart seasonal outlooks



The quiet Atlantic hurricane season of 2013 came as a surprise to many, as seasonal forecasts had consistently predicted an unusually large crop of named storms. A new study by scientists at NCAR and North-West University (South Africa) finds that internal variability—processes that unfold without being dictated by larger-scale features—can make one season twice as active as another, even when El Niño and other large-scale hurricane-shaping elements are unchanged. The results suggest that seasonal hurricane forecasts could be improved by conveying the amount of unavoidable uncertainty in the outlook.

Led by NCAR’s James Done, the study focused on the busy 1998 Atlantic season, which produced 14 tropical storms (10 of which became hurricanes). Half of the 14 named storms took shape over the deep North Atlantic tropics, the area south of about 23°N and east of 65°W. About 85% of major hurricanes originate from tropical waves that move off Africa into this region

Click on link above to read more
This is the 12z GFS at 78 hours... notice the big low up near the Azores-



That thing's been around for awhile already as a non-tropical low, but I just checked the phase diagrams on all the models and most of them show it becoming warm core in a few days.



Waters are way too cold for it to be purely tropical though, but maybe it's possible it tries to acquire subtropical characteristics?
Quoting 994. TropicalAnalystwx13:


Temporarily, misleadingly favorable. :)

Wind shear is always low in the center of upper-level lows (there's a strong one west of Jamaica as evidenced by the map below). As this feature moves north, expect shear to increase back to 30-50 knots over the Caribbean again.





Most models have it staying in the north Caribbean though, where shear should be moderate-low by the time the system gets there.



It then continues the decrease there after:



I'm not too sure about the GFS shear maps though, as comparing it to the current shear map, it seems it overdoes the shear. It's showing areas of 40kts of shear, where on the map there's about 25-30kts at the moment and shows 65kts of shear where there's currently around 50-55kts of shear.
Since they are in the neighborhood....


URNT15 KNHC 231559
AF304 0201A INVEST HDOB 07 20140723
154930 1642N 06045W 3751 08076 0442 -195 -478 213002 002 034 000 00
1005. GatorWX
*sigh


1006. MahFL
Is it me or is a new coc forming on ex TD2 ?
1007. Grothar
NHC back in 1992 did keep Andrew as a named tropical storm despite the fact recon could not close off a circulation, because it had winds, IIRC, to near 60 knots North of the center, and it was entering a region of much more favorable shear.

Bob Sheets made the decision himself because declaring it an open wave when he knew it would almost certainly be a TS again within 6 to 12 hours would be confusing to the public.


02L is different, it is not producing winds well in excess of tropical storm force, and I don't believe any credible model regenerates it anytime soon.

If you use the lat-long lines in a visible satellite for reference, there is no suggestion of a closed circulation in the low cloud motion.

Oh, it is July, like Spring Training, 2 or 3 weeks until the meat and potatoes season starts. Yeah, there are years like 1957 or 2005 when June or July has a filet mignon storm, but those are exceptions.

1009. Grothar
Much more recent image

1010. sar2401
Quoting nrtiwlnvragn:
Since they are in the neighborhood....


URNT15 KNHC 231559
AF304 0201A INVEST HDOB 07 20140723
154930 1642N 06045W 3751 08076 0442 -195 -478 213002 002 034 000 00
Can you translate for those of us who are gibberish challenged? :-)
Quoting 1004. nrtiwlnvragn:

Since they are in the neighborhood....


URNT15 KNHC 231559
AF304 0201A INVEST HDOB 07 20140723
154930 1642N 06045W 3751 08076 0442 -195 -478 213002 002 034 000 00


Practice???
1012. MahFL
Quoting 974. HuracanTaino:

Well, why in the world they were flying a plane in the middle of a hurricane?


Profit comes before safety, despite what they tell you.
Quoting 1010. sar2401:

Can you translate for those of us who are gibberish challenged? :-)


Recon is flying out to xTD02

Tropical Atlantic translates gibberish
1014. GatorWX
Quoting 1002. MAweatherboy1:

This is the 12z GFS at 78 hours... notice the big low up near the Azores-



That thing's been around for awhile already as a non-tropical low, but I just checked the phase diagrams on all the models and most of them show it becoming warm core in a few days.



Waters are way too cold for it to be purely tropical though, but maybe it's possible it tries to acquire subtropical characteristics?


Interesting. Won't be holding my breathe however.. It must be on to something with such a sudden turn towards wc.


1015. ncstorm
anyone remember TS Emily of 2011..what a nightmare for forecasters..



The cyclogenesis of Tropical Storm Emily was complicated, extending over several days from late July into early August. An easterly tropical wave—an equatorward trough of low pressure—exited the west African coast in the fourth week of July, at which point it became largely embedded within the monsoon trough.[1] Located to the south of a ride of high pressure, the wave moved west-northwestward across the open Atlantic; it retained a broad circulation with little to no precipitation for a day or two.[2][3] Over time, clusters of convection increased around the broad system, and it developed two distinct centers of circulation on August 30.[2][4][5] During the morning of July 31, the large low markedly gained in organization, and the National Hurricane Center (NHC) noted it was close to becoming a tropical depression.[6] Later that day, however, the main circulation became increasingly elongated; its westernmost component soon detached to form a separate tropical wave.[7] This new disturbance featured widely scattered convection and rainbands, which briefly affected the Lesser Antilles.[8] The next day, a new area of deep convection with a dominant center formed as the circulation became better defined. It passed through the Leeward Islands with some improvement in its structure, and the surface winds rose to near tropical storm force.[2][9] A reconnaissance flight into the system revealed the circulation center had become well defined near the deep convection. The system was upgraded to tropical storm status and given the name Emily at 0000 UTC on August 2, when it was located to the south of Dominica. During the initial stages of its existence, the storm accelerated toward the west-northwest in response to the strong high pressure to its north.[2][10]
TD2 will regenerate as it approaches the Bermuda Triangle.................
1017. SLU
Quoting 990. TropicalAnalystwx13:


If the system lacks a closed circulation, it's not a tropical cyclone. It could be producing 75 mph winds, but if there is no west wind on the southern side of the low (which is the case here), then it's just a disturbance. Remember Karen in the West Caribbean last year?


If a system is already named or numbered but loses its closed circulation while approaching land, it should be maintained as a tropical cyclone until it clears land mainly to protect lives and the adjustments can be made in hindsight after the season.
Q: Gro

Still a nice circle. To be honest, I was relieved to see it POOFed this AM, but like JRRP says, looks like here we go again.
1019. LemieT
Quoting 955. weathermanwannabe:

TD2 was a "bone" that Nature threw at us for late July and it was not able to flourish; it did not develop in the normal July regions (normally closer to the US this time of the year) and just not enough moisture to sustain it. With the E-Pac on the move again, and the inverse relationship between between the two basins, we may not see any Central Atlantic development for several weeks. I know I sound like a broken record but we will not see the long-range models start developing African waves until they actually start to emerge in earnest and the E-Pac quiets down again.

Will check back with everyone later today.................WW.


TD 2 was a very dry bone, and we all know what Chantal was supposed to mean last year. Not holding out too much hope for this season until I see at least a full-fledged Cat 2 in the MDR.
Quoting 1002. MAweatherboy1:

Waters are way too cold for it to be purely tropical though, but maybe it's possible it tries to acquire subtropical characteristics?


Water temperatures are about 20-22C where the GFS shows the center:



Subtropical threshold is around 23C, so could become a subtropical depression, especially if it goes a bit further south and east than the GFS is showing.
1021. GatorWX
Quoting 1009. Grothar:

Much more recent image




I think it wants to steal Marco's record.



Hey, with how the last few seasons have panned, why not? It's dead, no wait.... so on.
You know it's interesting to see after NHC brings it down
the system starts to make a comeback
LLC seems weak or just slightly open looks to be on SW side but now it's starting to tighten back up and redeveloping covective blob in the COC
It's good that recon is still flying mission to be honest
Quoting 1007. Grothar:




Is this the front you were talking about, when telling us to look at the SE coast? Or is it the next one?
Hmm... I think the center reformed under the new blob. Probably won't last for much longer though.
1025. SLU
Quoting 1015. ncstorm:

anyone remember TS Emily of 2011..what a nightmare for forecasters..



The cyclogenesis of Tropical Storm Emily was complicated, extending over several days from late July into early August. An easterly tropical wave—an equatorward trough of low pressure—exited the west African coast in the fourth week of July, at which point it became largely embedded within the monsoon trough.[1] Located to the south of a ride of high pressure, the wave moved west-northwestward across the open Atlantic; it retained a broad circulation with little to no precipitation for a day or two.[2][3] Over time, clusters of convection increased around the broad system, and it developed two distinct centers of circulation on August 30.[2][4][5] During the morning of July 31, the large low markedly gained in organization, and the National Hurricane Center (NHC) noted it was close to becoming a tropical depression.[6] Later that day, however, the main circulation became increasingly elongated; its westernmost component soon detached to form a separate tropical wave.[7] This new disturbance featured widely scattered convection and rainbands, which briefly affected the Lesser Antilles.[8] The next day, a new area of deep convection with a dominant center formed as the circulation became better defined. It passed through the Leeward Islands with some improvement in its structure, and the surface winds rose to near tropical storm force.[2][9] A reconnaissance flight into the system revealed the circulation center had become well defined near the deep convection. The system was upgraded to tropical storm status and given the name Emily at 0000 UTC on August 2, when it was located to the south of Dominica. During the initial stages of its existence, the storm accelerated toward the west-northwest in response to the strong high pressure to its north.[2][10]


A nightmare for many of us here too. A very stubborn system from Invest to death.
Pretty average for now...
1027. 7544
the hh is going to 92l? why bother
In that front moving off of the East Coast, there's some interesting stuff going on in the center-ish of it. There's a definite anticyclone centered above there and some pretty good lower convergence/upper divergence, as well as a weak lower vort trying to form.






There's also a stronger vorticity to the north but that's heading out to sea. So will this bit to the south in all likelihood, but it may be interesting to watch nonetheless.

1029. GatorWX
1315 UTC

1615 UTC
1030. ncstorm
Quoting 1028. RascalNag:

In that front moving off of the East Coast, there's some interesting stuff going on in the center-ish of it. There's a definite anticyclone centered above there and some pretty good lower convergence/upper divergence, as well as a weak lower vort trying to form.






There's also a stronger vorticity to the north but that's heading out to sea. So will this bit to the south in all likelihood, but it may be interesting to watch nonetheless.




yeah Dr. Maue mentioned it the other day to which I posted on the blog..


Ryan Maue @RyanMaue · Jul 21

Models showing weak tropical development off Florida Jax coast in 2-days. Moisture & weak low

Quoting 1024. EpsilonWeather:

Hmm... I think the center reformed under the new blob. Probably won't last for much longer though.


If it wasn't suceptible to dry air, it is now. Its also about to find itself in a region with a high amount of shear of about 20-30 knots. It's trying to pull some shenanigans, even though the NHC called it dead, but it will be soon enough.
The next systems in the WPAC:





Twins! Hopefully it happens so we can possibly see the fujiwhara effect in action. :)
1033. ncstorm
Quoting 1032. Envoirment:

The next systems in the WPAC:





Twins! Hopefully it happens so we can possibly see the fujiwhara effect in action. :)


Recon headed into the remnants of TD Two.
1035. sar2401
Quoting nrtiwlnvragn:


Recon is flying out to xTD02

Tropical Atlantic translates gibberish

Thank you very much. I had that link before but lost it. At least it will be some practice and should give a little more insight into what's left of the circulation.

All the Classic signs:-
The key indicators- Nature wise that can be relied on with irrefutable accuracy -AS OPPOSED TO MERE MODELS- ARE ALL INDICATING HERE ON THE ISLAND OF DOMINICA THAT SOMETHING IS 'COMING'. The climatology of these Lesser Antilles islands with its annual tropical cyclonic activity has lead to a certain array of 'full proof signs' which are spot-on should one be interested in 'testing' whether a bonafide tropical system was definitely approaching, but without the help of modern day Forecasting tools etc. Namely, these include the winds & sustained directional patterns, cloud spin & direction/formation, and most crucially the typical prevailing conditions of the ocean along with certain behaviours of animals, which are a give away clue as to what to EXPECT. Currently, all indicators are in the affirmative - so irrespective of what the NHC says tonight will be a long and stormy one- weather wise...
Even now looking at the satelite picks it would have made sense to weaken the intensity of the depression, BUT NOT TO DOWNGRADE IT. A VERY POOR CALL IMHO BY THE POWERS THAT BE...
GOD'S BLESSINGS TO ALL!
1037. GatorWX
Quoting 1034. TylerStanfield:

Recon headed into the remnants of TD Two.



The whole convective envelope is not much larger than Martinique lol. Interested to see what they find. Also, interesting NHC dropped it when recon would be heading in only hours later...
1038. WxLogic
Good afternoon... TD#2 Remnant sure doesn't want to give up.
1039. MahFL
Hm, ex TD2 has "cdo" and an S shape, best ex TD I've ever seen....

Quoting EpsilonWeather:
Hmm... I think the center reformed under the new blob. Probably won't last for much longer though.
It seems that It's going to continue fluctuating, with some ups and down, hopefully will bring some needed rain to the island, but unfortunately not much....
Quoting MahFL:
Hm, ex TD2 has "cdo" and an S shape, best ex TD I've ever seen....
Hmm.
1043. MahFL
Quoting 1027. 7544:

the hh is going to 92l? why bother


Research, get the ground truth of why a TD dies etc, although right now a new blob of convection has fired up, which again would be good research.
1044. Grothar
Quoting 1023. Envoirment:



Is this the front you were talking about, when telling us to look at the SE coast? Or is it the next one?


It is this one that I wrote about in my blog a few days ago. The pressure should be lowering off the SE US coast in a few days, and a good chance of a system developing. I wrote a very brief summary. Thanks for remembering. :):)
1045. ncstorm
Joe Bastardi @BigJoeBastardi · 22m

Will be interesting to see how"dead" td 2 really is as it crosses the islands tonight. Loop says still has life http://www.ssd.noaa.gov/PS/TROP/floaters/02L/flash -vis-short.html …


The due Westward path doesn't look too daunting; looks like drought relief is a sure-thing for the islands.
There doesn't appear to be a closed circulation.

Quoting GatorWX:


The whole convective envelope is not much larger than Martinique lol. Interested to see what they find. Also, interesting NHC dropped it when recon would be heading in only hours later...
They should wait until the latest blob fully develops, to see if it can be call a TD again,...
1050. Grothar
We have been getting blasted every few minutes with tropical downpours. Some minor street flooding and a lot of lightning. It may not look much on radar, but these are strong storms. A lot of instability in the air.

JeffMasters has created a new entry.
Quoting 1047. TropicalAnalystwx13:

There doesn't appear to be a closed circulation.



Ha. Nope.
Hmm it seems like it is slightly open on SW side but if convection can stay over the system and continue to build it might be able to close up that side and become a closed low once again

Anyway you guys remember Bonnie 2004



And based on this

1054. Grothar
This is not really at "blob" status yet. This is more what I like to call a SFUOC or Sudden Flare-up of Convection.
They happen all the time, we are just not focused on them.


1055. MahFL
Quoting 1041. HuracanTaino:

Isn't TD2 anymore, just a remnant low...

I added "ex". It's ex TD2, a remanent low, with now a big blow up of convection....

Convection continues to build and expand
Quoting Grothar:
This is not really at "blob" status yet. This is more what I like to call a SFUOC or Sudden Flare-up of Convection.
They happen all the time, we are just not focused on them.


Well, recon is inside of what ever it is, let see what they say it is...
3 out of 4 nio region now below 0.5
2 out of 4 nio region now below 0.0 (negative)(cold)
Below 0.5
Nio 3
Nio 3.4
Nio 4
Below 0.0
Nio 3.4
Nio 4
Recon finding stronger wind in NE sector
Quoting 1053. wunderkidcayman:

Hmm it seems like it is slightly open on SW side but if convection can stay over the system and continue to build it might be able to close up that side and become a closed low once again

Anyway you guys remember Bonnie 2004



And based on this


I'll take a Bonnie here to give us some more rain on the west coast of FL. That would be an added bonus on top of all these fronts coming down as well. :)