WPAC: NESAT - Post-Tropical

[1900hurricane]

GFS shear projections do not look favorable for Nesat through landfall in Taiwan. Not sure why it strengthens this so much.

Yeah, upper level winds looks pretty limiting from the north and then the east up to landfall. Perhaps a new GFS quirk? Between this, Noru, Hilary, and Irwin, I have not been very impressed with the GFS "upgrade."

Here's the 12Z GFS 200 mb wind output I used in my newest blog post earlier today. I looks like Nesat is at the mercy of the upper level winds without a well established anticyclone. The strengthening doesn't make much sense.

[euro6208]

WDPN34 PGTW 270900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (NESAT) WARNING NR
06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 11W (NESAT), LOCATED APPROXIMATELY 422 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-NORTHWESTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS FLARING CENTRAL CONVECTION WITH DENSE OVERCAST
PARTIALLY OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). THE
INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON A LOW
REFLECTIVITY CIRCULATION FEATURE IN A 270549Z 89GHZ SSMI IMAGE. THE
INITIAL INTENSITY IS ASSESSED AT 55 KNOTS AND IS BASED ON THE HIGHER
END OF MULTI-AGENCY DVORAK ESTIMATES RANGING FROM T3.0 TO T3.5 (45
TO 55 KNOTS). ENVIRONMENTAL CONDITIONS ARE CURRENTLY MARGINAL TO
FAVORABLE AS ROBUST EQUATORWARD OUTFLOW IS PRESENT WITH MARGINAL
NORTHEASTERLY WIND SHEAR RESTRICTING POLEWARD OUTFLOW. SSTS ARE ALSO
VERY CONDUCIVE FOR CYCLOGENESIS, AROUND 30 CELSIUS. CURRENTLY TS 11W
IS TRACKING NORTH-NORTHWESTWARD ALONG A WEEK MID TO LOW LEVEL
SUBTROPICAL RIDGE TO THE EAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 11W IS FORECAST TO CONTINUE TRACKING NORTH-NORTHWESTWARD BY
THE CURRENT STEERING RIDGE BEFORE IT SHIFTS TO ANOTHER RIDGE
BUILDING IN THE EAST CHINA SEA DRIVING THE SYSTEM NORTHWESTWARD.
VERTICAL WIND SHEAR IS EXPECTED TO RELAX AND POLEWARD OUTFLOW IS
EXPECTED TO IMPROVE OVER THE NEXT 36 HOURS ALLOWING TS 11W TO
INTENSIFY INTO A TYPHOON REACHING A PEAK INTENSITY OF 80 KNOTS.
SOMETIME AROUND TAU 48 EASTERLY WIND SHEAR FROM THE STEERING RIDGE
WILL BEGIN TO INCREASE, HELPING TO WEAKEN THE SYSTEM. LANDFALL OVER
THE MOUNTAINOUS REGION OF TAIWAN WILL ALSO OCCUR AROUND THIS TIME
FURTHER WEAKENING THE SYSTEM
C. IN THE EXTENDED FORECAST PERIOD TS 11W WILL TRACK ACROSS
TAIWAN AND REEMERGE OVER THE WARM WATERS OF THE TAIWAN STRAIT. THERE
IS A SHORT WINDOW FOR TS 11W TO REORGANIZE AND INTENSIFY SLIGHTLY
BEFORE MAKING LANDFALL AGAIN OVER CHINA. DURING THIS TIME THE
STEERING RIDGE WILL REORIENT, STEERING THE REMNANTS OF TS 11W
NORTHWARD. TS 11W WILL DISSIPATE COMPLETELY WHILE OVERLAND CHINA.
DYNAMIC MODEL GUIDANCE IS SHOWING MUCH BETTER AGREEMENT THAN ON
PREVIOUS RUNS WITH THE OUTLIER FROM THE JAPANESE ENSEMBLE MEAN
SHOWING AN UNREALISTIC TURN NORTHWARD INTO THE STEERING RIDGE PRIOR
TO MAKING LANDFALL OVER TAIWAN. DUE TO THE IMPROVEMENT IN MODEL
TRACK GUIDANCE THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.//
NNNN

[tolakram]

SLIDER live shortwave

http://rammb-slider.cira.colostate.edu/?sat=himawari&sec=full_disk&x=8192&y=7426&z=3&im=18&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=6&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider

[euro6208]

Not too bad with this system. EURO only peaks this at 990 mb and merges with another TC.

[euro6208]

GFS still saying a strong typhoon coming out of this. 962 mb into Southern Taiwan.

[euro6208]

[euro6208]

[NotoSans]

The Euro finally trends stronger and is now predicting a typhoon landfall. Looks like a more reasonable solution to me.

[wxmann_91]

GFS shear projections do not look favorable for Nesat through landfall in Taiwan. Not sure why it strengthens this so much.

Yeah, upper level winds looks pretty limiting from the north and then the east up to landfall. Perhaps a new GFS quirk? Between this, Noru, Hilary, and Irwin, I have not been very impressed with the GFS "upgrade."

Here's the 12Z GFS 200 mb wind output I used in my newest blog post earlier today. I looks like Nesat is at the mercy of the upper level winds without a well established anticyclone. The strengthening doesn't make much sense.

[image omitted]

Yeah, the new GFS has performed really poorly and has a bias to over-intensify TC's. Concerning esp. since there's been questions about its TC performance from the get-go.

[mrbagyo]

Nesat is trying to form a banding type eye right now.
Poleward outflow remains non-existent

[euro6208]

WDPN34 PGTW 272100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (NESAT) WARNING NR
08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 11W (NESAT), LOCATED APPROXIMATELY 426 NM SOUTH OF
KADENA AB, HAS TRACKED NORTH-NORTHWESTWARD AT 10 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
INDICATES THAT THE CENTRAL CONVECTION HAS WEAKENED OVER THE PAST
SIX HOURS, WITH WARMING CLOUD TOPS. THE SYSTEM STILL SHOWS A
SLIGHTLY ELONGATED APPEARANCE INDICATIVE OF SOME NORTHEASTERLY
SHEAR BUT IS BECOMING MORE SYMMETRICAL IN PAST COUPLE OF HOURS.
EARLIER IMAGERY INDICATED THAT THE LOW LEVEL CIRCULATION CENTER
(LLCC) WAS DISPLACED ALONG THE NORTHERN EDGE OF THE CONVECTION, BUT
OVER THE PAST THREE TO FOUR HOURS, IT HAS TUCKED BACK UNDER THE
CONVECTION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON RECENT SATELLITE FIXES AND A MICROWAVE EYE OBSERVED IN A
271821Z 91GHZ COMPOSITE GPM MICROWAVE IMAGE. THE INITIAL INTENSITY
IS ASSESSED AT 55 KNOTS AND IS BASED ON DVORAK ESTIMATES FROM ALL
AGENCIES OF T3.5 (55 TO 70 KNOTS). ENVIRONMENTAL CONDITIONS ARE
CURRENTLY FAVORABLE WITH ROBUST EQUATORWARD LOW VERTICAL WIND SHEAR
(VWS). THERE IS SOME PRESSURE ON THE NORTHEAST SIDE OF THE SYSTEM,
AS INDICATED BY THE SHARP POLEWARD EDGE OF THE CLOUD FIELD, IS
SOMEWHAT RESTRICTING POLEWARD OUTFLOW, BUT THE DEVELOPMENT OF A
POINT SOURCE OVER THE SYSTEM IS COUNTERACTING THIS PRESSURE. SSTS
OVER 31 DEG CELSIUS ARE VERY CONDUCIVE FOR INTENSIFICATION. TS 11W
IS TRACKING NORTHWESTWARD ALONG THE WESTERN BOUNDARY OF A WEAK MID
TO LOW LEVEL, NORTHWEST TO SOUTHEAST ORIENTED SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 11W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD AS
ANOTHER RIDGE ANCHORED OVER THE EAST CHINA SEA ASSUMES STEERING.
VWS IS EXPECTED TO RELAX AND OUTFLOW TO IMPROVE OVER THE NEXT 36
HOURS, AND TS 11W IS FORECAST TO STEADILY INTENSIFY IN RESPONSE,
REACHING A PEAK INTENSITY OF 85 KNOTS JUST PRIOR TO MAKING LANDFALL
IN CENTRAL TAIWAN. INCREASING NORTHEASTERLY VWS WILL RESULT IN A
SLIGHT WEAKENING JUST BEFORE MAKING LANDFALL. INTERACTION WITH THE
MOUNTAINOUS TERRAIN OF CENTRAL TAIWAN WILL LEAD TO A SIGNIFICANT
SLOWDOWN IN FORWARD MOTION AND RAPID WEAKENING AFTER TAU 48, THOUGH
THE SYSTEM WILL REEMERGE INTO THE TAIWAN STRAIT BY TAU 72 AS A WEAK
TROPICAL STORM.
C. IN THE EXTENDED FORECAST PERIOD TS 11W WILL TRACK ACROSS
TAIWAN STRAIT AND MAKE A SECOND LANDFALL IN EASTERN CHINA SHORTLY
THEREAFTER. AT THE SAME TIME, THE PRIMARY STEERING RIDGE WILL
REORIENT TO A NORTH-SOUTH AXIS, STEERING THE REMNANTS OF TS 11W
NORTHWARD. TS 11W WILL REMAIN OVER LAND AS A TROPICAL DEPRESSION
AND THERE IS THE POSSIBILITY THAT IT COULD REEMERGE INTO THE EAST
CHINA SEA NEAR SHANGHAI BEYOND THE FORECAST PERIOD. DYNAMIC MODEL
GUIDANCE IS TIGHT AGREEMENT THROUGH TAU 72, WITH INCREASING
UNCERTAINTY THEREAFTER. THE SOUTHERN OUTLIER REMAINS ECMWF, WHILE
THE NORTHERN OUTLIER IS HWRF. THE JTWC TRACK LIES NEAR THE MULTI-
MODEL CONSENSUS TRACK. DUE TO THE IMPROVED GUIDANCE, THERE HIGH
CONFIDENCE IN THE FORECAST TRACK.//
NNNN

[euro6208]

TXPQ29 KNES 272310
TCSWNP

A. 11W (NESAT)

B. 27/2030Z

C. 19.6N

D. 126.3E

E. THREE/HIMAWARI-8

F. T4.0/4.0/D1.5/24HRS

G. IR/EIR/SWIR

H. REMARKS...CENTER IS EMBEDDED IN MG. THIS CONFERS A DT OF 4.0. MET
IS 3.5 AND PT IS 4.0. FT IS BASED ON THE PT DUE TO UNCERTAINTY IN THE
LOCATION OF SYSTEM CENTER.

I. ADDL POSITIONS

NIL


...GAETANO

[euro6208]

Now a typhoon from JTWC and JMA.

WDPN34 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NESAT) WARNING NR
10//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 11W (NESAT), LOCATED APPROXIMATELY 342 NM SOUTHEAST OF
TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS
FLARING CENTRAL CONVECTION AND DENSE OVERCAST OBSCURING THE LOW
LEVEL CIRCULATION CENTER. THERE IS HIGH CONFIDENCE IN THE INITIAL
POSITION WHICH IS BASED ON A RAGGED EYE FEATURE IN A 280456Z 37 GHZ
IMAGE. THE INITIAL INTENSITY ASSESSMENT OF 65 KNOTS IS BASED ON
MULTI-AGENCY DVORAK ESTIMATES RANGING FROM T3.5 TO T4.5 (55 TO 77
KNOTS). UPPER-LEVEL OUTFLOW HAS IMPROVED SOME IN THE POLEWARD
DIRECTION AND VERTICAL WIND SHEAR HAS ALSO RELAXED. TD 12W IS ABOUT
510 NM WEST OF TY 11W WHICH WILL LIKELY INFLUENCE THE WESTERN
OUTFLOW IN THE IMMEDIATE FUTURE. SSTS ARE CURRENTLY OVER 31 CELSIUS
AND ARE VERY CONDUCIVE FOR INTENSIFICATION. TY 11W IS TRACKING
NORTHWESTWARD AS THE MAIN STEERING RIDGE TRANSITIONS FROM A WEAK MID
TO LOW LEVEL SUBTROPICAL RIDGE TO THE EAST TO A BUILDING RIDGE
ANCHORED OVER THE EAST CHINA SEA AND THE SOUTHERN PORTION OF
JAPAN.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 11W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD GUIDED
BY THE NORTHERN STEERING RIDGE. EASTERLY VWS IS EXPECTED TO BE
MINIMAL BUT GRADUALLY STRENGTHEN AS THE SYSTEM TRACKS NORTHWARD DUE
TO THE STRONG UPPER-LEVEL RIDGE SETTING UP TO THE NORTH. THE
DOMINANT WIND FLOW WILL RESTRICT POLEWARD OUTFLOW, BUT EQUATORWARD
EXHAUST SHOULD REMAIN FAIRLY ROBUST. SSTS IN THE REGION WILL ALSO
REMAIN VERY FAVORABLE AND TY 11W IS EXPECTED TO INTENSIFY OVER THE
NEXT 24 HOURS REACHING A PEAK INTENSITY OF 75 KNOTS BEFORE VWS
STARTS TO DOMINATE, INDUCING A WEAKENING TREND. LANDFALL OVER
CENTRAL
TAIWAN IS EXPECTED SOMETIME JUST AFTER TAU 36 AND TY 11W WILL SLOW
DOWN AND WEAKEN SIGNIFICANTLY AS IT TRACKS OVER THE MOUNTAINOUS
TERRAIN.
C. IN THE EXTENDED FORECAST PERIOD TY 11W WILL REEMERGE OVER THE
WARM OPEN WATER OF THE TAIWAN STRAIT. DURING THIS TIME TY 11W WILL
HAVE A BRIEF PERIOD TO REORGANIZE BEFORE MAKING LANDFALL AGAIN OVER
CHINA AROUND TAU 72. EASTERLY WIND SHEAR IS EXPECTED TO PERSIST AND
INFLUENCE THE ABILITY AND DEGREE TY 11W WILL RE-INTENSIFY.
SIMULTANEOUSLY TD 12W WILL BE IN CLOSE PROXIMITY, INTERACTING WITH
THE SYSTEM. THE STEERING RIDGE WILL ALSO REORIENT ITSELF TO A NORTH
SOUTH AXIS CAUSING TY 11W TO TURN NORTHWARD WHILE OVER LAND IN
CHINA. WHILE OVER LAND, THE REMNANTS OF TD 12W IS FORECAST TO MERGE
WITH TY 11W. DYNAMIC MODEL GUIDANCE SHOWS VERY GOOD AGREEMENT WITH
THE FORECAST, HOWEVER THERE IS INCREASING UNCERTAINTY IN THE
EXTENDED TAUS AS THE SYSTEM WEAKENS, TRACKS OVER LAND, AND MERGES
WITH 12W. OVERALL THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.//
NNNN

[euro6208]

TXPQ29 KNES 280324
TCSWNP

A. 11W (NESAT)

B. 28/0230Z

C. 20.0N

D. 125.5E

E. THREE/HIMAWARI-8

F. T4.5/4.5/D1.5/24HRS

G. IR/EIR/VIS

H. REMARKS...SYSTEM CENTER IS EMBEDDED IN B. THIS CONFERS A DT
OF 5.0. MET IS 4.0 AND THE PT IS 4.5. FT IS BASED ON THE PT DUE TO
UNCERTAINTY IN THE LOCATION OF THE SYSTEM CENTER.

I. ADDL POSITIONS

NIL


...GAETANO

TPPN13 PGTW 280914

A. TYPHOON 11W (NESAT)

B. 28/0850Z

C. 21.19N

D. 124.85E

E. FIVE/HMWRI8

F. T4.0/4.0/D0.5/24HRS STT: D0.5/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 40A/PBO SBC/ANMTN. LLCC EMBEDDED IN MG YIELDS A DT
OF 4.0. MET/PT 4.0. DBO DT.

I. ADDITIONAL POSITIONS: NONE


DAVIS

[euro6208]

Nesat looks to be rapidly intensifying.

[euro6208]

[euro6208]

EURO deepens this more to 967 mb.

Also GFS has Nesat and Haitang moving off the China coastline as one system and moving off to the Korean Peninsula.

[NotoSans]

JMA up to 960mb / 80kt at their latest advisory.

[1900hurricane]

I have to say, Nesat is doing better than I have expected so far. It's still being sheared, but the intense convection and moist surrounding airmass seem to be sufficient in offsetting it.

JMA just moved the Himawari-8 floater window to Nesat.

[mrbagyo]