WPAC: MAWAR - Post-Tropical

[Yellow Evan]

Neither of those estimates are close to being accurate. Nawar's intensity is very likely lower than it was 6 hours ago. The radar presentation has significantly degraded and shows the eyewall may be open on the north side.

Sure, it's still a beast, but let's pump the brakes on these off-the-chart cat-5 estimates.

https://i.imgur.com/teNujJ0.png

We’ve seen plenty of storms with reasonably similar structure at peak have Recon (Dean, Jagmi, Maria, Bess) and even some with warmer cloud tops (Andrew, Dorian, Irma). Anything above 150 knots is probably a reach though.

From https://journals.ametsoc.org/view/journals/wefo/25/5/2010waf2222375_1.xml#i1520-0434-25-5-1362-f03:

https://media.discordapp.net/attachments/619419338151034911/1110593174595981372/IMG_6775.jpg

Right, but it wasn’t sustained for long enough for the winds to catch up to that IR presentation. Irma maintained a phenomenal structure for days.

Irma reached 150 knots on the 12z on September 5 a few hours after reaching WMG - it didn’t need to sustain for days to become a Category 5.

Not convinced IR lag is important with in this instance. We’ve seen some ridiculous pressure drops with eyes of similar size (~10 nm). This storm was around T6.0/115 kts zone from 17z to 21z, leaving a ~9 hour window to drop 30 mbars or so to reach pressures indicative of >140 kts. It is possible that normal P-W relationship was not applicable here but given the lack of TCs with modern wind recon of this structure, I wouldn’t be confident in this.



The SMAP pass throws a wrench in to this, however. I’d wager anything between 130 and 150 knots is defendable though I’m not aware of how SMAP does with higher end TCs.

[Sciencerocks]

[wxman57]

Looks to have significantly weakening. Cyclones can easily weak a couple of SS categories while undergoing ERC. In 1980, Allen weakened from a 5 to a 3 two-three times in the Caribbean. Unfortunately, this weakening leads to an expansion of the core, resulting in a larger storm surge.

[Fountainguy97]

New eyewall rapidly forming on radar. It's definitely trying to finish this ERWC before Guam.

[InfernoFlameCat]

EWRC are only good news if they fail. but if the conditions are good, then it just means more overall power. That expansion of the core is scary sometimes. Like Ian when it busted out that mega eyewall.

[InfernoFlameCat]

looks like Guam is probably experiencing sustained ts force winds now.

[Yellow Evan]

Guam will probably be in the RMW regardless barring a sudden jog and surge is less of an issue without continental shelf waters. An ERC helps them I think.

[cycloneye]

Plenty of lightling in the south side.

[cycloneye]

WP, 02, 2023052318, , BEST, 0, 125N, 1457E, 135, 924, ST

[senorpepr]

WP, 02, 2023052318, , BEST, 0, 125N, 1457E, 135, 924, ST

JTWC revised the ATCF down to 120 kt:

02W MAWAR 230523 1800 12.5N 145.7E WPAC 120 940

[cycloneye]

 https://twitter.com/iCyclone/status/1661100488321044486

[cycloneye]

 https://twitter.com/MikeAdcockWx/status/1661110733550100480

[senorpepr]

Robert Speta discusses the near-term threat to Guam as well as the long-range outlook for both the Philippines and Okinawa.

[youtube]https://youtu.be/tmAKFIEQx24[/youtube]

[cycloneye]

WDPN31 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (MAWAR) WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 12.5N 145.7E
INITIAL INTENSITY: 120 KTS
GEOGRAPHIC REFERENCE: 86 NM SOUTH-SOUTHEAST OF ANDERSEN AFB,
GUAM
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
SOMEWHAT ASYMMETRICAL SYSTEM THAT HAS A SMALL (6 NM DIAMETER) EYE.
IN ADDITION, BANDS OF DEEP CONVECTION ARE NOTED IN THE WESTERN
SEMICIRCLE AND FRAGMENTED BANDS OF CONVECTION IN THE EASTERN
SEMI-CIRCLE. THESE FRAGMENTED BANDS ARE THE RESULT OF DRY AIR FROM
THE SOUTH BEING INTRODUCED INTO THE LOW LEVEL CIRCULATION CENTER
(LLCC). THERE WERE SEVERAL HOURS WITHOUT ANY USABLE MICROWAVE DATA,
HOWEVER A RECENT 231756Z SSMIS 91 GHZ PASS SHOWS THE INNER EYEWALL
HAS BEEN BROKEN DOWN AND A SECONDARY EYEWALL IS FORMING. DUE TO THE
ONSET OF THIS EYEWALL REPLACEMENT CYCLE (ERC), THE INITIAL
INTENSITY IS LOWER THAN PREVIOUSLY FORECAST. RADAR IMAGERY FROM
ANDERSEN AIR FORCE BASE (PGUA) SHOWS THE OUTER BANDS OF THE
NORTHWEST QUADRANT OVER GUAM, ROTA, AND THE NORTHERN MARIANA
ISLANDS, AS WELL AS THE EYE OF THE SYSTEM IN CLEAR VIEW AS IT
APPROACHES GUAM FROM THE SOUTHEAST. MOREOVER, RECENT SURFACE
WEATHER OBSERVATIONS FROM ANDERSEN AFB INDICATE CONSISTENT
NORTHEASTERLY WIND FLOW WITH GUSTS IN THE 35-40 KT RANGE OVER THE
PAST SEVERAL HOURS. TC MAWAR IS IN A MARGINALLY FAVORABLE
ENVIRONMENT FOR FURTHER TROPICAL DEVELOPMENT. THESE CONDITIONS ARE
CHARACTERIZED BY GOOD EQUATORWARD AND POLEWARD OUTFLOW ALOFT, A
PRONOUNCED 850 MB VORTICITY SIGNATURE, MODERATE (15-20 KTS)
VERTICAL WIND SHEAR (VWS), AND VERY WARM (29-30 C) SEA SURFACE
TEMPERATURES (SST). THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON MULTI-AGENCY FIXES, ALONG WITH THE
ABOVEMENTIONED RADAR IMAGERY AND RECENT SSMIS IMAGERY. THE INITIAL
INTENSITY OF 120 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED OFF
ANALYSIS OF THE ERC AND A BLEND OF MULTI-AGENCY AND AUTOMATED
DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: SMAP DATA AND SAR DATA

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.5 - 127 KTS
RJTD: T6.0 - 115 KTS
KNES: T5.5 - 102 KTS
CIMSS SATCON: 125 KTS AT 231553Z
CIMSS ADT: 120 KTS AT 231930Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 15-20 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
OTHER FACTORS: EYEWALL REPLACEMENT CYCLE (ERC)

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: DROPPED INITIAL INTENSITY TO 120
KNOTS BASED OFF RECENT SSMIS PASS AND ANALYSIS OF THE ERC

FORECAST DISCUSSION: TC 02W IS RIDING THE WESTERN PERIPHERY OF THE
STR TO THE EAST. THROUGH TAU 12, TC MAWAR WILL TRACK NORTHWESTWARD
AND STEADILY INTENSIFY TO 125 KNOTS AS THE STORM CENTER MAKES ITS
PASS OVER THE SOUTHERN SHORES OF GUAM. THIS INCREASE IN INTENSITY
WILL BE THE RESULT OF THE COMPLETION OF THE ERC. AFTER TAU 12, TC
MAWAR WILL MAKE THE TURN MORE WEST-NORTHWESTWARD AS THE STR TO THE
EAST BUILDS IN OVER THE NORTH. THIS STR WILL CONTINUE TO BUILD
THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD AND CONTINUE TO
STEER THE SYSTEM ON A WEST-NORTHWESTWARD TRAJECTORY. IN ADDITION,
THE SYSTEM WILL BE PASSING INTO A FAVORABLE AREA FOR FURTHER
DEVELOPMENT AS COPIOUS AMOUNTS OF DEEP OCEAN HEAT CONTENT (OHC) IN
THE PHILIPPINE SEA WILL INCREASE THE INTENSIFICATION TO 140 KNOTS
BY TAU 72. BY TAUS 96 AND 120, TC 02W WILL NEARING THE STR AXIS AND
WILL HEAD ON A NORTHWESTWARD TRAJECTORY. DURING THIS TIME IT WILL
BEGIN TO WEAKEN IN INTENSITY AS IT APPROACHES THE COOLER (26 C) SST
AT APPROXIMATELY THE 20TH LATITUDE.

MODEL DISCUSSION: THE DETERMINISTIC AND ENSEMBLE MODELS ARE ALL IN
TIGHT AGREEMENT THAT TC MAWAR WILL CONTINUE TO TRACK NORTHWESTWARD
THROUGH TAU 12, THEN MAKE THE TURN WEST-NORTHWESTWARD BY TAU 24. IN
THE SHORT TERM, THE JTWC FORECAST TRACK CONSENSUS MEMBERS ARE
SHOWING A 27 NM SPREAD AT TAU 12 THAT GRADUALLY INCREASES TO 50 NM
BY TAU 24, AND 80 NM BY TAU 36. AFTERWARDS, THE SPREAD INCREASES
AND STAYS STEADY AT APPROXIMATELY 90 NM THROUGHOUT THE FORECAST
PERIOD. AFTER TAU 12, THE NAVGEM TRACKER BECOMES THE OUTLIER
SHOWING A MORE POLEWARD TRACK AS COMPARED TO THE OTHER MEMBERS. DUE
TO THIS, THE JTWC TRACK IS PLACED WITH HIGH CONFIDENCE JUST TO THE
LEFT OF CONSENSUS THROUGH TAU 72, AND MEDIUM CONFIDENCE AFTERWARDS
DUE TO THE SPREAD OF THE MODELS. THE JTWC INTENSITY CONSENSUS
DISPLAYS AN AVERAGE OF A 30 KNOT SPREAD THROUGHOUT THE FORECAST
PERIOD. THE GFS INTENSITY SOLUTION IS THE OUTLIER SHOWING LOWER
VALUES THAN THE OTHER MEMBERS. HOWEVER, ALL INTENSITY MEMBERS AGREE
ON AN INCREASE UP TO TAU 72, FOLLOWED BY A DIP AFTERWARDS. THIS IS
LIKELY DUE TO THE SYSTEM PASSING INTO A MORE HOSTILE ENVIRONMENT IN
THE LATER TAUS. THE JTWC INTENSITY FORECAST IS SET SLIGHTLY HIGHER
THAN CONSENSUS WITH MEDIUM CONFIDENCE DUE TO THE MODEL SPREAD AND
RECENT ERC.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-

[Blown Away]

It appears that eye may clear out before Guam...

[wxman57]

120 kts is likely too high for current winds. Maybe 105-110 kts. Usually, a Cat 3 will have a clear eye.

[ChrisH-UK]

Mawar as sunrise. Source - https://col.st/pW5ep

[Hayabusa]

New SMAP fix from 2007Z or 3 hours ago 122.58 knots

WP, 02, 202305232007, 30, SMAP, IR, , 1250N, 14570E, , 1, 114, 1, , , , 34, NEQ, 88, 104, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 02, 202305232007, 30, SMAP, IR, , 1250N, 14570E, , 1, 114, 1, , , , 50, NEQ, 66, 65, 0, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained
WP, 02, 202305232007, 30, SMAP, IR, , 1250N, 14570E, , 1, 114, 1, , , , 64, NEQ, 48, 47, 42, 0, , , , , 1, 0, , W, NASA, RSS, , , , , , , , , , , , , , , , , , , , , , , , , , , , 1, max. wind is 10 minute sustained

[sikkar]

https://www.ipcamlive.com/5fcee202dbecb

[Hurricane2022]

 https://twitter.com/MatthewCuyugan/status/1661142545576112128



JMA. Model. is. forecasting. 886. mb. on. the. day. 5.