WPAC : TROPICAL DEPRESSION NIDA (26W)

Moderator: S2k Moderators

Message
Author
ozonepete
Professional-Met
Professional-Met
Posts: 4631
Joined: Mon Sep 07, 2009 3:23 pm
Location: From Ozone Park, NYC / Now in Brooklyn, NY

Re: WPAC : TYPHOON NIDA (26W)

#461 Postby ozonepete » Mon Nov 30, 2009 7:57 pm

Aslkahuna wrote: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


Thanks, Steve, for the explanation and history. I have also noticed and totally agree on the similarity they have on the gusts.

I also read online that "Another aspect is that different methods are used for estimating maximum sustained wind from observation." What are the methods of "observation"? As far as I know, there are only satellite derived winds using cloud motion or wave/sea spray. Dvorak clearly uses cloud motion and specific historic formations to get their numbers, and I'm well aware that JTWC uses a blend of the available Dvorak estimates in concert with other criteria. Who uses what? If you have the links, I'll go look it up - just have had trouble finding this info. :)
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 117486
Age: 63
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: WPAC : TYPHOON NIDA (26W)

#462 Postby cycloneye » Mon Nov 30, 2009 8:22 pm

JMA 00:45 UTC Warning- 70 KTS

TY 0922 (Nida)
Issued at 00:45 UTC, 1 December 2009
<Analyses at 01/00 UTC>
Scale -
Intensity Strong
Center position N20°10'(20.2°)
E138°10'(138.2°)
Direction and speed of movement WNW Slowly
Central pressure 965hPa
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 02/00 UTC>
Intensity -
Center position of probability circle N20°10'(20.2°)
E136°25'(136.4°)
Direction and speed of movement W Slowly
Central pressure 975hPa
Maximum wind speed near the center 30m/s(60kt)
Maximum wind gust speed 45m/s(85kt)
Radius of probability circle 130km(70NM)
Storm warning area Wide 200km(110NM)

<Forecast for 03/00 UTC>
Intensity -
Center position of probability circle N20°05'(20.1°)
E135°10'(135.2°)
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 260km(140NM)

<Forecast for 04/00 UTC>
Intensity -
Center position of probability circle N20°00'(20.0°)
E133°35'(133.6°)
Direction and speed of movement W Slowly
Central pressure 992hPa
Maximum wind speed near the center 23m/s(45kt)
Maximum wind gust speed 35m/s(65kt)
Radius of probability circle 410km(220NM)

Image
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

ozonepete
Professional-Met
Professional-Met
Posts: 4631
Joined: Mon Sep 07, 2009 3:23 pm
Location: From Ozone Park, NYC / Now in Brooklyn, NY

Re: WPAC : TYPHOON NIDA (26W)

#463 Postby ozonepete » Mon Nov 30, 2009 8:55 pm

I'm posting the latest IR satellite image here to show that as Nida has drifted to the northwest somewhat this has allowed the core to move away from upwelled water. Convection is re-blossomong and if it remains a deeper storm it will once again be more likely to get steered northeastward.

Also, if you look at the water vapor loops (here's the most recent one) it once again seems fairly likely that Nida will get swept up into the westerlies. It is hanging on to the tail-end of the upper level boundary along the western edge of the STR and it won't take much for it to get absorbed into that very fast northeastward flow - look at the cirrus and other high clouds marking the fast-moving 500mb trough moving eastward across China. No wonder the JTWC track is bending back again to the northeast. This is a very similar situation to LUPIT, by the way, and the JTWC did a better job than the JMA on forecasting a recurve for LUPIT- let's see if they do it again. This is a really difficult forecast.

Image

Image

Image
Last edited by ozonepete on Mon Nov 30, 2009 9:08 pm, edited 1 time in total.
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 117486
Age: 63
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: WPAC : TYPHOON NIDA (26W)

#464 Postby cycloneye » Mon Nov 30, 2009 9:07 pm

JTWC 00:00Z Warning=75kts

WTPN31 PGTW 010300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 037
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
010000Z --- NEAR 20.3N 138.1E
MOVEMENT PAST SIX HOURS - 315 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 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: 20.3N 138.1E
---
FORECASTS:
12 HRS, VALID AT:
011200Z --- 20.7N 137.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
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 - 120 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
125 NM SOUTHWEST QUADRANT
125 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 305 DEG/ 04 KTS
---
24 HRS, VALID AT:
020000Z --- 21.2N 136.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 320 DEG/ 05 KTS
---
36 HRS, VALID AT:
021200Z --- 22.0N 135.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 010 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
030000Z --- 23.4N 136.2E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 040 DEG/ 15 KTS
---
72 HRS, VALID AT:
040000Z --- 27.8N 140.8E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
010300Z POSITION NEAR 20.4N 137.9E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 325 NM SOUTH-
SOUTHWEST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 03 KNOTS OVER THE
PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010000Z IS 30
FEET. NEXT WARNINGS AT 010900Z, 011500Z, 012100Z AND 020300Z.//
NNNN

Image
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

ozonepete
Professional-Met
Professional-Met
Posts: 4631
Joined: Mon Sep 07, 2009 3:23 pm
Location: From Ozone Park, NYC / Now in Brooklyn, NY

Re: WPAC : TYPHOON NIDA (26W)

#465 Postby ozonepete » Mon Nov 30, 2009 11:20 pm

Although it can't count because this wasn't measured by aircraft, this very well could have been the strongest typhoon we've ever seen. The Advanced Dvorak Technique had Nida at 869.5 mb on November 25, almost 2 mb lower than Typhoon Tip. Just food for thought.
0 likes   

Squarethecircle
Category 5
Category 5
Posts: 2165
Joined: Fri Oct 19, 2007 4:00 pm
Location: Fairfax, VA

#466 Postby Squarethecircle » Mon Nov 30, 2009 11:26 pm

:uarrow: Importantly, that estimate came from a computed T-number of 7.9. When was the last time ADT recorded an 8.0?
0 likes   

oaba09
S2K Supporter
S2K Supporter
Posts: 1494
Age: 32
Joined: Thu Oct 01, 2009 10:02 am
Location: Valenzuela, Philippines
Contact:

#467 Postby oaba09 » Mon Nov 30, 2009 11:31 pm

:uarrow:
it's a record breaking system,something we probably won't see for a long time. Thank God it didn't hit land with that power :)
0 likes   

User avatar
Aslkahuna
Professional-Met
Professional-Met
Posts: 4550
Joined: Thu Feb 06, 2003 5:00 pm
Location: Tucson, AZ
Contact:

Re: WPAC : TYPHOON NIDA (26W)

#468 Postby Aslkahuna » Tue Dec 01, 2009 12:10 am

Actually, there are a small number of typhoons that have had Dvoraks of 8.0 or even a bit higher including Gay (1992) and Angela (1995) and in fact those storms had higher Dvoraks than Tip but JTWC will probably never declare a storm stronger than Tip because Tip had in situ recon measurements whereas the others did not. This same discussion came out a couple of years ago during TC Monica. As for the techniques used by JTWC, their ATCRs usually provide an explanation some years more detailed than others. There have been some published papers discussing intensities of WPAC storms and specifically the disparity between JMA and JTWC but my copies of them are buried somewhere right now.

Steve
0 likes   

User avatar
RattleMan
Category 5
Category 5
Posts: 1219
Joined: Wed Aug 24, 2005 7:14 pm
Location: Phoenix, AZ

Re:

#469 Postby RattleMan » Tue Dec 01, 2009 12:40 am

Squarethecircle wrote::uarrow: Importantly, that estimate came from a computed T-number of 7.9. When was the last time ADT recorded an 8.0?

Code: Select all

2006APR23 193300  8.0  868.6/ +10.6 /170.0  8.0 8.0 8.0 8.0
2006APR23 203300  8.0  868.5/ +10.5 /170.0  8.0 8.0 8.0 8.0
2006APR23 213300  8.0  868.6/ +10.6 /170.0  8.0 8.0 8.0 8.0
2006APR23 223300  8.0  868.6/ +10.6 /170.0  8.0 8.0 8.0 8.0
2006APR24 000000  8.0  868.5/ +10.5 /170.0  8.0 8.0 8.0 8.0
2006APR24 003300  8.0  868.5/ +10.5 /170.0  8.0 8.0 8.0 8.0

Monica
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 117486
Age: 63
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: WPAC : TYPHOON NIDA (26W)

#470 Postby cycloneye » Tue Dec 01, 2009 8:10 am

JMA 12:00 UTC warning - 70 kts

TY 0922 (Nida)
Issued at 12:45 UTC, 1 December 2009
<Analyses at 01/12 UTC>
Scale -
Intensity Strong
Center position N20°40'(20.7°)
E137°35'(137.6°)
Direction and speed of movement STR
Central pressure 970hPa
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 02/12 UTC>
Intensity -
Center position of probability circle N20°50'(20.8°)
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 130km(70NM)
Storm warning area Wide 200km(110NM)

<Forecast for 03/12 UTC>
Intensity -
Center position of probability circle N20°55'(20.9°)
E134°20'(134.3°)
Direction and speed of movement W Slowly
Central pressure 990hPa
Maximum wind speed near the center 23m/s(45kt)
Maximum wind gust speed 35m/s(65kt)
Radius of probability circle 260km(140NM)

<Forecast for 04/12 UTC>
Intensity -
TD
Center position of probability circle N21°05'(21.1°)
E132°55'(132.9°)
Direction and speed of movement W Slowly
Central pressure 998hPa
Radius of probability circle 410km(220NM)

Image
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

oaba09
S2K Supporter
S2K Supporter
Posts: 1494
Age: 32
Joined: Thu Oct 01, 2009 10:02 am
Location: Valenzuela, Philippines
Contact:

#471 Postby oaba09 » Tue Dec 01, 2009 8:13 am

JTWC now has it moving NW then possibly recurving...This system has been a tough one....
0 likes   

ozonepete
Professional-Met
Professional-Met
Posts: 4631
Joined: Mon Sep 07, 2009 3:23 pm
Location: From Ozone Park, NYC / Now in Brooklyn, NY

Re: WPAC : TYPHOON NIDA (26W)

#472 Postby ozonepete » Tue Dec 01, 2009 8:18 am

Aslkahuna wrote:Actually, there are a small number of typhoons that have had Dvoraks of 8.0 or even a bit higher including Gay (1992) and Angela (1995) and in fact those storms had higher Dvoraks than Tip but JTWC will probably never declare a storm stronger than Tip because Tip had in situ recon measurements whereas the others did not. This same discussion came out a couple of years ago during TC Monica. As for the techniques used by JTWC, their ATCRs usually provide an explanation some years more detailed than others. There have been some published papers discussing intensities of WPAC storms and specifically the disparity between JMA and JTWC but my copies of them are buried somewhere right now.

Steve


Thanks for all the info, Steve. I plan on doing some research on this during the off season and I'll post it here on storm2K when I'm done.
0 likes   

oaba09
S2K Supporter
S2K Supporter
Posts: 1494
Age: 32
Joined: Thu Oct 01, 2009 10:02 am
Location: Valenzuela, Philippines
Contact:

#473 Postby oaba09 » Tue Dec 01, 2009 8:30 am

Image

This is definitely going to recurve...at least based on what my amateur eyes see :)

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
0 likes   

oaba09
S2K Supporter
S2K Supporter
Posts: 1494
Age: 32
Joined: Thu Oct 01, 2009 10:02 am
Location: Valenzuela, Philippines
Contact:

#474 Postby oaba09 » Tue Dec 01, 2009 8:45 am

LATEST FROM JTWC:

Image

WTPN31 PGTW 011500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 039
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
011200Z --- NEAR 20.6N 137.3E
MOVEMENT PAST SIX HOURS - 300 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 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 - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
135 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
REPEAT POSIT: 20.6N 137.3E
---
FORECASTS:
12 HRS, VALID AT:
020000Z --- 21.1N 136.6E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 315 DEG/ 04 KTS
---
24 HRS, VALID AT:
021200Z --- 21.7N 135.9E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 340 DEG/ 04 KTS
---
36 HRS, VALID AT:
030000Z --- 22.5N 135.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 020 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
031200Z --- 23.9N 136.1E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 035 DEG/ 12 KTS
---
72 HRS, VALID AT:
041200Z --- 27.8N 139.1E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
011500Z POSITION NEAR 20.7N 137.1E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 335 NM SOUTHWEST OF
IWO TO, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX
HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 011200Z IS 28 FEET.
NEXT WARNINGS AT 012100Z, 020300Z, 020900Z AND 021500Z.//
NNNN
**********************
PROGNOSTIC REASONING
WDPN31 PGTW 011500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (NIDA) WARNING NR 39//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 335 NM SOUTH-
WEST OF IWO TO, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS THAT OVER
THE PAST 12 HOURS THERE HAS BEEN A LARGE CHANGE IN THE STRUCTURE OF
TY 26W. THE EYE HAS DEGENERATED TO AN EMBEDDED CENTER ON THE MOST
RECENT PGTW DVORAK FIX. THE SYMMETRIC SHAPE THAT TY 26W HAS HAD OVER
THE PAST FEW DAYS HAS STARTED TO ELONGATE IN THE NORTHEAST TO SOUTH-
WEST DIRECTION. ANIMATED TOTAL PRECIPITABLE WATER PRODUCTS REFLECT
THIS ELONGATION WITH DRY AIR EVIDENT IN POCKETS IN ALL QUADRANTS OF
THE SYSTEM. INTENSITY HAS BEEN ABLE TO MAINTAIN AT THE CURRENT
ESTIMATE OF 75 KNOTS OVER THE PAST 12 HOURS BASED ON DVORAK FIXES
FROM PGTW, RJTD, AND KNES INDICATING 77 KNOTS. BUILDING DEEP
CONVECTION HAS OBSCURED THE LOW LEVEL CIRCULATION CENTER (LLCC) OVER
THE PAST THREE HOURS.
3. FORECAST REASONING.
A. THE FORECAST PHILOSOPHY HAS NOT CHANGED SIGNIFICANTLY SINCE
THE LAST PROGNOSTIC REASONING BULLETIN.
B. TY 26W WILL CONTINUE TO TRACK TO THE WEST-NORTHWEST UNDER
THE INFLUENCE OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST THAT
IS SLOWLY BUILDING WESTWARD TO THE NORTHEAST OF THE SYSTEM. AS
TY 26W MOVES FURTHER TO THE WEST-NORTHWEST, DRY AIR ENTRAINMENT
WITH INCREASING VERTICAL WIND SHEAR WILL CAUSE TY 26W TO WEAKEN
THROUGH THE REMAINDER OF THE FORECAST PERIOD. BETWEEN TAU 36 AND 48
A MID-LATITUDE TROUGH, CURRENTLY OVER CENTRAL CHINA, WILL TRACK AND
DIG TO THE NORTH OF TY 26W, CAUSING A WEAKNESS IN THE EASTERN STR.
THIS WEAKNESS WILL ALLOW FOR A MORE NORTHWARD TRACK AND EVENTUALLY
ALLOW TY 26W TO BE CAPTURED IN THE MID-LATITUDE WESTERLIES WHERE IT
WILL QUICKLY COMPLETE AN EXTRATROPICAL TRANSITION BY TAU 72. AN
ALTERNATE SCENARIO EXISTS, IN WHICH THE WEAKENING OF TY 26W OCCURS
MORE QUICKLY THAN CURRENTLY FORECAST, ALLOWING FOR THE REMNANT
LLCC TO BE SHEARED FROM THE UPPER LEVEL CIRCULATION. THE LLCC WOULD
THEN BE PICKED UP IN THE NORTHEASTERLY LOW LEVEL FLOW AND BEGIN TO
TRACK TO THE SOUTHWEST WHILE THE MAJORITY OF CONVECTION TRACKS TO
THE NORTHEAST. MODEL GUIDANCE IS PREDOMINANTLY INDICATING THAT THE
EXTRATROPICAL SCENARIO IS MORE LIKELY FOR A STRONGER SYSTEM (WHICH
IS CURRENTLY PROVING TO BE THE CASE, EVIDENCED BY THE PERSISTENT
INTENSITY OVER THE PAST 12 HOURS), AND IN CASE TY 26W SHOULD
RAPIDLY WEAKEN, THE DISSIPATION SCENARIO WOULD BE MORE FEASIBLE.//
NNNN
0 likes   

oaba09
S2K Supporter
S2K Supporter
Posts: 1494
Age: 32
Joined: Thu Oct 01, 2009 10:02 am
Location: Valenzuela, Philippines
Contact:

#475 Postby oaba09 » Tue Dec 01, 2009 8:47 am

Image

<Analyses at 01/12 UTC>
Scale -
Intensity Strong
Center position N20°40'(20.7°)
E137°35'(137.6°)
Direction and speed of movement STR
Central pressure 970hPa
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 02/12 UTC>
Intensity -
Center position of probability circle N20°50'(20.8°)
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 130km(70NM)
Storm warning area Wide 200km(110NM)
<Forecast for 03/12 UTC>
Intensity -
Center position of probability circle N20°55'(20.9°)
E134°20'(134.3°)
Direction and speed of movement W Slowly
Central pressure 990hPa
Maximum wind speed near the center 23m/s(45kt)
Maximum wind gust speed 35m/s(65kt)
Radius of probability circle 260km(140NM)
<Forecast for 04/12 UTC>
Intensity -
TD
Center position of probability circle N21°05'(21.1°)
E132°55'(132.9°)
Direction and speed of movement W Slowly
Central pressure 998hPa
Radius of probability circle 410km(220NM)
0 likes   

User avatar
HURAKAN
Professional-Met
Professional-Met
Posts: 46086
Age: 32
Joined: Thu May 20, 2004 4:34 pm
Location: Key West, FL
Contact:

#476 Postby HURAKAN » Tue Dec 01, 2009 9:33 am

Image

Latest
0 likes   

User avatar
HURAKAN
Professional-Met
Professional-Met
Posts: 46086
Age: 32
Joined: Thu May 20, 2004 4:34 pm
Location: Key West, FL
Contact:

#477 Postby HURAKAN » Tue Dec 01, 2009 10:52 am

Image

Latest
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 117486
Age: 63
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: WPAC : SEVERE TROPICAL STORM NIDA (26W)

#478 Postby cycloneye » Tue Dec 01, 2009 2:08 pm

JMA downgrades to Severe Tropical Storm.

STS 0922 (Nida)
Issued at 18:45 UTC, 1 December 2009
<Analyses at 01/18 UTC>
Scale -
Intensity -
Center position N20°55'(20.9°)
E137°30'(137.5°)
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)
Area of 50kt winds or more Wide 70km(40NM)
Area of 30kt winds or more NW460km(250NM)
SE300km(160NM)

<Forecast for 02/18 UTC>
Intensity -
Center position of probability circle N20°55'(20.9°)
E136°00'(136.0°)
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 130km(70NM)

<Forecast for 03/18 UTC>
Intensity -
TD
Center position of probability circle N21°00'(21.0°)
E134°25'(134.4°)
Direction and speed of movement W Slowly
Central pressure 998hPa
Radius of probability circle 260km(140NM)

Image
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 117486
Age: 63
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: WPAC : SEVERE TROPICAL STORM NIDA (26W)

#479 Postby cycloneye » Tue Dec 01, 2009 4:17 pm

JTWC 21:00Z Warning=65kts

WTPN31 PGTW 012100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (NIDA) WARNING NR 040
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
011800Z --- NEAR 21.4N 136.8E
MOVEMENT PAST SIX HOURS - 330 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
135 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
REPEAT POSIT: 21.4N 136.8E
---
FORECASTS:
12 HRS, VALID AT:
020600Z --- 22.4N 135.9E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 345 DEG/ 05 KTS
---
24 HRS, VALID AT:
021800Z --- 23.3N 135.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 020 DEG/ 06 KTS
---
36 HRS, VALID AT:
030600Z --- 24.4N 136.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
VECTOR TO 48 HR POSIT: 035 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
031800Z --- 26.4N 137.5E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
VECTOR TO 72 HR POSIT: 045 DEG/ 13 KTS
---
72 HRS, VALID AT:
041800Z --- 30.0N 141.7E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
EXTRATROPICAL
---
REMARKS:
012100Z POSITION NEAR 21.7N 136.6E.
TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 315 NM SOUTHWEST OF
IWO TO, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER THE LAST
SIX HOURS. A FINGER OF THE MID-LEVEL SUBTROPICAL RIDGE LOCATED TO
THE EAST HAS CONTINUED TO STEER THE SYSTEM WESTWARD. ANIMATED
INFRARED SATELLITE IMAGERY SHOWS WEAKENING CONVECTION WITH AN
EMBEDDED CENTER WHILE ANIMATED WATER VAPOR IMAGERY AND A 011011Z
SSMIS MICRWOAVE IMAGE INDICATE THE DEEP CONVECTION HAS SHIFTED
SOMEWHAT TO THE EAST OF THE LOW LEVEL CIRCULATION CENTER (LLCC),
SUGGESTING THE SYSTEM HAS MOVED INTO AN ENVIRONMENT OF MODERATE
VERTICAL WIND SHEAR. ACCORDINGLY, DVORAK ESTIMATES FROM PGTW, RJTD,
AND KNES HAVE DROPPED TO 55-65 KNOTS. TY NIDA IS STILL EXPECTED TO
CONTINUE TRACKING GENERALLY NORTHWESTWARD BEFORE RECURVING AHEAD OF
A QUICKLY APPROACHING MID-LATITUDE TROUGH CURRENTLY DIGGING NORTH OF
CHINA. OVER THE NEXT TWO DAYS THE SYSTEM WILL CONTINUE TO WEAKEN DUE
TO INCREASING VERTICAL WIND SHEAR AND DRY AIR ENTRAINMENT. BY TAU 48
NIDA WILL COMPLETE TRANSITION INTO A VERY WEAK EXTRATROPICAL CYCLONE
AND ITS ENERGY WILL CONTINUE TRACKING NORTHEASTWARD INTO THE MID-
LATITUDES. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 011800Z IS 26 FEET.
NEXT WARNINGS AT 020300Z, 020900Z, 021500Z AND 022100Z.//
NNNN

Image
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

ozonepete
Professional-Met
Professional-Met
Posts: 4631
Joined: Mon Sep 07, 2009 3:23 pm
Location: From Ozone Park, NYC / Now in Brooklyn, NY

Re: WPAC : SEVERE TROPICAL STORM NIDA (26W)

#480 Postby ozonepete » Tue Dec 01, 2009 7:07 pm

Nida has produced impressive convection once again, no doubt in part due to it's moving away from upwelled water, but more importantly due to really strong outflow to the northeast at upper levels.

Having said that, I'm still waiting for JMA to change their track to a recurve. Just look at the water vapor loops. The only other option that seems viable right now other than a recurve to the northeast is that it spins down in place to a few clouds.

Image
0 likes   


Return to “2009”

Who is online

Users browsing this forum: No registered users and 3 guests