WPAC : TROPICAL DEPRESSION NIDA (26W)

[cycloneye]

JTWC 00:00Z Warning - 100 KTS

WTPN31 PGTW 300300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 033
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
300000Z --- NEAR 19.5N 139.3E
MOVEMENT PAST SIX HOURS - 360 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.5N 139.3E
---
FORECASTS:
12 HRS, VALID AT:
301200Z --- 19.7N 138.7E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
140 NM SOUTHEAST QUADRANT
140 NM SOUTHWEST QUADRANT
145 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 295 DEG/ 04 KTS
---
24 HRS, VALID AT:
010000Z --- 20.0N 138.0E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
130 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 305 DEG/ 03 KTS
---
36 HRS, VALID AT:
011200Z --- 20.4N 137.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 300 DEG/ 02 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
020000Z --- 20.6N 137.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 270 DEG/ 02 KTS
---
72 HRS, VALID AT:
030000Z --- 20.6N 136.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 250 DEG/ 02 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
040000Z --- 20.3N 135.4E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 240 DEG/ 02 KTS
---
120 HRS, VALID AT:
050000Z --- 19.9N 134.7E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
300300Z POSITION NEAR 19.6N 139.1E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 330 NM SOUTH-
SOUTHWEST OF IWO TO, HAS REMAINED QUASI-STATIONARY OVER THE
PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300000Z
IS 35 FEET. NEXT WARNINGS AT 300900Z, 301500Z, 302100Z AND
010300Z.//
NNNN

[cycloneye]

With the 100kts warning,it surpasses the ACE number that Melor got at 39.16 and now Nida takes the #1 spot for the most ACE in the WPAC.See the ACE thread at Talking Tropics forum for more about this.

[oaba09]

WDPN31 PGTW 300300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (NIDA) WARNING NR 33//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 330 NM SOUTH-
SOUTHWEST OF IWO TO, HAS REMAINED QUASI-STATIONARY (QS) OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS
WEAKENING CONVECTION OVER ALL QUADRANTS WITH A RAGGED 50NM EYE. TY
26W HAS, IN FACT, REMAINED QS OVER THE PAST 36 HOURS AND IS LIKELY
WEAKENING DUE TO A COMBINATION OF DRY AIR ENTRAINMENT (DAE) AND COLD
WATER UPWELLING. THE TOTAL PRECIPITABLE WATER (TPW) PRODUCTS
INDICATE DRY AIR ADVECTION JUST WEST OF THE SYSTEM WITH A WEDGE OF
DRY AIR (25-40MM) WRAPPING INTO THE NORTHEAST QUADRANT. A 292032Z
SSMI/S IMAGE DEPICTS EYEWALL EROSION TO THE SOUTH AS DRY AIR IS
BEING PULLED INTO THE CORE, AND A ROUND 50NM DIAMETER EYE. ANIMATED
WATER VAPOR IMAGERY CONTINUES TO SHOW GOOD RADIAL OUTFLOW WITH
ENHANCED POLEWARD OUTFLOW INTO THE MIDLATITUDE WESTERLIES. THERE IS
FAIR CONFIDENCE IN THE CURRENT POSITION AND MOTION DUE TO THE
ERRATIC SLOW TRACK AND LARGE EYE, HOWEVER, 37 GHZ MICROWAVE IMAGERY
SUPPORTS BOTH. THE CURRENT INTENSITY OF 100 KNOTS IS BASED ON THE
HIGHER DVORAK ESTIMATES RANGING FROM 77 TO 102 KNOTS. THE 29/12Z 500
MB ANALYSIS DEPICTS A WEAK MID-LEVEL STEERING ENVIRONMENT WITH TY
26W POSITIONED BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE EAST AND
WEST WITH STRONG MIDLATITUDE (ZONAL) WESTERLIES NORTH OF 25N. THE
UPPER-LEVEL FLOW REMAINS HIGH ZONAL ACROSS ASIA WITH NO SIGNIFICANT
MID-LEVEL SHORT-WAVE TROUGHS EVIDENT IN THE UPSTREAM FLOW (IN
IMAGERY AS WELL). THE 30/00Z SURFACE ANALYSIS DEPICTS STRONG LOW-
LEVEL RIDGING ENTRENCHED NORTH AND WEST OF TY 26W.
3. FORECAST REASONING.
A. NO CHANGES TO FORECAST PHILOSOPHY.
B. NUMERICAL GUIDANCE REMAINS IN POOR AGREEMENT WITH TWO
DISTINCT CLUSTERS; NOGAPS, GFDN, AND WBAR STILL FAVOR A RECURVATURE
SCENARIO AND TRACK THE SYSTEM NORTH-NORTHEASTWARD TO NORTHEASTWARD
RAPIDLY, WHILE JGSM, TC-LAPS, UKMO, ECMWF, AND GFS FAVOR A SLOWER
WESTWARD TRACK WITH DISSIPATION. THE OFFICIAL FORECAST FAVORS THE
SLOW WESTWARD MOVEMENT WITH DISSIPATION AFTER TAU 72. AS THE SYSTEM
WEAKENS, STEERING IS EXPECTED TO SHIFT TO THE LOW-LEVELS AND TY 26W
IS LIKELY TO TRACK WESTWARD TO SOUTHWESTWARD UNDER THE NORTHEASTERLY
FLOW. THE DISSIPATION SCENARIO IS BASED ON INCREASING VERTICAL WIND
SHEAR DUE TO A COMBINATION OF LOW-LEVEL NORTHEASTERLY FLOW,
ASSOCIATED WITH THE RIDGE BUILDING NORTH OF THE SYSTEM, AND ZONAL
UPPER-LEVEL WESTERLY FLOW AS WELL AS DAE AND COOL WATER UPWELLING.
C. IN THE EXTENDED TAUS, TY 26W WILL CONTINUE TO WEAKEN AND
SHOULD TURN SOUTHWESTWARD AND ACCELERATE WITHIN THE LOW-LEVEL FLOW.
THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE DISSIPATION AND
THE TURN SOUTHWESTWARD. ADDITIONALLY, SEVERAL MODELS INDICATE THAT
THE REMNANTS WILL TRACK CYCLONICALLY AND GET ABSORBED INTO A
DEVELOPING STORM NEAR OR NORTHWEST OF GUAM.//
NNNN

[ozonepete]

Not looking too good now. This could be a pretty fast decline. There appears to be increasing shear - the eye looks distorted and stretched from SW to NE - look at Hurakan's last image. And there's a lot of dry air near it now. It still has a couple of pretty good convective areas considering how long it's been sitting there with upwellling, but the organization is shot. The JTWC estimate of 120KT just doesn't seem possible. The JMA number of 90KT is much more realistic.

Remember that you can't compare directly the JMA estimate with the JTWC one because JMA is based 10-min sustained winds and JTWC uses 1-min sustained winds, although the 110 kt on the last warning may be a little high I would say it is 100 kt right now.

Thanks Macro. I actually did know that, but I've never understood why JTWC does it in the first place. They so often seem way over the mark. I have to admit that I don't know to which data they apply the 10 minute rule - is it microwave satellite derived winds or cloud derived or both? And how do you take 10 minutes of satellite derived winds as opposed to 1 minute; how are time periods decided on?

[Macrocane]

Thanks Macro. I actually did know that, but I've never understood why JTWC does it in the first place. They so often seem way over the mark. I have to admit that I don't know to which data they apply the 10 minute rule - is it microwave satellite derived winds or cloud derived or both? And how do you take 10 minutes of satellite derived winds as opposed to 1 minute; how are time periods decided on?

Those are very good questions, I don't know the answers but if someone knows please let us know. Sometimes I think the oppossite, the JMA is too low, actually I prefer the 1 minute estimated winds. By the way, as I said on the ACE thread, I think that Nida is the tropical cyclone with the highest ACE since Ioke, correct me if it is not please.

[HURAKAN]

Latest

[CrazyC83]

The structure is somewhat reminiscent of Isabel as it was approaching the coastline. Given its large size and shallow nature despite the solid core, it definitely looks like a Category 2 storm.

[oaba09]

<Analyses at 30/03 UTC>
Scale -
Intensity Strong
Center position N19°50'(19.8°)
E139°20'(139.3°)
Direction and speed of movement N Slowly
Central pressure 950hPa
Maximum wind speed near the center 40m/s(80kt)
Maximum wind gust speed 60m/s(115kt)
Area of 50kt winds or more Wide 100km(55NM)
Area of 30kt winds or more NW460km(250NM)
SE300km(160NM)
<Forecast for 01/03 UTC>
Intensity Strong
Center position of probability circle N19°50'(19.8°)
E138°30'(138.5°)
Direction and speed of movement STR
Central pressure 960hPa
Maximum wind speed near the center 40m/s(75kt)
Maximum wind gust speed 55m/s(105kt)
Radius of probability circle 160km(85NM)
Storm warning area Wide 240km(130NM)
<Forecast for 02/00 UTC>
Intensity Strong
Center position of probability circle N19°40'(19.7°)
E137°50'(137.8°)
Direction and speed of movement STR
Central pressure 965hPa
Maximum wind speed near the center 35m/s(70kt)
Maximum wind gust speed 50m/s(100kt)
Radius of probability circle 260km(140NM)
Storm warning area Wide 330km(180NM)
<Forecast for 03/00 UTC>
Intensity Strong
Center position of probability circle N19°30'(19.5°)
E136°35'(136.6°)
Direction and speed of movement W Slowly
Central pressure 970hPa
Maximum wind speed near the center 35m/s(65kt)
Maximum wind gust speed 50m/s(95kt)
Radius of probability circle 410km(220NM)
Storm warning area Wide 480km(260NM)
<Forecast for 04/00 UTC>
Center position of probability circle N19°20'(19.3°)
E134°50'(134.8°)
Direction and speed of movement W Slowly
Radius of probability circle 650km(350NM)
<Forecast for 05/00 UTC>
Center position of probability circle N18°55'(18.9°)
E132°55'(132.9°)
Direction and speed of movement W Slowly
Radius of probability circle 950km(500NM)

[oaba09]

LATEST FROM JMA(Starting to move west) --- 80 kts



<Analyses at 30/06 UTC>
Scale -
Intensity Strong
Center position N19°40'(19.7°)
E139°05'(139.1°)
Direction and speed of movement W Slowly
Central pressure 950hPa
Maximum wind speed near the center 40m/s(80kt)
Maximum wind gust speed 60m/s(115kt)
Area of 50kt winds or more Wide 100km(55NM)
Area of 30kt winds or more NW460km(250NM)
SE300km(160NM)
<Forecast for 01/06 UTC>
Intensity Strong
Center position of probability circle N19°50'(19.8°)
E138°00'(138.0°)
Direction and speed of movement W Slowly
Central pressure 960hPa
Maximum wind speed near the center 40m/s(75kt)
Maximum wind gust speed 55m/s(105kt)
Radius of probability circle 160km(85NM)
Storm warning area Wide 240km(130NM)
<Forecast for 02/06 UTC>
Intensity Strong
Center position of probability circle N19°50'(19.8°)
E136°55'(136.9°)
Direction and speed of movement W Slowly
Central pressure 965hPa
Maximum wind speed near the center 35m/s(70kt)
Maximum wind gust speed 50m/s(100kt)
Radius of probability circle 260km(140NM)
Storm warning area Wide 330km(180NM)
<Forecast for 03/06 UTC>
Intensity Strong
Center position of probability circle N19°40'(19.7°)
E135°40'(135.7°)
Direction and speed of movement W Slowly
Central pressure 970hPa
Maximum wind speed near the center 35m/s(65kt)
Maximum wind gust speed 50m/s(95kt)
Radius of probability circle 410km(220NM)
Storm warning area Wide 480km(260NM)

[oaba09]

WTPN31 PGTW 300900
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 034
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
300600Z --- NEAR 19.6N 139.1E
MOVEMENT PAST SIX HOURS - 300 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.6N 139.1E
---
FORECASTS:
12 HRS, VALID AT:
301800Z --- 19.9N 138.5E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 145 NM NORTHEAST QUADRANT
140 NM SOUTHEAST QUADRANT
140 NM SOUTHWEST QUADRANT
145 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 295 DEG/ 04 KTS
---
24 HRS, VALID AT:
010600Z --- 20.2N 137.8E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 290 DEG/ 03 KTS
---
36 HRS, VALID AT:
011800Z --- 20.4N 137.2E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 280 DEG/ 02 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
020600Z --- 20.5N 136.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 260 DEG/ 02 KTS
---
72 HRS, VALID AT:
030600Z --- 20.4N 136.0E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 255 DEG/ 02 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
040600Z --- 20.2N 135.3E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 240 DEG/ 02 KTS
---
120 HRS, VALID AT:
050600Z --- 19.8N 134.6E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
300900Z POSITION NEAR 19.7N 138.9E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 330 NM SOUTH-SOUTHWEST
OF IWO TO, HAS REMAINED QUASI-STATIONARY OVER THE PAST SIX HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE EYE HAS STARTED TO
EXPAND RADIALLY OUTWARDS, INDICATING A WEAKENING OF THE SYSTEM OVER
THE PAST 12 HOURS. THIS IS SUPPORTED BY THE ENHANCED INFRARED IMAGERY
WHICH SHOWS CLOUD TOP TEMPERATURES AROUND THE EYEWALL HAVE BEEN UNDER
CONTINUOUS WARMING FOR THE PAST 12 HOURS AS WELL. THE INTENSITY FOR
THE SYSTEM REMAINS AT 100 KNOTS BASED ON DVORAK ESTIMATES FROM PGTW
AND RJTD INDICATING THE SYSTEM HAS BEEN PERSISTING OVER THE PAST SIX
HOURS. HOWEVER, THE OVERALL WEAKENING TREND WILL PERSIST THROUGHOUT
THE FORECAST PERIOD. ANIMATED TOTAL PRECIPITABLE WATER PRODUCTS SHOW
A LARGE INCREASE IN DRY AIR (30-40 MM) WRAPPING AROUND THE SOUTHERN
PERIPHERY OF TY 26W INTO THE NORTHEASTERN QUADRANT. THIS FINGER OF
DRY AIR HAS ALMOST COMPLETELY SURROUNDED THE CENTRAL REGION OF
WARM/MOIST AIR (55 PLUS MM) AT THE CORE OF TY 26W. IN ADDITION THE
NORTHWESTERN QUADRANT OF TY 26W HAS STARTED TO BE DEPRESSED BY A
SHARP PUSH OF VERY DRY AIR (10-15 MM). THE OVERALL ENVIRONMENT FOR
TY 26W WILL CONTINUE TO WORSEN THROUGHOUT THE FORECAST PERIOD, WITH
DISSIPATION EXPECTED AROUND TAU 120. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 300600Z IS 35 FEET. NEXT WARNINGS AT 301500Z, 302100Z, 010300Z
AND 010900Z.//
NNNN

[alexx_2010]

amazing work you did.

[ManilaTC]

This set now points to a NE track now



This set still points West-WSW

[oaba09]

70 KTS

<Analyses at 30/12 UTC>
Scale -
Intensity Strong
Center position N20°00'(20.0°)
E138°55'(138.9°)
Direction and speed of movement NNW Slowly
Central pressure 960hPa
Maximum wind speed near the center 35m/s(70kt)
Maximum wind gust speed 50m/s(100kt)
Area of 50kt winds or more Wide 90km(50NM)
Area of 30kt winds or more NW460km(250NM)
SE300km(160NM)
<Forecast for 01/12 UTC>
Intensity Strong
Center position of probability circle N20°10'(20.2°)
E137°55'(137.9°)
Direction and speed of movement STR
Central pressure 970hPa
Maximum wind speed near the center 35m/s(65kt)
Maximum wind gust speed 50m/s(95kt)
Radius of probability circle 160km(85NM)
Storm warning area Wide 220km(120NM)
<Forecast for 02/12 UTC>
Intensity -
Center position of probability circle N20°05'(20.1°)
E136°55'(136.9°)
Direction and speed of movement STR
Central pressure 975hPa
Maximum wind speed near the center 30m/s(60kt)
Maximum wind gust speed 45m/s(85kt)
Radius of probability circle 260km(140NM)
Storm warning area Wide 310km(170NM)
<Forecast for 03/12 UTC>
Intensity -
Center position of probability circle N20°00'(20.0°)
E135°40'(135.7°)
Direction and speed of movement W Slowly
Central pressure 980hPa
Maximum wind speed near the center 30m/s(55kt)
Maximum wind gust speed 40m/s(80kt)
Radius of probability circle 410km(220NM)
Storm warning area Wide 460km(250NM)

[oaba09]

90 kts



WTPN31 PGTW 301500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 035
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
301200Z --- NEAR 19.9N 138.8E
MOVEMENT PAST SIX HOURS - 315 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
150 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.9N 138.8E
---
FORECASTS:
12 HRS, VALID AT:
010000Z --- 20.2N 138.2E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
135 NM SOUTHEAST QUADRANT
135 NM SOUTHWEST QUADRANT
140 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 310 DEG/ 04 KTS
---
24 HRS, VALID AT:
011200Z --- 20.7N 137.6E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 135 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 300 DEG/ 03 KTS
---
36 HRS, VALID AT:
020000Z --- 21.0N 137.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 265 DEG/ 04 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
021200Z --- 20.9N 136.2E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 250 DEG/ 02 KTS
---
72 HRS, VALID AT:
031200Z --- 20.6N 135.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 240 DEG/ 02 KTS
---
LONG RANGE OUTLOOK:
NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
NEAR 20 KT EACH DAY.
---
96 HRS, VALID AT:
041200Z --- 20.2N 134.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 230 DEG/ 02 KTS
---
120 HRS, VALID AT:
051200Z --- 19.7N 134.1E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
301500Z POSITION NEAR 20.0N 138.6E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 325 NM SOUTH-SOUTHWEST
OF IWO TO, HAS TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX
HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 301200Z IS 34 FEET.
NEXT WARNINGS AT 302100Z, 010300Z, 010900Z AND 011500Z.//
NNNN

WDPN31 PGTW 301500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (NIDA) WARNING NR 35//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 325 NM SOUTH-
SOUTHWEST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS
WEAKENING CONVECTION OVER ALL QUADRANTS WITH A RAGGED 40 NM EYE. TY
26W HAS SLOWLY INCREASED TRACK SPEED TO THE NORTHWEST, AFTER HAVING
BEEN QUASI-STATIONARY FOR THE PAST 48 TO 72 HOURS. DVORAK FIXES FROM
RJTD, KNES AND PGTW ALSO INDICATE WEAKENING OVER THE PAST 12 HOURS,
WITH A 4.5/5.0 FROM PGTW, A 5.0 FROM RJTD AND A 4.5 FROM KNES. THE
CURRENT INTENSITY OF 90 KNOTS REMAINS ON THE HIGH SIDE OF THE FIXES.
ANIMATED TOTAL PRECIPITABLE WATER (TPW) PRODUCTS SHOW A WEDGE OF DRY
AIR (30-40 MM) HAS BEEN ABLE TO COMPLETELY WRAP AROUND TY 26W,
HOWEVER, DUE TO THE SMALL EXTENT OF THE FINGER ON THE NORTHEASTERN
QUADRANT, THE DRY AIR HAS NOT BEEN ABLE TO PERSIST FOR VERY LONG IN
THAT REGION. A MASS OF VERY DRY AIR (10-20 MM) HAS BUILT ALONG THE
NORTHWESTERN QUADRANT OF TY 26W AND HAS STARTED TO DEFORM THE
SYMMETRICAL STRUCTURE OF THE SYSTEM, SUPPORTED BY THE SURFACE HIGH
PRESSURE RIDGE THAT CONTINUES TO DEVELOP EASTWARD TOWARDS TY 26W.
THIS SURFACE RIDGE IS PROVIDING COOL/DRY NORTHEASTERLY FLOW WHILE A
STRONG MID-LATITUDE WESTERLY FLOW ALOFT IS CREATING A MODERATE TO
STRONG VERTICAL WIND SHEAR ENVIRONMENT ALONG THE NORTHWESTERN
QUADRANT. THE 30/00Z 500 MB ANALYSIS SHOWS THE SUBTROPICAL RIDGE
(STR) ON BOTH SIDES OF THE SYSTEM HAS BUILT IN TOWARDS TY 26W, AND
IS BEGINNING TO TRACK THE SYSTEM SLOWLY TO THE NORTHWEST. DUE IN
PART TO THE SYSTEM REMAINING QUASI-STATIONARY OVER THE PAST FEW
DAYS, COLD WATER UPWELLING IS LIKELY CAUSING THE LOW LEVEL TO
SUFFER, WHICH IS THE PROBABLE CAUSE FOR THE RECENT WEAKENING TREND
NOTED EARLIER.
3. FORECAST REASONING.
A. NO CHANGES TO FORECAST PHILOSOPHY.
B. INCREASING VWS, WITH DECREASING OCEAN HEAT CONTENT/SEA
SURFACE TEMPERATURES AND DRY AIR ENTRAINMENT WILL BEGIN TO QUICKLY
CAUSE TY 26W TO WEAKEN. AS TY 26W WEAKENS THE STEERING INFLUENCES
WILL SHIFT TO LOWER LEVELS IN THE ATMOSPHERIC COLUMN. THE 700 MB
LEVEL IS EXPECTED TO SEE A STRONGER SUBTROPICAL RIDGE EXTENSION TO
THE WEST OF TY 26W THAN INDICATED AT 500 MB, WHICH WILL BEGIN TO
STEER THE WEAKENING LOW LEVEL CIRCULATION CENTER (LLCC) TO THE WEST
AROUND TAU 36, SHIFTING TO THE WEST-SOUTHWEST AS THE LLCC CONTINUES
WEAKENING AFTER TAU 48. NUMERICAL GUIDANCE REMAINS IN POOR AGREEMENT
WITH TWO DISTINCT CLUSTERS; NOGAPS, GFDN, TC-LAPS AND WBAR FAVOR A
RECURVATURE SCENARIO, WHILE JGSM, UKMO, ECMWF, AND GFS FAVOR A
SLOWER WESTWARD TRACK WITH DISSIPATION. THE OFFICIAL FORECAST FAVORS
THE SLOW WESTWARD MOVEMENT WITH DISSIPATION AFTER TAU 72.
C. IN THE EXTENDED TAUS, TY 26W WILL CONTINUE TO WEAKEN AND
TRACK SOUTHWESTWARD, ACCELERATING WITHIN THE LOW-LEVEL FLOW.
THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE DISSIPATION AND
THE TURN SOUTHWESTWARD. ADDITIONALLY, SEVERAL MODELS INDICATE THE
REMNANTS WILL BE ABSORBED INTO A STORM DEVELOPING NEAR GUAM.//
NNNN

[HURAKAN]

Latest

[Crostorm]

[cycloneye]

JMA 18:40 UTC Warning - 70 KTS

TY 0922 (Nida)
Issued at 18:40 UTC, 30 November 2009
<Analyses at 30/18 UTC>
Scale -
Intensity Strong
Center position N20°00'(20.0°)
E138°25'(138.4°)
Direction and speed of movement W Slowly
Central pressure 960hPa
Maximum wind speed near the center 35m/s(70kt)
Maximum wind gust speed 50m/s(100kt)
Area of 50kt winds or more Wide 90km(50NM)
Area of 30kt winds or more NW460km(250NM)
SE300km(160NM)

<Forecast for 01/18 UTC>
Intensity Strong
Center position of probability circle N20°10'(20.2°)
E137°20'(137.3°)
Direction and speed of movement W Slowly
Central pressure 970hPa
Maximum wind speed near the center 35m/s(65kt)
Maximum wind gust speed 50m/s(95kt)
Radius of probability circle 130km(70NM)
Storm warning area Wide 200km(110NM)

<Forecast for 02/18 UTC>
Intensity -
Center position of probability circle N20°05'(20.1°)
E136°05'(136.1°)
Direction and speed of movement W Slowly
Central pressure 980hPa
Maximum wind speed near the center 30m/s(55kt)
Maximum wind gust speed 40m/s(80kt)
Radius of probability circle 260km(140NM)
Storm warning area Wide 310km(170NM)

<Forecast for 03/18 UTC>
Intensity -
Center position of probability circle N20°00'(20.0°)
E134°35'(134.6°)
Direction and speed of movement W Slowly
Central pressure 985hPa
Maximum wind speed near the center 25m/s(50kt)
Maximum wind gust speed 35m/s(70kt)
Radius of probability circle 410km(220NM)

[HURAKAN]

Latest

[cycloneye]

JTWC 21:00Z Warning - 80 KTS



WTPN31 PGTW 302100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 036
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
301800Z --- NEAR 20.0N 138.2E
MOVEMENT PAST SIX HOURS - 280 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
140 NM SOUTHEAST QUADRANT
150 NM SOUTHWEST QUADRANT
150 NM NORTHWEST QUADRANT
REPEAT POSIT: 20.0N 138.2E
---
FORECASTS:
12 HRS, VALID AT:
010600Z --- 20.3N 137.3E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
125 NM SOUTHEAST QUADRANT
130 NM SOUTHWEST QUADRANT
135 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 295 DEG/ 05 KTS
---
24 HRS, VALID AT:
011800Z --- 20.7N 136.4E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 305 DEG/ 05 KTS
---
36 HRS, VALID AT:
020600Z --- 21.3N 135.5E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 335 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
021800Z --- 22.2N 135.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 040 DEG/ 13 KTS
---
72 HRS, VALID AT:
031800Z --- 26.2N 138.6E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
302100Z POSITION NEAR 20.1N 138.0E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 330 NM SOUTH-
SOUTHWEST OF IWO TO, HAS TRACKED WESTWARD AT 06 KNOTS OVER THE PAST
SIX HOURS. ANIMATED INFRARED IMAGERY SHOWS A RAGGED EYE AND AN
ELONGATED AREA OF DEEP CONVECTION WITH THE GREATEST EXTENT TO THE
WEST-NORTHWEST OF THE LOW LEVEL CIRCULATION CENTER (LLCC). THE
CURRENT POSITION IS SUPPORTED BY A 301913Z AMSU MICROWAVE IMAGE. THE
CURRENT INTENSITY IS A COMPILATION OF DVORAK ESTIMATES FROM PGTW (90
KNOTS), RJTD (90 KNOTS), AND KNES (77 KNOTS). THE FORECAST TRACK
PHILOSPHY FOR THIS SYSTEM HAS CHANGED SINCE WARNING NR 035. DUE TO
MODERATE VERTICAL WIND SHEAR AND AN INCREASE IN DRY AIR ENTRAINMENT,
TY NIDA IS STILL EXPECTED TO WEAKEN SIGNIFICANTLY OVER THE NEXT 48
HOURS. HOWEVER, THE NUMERICAL MODELS NOW DEPICT A LESS ZONAL MID-
LATITUDE PATTERN AND SHOW AN UPSTREAM MID-LATITUDE TROUGH THAT IS
FORECAST TO DIG EASTWARD. THIS DIGGING TROUGH, REFLECTED AT BOTH 500
AND 700 MB, WILL ENABLE A MUCH-WEAKENED NIDA TO RECURVE INTO THE MID-
LATITUDES AFTER TAU 48. BY TAU 72, TY 26W IS EXPECTED TO COMPLETE
TRANSITION INTO A WEAK BAROCLINIC SYSTEM. THERE IS STILL UNCERTAINTY
WITH THIS FORECAST AND IF THE SYSTEM DISSIPATES EVEN FASTER THAN
EXPECTED THROUGH 48 HOURS, IT MAY TRACK WITH THE LOW-LEVEL NORTH-
EASTERLY FLOW AS A TROPICAL DEPRESSION. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 301800Z IS 32 FEET. NEXT WARNINGS AT 010300Z, 010900Z,
011500Z AND 012100Z.//
NNNN

[Aslkahuna]

JTWC uses 1 minute winds because that's the US standard for sustained winds. This criterion was derived some time ago as a result of coordination between the US Weather Bureau (predecessor to NOAA), FAA, Civil Airlines, other Civil Users and the Military services. The WMO criterion may have come later. I remember that when METAR first originally came out in the 1960's that we in Air Weather Service units overseas were told to use the 10 minute criterion (the US Navy refused for years to even consider using Metar). The Air Force went ballistic and within months we went back to one minute winds. US Military prefers the shorter period because it provides a better indication of the winds being experienced by the aircraft on takeoff and landing. Additionally, the definition of gusts back when METAR first came out were different between the WMO (10 kts+ over the average wind) and the US (9 kt+ between peaks and lulls) which the military didn't like either because of certain gust limitations of various aircraft. JMA besides using the WMO definition for sustained winds also uses a different Wind/Pressure/Dvorak relationship than does JTWC. However, if you look closely at the JMA wind forecasts, you will find that their gusts equate closely to the JTWC sustained suggesting that JMA is using a one minute peak average wind for their gusts.

Steve