Tropical Cyclone Pam - SW Pacific

jamie · Unread post by **jamie** » Wed 11/03/2015 07:27

That sort of pass is very similar to the feb 2004 cyclone. Can't remember it's name. It was a day after the big floods. We got no rain from the cyclone and I don't expect any from this unless it tracks right down the country or to the west. We are too sheltered from the east for rain.

David · Unread post by **David** » Wed 11/03/2015 07:35

This is the latest GFS rain accumulation forecast for NZ

Manukau heads obs · Wed 11/03/2015 07:40

I suspect the rain chances are better for this system because of the size of thing

Nev · Unread post by **Nev** » Wed 11/03/2015 08:41

jamie wrote:That sort of pass is very similar to the feb 2004 cyclone. Can't remember it's name. It was a day after the big floods. We got no rain from the cyclone and I don't expect any from this unless it tracks right down the country or to the west. We are too sheltered from the east for rain.

Huh? Wasn't it Ex-tropical Cyclone Ivy which caused those floods at the end of Feb 2004, i.e. 115mm at Hamilton Aero and 94mm at Ruakura?

spwill · Unread post by **spwill** » Wed 11/03/2015 08:55

Interesting to see both GFS and ECMWF have it tracking closer, see what next few model runs look like

Nev · Unread post by **Nev** » Wed 11/03/2015 08:58

Latest remarks from RSMC Nadi…

TROPICAL DISTURBANCE ADVISORY NUMBER A15 ISSUED FROM RSMC NADI
Mar 10/1947 UTC 2015 UTC.

SEVERE TROPICAL CYCLONE PAM CENTRE 963HPA WAS LOCATED NEAR 10.9S
170.2E AT 101800 UTC. POSITION POOR BASED ON HR GMS EIR IMAGERY AND
PERIPHERAL SURFACE REPORTS. CYCLONE MOVING SOUTH AT ABOUT 04 KNOTS.
MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 75
KNOTS.
...
ORGANISATION HAS SIGNIFICANTLY IMPROVED IN THE PAST 24 HOURS. DEEP
CONVECTION REMAINS PESISTENT. SYSTEM LIES UNDER AN UPPER RIDGE IN A
MODERATE SHEARED ENVIRONMENT. OUTFLOW GOOD. CYCLONIC CIRCULATION
EXTENDS TO 300HPA. SST AROUND 30 DEGREES CELSIUS. DVORAK ANALYSIS
BASED ON EMBD PATTERN, LLCC EMBD IN CMG, YEILDS DT=5.0, MET=
4.5,PT=4.5. FT BASED ON MET. THUS YIELDING T4.5/4.5/D1.5/24HRS.

GLOBAL MODEL HAVE PICKED THE SYSTEM AND MOVE IT SOUTHWARDS WITH
FURTHER INTENSIFICATION.
...

Manukau heads obs · Wed 11/03/2015 09:42

latest GFS run now has it close enough to cause damaging winds for eastern NI areas....

Nev · Unread post by **Nev** » Wed 11/03/2015 10:10

Yes, models starting to get way too close for comfort. Latest from JTWC...

WTPS31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 17P (PAM) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 17P (PAM) WARNING NR 005
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
101800Z --- NEAR 11.1S 170.1E
MOVEMENT PAST SIX HOURS - 200 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
...
REMARKS:
102100Z POSITION NEAR 11.3S 170.0E.
TROPICAL CYCLONE (TC) 17P (PAM), LOCATED APPROXIMATELY 699 NM NORTH-
NORTHEAST OF NOUMEA, NEW CALEDONIA, HAS TRACKED SOUTH-
SOUTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A DEEP CENTRAL DENSE OVERCAST
WITH EXPANSIVE DEEP CONVECTIVE BANDING WRAPPING INTO THE TIGHTLY
WRAPPED LOW LEVEL CIRCULATION CENTER (LLCC). THE LOCATION IS BASED
ON A 101842Z SSMIS MICROWAVE EYE FEATURE WITH HIGH CONFIDENCE. THE
INITIAL INTENSITY OF 90 KNOTS IS BASED ON CONCURRING DVORAK
INTENSITY ESTIMATES FROM ALL AGENCIES. UPPER LEVEL ANALYSIS
CONTINUES TO SHOW THE SYSTEM WITH MODERATE (10 TO 20 KNOT) VERTICAL
WIND SHEAR OFFSET BY RADIAL OUTFLOW, WHICH IS EVIDENT ON WATER VAPOR
IMAGERY. TC PAM IS TRACKING ALONG THE WESTERN EXTENSION OF THE SUB-
TROPICAL RIDGE (STR) TO THE EAST. THIS STR WILL BE THE DOMINANT
STEERING MECHANISM THROUGH THE REMAINDER OF THE FORECAST PERIOD
UNTIL THE SYSTEM EMBEDS IN THE MID-LATITUDE WESTERLIES. TC 17P WILL
CONTINUE TO INTENSIFY OVER THE NEXT 48 HOURS DUE TO A FAVORABLE
ENVIRONMENT WITH EXCELLENT OUTFLOW AND SEA SURFACE TEMPERATURE (SST)
ABOVE 29 CELSIUS. BEYOND TAU 48, TC PAM WILL BEGIN TO WEAKEN AS IT
ROUNDS THE STR AXIS WHERE VWS WILL INCREASE AND SST BEGINS TO DROP
OFF. THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) NEAR TAU
96 AS IT EMBEDS IN THE BAROCLINIC ZONE AND IS EXPECTED TO COMPLETE
ETT BY TAU 120. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE
OVERALL TRACK, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
OFFICIAL FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101800Z IS 28
FEET. NEXT WARNINGS AT 110300Z, 110900Z, 111500Z AND 112100Z. REFER
TO TROPICAL CYCLONE 18P (NATHAN) WARNINGS (WTPS32 PGTW) FOR TWELVE-
HOURLY UPDATES.//

David · Unread post by **David** » Wed 11/03/2015 10:17

Manukau heads obs wrote:latest GFS run now has it close enough to cause damaging winds for eastern NI areas....

Yup, onshore winds up to 50 knots, and even 60 knots showing for East Cape area

03Stormchaser · Unread post by **03Stormchaser** » Wed 11/03/2015 10:25

Some models still showing a sub 900 system, cant imagine this not going CAT 5 at some point.

Nev · Unread post by **Nev** » Wed 11/03/2015 14:55

Nice eye on this morn's sat-pics.

TROPICAL DISTURBANCE ADVISORY NUMBER A16 ISSUED FROM RSMC NADI
Mar 11/0131 UTC 2015 UTC.

SEVERE TROPICAL CYCLONE PAM CENTRE 958HPA WAS LOCATED NEAR 11.1S
169.7E AT 110000 UTC. POSITION FAIR BASED ON HR GMS VIS IMAGERY AND
PERIPHERAL SURFACE REPORTS. CYCLONE MOVING SOUTH-SOUTHWEST AT ABOUT
04 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED
AT ABOUT 80 KNOTS.
...
ORGANISATION HAS SIGNIFICANTLY IMPROVED WITH EYE DISCERNABLE ON MTSAT
VIS IMAGERY IN THE PAST 3 HOURS. DEEP CONVECTION REMAINS PESISTENT.
SYSTEM LIES UNDER AN UPPER RIDGE IN A MODERATE SHEARED ENVIRONMENT.
OUTFLOW GOOD. CYCLONIC CIRCULATION EXTENDS TO 300HPA. SST AROUND 30
DEGREES CELSIUS. DVORAK ANALYSIS BASED ON EMBD PATTERN, LLCC EMBD IN
B, YEILDS DT=5.0, MET AND PT AGREE. THUS YIELDING
T5.0/5.0/D1.5/24HRS.

GLOBAL MODELS MOVE THE SYSTEM SOUTHWARDS WITH FURTHER
INTENSIFICATION.
...

Nev · Unread post by **Nev** » Wed 11/03/2015 16:06

Wouldn't want to be in Vanuatu in the next couple days... JTWC has nearby gusts to 175 kts (324 km/h)…

WTPS31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 17P (PAM) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 17P (PAM) WARNING NR 006
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110000Z --- NEAR 11.0S 169.6E
MOVEMENT PAST SIX HOURS - 245 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
...
REMARKS:
110300Z POSITION NEAR 11.2S 169.5E.
TROPICAL CYCLONE (TC) 17P (PAM), LOCATED APPROXIMATELY 696 NM NORTH-
NORTHEAST OF NOUMEA, NEW CALEDONIA, HAS TRACKED WEST-SOUTHWESTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A CONSOLIDATING SYSTEM WITH A DEVELOPING
EYE AND INTENSE DEEP CONVECTIVE BANDING. A 102224Z METOP-A IMAGE
ALSO SHOWS TIGHTLY-CURVED BANDING WRAPPING INTO A MICROWAVE EYE
FEATURE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE.
THE INITIAL INTENSITY OF 100 KNOTS IS BASED ON DVORAK CURRENT
INTENSITY ESTIMATES AS HIGH AS 102 KNOTS. UPPER-LEVEL ANALYSIS
INDICATES A FAVORABLE ENVIRONMENT WITH NEAR-RADIAL OUTFLOW AND LOW
VERTICAL WIND SHEAR (VWS). TC PAM IS TRACKING ALONG THE WESTERN
EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE EAST. THIS STR WILL
BE THE DOMINANT STEERING MECHANISM THROUGH THE REMAINDER OF THE
FORECAST PERIOD UNTIL THE SYSTEM EMBEDS IN THE MID-LATITUDE
WESTERLIES. TC 17P WILL CONTINUE TO INTENSIFY RAPIDLY OVER THE NEXT
36 HOURS DUE TO THE FAVORABLE ENVIRONMENT AND SEA SURFACE
TEMPERATURE (SST) ABOVE 29 CELSIUS. BEYOND TAU 48, TC PAM WILL BEGIN
TO WEAKEN AS IT ROUNDS THE STR AXIS WHERE VWS WILL INCREASE AND SST
BEGINS TO DROP OFF. THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) NEAR TAU 96 AS IT BEGINS TO INTERACT WITH THE BAROCLINIC ZONE
AND IS EXPECTED TO COMPLETE ETT BY TAU 120. DYNAMIC MODEL GUIDANCE
IS IN GOOD AGREEMENT WITH THE OVERALL TRACK, THEREFORE, THERE IS
HIGH CONFIDENCE IN THE JTWC OFFICIAL FORECAST. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 110000Z IS 31 FEET. NEXT WARNINGS AT 110900Z,
111500Z, 112100Z AND 120300Z.
…

Manukau heads obs · Wed 11/03/2015 16:12

you cant rule out an even closer path to NZ yet..

jamie · Unread post by **jamie** » Wed 11/03/2015 17:08

Nev wrote:
jamie wrote:That sort of pass is very similar to the feb 2004 cyclone. Can't remember it's name. It was a day after the big floods. We got no rain from the cyclone and I don't expect any from this unless it tracks right down the country or to the west. We are too sheltered from the east for rain.
Huh? Wasn't it Ex-tropical Cyclone Ivy which caused those floods at the end of Feb 2004, i.e. 115mm at Hamilton Aero and 94mm at Ruakura?

Perhaps I'm wrong..... But my recollection of it was we got the rain then about 12 hours it passed down past coromandel. I remember because we were flooded and we discussed that we were lucky the cyclone didn't come over or we would be having rain on flooded land. I remember it being as a massive front moving in from the west that flooded us.

Anyway back on topic....

Avalanche · Unread post by **Avalanche** » Wed 11/03/2015 17:46

Yes i couldnt agree more Manukau Heads Obs, Ive been reading a few maps/models theres nothing to suggest that it wont come further to the west. Question though: If this cyclone maintains 950hPa pressure just off the east coast of NZ. Why would they call it an ex tropical cyclone when it still maintains the same if not lower barometric pressure and intensity? Would love to know as people think that oh its not as bad now scenario if they think its an ex cyclone if that makes sense?

David · Unread post by **David** » Wed 11/03/2015 17:58

Last 2 runs of GFS have it a bit farther east again...

David · Unread post by **David** » Wed 11/03/2015 18:06

Metservice 5 day model based on UKMO model shows it crossing BOP coast...

Manukau heads obs · Wed 11/03/2015 18:09

@ avalanche...to be still be a TC it would need to have cyclone characteristics
but it will still be refered to as cyclone Pam afterwards

@David , yeah will be flip flopping still yet...

re M/S 5 day map..wow

Nev · Unread post by **Nev** » Wed 11/03/2015 21:17

Nadi now expect Pam to be Cat 5 by Friday...

TROPICAL DISTURBANCE ADVISORY NUMBER A17 ISSUED FROM RSMC NADI
Mar 11/0800 UTC 2015 UTC.

SEVERE TROPICAL CYCLONE PAM CENTRE 950HPA CATEGORY 3 WAS LOCATED NEAR
11.1S 169.4E AT 110600 UTC. POSITION GOOD BASED ON HR GMS EIR/VIS
IMAGERY AND PERIPHERAL SURFACE REPORTS. CYCLONE MOVING
SOUTH-SOUTHWEST AT ABOUT 03 KNOTS. MAXIMUM 10-MINUTE AVERAGE WINDS
NEAR THE CENTRE ESTIMATED AT ABOUT 85 KNOTS.
EXPECT WINDS ABOVE 63 KNOTS WITHIN 45 NAUTICAL MILES OF CENTRE,
AND ABOVE 47 KNOTS WITHIN 120 NAUTICAL MILES IN N SEMI-CIRCLE,
…
ORGANISATION REMAINS GOOD. DEEP CONVECTION REMAINS PESISTENT. SYSTEM
LIES IN A MODERATE TO HIGH SHEARED ENVIRONMENT WITH MODERATE TO
STRONG UPPER DIVERGENCE. OUTFLOW GOOD. CYCLONIC CIRCULATION EXTENDS
TO 250HPA. SST AROUND 30 DEGREES CELSIUS. SYSTEM TRACKING ALONG THE
WESTERN PERIPHERY OF THE SUB-TROPICAL RIDGE LOCATED TO THE EAST.
DVORAK ANALYSIS BASED ON EMBD CENTRE PATTERN, LLCC EMBD IN W, YEILDS
DT=5.0, MET=5.0,PT=5.0. FT BASED ON DT. THUS YIELDING
5.0/5.0/D1.0/24HRS.

GLOBAL MODELS AGREE ON A SOUTHWARDS MOVEMENT WITH FURTHER
INTENSIFICATION.
...

Avalanche · Unread post by **Avalanche** » Wed 11/03/2015 21:22

Ok cool what are the cyclone characteristics you are referring to Manukau Heads Obs? Its just the models show no decrease in intensity when it hits NZ or near NZ.

Nev · Unread post by **Nev** » Wed 11/03/2015 21:23

Hmm… New Category added to the TC scale… lol

Nev · Unread post by **Nev** » Wed 11/03/2015 21:49

Latest remarks from JTWC…

WTPS31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 17P (PAM) WARNING NR 007//
RMKS/
1. TROPICAL CYCLONE 17P (PAM) WARNING NR 007
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110600Z --- NEAR 11.2S 169.7E
MOVEMENT PAST SIX HOURS - 205 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT
…
REMARKS:
110900Z POSITION NEAR 11.4S 169.7E.
TROPICAL CYCLONE (TC) 17P (PAM), LOCATED APPROXIMATELY 653 NM
NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHWESTWARD AT 02
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A WELL CONSOLIDATED SYSTEM WITH A DEVELOPING
EYE AND INTENSE DEEP CONVECTIVE BANDING. A 110519Z SSMIS IMAGE SHOWS
TIGHTLY-CURVED BANDING WRAPPING INTO A DEVELOPING MICROWAVE EYE
FEATURE WITH THE BULK OF THE DEEP CONVECTION IN THE NORTHWESTERN
QUADRANT. THE INITIAL POSITION AND INTENSITY IS BASED ON DVORAK
CURRENT INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES WITH HIGH
CONFIDENCE. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT
WITH NEAR-RADIAL VIGOROUS OUTFLOW AND MODERATE VERTICAL WIND SHEAR
(VWS). TC PAM IS TRACKING ALONG THE WESTERN EXTENSION OF THE
SUBTROPICAL RIDGE (STR) TO THE EAST. AS THE STR CONTINUES TO BUILD
INTO THE WEST, TC PAM WILL CONTINUE TO INTENSIFY RAPIDLY OVER THE
NEXT 36 HOURS DUE TO THE FAVORABLE ENVIRONMENT AND SEA SURFACE
TEMPERATURE (SST). IN THE EXTENDED FORECAST, TC 17P WILL BEGIN
TO WEAKEN AS IT ROUNDS THE STR AXIS WHERE VWS WILL INCREASE AND SST
BEGINS TO DROP OFF. THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) NEAR TAU 96 AS IT BEGINS TO INTERACT WITH THE BAROCLINIC ZONE
AND IS EXPECTED TO COMPLETE ETT BY TAU 120. DYNAMIC MODEL GUIDANCE
IS IN GOOD AGREEMENT WITH THE OVERALL TRACK, THEREFORE, THERE IS
HIGH CONFIDENCE IN THE JTWC OFFICIAL FORECAST. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 110600Z IS 33 FEET. NEXT WARNINGS AT 111500Z,
112100Z, 120300Z AND 120900Z. REFER TO TROPICAL CYCLONE 18P (NATHAN)
WARNINGS (WTPS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
NNNN

Manukau heads obs · Wed 11/03/2015 22:34

Ok cool what are the cyclone characteristics you are referring to Manukau Heads Obs?

in a nutshell:
an eyewall
(i.e CB's that circle right around the center)
note that an extropical cyclone can still have persistant convection in one quarter though
what normally happens is that it encounters wind sheer, which basiscly topples over the CB's that are the eye wall...
also it needs ocean temperature of at least 26C ..to be a 'warm core' system

David · Unread post by **David** » Wed 11/03/2015 22:43

Nev wrote:Latest remarks from JTWC…

Interesting they still think it's going to pass well to the east, when most models have it closer.

Blowy · Unread post by **Blowy** » Wed 11/03/2015 23:39

de javu Cyclone Bola .... light rain was forecast for Gisborne!

NZ Weather Forum