CPAC: NIALA - Post-Tropical

[Kingarabian]

Lots of improvements to its core.



Also looks like there's a ragged eye feature on satellite.

CDO has expended nicely over the center:

[Yellow Evan]

Looks much better. Shear has relaxed as an upper trough has passed to its north, providing great outflow to its north.

[Yellow Evan]

CENTRAL PACIFIC TROPICAL CYCLONE SUMMARY - FIXES
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
1805 UTC FRI SEP 25 2015

A. Tropical storm Niala.

B. 25/1730Z.

C. 15.5°N.

D. 150.3°W.

E. Goes-15.

F. T2.5/2.5/d1.0/24 hrs.

G. Vis/ir/eir.

H. Remarks: Used central dense overcast /cdo/ pattern. Irregular edge pattern with a diameter less than 1.5 deg and banding feature lead to a DT of 2.5. MET and Pat agree. FT is based on the DT.

I. Addl positions 25/1452Z 15.3°N 149.9°W gpm.

$$

Eaton/bravender

What is an irregular CDO pattern? Is the CPHC making stuff up?

[Kingarabian]

No idea. But sometimes ADT labels the scene type as an "IRREGULAR CDO*". They could be implying that. But right now, I don't see any irregular CDO's. Microwave shows a solid developing core as well.

[Kingarabian]

Did SAB issue any new numbers?

[Yellow Evan]

:uarrow:

No idea. But sometimes ADT labels the scene type as an "IRREGULAR CDO*". They could be implying that. But right now, I don't see any irregular CDO's. Microwave shows a solid developing core as well.

Yea, but Dvorak 1984 mentions nothing of an irregular CDO. Judging by the band signature, I'm getting a T3.0/45 knts

Dvorak aside, this is likely around 50 knots.

[Yellow Evan]

CP, 06, 2015092518, , BEST, 0, 155N, 1502W, 35, 1002, TS, 34, NEQ, 65, 50, 0, 25, 1009, 160, 25, 0, 0, C, 0, , 0, 0, NIALA, D,

Stuff like this is why I am very critical of most agencies aside from MFR/NHC.

For starters, they are placing no weight towards microwave. Secondly, they aren't Dvoraking very well (irregular CDO pattern doesn't make much sense) an the JTWC estimate of T2.5 is too low (they gave it .5 banding, looks around .6 banding) to me which is T3.0/45 knts per Dvorak (1984). Third, they started up ADT too late (at 9z rather than when it was first declared) and this is messing up the constraints to be to strict, thus reducing the overall ADT estimate.

CPHC isn't alone here though. The JTWC has the exact same problem. Ditto with the JMA (haven't tracked SHEM much but form what little I've seen, the same problems apply).

[Kingarabian]

CP, 06, 2015092518, , BEST, 0, 155N, 1502W, 35, 1002, TS, 34, NEQ, 65, 50, 0, 25, 1009, 160, 25, 0, 0, C, 0, , 0, 0, NIALA, D,

Stuff like this is why I am very critical of most agencies aside from MFR/NHC.

For starters, they are placing no weight towards microwave. Secondly, they aren't Dvoraking very well (irregular CDO pattern doesn't make much sense) an the JTWC estimate of T2.5 is too low (they gave it .5 banding, looks around .6 banding) to me which is T3.0/45 knts per Dvorak (1984). Third, they started up ADT too late (at 9z rather than when it was first declared) and this is messing up the constraints to be to strict, thus reducing the overall ADT estimate.

CPHC isn't alone here though. The JTWC has the exact same problem. Ditto with the JMA (haven't tracked SHEM much but form what little I've seen, the same problems apply).

The CDO looks thick enough + MW imagery show this is at least 45-50kts. The CPHC and the JTWC are located in Hawaii. So it does not surprise me with the way they do things. The State of Hawaii is behind in everything.

[Yellow Evan]

CP, 06, 2015092518, , BEST, 0, 155N, 1502W, 35, 1002, TS, 34, NEQ, 65, 50, 0, 25, 1009, 160, 25, 0, 0, C, 0, , 0, 0, NIALA, D,

Stuff like this is why I am very critical of most agencies aside from MFR/NHC.

For starters, they are placing no weight towards microwave. Secondly, they aren't Dvoraking very well (irregular CDO pattern doesn't make much sense) an the JTWC estimate of T2.5 is too low (they gave it .5 banding, looks around .6 banding) to me which is T3.0/45 knts per Dvorak (1984). Third, they started up ADT too late (at 9z rather than when it was first declared) and this is messing up the constraints to be to strict, thus reducing the overall ADT estimate.

CPHC isn't alone here though. The JTWC has the exact same problem. Ditto with the JMA (haven't tracked SHEM much but form what little I've seen, the same problems apply).

The CDO looks thick enough + MW imagery show this is at least 45-50kts. The CPHC and the JTWC are located in Hawaii. So it does not surprise me with the way they do things. The State of Hawaii is behind in everything.

I'm pretty sure they are in close coordination with each other.

Anyhow, they've revised up.

CP, 06, 2015092518, , BEST, 0, 155N, 1502W, 40, 1001, TS, 34, NEQ, 65, 50, 0, 25, 1009, 160, 25, 0, 0, C, 0, , 0, 0, NIALA, D,

[Kingarabian]

Constraints are bottlenecking ADT right now. Or else it would at least be 3.0.

[Yellow Evan]

:uarrow:

Constraints are bottlenecking ADT right now. Or else it would at least be 3.0.

As I said, the reason is at least partially because the CPHC started running ADT at T2.0 at 9z (even though this was upgraded at 3z), which caused constraints to kick in more so than had the CPHC started ADT at 3z since the ADT at 9z would have likely been greater than T2.0.

[Kingarabian]

:uarrow:

Constraints are bottlenecking ADT right now. Or else it would at least be 3.0.

As I said, the reason is at least partially because the CPHC started running ADT at T2.0 at 9z (even though this was upgraded at 3z), which caused constraints to kick in more so than had the CPHC started ADT at 3z since the ADT at 9z would have likely been greater than T2.0.

That warm spot on visible satellite makes it clear as day that this is at least 50kts.

[Yellow Evan]

:uarrow:

Constraints are bottlenecking ADT right now. Or else it would at least be 3.0.

As I said, the reason is at least partially because the CPHC started running ADT at T2.0 at 9z (even though this was upgraded at 3z), which caused constraints to kick in more so than had the CPHC started ADT at 3z since the ADT at 9z would have likely been greater than T2.0.

That warm spot on visible satellite makes it clear as day that this is at least 50kts.

Might be around 55 knots now. Now, will the eye feature fully clear out? That I'm not sure, but I think this becomes a hurricane before conditions become less favorable.

[supercane]

673
WTPA41 PHFO 252059
TCDCP1

TROPICAL STORM NIALA DISCUSSION NUMBER 4
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP062015
1100 AM HST FRI SEP 25 2015

THE SATELLITE PRESENTATION OF NIALA HAS IMPROVED THIS MORNING AS
THE LOW LEVEL CENTER BECAME SURROUNDED BY DEEP CONVECTION. ALTHOUGH
OUTFLOW REMAINS SOMEWHAT DISRUPTED WITHIN THE WESTERN SEMICIRCLE...
OUTFLOW TO THE NORTHEAST THROUGH SOUTH PERSISTS AS THE CYCLONE IS
ROUGHLY UNDER THE HIGH LEVEL RIDGE AXIS. DVORAK CURRENT INTENSITY
ESTIMATES CAME IN AT 2.5/35 KT FROM HFO AND JTWC...WHILE CIMSS ADT
SUGGESTED MAXIMUM WINDS OF 39 KT. GIVEN THE IMPROVEMENT IN THE
SATELLITE PRESENTATION AND A 1505 CIMSS SATCON OF 38 KT...THE
INITIAL INTENSITY WILL BE RAISED TO 40 KT.

THE INITIAL MOTION IS NEARLY UNCHANGED FROM THE LAST ADVISORY AND
IS SET AT NORTHWEST...OR 320 DEGREES...AT 6 KT. NIALA IS MOVING
NORTHWESTWARD TOWARD A WEAKNESS ALOFT IN THE LOW LEVEL RIDGE
CENTERED SEVERAL HUNDRED MILES TO THE NORTH. THIS WEAKNESS IS BEING
CREATED BY A STRONG MID TO UPPER LEVEL LOW FAR NORTHEAST OF THE
HAWAIIAN ISLANDS WITH AN ASSOCIATED TROUGH EXTENDING NEAR THE
ISLANDS. THIS FEATURE IS PRODUCING WESTERLY WINDS ALOFT THAT ARE
DISRUPTING OUTFLOW IN THE WEST SEMICIRCLE OF NIALA. AS NIALA
CONTINUES ON A GENERAL NORTHWESTWARD TRACK DURING THE NEXT 24 TO 36
HOURS...THE TROUGH WILL IMPART INCREASING VERTICAL WIND SHEAR THAT
IS EXPECTED TO CAUSE THE CYCLONE TO TURN TOWARD THE WEST AND
EVENTUALLY THE WEST-SOUTHWEST AS THE LOW LEVEL RIDGE BECOMES THE
DOMINANT STEERING SOURCE. THE FORECAST TRACK WAS NUDGED NORTHWARD
SLIGHTLY THROUGH 24 HOURS AND INDICATES A SLOWING OF FORWARD MOTION
BEYOND THAT TIME. THE FORECAST IS NEAR OR JUST SOUTH OF TVCN AND IS
CLOSER TO THE ECMWF AND GFS ENSEMBLE...SINCE THE OPERATIONAL GFS IS
NOW THE NORTHERN OUTLIER THAT IS CAUSING DIFFERENCES IN THE
CONSENSUS GUIDANCE.

A SMALL WINDOW FOR INTENSIFICATION EXISTS IN THE SHORT TERM. CIMSS
VERTICAL WIND SHEAR IS ANALYZED AT 21 KT OUT OF THE WEST-
SOUTHWEST...WHILE SHIPS IS SLIGHTLY LOWER. GIVEN RECENT SATELLITE
TRENDS...THERE COULD BE SOME INTENSIFICATION IN THE NEXT 24 HOURS
BEFORE VERTICAL WIND SHEAR RAMPS UP AS INTERACTION WITH THE MID TO
UPPER LEVEL TROUGH INCREASES. STEADY WEAKENING IS EXPECTED AROUND
48 HOURS AND BEYOND. THE INTENSITY FORECAST IS WITHIN THE MIDDLE OF
THE GUIDANCE ENVELOPE NEAR ICON.

THE PROBABILITIES OF TROPICAL STORM WINDS REMAIN STEADY OVER THE
BIG ISLAND. DUE TO INHERENT UNCERTAINTY IN THE TIMING OF THE
EXPECTED TURN TOWARD THE WEST...A TROPICAL STORM WATCH HAS BEEN
ISSUED FOR THE BIG ISLAND.



FORECAST POSITIONS AND MAX WINDS

INIT 25/2100Z 15.7N 150.4W 40 KT 45 MPH
12H 26/0600Z 16.5N 151.3W 45 KT 50 MPH
24H 26/1800Z 17.2N 152.5W 45 KT 50 MPH
36H 27/0600Z 17.4N 153.6W 45 KT 50 MPH
48H 27/1800Z 17.3N 154.5W 40 KT 45 MPH
72H 28/1800Z 17.1N 155.8W 35 KT 40 MPH
96H 29/1800Z 16.8N 157.0W 30 KT 35 MPH
120H 30/1800Z 16.3N 158.3W 25 KT 30 MPH


FORECASTER WROE

[Kingarabian]

This is a hurricane.

[Yellow Evan]

WTPA31 PHFO 252359
TCPCP1

BULLETIN
TROPICAL STORM NIALA INTERMEDIATE ADVISORY NUMBER 4A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP062015
200 PM HST FRI SEP 25 2015

...TROPICAL STORM NIALA SOUTHEAST OF HAWAII AND MOVING
NORTHWESTWARD...


SUMMARY OF 200 PM HST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...16.0N 150.6W
ABOUT 390 MI...630 KM SE OF HILO HAWAII
ABOUT 600 MI...965 KM SE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* HAWAII COUNTY

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

INTERESTS ELSEWHERE IN THE MAIN HAWAIIAN ISLANDS SHOULD MONITOR THE
PROGRESS OF TROPICAL STORM NIALA.


FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY THE NATIONAL WEATHER SERVICE OFFICE IN
HONOLULU HAWAII.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 PM HST...0000 UTC...THE CENTER OF TROPICAL STORM NIALA WAS
LOCATED NEAR LATITUDE 16.0 NORTH...LONGITUDE 150.6 WEST. NIALA IS
MOVING TOWARD THE NORTHWEST NEAR 7 MPH...11 KM/H. THIS MOTION IS
EXPECTED TO CONTINUE THROUGH TONIGHT...FOLLOWED BY A TURN TOWARD
THE WEST AND A SLOWING OF THE FORWARD MOTION SATURDAY NIGHT AND
SUNDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 50 MPH...85 KM/H...WITH HIGHER
GUSTS. SOME INTENSIFICATION IS EXPECTED INTO SATURDAY...FOLLOWED
BY WEAKENING SATURDAY NIGHT AND SUNDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 80 MILES...130 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB...29.53 INCHES.


HAZARDS AFFECTING LAND
----------------------
RAINFALL...DEEP TROPICAL MOISTURE ASSOCIATED WITH TROPICAL STORM
NIALA WILL LIKELY REACH PARTS OF THE MAIN HAWAIIAN ISLANDS THIS
WEEKEND. THIS ENHANCED TROPICAL MOISTURE MAY PRODUCE LIFE
THREATENING FLOODS AND MUDSLIDES INTO EARLY NEXT WEEK...MAINLY OVER
THE BIG ISLAND.

SURF...SWELLS ASSOCIATED WITH TROPICAL STORM NIALA WILL PRODUCE
ELEVATED SURF ALONG EAST AND SOUTHEAST FACING SHORES ACROSS
PORTIONS OF THE MAIN HAWAIIAN ISLANDS...MAINLY THE BIG
ISLAND...STARTING THIS WEEKEND AND CONTINUING INTO EARLY NEXT WEEK.

WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE ON THE BIG ISLAND ON
SUNDAY.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 PM HST.

$$
FORECASTER WROE

[Yellow Evan]

TXPN42 PHFO 260004
TCSNP2

CENTRAL PACIFIC TROPICAL CYCLONE SUMMARY - FIXES
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
0000 UTC SAT SEP 26 2015

A. Tropical storm Niala.

B. 25/2330Z.

C. 15.9°N.

D. 150.6°W.

E. Goes-15.

F. T3.0/3.0/d1.0/24 hrs.

G. Vis/ir/eir.

H. Remarks: Used central dense overcast /cdo/ pattern. Irregular edge pattern with a diameter greater than 1.5 deg with no banding feature yields a DT of 3.0. MET agrees. Pat yields 3.5. FT is based on the DT.

I. Addl positions none.

$$

Eaton/bravender.

CPHC still 3.0.

[Kingarabian]

Why would they go with Dvorak when visible satellite says otherwise? Not a single mention of the intermittent eye.

[AbcdeerHI]

Why would they go with Dvorak when visible satellite says otherwise? Not a single mention of the intermittent eye.

My guess would be theyre look for consistency raher then jumping the gun in the short term. As i write this the "intermittent eye" has dissipated. Im sure this will be mentioned in the 5pm discussion.

I do wonder if Naiala gets stronger than anticipated will the track shift to the right? If so, does that mean stronger shear and quicker decoupling or possibly traveling farther north then currently predicted and more islands get caught in the remnants?

[Yellow Evan]

Why would they go with Dvorak when visible satellite says otherwise? Not a single mention of the intermittent eye.

My guess would be theyre look for consistency raher then jumping the gun in the short term. As i write this the "intermittent eye" has dissipated. Im sure this will be mentioned in the 5pm discussion.

I do wonder if Naiala gets stronger than anticipated will the track shift to the right? If so, does that mean stronger shear and quicker decoupling or possibly traveling farther north then currently predicted and more islands get caught in the remnants?

Sometimes when you don't jump the gun, you fall behind the rapid intensification curve.

Unless new microwave in recent hours suggests otherwise, this is a 55-60 knot storm.