WPAC: SURIGAE - Post-Tropical

Moderator: S2k Moderators

Message
Author
rileydoxsee98
Tropical Low
Tropical Low
Posts: 25
Joined: Fri Sep 04, 2020 6:19 am

Re: WPAC: SURIGAE - Typhoon

#641 Postby rileydoxsee98 » Mon Apr 19, 2021 9:33 am

InfernoFlameCat wrote:The thing about this storm is that when mesovortices are present, they tend to suck out bits of the wall cloud and spin it around the edge of the eye. Thats why Dvorak becomes somewhat unreliable with 150mph + systems along with some other strange things that occur with super TCs. Also Surigae was a compact Cyclone which means it doesn't need to be as impressive as say Hayian to reach 190mph (I know Hayian was 195 but it looked quite a bit better than Surigae) which was a much larger system and needed alot more energy to achieve those kinds of windspeeds. Goni was exceptionally compact as well. The smaller the storm the sharper the pressure gradient and therefore the less power needed to achieve higher windspeeds. This is why I think Surigae achieved 165+knots.



I’m not trying to get off topic, but in the case of Goni (peak 1) there wasn’t a single weakness present in the storm. The CDO, cloud tops, eye shape, eye structure, eye temperature, eye humidity and microwave imagery. Literally everything about Goni peak 1 was perfect. That’s why I have given an intensity of 175knots/890mb for Goni’s first peak. Is it possible Surigae is 165knots+? Yes it is possible. But a lot of the features on Surigae was lackluster or below average for what you would expect for a 165+knot cyclone and was more typical of a 155knot storm. Maybe I’m just being too picky, but I think that 165+knots should be given to only the most impressive of storms. And while is possible Surigae was 165+knots, there is some things like the eye shape and eye structure and humidity which suggest more of a 155kts storm more than a 165knots storm. I personally believe the JTWC did the right thing Holding Dvorak Numbers at T7.5 despite SAB and JMA going with T8.0. I also feel the same way about Halong (2019), I think it was more deserving of 155kts than the official 165kt intensity given by JTWC in post analysis.
0 likes   

User avatar
euro6208
Category 5
Category 5
Posts: 18547
Joined: Mon Mar 08, 2004 7:50 pm
Location: Guam

Re: WPAC: SURIGAE - Typhoon

#642 Postby euro6208 » Mon Apr 19, 2021 9:33 am

Image
1 likes   
Remember, all of my post aren't official. For official warnings and discussions, Please refer to your local NWS products...

NWS for the Western Pacific

https://www.weather.gov/gum/

User avatar
Iceresistance
Category 5
Category 5
Posts: 8887
Age: 20
Joined: Sat Oct 10, 2020 9:45 am
Location: Tecumseh, OK/Norman, OK

Re: WPAC: SURIGAE - Typhoon

#643 Postby Iceresistance » Mon Apr 19, 2021 9:50 am

:uarrow: Surigae is almost EXACTLY like Trami in 2018 on how slow it's moving! Except it's weaker than Trami . . .
0 likes   
Bill 2015 & Beta 2020

Winter 2020-2021 :cold:

All observations are in Tecumseh, OK unless otherwise noted.

Winter posts are focused mainly for Oklahoma & Texas.

Take any of my forecasts with a grain of salt, refer to the NWS, SPC, and NHC for official information

Never say Never with weather! Because ANYTHING is possible!

User avatar
InfernoFlameCat
Category 5
Category 5
Posts: 1966
Age: 20
Joined: Mon Dec 14, 2020 10:52 am
Location: Buford, GA

Re: WPAC: SURIGAE - Typhoon

#644 Postby InfernoFlameCat » Mon Apr 19, 2021 10:27 am

Surigae very stable in structure. I believe it is/was a semi annular cyclone but not a true one. It was missing some criteria for the perfect 1.0 .
0 likes   
I am by no means a professional. DO NOT look at my forecasts for official information or make decisions based on what I post.

Goal: to become a registered expert over tropical and subtropical cyclones.

rileydoxsee98
Tropical Low
Tropical Low
Posts: 25
Joined: Fri Sep 04, 2020 6:19 am

Re: WPAC: SURIGAE - Typhoon

#645 Postby rileydoxsee98 » Mon Apr 19, 2021 11:31 am

Anyone know when the last time the WPac had its strongest storm all season before June? And how many times it happened? Because it’s possible Surigae could be the strongest of the year. Unless a classic WPac monster comes along and beats it in September-November, which is usually when the strongest storm occurs. But given Surigae’s intensity it’ll be hard to beat even in peak season.
0 likes   

User avatar
Yellow Evan
Professional-Met
Professional-Met
Posts: 15948
Age: 25
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Honolulu, HI
Contact:

Re: WPAC: SURIGAE - Typhoon

#646 Postby Yellow Evan » Mon Apr 19, 2021 11:38 am

InfernoFlameCat wrote:Surigae very stable in structure. I believe it is/was a semi annular cyclone but not a true one. It was missing some criteria for the perfect 1.0 .


The eye is literally 20C, easily past the WMG threshold for +1.0 eye adjustment as long as it’s surrounded by B cloud tops.
0 likes   

User avatar
Yellow Evan
Professional-Met
Professional-Met
Posts: 15948
Age: 25
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Honolulu, HI
Contact:

Re: WPAC: SURIGAE - Typhoon

#647 Postby Yellow Evan » Mon Apr 19, 2021 11:46 am

rileydoxsee98 wrote:
InfernoFlameCat wrote:The thing about this storm is that when mesovortices are present, they tend to suck out bits of the wall cloud and spin it around the edge of the eye. Thats why Dvorak becomes somewhat unreliable with 150mph + systems along with some other strange things that occur with super TCs. Also Surigae was a compact Cyclone which means it doesn't need to be as impressive as say Hayian to reach 190mph (I know Hayian was 195 but it looked quite a bit better than Surigae) which was a much larger system and needed alot more energy to achieve those kinds of windspeeds. Goni was exceptionally compact as well. The smaller the storm the sharper the pressure gradient and therefore the less power needed to achieve higher windspeeds. This is why I think Surigae achieved 165+knots.



I’m not trying to get off topic, but in the case of Goni (peak 1) there wasn’t a single weakness present in the storm. The CDO, cloud tops, eye shape, eye structure, eye temperature, eye humidity and microwave imagery. Literally everything about Goni peak 1 was perfect. That’s why I have given an intensity of 175knots/890mb for Goni’s first peak. Is it possible Surigae is 165knots+? Yes it is possible. But a lot of the features on Surigae was lackluster or below average for what you would expect for a 165+knot cyclone and was more typical of a 155knot storm. Maybe I’m just being too picky, but I think that 165+knots should be given to only the most impressive of storms. And while is possible Surigae was 165+knots, there is some things like the eye shape and eye structure and humidity which suggest more of a 155kts storm more than a 165knots storm. I personally believe the JTWC did the right thing Holding Dvorak Numbers at T7.5 despite SAB and JMA going with T8.0. I also feel the same way about Halong (2019), I think it was more deserving of 155kts than the official 165kt intensity given by JTWC in post analysis.


Dvorak numbers don’t depend on the eye shape and structure, just eye temperature FWIW.
2 likes   

User avatar
Iceresistance
Category 5
Category 5
Posts: 8887
Age: 20
Joined: Sat Oct 10, 2020 9:45 am
Location: Tecumseh, OK/Norman, OK

Re: WPAC: SURIGAE - Typhoon

#648 Postby Iceresistance » Mon Apr 19, 2021 11:50 am

rileydoxsee98 wrote:Anyone know when the last time the WPac had its strongest storm all season before June? And how many times it happened? Because it’s possible Surigae could be the strongest of the year. Unless a classic WPac monster comes along and beats it in September-November, which is usually when the strongest storm occurs. But given Surigae’s intensity it’ll be hard to beat even in peak season.


The only other Pre-June CAT 5 recorded was Typhoon Amy in 1971 from April to May with a wind speed of 175 mph & a pressure 890 MB
0 likes   
Bill 2015 & Beta 2020

Winter 2020-2021 :cold:

All observations are in Tecumseh, OK unless otherwise noted.

Winter posts are focused mainly for Oklahoma & Texas.

Take any of my forecasts with a grain of salt, refer to the NWS, SPC, and NHC for official information

Never say Never with weather! Because ANYTHING is possible!

User avatar
ElectricStorm
Category 5
Category 5
Posts: 4493
Age: 23
Joined: Tue Aug 13, 2019 11:23 pm
Location: Skiatook, OK / Norman, OK

Re: WPAC: SURIGAE - Typhoon

#649 Postby ElectricStorm » Mon Apr 19, 2021 11:58 am

Iceresistance wrote:
rileydoxsee98 wrote:Anyone know when the last time the WPac had its strongest storm all season before June? And how many times it happened? Because it’s possible Surigae could be the strongest of the year. Unless a classic WPac monster comes along and beats it in September-November, which is usually when the strongest storm occurs. But given Surigae’s intensity it’ll be hard to beat even in peak season.


The only other Pre-June CAT 5 recorded was Typhoon Amy in 1971 from April to May with a wind speed of 175 mph & a pressure 890 MB

Theres been several pre-June Cat 5s. Maybe you mean the only year that the strongest storm was before June?
2 likes   
I am in no way a professional. Take what I say with a grain of salt as I could be totally wrong. Please refer to the NHC, NWS, or SPC for official information.

Boomer Sooner!

rileydoxsee98
Tropical Low
Tropical Low
Posts: 25
Joined: Fri Sep 04, 2020 6:19 am

Re: WPAC: SURIGAE - Typhoon

#650 Postby rileydoxsee98 » Mon Apr 19, 2021 11:59 am

Yellow Evan wrote:
rileydoxsee98 wrote:
InfernoFlameCat wrote:The thing about this storm is that when mesovortices are present, they tend to suck out bits of the wall cloud and spin it around the edge of the eye. Thats why Dvorak becomes somewhat unreliable with 150mph + systems along with some other strange things that occur with super TCs. Also Surigae was a compact Cyclone which means it doesn't need to be as impressive as say Hayian to reach 190mph (I know Hayian was 195 but it looked quite a bit better than Surigae) which was a much larger system and needed alot more energy to achieve those kinds of windspeeds. Goni was exceptionally compact as well. The smaller the storm the sharper the pressure gradient and therefore the less power needed to achieve higher windspeeds. This is why I think Surigae achieved 165+knots.



I’m not trying to get off topic, but in the case of Goni (peak 1) there wasn’t a single weakness present in the storm. The CDO, cloud tops, eye shape, eye structure, eye temperature, eye humidity and microwave imagery. Literally everything about Goni peak 1 was perfect. That’s why I have given an intensity of 175knots/890mb for Goni’s first peak. Is it possible Surigae is 165knots+? Yes it is possible. But a lot of the features on Surigae was lackluster or below average for what you would expect for a 165+knot cyclone and was more typical of a 155knot storm. Maybe I’m just being too picky, but I think that 165+knots should be given to only the most impressive of storms. And while is possible Surigae was 165+knots, there is some things like the eye shape and eye structure and humidity which suggest more of a 155kts storm more than a 165knots storm. I personally believe the JTWC did the right thing Holding Dvorak Numbers at T7.5 despite SAB and JMA going with T8.0. I also feel the same way about Halong (2019), I think it was more deserving of 155kts than the official 165kt intensity given by JTWC in post analysis.


Dvorak numbers don’t depend on the eye shape and structure, just eye temperature FWIW.



Yeah I know that. But I’m just saying that I factor eye shape and quality as well as temperature into my analysis. Anyways the SAB CDG rules make it feel like a T8.0 is not of the same value it used to be. A T8.0 is something that you will rarely ever see, usually once or twice a decade. With SABs CDG rules they are becoming more common and around half of WPac 7.5s will reach 8.0 on those SAB CDG rules. I don’t think there is actually a 15knots difference between a storm with a CMG ring and storm with a CDG ring. Maybe 5knots. But that’s it. Per standard Dvorak rules, CDG doesn’t mean anything more than CMG. But under SABs CDG rules it is another half T number.
1 likes   

User avatar
aspen
Category 5
Category 5
Posts: 8029
Joined: Sat Oct 12, 2019 7:10 pm
Location: Connecticut, USA

Re: WPAC: SURIGAE - Typhoon

#651 Postby aspen » Mon Apr 19, 2021 12:04 pm

rileydoxsee98 wrote:
InfernoFlameCat wrote:The thing about this storm is that when mesovortices are present, they tend to suck out bits of the wall cloud and spin it around the edge of the eye. Thats why Dvorak becomes somewhat unreliable with 150mph + systems along with some other strange things that occur with super TCs. Also Surigae was a compact Cyclone which means it doesn't need to be as impressive as say Hayian to reach 190mph (I know Hayian was 195 but it looked quite a bit better than Surigae) which was a much larger system and needed alot more energy to achieve those kinds of windspeeds. Goni was exceptionally compact as well. The smaller the storm the sharper the pressure gradient and therefore the less power needed to achieve higher windspeeds. This is why I think Surigae achieved 165+knots.



I’m not trying to get off topic, but in the case of Goni (peak 1) there wasn’t a single weakness present in the storm. The CDO, cloud tops, eye shape, eye structure, eye temperature, eye humidity and microwave imagery. Literally everything about Goni peak 1 was perfect. That’s why I have given an intensity of 175knots/890mb for Goni’s first peak. Is it possible Surigae is 165knots+? Yes it is possible. But a lot of the features on Surigae was lackluster or below average for what you would expect for a 165+knot cyclone and was more typical of a 155knot storm. Maybe I’m just being too picky, but I think that 165+knots should be given to only the most impressive of storms. And while is possible Surigae was 165+knots, there is some things like the eye shape and eye structure and humidity which suggest more of a 155kts storm more than a 165knots storm. I personally believe the JTWC did the right thing Holding Dvorak Numbers at T7.5 despite SAB and JMA going with T8.0. I also feel the same way about Halong (2019), I think it was more deserving of 155kts than the official 165kt intensity given by JTWC in post analysis.

Halong maintained a T#7.8-7.9 look for 6-7 hours (or more) with a perfect CDG ring and a >20C eye. It was absolutely deserving of 165 kt like Surigae. As for Goni, its eye when it was assessed at 170 kt wasn’t perfectly clear, but it was an extremely intense system for 1-2 days prior to that eyewall meld, so it’s reasonable to assume that it was already 155-165 kt and slightly intensified into 170 kt.

Surigae was clearly undergoing an exceptional phase of RI and maintained an excellent appearance for quite some time, so it’s not like it didn’t have enough time to reach 165-170 kt. It was certainly in that “great enough” category to be worthy of T#8.0.
2 likes   
Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21

I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.

styzeb
Tropical Low
Tropical Low
Posts: 14
Joined: Mon Oct 03, 2016 2:47 am

Re: WPAC: SURIGAE - Typhoon

#652 Postby styzeb » Mon Apr 19, 2021 12:13 pm

rileydoxsee98 wrote:Anyone know when the last time the WPac had its strongest storm all season before June? And how many times it happened? Because it’s possible Surigae could be the strongest of the year. Unless a classic WPac monster comes along and beats it in September-November, which is usually when the strongest storm occurs. But given Surigae’s intensity it’ll be hard to beat even in peak season.


Lola 86 150 kt, Damrey 2000 155 kt (both in May).
1 likes   

User avatar
Iceresistance
Category 5
Category 5
Posts: 8887
Age: 20
Joined: Sat Oct 10, 2020 9:45 am
Location: Tecumseh, OK/Norman, OK

Re: WPAC: SURIGAE - Typhoon

#653 Postby Iceresistance » Mon Apr 19, 2021 12:32 pm

Weather Dude wrote:
Iceresistance wrote:
rileydoxsee98 wrote:Anyone know when the last time the WPac had its strongest storm all season before June? And how many times it happened? Because it’s possible Surigae could be the strongest of the year. Unless a classic WPac monster comes along and beats it in September-November, which is usually when the strongest storm occurs. But given Surigae’s intensity it’ll be hard to beat even in peak season.


The only other Pre-June CAT 5 recorded was Typhoon Amy in 1971 from April to May with a wind speed of 175 mph & a pressure 890 MB

Theres been several pre-June Cat 5s. Maybe you mean the only year that the strongest storm was before June?


No, Phyllis & Hester was the strongest, I forgot all others than Amy in 1971 :P

  • Typhoon Iris - May 1951
    170 mph & 909 MB
  • Typhoon Hester - December 1952 - January 1953
    185 mph, Pressure unknown
  • Typhoon Rose - January 1957
    160 mph winds, Pressure Unknown
  • Typhoon Ophelia - January 1958
    160 mph & ~920 MB
  • Typhoon Phyllis - May 1958
    185 mph, Pressure unknown
  • Typhoon Amy - April/May 1971
    175 mph, Pressure Unknown
  • Typhoon Lola - May 1986
    170 mph & 910 MB
  • Typhoon Damrey - May 2000
    175 mph & 920 MB
  • Typhoon Maysak - March/April 2015
    175 mph & 910 MB
  • Typhoon Wutip - February/March 2019 (I tracked the storm)
    160 mph & 920 MB
Last edited by Iceresistance on Mon Apr 19, 2021 3:53 pm, edited 1 time in total.
0 likes   
Bill 2015 & Beta 2020

Winter 2020-2021 :cold:

All observations are in Tecumseh, OK unless otherwise noted.

Winter posts are focused mainly for Oklahoma & Texas.

Take any of my forecasts with a grain of salt, refer to the NWS, SPC, and NHC for official information

Never say Never with weather! Because ANYTHING is possible!

User avatar
Yellow Evan
Professional-Met
Professional-Met
Posts: 15948
Age: 25
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Honolulu, HI
Contact:

Re: WPAC: SURIGAE - Typhoon

#654 Postby Yellow Evan » Mon Apr 19, 2021 3:40 pm

rileydoxsee98 wrote:
Yellow Evan wrote:
rileydoxsee98 wrote:

I’m not trying to get off topic, but in the case of Goni (peak 1) there wasn’t a single weakness present in the storm. The CDO, cloud tops, eye shape, eye structure, eye temperature, eye humidity and microwave imagery. Literally everything about Goni peak 1 was perfect. That’s why I have given an intensity of 175knots/890mb for Goni’s first peak. Is it possible Surigae is 165knots+? Yes it is possible. But a lot of the features on Surigae was lackluster or below average for what you would expect for a 165+knot cyclone and was more typical of a 155knot storm. Maybe I’m just being too picky, but I think that 165+knots should be given to only the most impressive of storms. And while is possible Surigae was 165+knots, there is some things like the eye shape and eye structure and humidity which suggest more of a 155kts storm more than a 165knots storm. I personally believe the JTWC did the right thing Holding Dvorak Numbers at T7.5 despite SAB and JMA going with T8.0. I also feel the same way about Halong (2019), I think it was more deserving of 155kts than the official 165kt intensity given by JTWC in post analysis.


Dvorak numbers don’t depend on the eye shape and structure, just eye temperature FWIW.



Yeah I know that. But I’m just saying that I factor eye shape and quality as well as temperature into my analysis. Anyways the SAB CDG rules make it feel like a T8.0 is not of the same value it used to be. A T8.0 is something that you will rarely ever see, usually once or twice a decade. With SABs CDG rules they are becoming more common and around half of WPac 7.5s will reach 8.0 on those SAB CDG rules. I don’t think there is actually a 15knots difference between a storm with a CMG ring and storm with a CDG ring. Maybe 5knots. But that’s it. Per standard Dvorak rules, CDG doesn’t mean anything more than CMG. But under SABs CDG rules it is another half T number.


Without recon, no one really knows for sure. We've seen a lot of Atlantic systems have round circular eyes and completely outrun their Dvorak intensity (though by how much depends on how much weight to be placed towards SFMR). Given I've seldom seen Recon find weaker than Dvorak at high end intensity, I'm more inclined to believe CMG/WMG being stronger than T7.5 rather than CDG/WMG being weaker than T8.0.
1 likes   

JW-_-
Category 1
Category 1
Posts: 281
Joined: Thu Mar 04, 2021 4:46 pm

Re: WPAC: SURIGAE - Typhoon

#655 Postby JW-_- » Mon Apr 19, 2021 8:29 pm

18z EC thinks maybe up to a metre of rain for some coastal fringe areas over the next few days.
Image
Image
0 likes   

User avatar
1900hurricane
Category 5
Category 5
Posts: 6044
Age: 32
Joined: Fri Feb 06, 2015 12:04 pm
Location: Houston, TX
Contact:

Re: WPAC: SURIGAE - Typhoon

#656 Postby 1900hurricane » Mon Apr 19, 2021 10:07 pm

All in all, Surigae has been very well behaved in terms of track. Here is verification (mean absolute error in nautical miles) from my personal custom model consensus. Scores are very good.

Image

Now, intensity on the other hand...
3 likes   
Contract Meteorologist. TAMU & MSST. Fiercely authentic, one of a kind. We are all given free will, so choose a life meant to be lived. We are the Masters of our own Stories.
Opinions expressed are mine alone.

Follow me on Twitter at @1900hurricane : Read blogs at https://1900hurricane.wordpress.com/

JW-_-
Category 1
Category 1
Posts: 281
Joined: Thu Mar 04, 2021 4:46 pm

Re: WPAC: SURIGAE - Typhoon

#657 Postby JW-_- » Tue Apr 20, 2021 6:33 am

Image

Image
https://imgur.com/3TvLPvg
The eye looks roughly at least 50miles across. I like the false-color image.
0 likes   

User avatar
InfernoFlameCat
Category 5
Category 5
Posts: 1966
Age: 20
Joined: Mon Dec 14, 2020 10:52 am
Location: Buford, GA

Re: WPAC: SURIGAE - Typhoon

#658 Postby InfernoFlameCat » Tue Apr 20, 2021 7:23 am

Yellow Evan wrote:
InfernoFlameCat wrote:Surigae very stable in structure. I believe it is/was a semi annular cyclone but not a true one. It was missing some criteria for the perfect 1.0 .


The eye is literally 20C, easily past the WMG threshold for +1.0 eye adjustment as long as it’s surrounded by B cloud tops.

It wasnt at the time I posted
It is now Annular
0 likes   
I am by no means a professional. DO NOT look at my forecasts for official information or make decisions based on what I post.

Goal: to become a registered expert over tropical and subtropical cyclones.

User avatar
euro6208
Category 5
Category 5
Posts: 18547
Joined: Mon Mar 08, 2004 7:50 pm
Location: Guam

Re: WPAC: SURIGAE - Typhoon

#659 Postby euro6208 » Tue Apr 20, 2021 7:34 am

WDPN31 PGTW 200900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 02W (SURIGAE), LOCATED APPROXIMATELY 300 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-NORTHWESTWARD AT
05 KTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT
TY SURIGAE CONTINUES TO MAINTAIN A ROUGHLY 30-NM WIDE EYE, THOUGH AT
LEAST IN THE VISIBLE AND INFRARED BANDS HAS BECOME SLIGHTLY MORE
RAGGED. A 200502Z AMSR2 MICROWAVE PASS CONFIRMED A VERY WELL DEFINED
AND INTENSE 30-NM EYEWALL AND THE 37GHZ IMAGE REVEALED A SMALLER AND
WEAKER INNER EYEWALL AT ABOUT 15-NM FROM THE CENTER. THE INITIAL
INTENSITY REMAINS STEADY AT 115 KTS, SUPPORTED BY MULTI-AGENCY
DVORAK CURRENT INTENSITY ESTIMATES OF T6.5 FROM PGTW, AND T6.0 FROM
RJTD AND KNES, AN ADT ESTIMATE OF T6.1 AND A SATCON ESTIMATE OF 121
KTS AND IS HEDGED SLIGHTLY LOWER IN LIGHT OF A 200502Z AMSR2
WINDSPEED MEASUREMENT OF 110 KTS. TY 02W REMAINS IN A GENERALLY
FAVORABLE ENVIRONMENT CHARACTERIZED BY LOW (8-12 KTS) AND STRONG
POLEWARD AND EQUATORWARD OUTFLOW. SSTS REMAIN GENERALLY WARM, THOUGH
RECENT HYCOM MODEL ANALYSIS SUGGESTS SIGNIFICANT UPWELLING,
PRIMARILY TO THE SOUTH IN THE STORMS WAKE. HOWEVER, NOW THAT THE
SYSTEM HAS PICKED UP FORWARD SPEED ONCE MORE, IT IS MOVING AWAY FROM
THE INDUCED POOL OF COOLER WATERS AND INTO A REGION OF 27-28C
WATERS.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY SURIGAE IS FORECAST TO TRACK NORTHEASTWARD ALONG THE
WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) THROUGH TAU 36,
THEN ROUND THE RIDGE AXIS AND TURN SHARPLY NORTHEAST AHEAD OF STRONG
MID-LATITUDE SHORTWAVE TROUGH MOVING IN FROM THE WEST. BY TAU 72,
SURIGAE WILL BE ON A NEAR EASTWARD COURSE, STEADILY ACCELERATING AS
IT BEGINS TO INTERACT WITH THE SUBTROPICAL JET ALOFT. THERE IS NO
SIGNIFICANT CHANGE EXPECTED IN THE UPPER-LEVEL ENVIRONMENT, WITH LOW
VWS AND STRONG POLEWARD OUTFLOW PERSISTING THROUGH TAU 36. THE
PRIMARY INTENSITY FACTORS ARE THUS THE RELATIVELY MARGINAL SSTS
(27C) AND THE LARGE SIZE OF THE CORE AND THE TWO FACTORS TOGETHER
SUPPORT A STEADY OR GRADUAL DECREASE IN INTENSITY THOUGH TAU 12 AND
THEN STEADIER WEAKENING THROUGH TAU 36. ONCE THE SYSTEM MAKES THE
TURN NORTHEAST BY TAU 48, STEADY WEAKENING IS FORECAST AS THE SYSTEM
ENCOUNTERS STEADILY COOLER SSTS, AT OR BELOW 26C, AND DRAMATICALLY
INCREASED MID-LEVEL SHEAR. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 AND THE JTWC FORECAST TRACK IS SET WITH
HIGH CONFIDENCE. THE INTENSITY FORECAST IS SET ON THE HIGH END OF
THE GUIDANCE ENVELOPE AND CLOSELY TRACKS THE HWRF SOLUTION WITH
MODERATE CONFIDENCE.
C. IN THE LATER PORTION OF THE FORECAST, TY SURIGAE WILL CONTINUE
TO ACCELERATE EAST-NORTHEASTWARD AHEAD OF AN ADVANCING MAJOR
SHORTWAVE TROUGH AND ALONG THE NORTHERN PERIPHERY OF THE STR TO THE
SOUTHEAST. MOST AVAILABLE GUIDANCE SUGGESTS THAT TC 02W WILL NOT BE
CAPTURED BY THE PASSING SHORTWAVE, WHICH WILL MISS THE SYSTEM TO THE
NORTH, BUT WILL CONTINUE TRACKING EASTWARD AS IT WEAKENS. THE
PRIMARY IMPACT OF THE SHORTWAVE WILL BE TO IMPART A STRONG WESTERLY
FLOW ALOFT, INCREASING VWS TO ABOVE 50 KTS. THE SYSTEM WILL TRANSIT
GENERALLY ALONG THE 26C ISOTHERM, BUT DUE TO THE VERY HIGH SHEAR AND
THE CONVERGENT NATURE OF THE WESTERLY FLOW ALOFT, WILL STEADILY
WEAKEN THROUGH TAU 120. AS TY 02W MOVES EASTWARD ALONG THE
BAROCLINIC ZONE AND DEVELOPS A FRONTAL STRUCTURE, IT IS FORECAST TO
BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY TAU 96. NUMERICAL MODEL
GUIDANCE IS IN OVERALL GOOD AGREEMENT THOUGH BEGINS TO SHOW
SIGNIFICANT SPREAD IN BOTH ALONG AND CROSS-TRACK UNCERTAINTY AFTER
TAU 96 DUE TO THE UNCERTAINTY SURROUNDING THE IMPACT OF THE
SHORTWAVE TROUGH. THE JTWC FORECAST TRACK IS SET JUST SOUTH FROM THE
PREVIOUS FORECAST AND LIES JUST NORTH OF THE MULTI-MODEL CONSENSUS
WITH MODERATE CONFIDENCE.//
NNNN
0 likes   
Remember, all of my post aren't official. For official warnings and discussions, Please refer to your local NWS products...

NWS for the Western Pacific

https://www.weather.gov/gum/

User avatar
euro6208
Category 5
Category 5
Posts: 18547
Joined: Mon Mar 08, 2004 7:50 pm
Location: Guam

Re: WPAC: SURIGAE - Typhoon

#660 Postby euro6208 » Tue Apr 20, 2021 7:34 am

Both EURO and GFS keeps Surigae around for another 6-7 days.
0 likes   
Remember, all of my post aren't official. For official warnings and discussions, Please refer to your local NWS products...

NWS for the Western Pacific

https://www.weather.gov/gum/


Return to “2021”

Who is online

Users browsing this forum: No registered users and 14 guests