WPAC: ATSANI - Post-Tropical

Moderator: S2k Moderators

Message
Author
User avatar
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#81 Postby Hayabusa » Thu Oct 29, 2020 7:25 pm

Image
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

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

Re: WPAC: ATSANI - Tropical Storm

#82 Postby euro6208 » Thu Oct 29, 2020 7:44 pm

000
WTPQ32 PGUM 292143
TCPPQ2

BULLETIN
Tropical Depression Atsani (23W) Advisory Number 2
National Weather Service Tiyan GU WP212020
800 AM ChST Fri Oct 30 2020

...TROPICAL DEPRESSION ATSANI MOVING NORTH-NORTHWEST...

CHANGES WITH THIS ADVISORY
--------------------------
A Tropical Storm Watch is in effect for Guam.

WATCHES AND WARNINGS
--------------------
A Tropical Storm Watch is now in effect for Guam. Tropical storm
conditions, including damaging winds of 39 mph or more, are
possible this evening.

SUMMARY OF 700 AM CHST...2100 UTC...INFORMATION
-----------------------------------------------
Location...9.8N 146.8E

About 595 miles east of Yap
About 375 miles south of Saipan
About 290 miles south-southeast of Guam

Maximum sustained winds...30 mph
Present movement...NNW...330 degrees at 15 mph

DISCUSSION AND OUTLOOK
----------------------
At 700 AM CHST, the center of Tropical Depression Atsani was
located near Latitude 9.8 degrees North and Longitude 146.8
degrees East, moving north-northwest at 14 mph. Atsani is
expected to turn to a west-northwest track later this morning,
and continue in that direction through the weekend. Tropical
Depression Atsani is forecast to pass about 140 miles southwest
of Guam by late this evening.

Maximum sustained winds are 30 mph. Atsani is forecast to
intensify steadily the next couple of days, becoming a tropical
storm later today and a typhoon on Sunday.

NEXT ADVISORY
-------------
An intermediate advisory will be issued by the National Weather
Service this morning at 1100 AM, followed by the next scheduled
advisory at 200 PM this afternoon.

$$

Middlebrooke
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
Ed_2001
Tropical Storm
Tropical Storm
Posts: 228
Age: 22
Joined: Wed Jun 21, 2017 11:39 pm
Location: Santa Barbara, CA>>Tampa, FL

Re: WPAC: ATSANI - Tropical Storm

#83 Postby Ed_2001 » Thu Oct 29, 2020 11:09 pm

Still early in the storm's lifespan, but while 0z GFS haven't completed yet it's now keeping Atsani as a TD over the next 4 days and only showing signs of real intesification once it's already quite close to Luzon. What was supposed to be a weaker Goni has grown far stronger than anticipated is stealing the spotlight now. Probably explains the changes in the model forecat.
0 likes   
The answer my friend, is blowing in the wind...

User avatar
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#84 Postby Hayabusa » Thu Oct 29, 2020 11:14 pm

00Z weak like 18Z is GFS caving in to ECMWF? :lol: But this is also happened with Goni (99W), models turned weak (or no development like ECMWF) only then to return to intensifying again later but then again at that time when models were in the weak development stage Goni was still an invest unlike Atsani, also its location is close to Goni.
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

User avatar
ElectricStorm
Category 5
Category 5
Posts: 4492
Age: 23
Joined: Tue Aug 13, 2019 11:23 pm
Location: Skiatook, OK / Norman, OK

Re: WPAC: ATSANI - Tropical Storm

#85 Postby ElectricStorm » Fri Oct 30, 2020 12:38 am

HWRF running. Has a major in 84 hours... Run ends still strengthening at 933mb...
0 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!

User avatar
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#86 Postby Hayabusa » Fri Oct 30, 2020 1:55 am

00Z GFS and ECMWF are in agreement in track
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

User avatar
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#87 Postby Hayabusa » Fri Oct 30, 2020 2:07 am

Except for CMC and NAVGEM the rest are towards the Philippines
Image
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

User avatar
ElectricStorm
Category 5
Category 5
Posts: 4492
Age: 23
Joined: Tue Aug 13, 2019 11:23 pm
Location: Skiatook, OK / Norman, OK

Re: WPAC: ATSANI - Tropical Storm

#88 Postby ElectricStorm » Fri Oct 30, 2020 2:08 am

No upgrade yet from JTWC
23W ATSANI 201030 0600 11.3N 143.3E WPAC 30 1005
0 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!

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

Re: WPAC: ATSANI - Tropical Storm

#89 Postby euro6208 » Fri Oct 30, 2020 4:30 am

Imran_doomhaMwx wrote:Atsani is contributed by Thailand and means "Lightening flash". A fitting name for this.


Indeed. Its moving at over 20 knots. Too fast. NWS canceled the TS watch for Guam when it was expected to make its closest approach late tonight into early morning tomorrow. :lol:

Atsani better slow down or else it'll be sheared by Goni. That's why the models are showing less intensification.
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: ATSANI - Tropical Storm

#90 Postby euro6208 » Fri Oct 30, 2020 4:40 am

Image


WDPN32 PGTW 300900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 23W (ATSANI)
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION 23W (ATSANI), LOCATED APPROXIMATELY 147 NM
SOUTH-SOUTHWEST OF ANDERSEN AFB, GUAM HAS TRACKED NORTHWESTWARD AT
26 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A VERY DISORGANIZED SYSTEM WITH FLARING
CONVECTION WRAPPING INTO A BROAD AREA OF WEAK TURNING, WITH NO
DISTINCT LOW LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN AVAILABLE
IMAGERY. THERE HAVE BEEN NO MICROWAVE OR SCATTEROMETER PASSES SINCE
THE 0000Z HOUR AND THERE ARE POSSIBLY MULTIPLE CIRCULATIONS EMBEDDED
IN THE BROADER CIRCULATION. THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BASED PRIMARILY ON SPIRAL BAND ANALYSIS OF THE FEW LOW-
LEVEL CLOUD BANDS EVIDENT IN ANIMATED MSI. THE INITIAL INTENSITY IS
ASSESSED AT 30 KTS BASED ON SUBJECTIVE DVORAK ESTIMATES OF T2.0 (30
KNOTS) FROM PGTW, AN ADVANCED DVORAK TECHNIQUE ESTIMATE OF 2.8 AND A
SATELLITE CONSENSUS ESTIMATE OF 39 KNOTS; HOWEVER, THE AUTOMATED
TECHNIQUES ARE ANALYZING A POSITION DISPLACED WELL TO THE SOUTHEAST
OF THE ASSESSED LLCC, AND ARE UNREPRESENTATIVE. ENVIRONMENTAL
ANALYSIS INDICATES THE SYSTEM LIES IN A REGION OF MODERATE TO STRONG
(20-25 KNOT) VWS FROM THE OUTFLOW FROM STY 22W, OFFSETTING ROBUST
EQUATORWARD OUTFLOW AND WARM (30 TO 31 DEGREE CELSIUS) SEA SURFACE
TEMPERATURES. TD 23 IS CURRENTLY TRACKING RAPIDLY NORTHWESTWARD
ALONG THE SOUTHWEST PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE
(STR) CENTERED TO THE NORTHEAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TD 23W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD,
TRACKING ALONG THE SOUTHWESTERN EDGE OF THE STR TO THE NORTHEAST
THROUGH TAU 72. THE SYSTEM WILL CONTINUE TO SLOWLY AND STEADILY
INTENSIFY THROUGH TAU 48 IN SPITE OF MARGINAL ENVIRONMENTAL
CONDITIONS, WITH THE CONVERGENT EQUATORWARD OUTFLOW FROM STY 22W
LIMITING THE OUTFLOW AVAILABLE FOR TD 23W TO A SINGLE EQUATORWARD
CHANNEL. THIS CONVERGENCE, COMBINED WITH MODERATE VWS (15-20 KTS),
WILL SERVE TO OFFSET THE VERY WARM (30 DEG CELSIUS) WATERS. AFTER
TAU 48 THE SYSTEM IS FORECAST TO MOVE UNDER A DEVELOPING UPPER-LEVEL
ANTICYCLONE, WHICH WILL PROVIDE FOR MORE ROBUST RADIAL OUTFLOW AND
RESULT IN A STEEPER RATE OF INTENSIFICATION THROUGH TAU 72. DYNAMIC
MODEL GUIDANCE IS IN POOR AGREEMENT, WITH A DISTINCT BIFURCATION
FROM TAU 12. THE NAVGEM MODEL IS CURRENTLY THE ONLY CONSENSUS MEMBER
THE CONTINUES TO RECURVE THE SYSTEM NORTHEAST INTO THE WESTERLIES,
WHILE GFS, ECMWF AND THEIR ENSEMBLES, AS WELL AS THE AFUM MODEL, ALL
INDICATE A SLOWING OF THE FORWARD SPEED BEGINNING AT TAU 72, AND
THEN A TURN WESTWARD, LEADING TO A CROSS-TRACK SPREAD OF 400 NM AT
TAU 72. THE REMAINDER OF THE GUIDANCE PACKAGE LIES VERY CLOSE TO THE
MULTI-MODEL CONSENSUS AVERAGE. THE JTWC FORECAST TRACK HAS BEEN
PLACED ALONG THE SOUTHERN EDGE OF THE GUIDANCE ENVELOPE THROUGH TAU
72, AS A NOD TOWARDS THE GFS AND ECMWF SOLUTIONS WITH LOW
CONFIDENCE.
C. BEYOND TAU 72, THE SYSTEM WILL SLOW SIGNIFICANTLY AS IT MOVES
INTO A WEAK STEERING ENVIRONMENT, DOMINATED BY A COL AREA WHICH
DEVELOPS DUE TO A WEAKNESS IN THE STR INDUCED BY THE APPROACH OF
DEEP MID-LATITUDE TROUGH TO THE NORTH. AS IT TRACKS NORTHWESTWARD IT
BEGINS TO TAP INTO DUAL-CHANNEL OUTFLOW, ALLOWING IT TO INTENSIFY TO
95 KNOTS AT TAU 120. THE STEERING MECHANISM SHIFTS BY TAU 96 TO THE
STR TO THE WEST OVER CHINA LEADING TO A MORE WESTWARD TRACK THROUGH
THE END OF THE FORECAST. NUMERICAL MODEL GUIDANCE IS HIGHLY
DIVERGENT, WITH THE AFOREMENTIONED BIFURCATION BECOMING INCREASINGLY
EVIDENT IN LONG RANGE FORECAST. THE CROSS-TRACK SPREAD BETWEEN THE
NAVGEM AND GFS OUTLIERS INCREASES TO NEARLY 900 NM BY TAU 120 WITH
THE REMAINDER OF THE CONSENSUS MEMBERS TIGHTLY PACKED AND FAIRLY
EVENLY DISTRIBUTED IN ROUGHLY THE MIDDLE OF THE BIFURCATION
ENVELOPE. THE JTWC TRACK IS PLACED ALONG THE SOUTHERN SIDE OF THE
TIGHTEST MODEL PACKING, AS A HEDGE TOWARDS THE GFS AND ECMWF
SOLUTIONS, WITH VERY LOW 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
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#91 Postby Hayabusa » Fri Oct 30, 2020 5:05 am

06Z even weaker :lol:
1 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

User avatar
doomhaMwx
Category 5
Category 5
Posts: 2396
Age: 25
Joined: Tue Apr 18, 2017 4:01 am
Location: Baguio/Benguet, Philippines
Contact:

Re: WPAC: ATSANI - Tropical Storm

#92 Postby doomhaMwx » Fri Oct 30, 2020 6:43 am

Don't know how GFS can keep Atsani a ~1005mb low all throughout it's passage over the PHL Sea. Still more likely that this'll begin to ramp up once Goni is out of the picture 2-3 days from now.
2 likes   

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

Re: WPAC: ATSANI - Tropical Storm

#93 Postby euro6208 » Fri Oct 30, 2020 7:33 am

So much potential with Atsani when it finds better conditions.

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

Re: WPAC: ATSANI - Tropical Storm

#94 Postby aspen » Fri Oct 30, 2020 7:46 am

euro6208 wrote:So much potential with Atsani when it finds better conditions.

https://i.imgur.com/N3novmL.gif

The HWRF certainly thinks so. It has a RI phase starting at the beginning of the week and culminating in another tight core, tiny eye system like Goni on Tuesday, but it then starts an EWRC.
0 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.

User avatar
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#95 Postby Hayabusa » Fri Oct 30, 2020 8:12 am

Hmmm
Image

TS 2020 (Atsani)
Issued at 13:05 UTC, 30 October 2020

<Analysis at 12 UTC, 30 October>
Scale -
Intensity -
Center position N11°30' (11.5°)
E141°40' (141.7°)
Direction and speed of movement WNW 35 km/h (19 kt)
Central pressure 1002 hPa
Maximum sustained wind speed 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
≥ 30 kt wind area ALL 280 km (150 NM)

<Forecast for 00 UTC, 31 October>
Intensity -
Center position of probability circle N12°50' (12.8°)
E139°40' (139.7°)
Direction and speed of movement WNW 20 km/h (12 kt)
Central pressure 996 hPa
Maximum sustained wind speed 20 m/s (40 kt)
Maximum wind gust speed 30 m/s (60 kt)
Radius of probability circle 85 km (45 NM)

<Forecast for 12 UTC, 31 October>
Intensity -
Center position of probability circle N14°30' (14.5°)
E138°10' (138.2°)
Direction and speed of movement NW 20 km/h (12 kt)
Central pressure 992 hPa
Maximum wind speed near center 23 m/s (45 kt)
Maximum wind gust speed 35 m/s (65 kt)
Radius of probability circle 120 km (65 NM)

<Forecast for 12 UTC, 1 November>
Intensity -
Center position of probability circle N17°05' (17.1°)
E134°00' (134.0°)
Direction and speed of movement WNW 20 km/h (12 kt)
Central pressure 980 hPa
Maximum wind speed near center 30 m/s (60 kt)
Maximum wind gust speed 45 m/s (85 kt)
Radius of probability circle 220 km (120 NM)
Storm warning area ALL 300 km (160 NM)

<Forecast for 12 UTC, 2 November>
Intensity -
Center position of probability circle N18°30' (18.5°)
E130°30' (130.5°)
Direction and speed of movement WNW 15 km/h (9 kt)
Central pressure 970 hPa
Maximum wind speed near center 35 m/s (70 kt)
Maximum wind gust speed 50 m/s (100 kt)
Radius of probability circle 330 km (180 NM)
Storm warning area ALL 430 km (230 NM)

<Forecast for 12 UTC, 3 November>
Intensity -
Center position of probability circle N17°55' (17.9°)
E129°00' (129.0°)
Direction and speed of movement WSW Slow
Central pressure 955 hPa
Maximum wind speed near center 40 m/s (80 kt)
Maximum wind gust speed 60 m/s (115 kt)
Radius of probability circle 480 km (260 NM)
Storm warning area ALL 600 km (330 NM)

<Forecast for 12 UTC, 4 November>
Intensity Very strong
Center position of probability circle N16°55' (16.9°)
E125°50' (125.8°)
Direction and speed of movement WSW 15 km/h (8 kt)
Central pressure 950 hPa
Maximum wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of probability circle 650 km (360 NM)
Storm warning area ALL 800 km (440 NM)
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

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

Re: WPAC: ATSANI - Tropical Storm

#96 Postby euro6208 » Fri Oct 30, 2020 8:18 am

Atsani must be getting jealous that everyone's attention is to Goni when the models predicted her to be the strongest out of the two. I have a weird feeling Atsani is not done yet despite the models trending weaker.

A sleeping monster.
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
Hayabusa
Category 5
Category 5
Posts: 3735
Joined: Sun Sep 16, 2018 1:05 pm

Re: WPAC: ATSANI - Tropical Storm

#97 Postby Hayabusa » Fri Oct 30, 2020 8:32 am

It got downgraded to 25 knots
23W ATSANI 201030 1200 12.0N 142.2E WPAC 25 1007
0 likes   
ヤンデレ女が寝取られるているのを見たい!!!
ECMWF ensemble NWPAC plots: https://ecmwfensnwpac.imgbb.com/
Multimodel NWPAC plots: https://multimodelnwpac.imgbb.com/
GFS Ensemble NWPAC plots (16 & 35 day forecast): https://gefsnwpac.imgbb.com/
Plots updated automatically

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

Re: WPAC: ATSANI - Tropical Storm

#98 Postby aspen » Fri Oct 30, 2020 8:34 am

Hayabusa wrote:It got downgraded to 25 knots
23W ATSANI 201030 1200 12.0N 142.2E WPAC 25 1007

I mean it does look like ****. Might not even be a TC right now, but that’ll change as it finds better conditions without the influence of Goni.
0 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.

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

Re: WPAC: ATSANI - Tropical Storm

#99 Postby euro6208 » Fri Oct 30, 2020 10:12 am

Relocated.

A period of rapid intensification starting in 48 hours.



WDPN32 PGTW 301200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 23W (ATSANI)
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION 23W (ATSANI), LOCATED APPROXIMATELY 164 NM
WEST-SOUTHWEST OF ANDERSEN AFB, GUAM HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A VERY DISORGANIZED AND WEAK SYSTEM, WITH MODERATE
DISORGANIZED FLARING CONVECTION NEAR THE ASSESSED LOW LEVEL
CIRCULATION CENTER (LLCC). THE SYSTEM HAS BEEN RELOCATED AND THE
INITIAL POSITION HAS BEEN UPDATED WITH MODERATE CONFIDENCE BASED ON
ANALYSIS OF THE SCATTEROMETER AMBIGUITIES FROM A 301014Z ASCAT-A AND
301137Z ASCAT-B PASSES WHICH INDICATE A VERY ELONGATED CIRCULATION
TO THE SOUTHWEST OF GUAM. THE INITIAL INTENSITY HAS BEEN LOWERED TO
25 KNOTS BASED ON A T1.5 (25 KNOTS) DVORAK CURRENT INTENSITY
ESTIMATE FROM PGTW, CONFIRMING THE LOW WINDSPEEDS FROM THE
SCATTEROMETER PASSES MENTIONED EARLIER, BOTH OF WHICH SHOWED A
SMATTERING OF VERY ISOLATED 25 KNOT WINDS IN THE NORTHEAST QUADRANT.
TD 23W REMAINS IN A GENERALLY UNFAVORABLE ENVIRONMENT, HINDERING
DEVELOPMENT. WHILE SSTS ARE VERY WARM (30 TO 31 DEG CELSIUS), VWS IS
MODERATE (15-20) AND THE UPPER-LEVEL OUTFLOW IS RELATIVELY WEAK WITH
NORTHEASTERLY FLOW ASSOCIATED WITH THE OUTFLOW PATTERN OF STY 23W
CONVERGING OVER TOP OF THE SYSTEM. TD 23W IS TRACKING NORTHWESTWARD
ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE
(STR) CENTERED TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE OVERALL TRACK
PHILOSOPHY; HOWEVER, THE INITIAL POSITION HAS BEEN RELOCATED AFTER
RECEIPT OF UPDATED SCATTEROMETER DATA, LEADING TO SIGNIFICANT
ADJUSTMENT IN TRACK SPEED FROM THE PREVIOUS FORECAST.
B. TD 23W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD THROUGH
TAU 48 ALONG THE SOUTHWESTERN EDGE OF THE STR TO THE NORTHEAST.
THEREAFTER THE TRACK BEGINS TO FLATTEN TO MORE WESTWARD AS A
NEW, EAST-WEST ORIENTED STR BEGINS TO THE DEVELOP TO THE NORTH OF
THE SYSTEM. WHILE IT CONTINUES TO STRUGGLE, THE ENVIRONMENT IS
SUPPORTIVE OF SLOW INTENSIFICATION AS STY 23W MOVES WESTWARD, AND
THE UPPER-LEVEL OUTFLOW PATTERN SLOWLY BECOMES MORE FAVORABLE
THROUGH TAU 48. AFTER TAU 48, AN UPPER-LEVEL ANTICYCLONE IS FORECAST
TO DEVELOP NEAR THE SYSTEM, WHICH WILL SERVE TO DECREASE VWS AND
INCREASE OUTFLOW, ALLOWING FOR A PERIOD OF MORE RAPID
INTENSIFICATION THROUGH TAU 72. MODEL GUIDANCE IS IN FAIR AGREEMENT
THROUGH TAU 36, WITH INCREASING UNCERTAINTY THEREAFTER, WITH A
DISTINCT BIFURCATION SCENARIO SETTING UP BY TAU 72. NAVGEM CONTINUES
TO BE THE SOLE MODEL SOLUTION PREDICTING A FULL RECURVE OF THE
SYSTEM TO THE NORTHEAST STARTING AT TAU 72. HOWEVER, AFUM AND
ECMWF ARE TRACKING ON THE NORTHERN EDGE OF THE GUIDANCE PACKAGE ON
THIS RUN THROUGH TAU 72 AS WELL, BUT NOT TO THE SAME DEGREE AS
NAVGEM. MEANWHILE, GFS IS THE SOUTHERN OUTLIER SHOWING A FLATTER
TRACK THAN ALL OTHER MODELS. THE JTWC TRACK LIES ALONG THE SOUTHERN
EDGE OF A GROUPING OF MODELS THROUGH TAU 48 THEN DIVERGES FURTHER
SOUTH TOWARDS THE GFS SOLUTION BY TAU 72 WITH LOW FAIR CONFIDENCE.
C. BEYOND TAU 72, THE SYSTEM SLOWS SIGNIFICANTLY WHILE TURNING
WEST AS THE STEERING RIDGE WEAKENS SLIGHTLY AS IT REORIENTS TO A
MORE EAST-WEST PATTERN. FROM TAU 72 TO 120, THE DEVELOPMENT OF MUCH
IMPROVED OUTFLOW AND DECREASED VWS WILL ALLOW FOR STEADY
INTENSIFICATION, PEAKING AT 90 KNOTS AT TAU 96. NUMERICAL MODEL
GUIDANCE IS HIGHLY UNCERTAIN IN THE EXTENDED FORECAST, WITH
AFOREMENTIONED BIFURCATION BECOMING VERY DISTINCT BY TAU 120, WITH A
1000 NM SPREAD BETWEEN THE GFS AND NAVGEM OUTLIERS. HOWEVER, ALL
REMAINING MEMBERS OF THE CONSENSUS DO CONCUR THAT THE TRACK FLATTENS
OUT TO WESTWARD AFTER TAU 72 BUT DISAGREE PRIMARILY ON THE SPEED,
WITH GFS ACCELERATING THE SYSTEM TO WELL OVER 20 KNOTS, AND THE
REMAINDER INDICATING A MORE REALISTIC SPEED NEAR 10-15 KNOTS. THE
JTWC FORECAST TRACK LIES CLOSE TO THE MULTI-MODEL CONSENSUS AT TAU
120 BUT FAVORS THE GFS SOLUTION OVERALL. HOWEVER, WITH THE VERY
LARGE UNCERTAINTIES ASSOCIATED WITH THE BIFURCATION THERE IS LOW
CONFIDENCE IN THE JTWC FORECAST TRACK.//
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
ElectricStorm
Category 5
Category 5
Posts: 4492
Age: 23
Joined: Tue Aug 13, 2019 11:23 pm
Location: Skiatook, OK / Norman, OK

Re: WPAC: ATSANI - Tropical Storm

#100 Postby ElectricStorm » Fri Oct 30, 2020 2:09 pm

Pressure down a bit
23W ATSANI 201030 1800 12.4N 140.7E WPAC 25 1003
0 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!


Return to “2020”

Who is online

Users browsing this forum: No registered users and 8 guests