CPAC: ANA - Post-Tropical

[Kingarabian]

18z Best Track stays at 60kts and that makes it three times in a row on Best Track. (06z,12z and 18z)

CP, 02, 2014101518, , BEST, 0, 143N, 1470W, 60, 994, TS

Is shear affecting Ana that is not letting her go to Hurricane status yet?

Appears to be. The LLC is directly to the north of that huge ball of convection.

SAB is at 3.0/4.0.

ADT is dropping fast.

But all models show it becoming a hurricane very soon.

[cycloneye]

11 AM HST track.

[Kingarabian]

They have it becoming a hurricane within the next 12 hours.

[cycloneye]

TROPICAL STORM ANA DISCUSSION NUMBER 9
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP022014
1100 AM HST WED OCT 15 2014

ANA HAS BEEN MAINTAINING A PERSISTENT CENTRAL DENSE OVERCAST
OVERNIGHT AND THROUGH THE MORNING. MICROWAVE DATA FROM
1435 AND 1744 UTC SHOWED THAT THE ACTIVE DEEP CONVECTION WAS
DISPLACED SOUTH OF THE LLCC WHICH IS INDICATIVE OF SHEAR IMPINGING
ON THE SYSTEM. HOWEVER...THE LATEST VISIBLE AND INFRARED IMAGES SHOW
AN EXPANDING AND MORE SYMMETRIC OUTFLOW WHICH SUGGESTS THAT THE
SHEAR IS EASING AND THE SYSTEM IS BECOMING BETTER ORGANIZED. THE
LATEST SUBJECTIVE DVORAK INTENSITY ESTIMATES CAME IN AT 55 KT FROM
PHFO AND JTWC...AND 65 KT FROM SAB. BASED ON A BLEND OF THESE
ESTIMATES...THE INITIAL INTENSITY WILL BE MAINTAINED AT 60 KT.
CONSIDERING THE VIGOROUS NATURE OF THE DEEP CONVECTION...ANA MAY BE
CLOSE TO BECOMING A HURRICANE.

THE INITIAL MOVEMENT IS 270/8KT WITH A DEEP LAYER RIDGE NORTH OF
THE CYCLONE PROVIDING THE WESTWARD STEERING CURRENT. IN THE
NEXT 12 TO 24 HRS...THE ORIENTATION OF THE RIDGE WILL SHIFT AND
PRODUCE A NORTHWESTWARD STEERING FLOW WHICH IS EXPECTED TO BRING ANA
TOWARD THE MAIN HAWAIIAN ISLANDS. THE LATEST OBJECTIVE AIDS HAVE
BECOME TIGHTLY CLUSTERED...EVEN BEYOND 72 HOURS AND THE CONSENSUS
TRACK HAS REMAINED LARGELY UNCHANGED. THUS...THE CURRENT TRACK IS
CONSISTENT WITH THE PREVIOUS FORECAST PACKAGE EXCEPT FOR A VERY
SMALL INCREASE IN SPEED. THE TRACK TAKES THE CENTER OF ANA JUST
SOUTH OF THE BIG ISLAND OF HAWAII THEN NORTHWEST NEAR KAUAI AND
OAHU. THE FORWARD MOTION SLOWS LATE FRIDAY AND INTO SATURDAY AS THE
STEERING CURRENTS WEAKEN DUE TO THE PASSAGE OF A LOW PRESSURE SYSTEM
NORTH OF THE HAWAIIAN ISLANDS. THE NOAA GULFSTREAM IV IS SCHEDULED
TO BEGIN SAMPLING THE ENVIRONMENT AROUND ANA LATER TODAY. THE DATA
FROM THESE FLIGHTS SHOULD HELP IMPROVE SUBSEQUENT MODEL GUIDANCE.

DESPITE THE VERTICAL SHEAR CURRENTLY AFFECTING ANA...INTENSITY
GUIDANCE CONTINUES TO SHOW AN INTENSIFICATION OF ANA...THOUGH NOT
QUITE AS STRONG AS EARLIER PACKAGES. HWRF AND GFDL ARE THE MOST
AGGRESSIVE WHILE SHIPS INDICATES ANA WILL BECOME A HURRICANE IN 24
TO 36 HOURS. WITH SUFFICIENTLY WARM SSTS AND OCEANIC HEAT
CONTENT...THE FORECAST PACKAGE LEANS TOWARD THE HWRF SOLUTION AND
CALLS FOR ANA TO BECOME A HURRICANE LATER TODAY OR TONIGHT. A PEAK
INTENSITY FORECAST OF 80 KT IS EXPECTED EARLY FRIDAY. THIS IS
CONSISTENT WITH THE PREVIOUS PACKAGE AND IS ABOVE THE LATEST
INTENSITY CONSENSUS. SHIPS CALLS FOR INCREASING VERTICAL SHEAR TO
START WEAKENING ANA LATE FRIDAY OR SATURDAY.

INTERESTS IN THE MAIN HAWAIIAN ISLANDS SHOULD CONTINUE TO MONITOR
THE FUTURE PROGRESS OF ANA. A HURRICANE WATCH MAY BE REQUIRED FOR
PORTIONS OF THE ISLAND CHAIN LATER TODAY OR TONIGHT.

FORECAST POSITIONS AND MAX WINDS

INIT 15/2100Z 14.3N 147.4W 60 KT 70 MPH
12H 16/0600Z 14.6N 148.7W 65 KT 75 MPH
24H 16/1800Z 15.1N 150.4W 70 KT 80 MPH
36H 17/0600Z 15.9N 152.1W 75 KT 85 MPH
48H 17/1800Z 17.0N 153.7W 80 KT 90 MPH
72H 18/1800Z 19.4N 156.4W 75 KT 85 MPH
96H 19/1800Z 21.0N 158.0W 65 KT 75 MPH
120H 20/1800Z 22.5N 159.5W 60 KT 70 MPH

$$
FORECASTER KODAMA

[tolakram]

Live Visible, still on the southern edge of this sat view.

http://wwwghcc.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-W%20PACUS&lat=13&lon=-148&info=vis&zoom=2&width=1000&height=550&type=Animation&quality=95&palette=ir1.pal&numframes=10

[Kingarabian]

CDO/CCC or whatever it is continues to expand to the north.

[Alyono]

this has clearly weakened today. Probably in the 50-55 kt range now

The expansion to the north is merely the cirrus chield. Has not been able to get rid of the CCC pattern. TCs simply cannot intensify under this pattern

[Kingarabian]

this has clearly weakened today. Probably in the 50-55 kt range now

The expansion to the north is merely the cirrus chield. Has not been able to get rid of the CCC pattern. TCs simply cannot intensify under this pattern

One would say that those super cold tops would aid development. In a CCC, development is arrested.

[Alyono]

it appears that we have CCC because there is moderate to strong mid level shear from the northeast impacting this. The shear is underneath the outflow layer

[Yellow Evan]

it appears that we have CCC because there is moderate to strong mid level shear from the northeast impacting this. The shear is underneath the outflow layer

Is the shear going to diminish?

[Kingarabian]

AMSU passes although in low resolution, show the difference in the past 6 hours. Convection expanding over the center it seems.

[Alyono]

it appears that we have CCC because there is moderate to strong mid level shear from the northeast impacting this. The shear is underneath the outflow layer

Is the shear going to diminish?

not sure. Models have become better at predicting the high level shear, but remain clueless regarding the mid level stuff. Be interested to see what the dropsondes show

[Yellow Evan]

it appears that we have CCC because there is moderate to strong mid level shear from the northeast impacting this. The shear is underneath the outflow layer

Is the shear going to diminish?

not sure. Models have become better at predicting the high level shear, but remain clueless regarding the mid level stuff. Be interested to see what the dropsondes show

Levi did mention that the ULL is backing away, which should give it a nice outflow and room to deepen.

[AFWeather]

The 18z models continue to shift to the left. GFS has this now staying far enough south of the big island to remain totally intact, and it then passes SW of the other islands. GFS doesn't have Ana ever becoming a hurricane either. A scenario that is becoming more likely as I look at everything. The latest HWRF has a 971 mb cane just off south point, then in 3 hours she completely vanishes.

[Alyono]

Levi did mention that the ULL is backing away, which should give it a nice outflow and room to deepen.

now how would the upper low produce mid level shear? Not sure what Levi is talking about. The upper winds are fine. It's the mid level winds that are not

[Kingarabian]

The 18z models continue to shift to the left. GFS has this now staying far enough south of the big island to remain totally intact, and it then passes SW of the other islands. GFS doesn't have Ana ever becoming a hurricane either. A scenario that is becoming more likely as I look at everything. The latest HWRF has a 971 mb cane just off south point, then in 3 hours she completely vanishes.

[Kingarabian]

Levi did mention that the ULL is backing away, which should give it a nice outflow and room to deepen.

now how would the upper low produce mid level shear? Not sure what Levi is talking about. The upper winds are fine. It's the mid level winds that are not

You think it's best that the CPHC drop the windspeed?

[Yellow Evan]

Levi did mention that the ULL is backing away, which should give it a nice outflow and room to deepen.

now how would the upper low produce mid level shear? Not sure what Levi is talking about. The upper winds are fine. It's the mid level winds that are not

It won't. What is causing mid-level shear?

[Alyono]

Levi did mention that the ULL is backing away, which should give it a nice outflow and room to deepen.

now how would the upper low produce mid level shear? Not sure what Levi is talking about. The upper winds are fine. It's the mid level winds that are not

You think it's best that the CPHC drop the windspeed?

Yeah, the winds have clearly dropped based upon Dvorak numbers.

[Alyono]

It won't. What is causing mid-level shear?

Not entirely sure, trying to figure that out now