EPAC: IGNACIO - Post-Tropical

[cycloneye]

TS watch extended westward to Maui.

[cycloneye]

HURRICANE IGNACIO DISCUSSION NUMBER 21
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122015
500 PM HST SAT AUG 29 2015

IGNACIO CONTINUES TO HAVE A WELL DEFINED...20 NM WIDE EYE SURROUNDED
BY A RING OF COLD CONVECTIVE CLOUDS. DVORAK INTENSITY ESTIMATES
WERE A UNANIMOUS 6.0 FROM THE SATELLITE AGENCIES...AND THE UW-CIMSS
ADT INTENSITY ESTIMATE WAS 6.4. BASED ON A BLEND OF THESE DATA...
WILL MAINTAIN THE 120 KT /CATEGORY 4 ON THE SAFFIR-SIMPSON SCALE/
INTENSITY. THE NEXT RECONNAISSANCE MISSION IS SCHEDULED TO
INVESTIGATE IGNACIO AT 0600 UTC. NOTE THAT HURRICANES IGNACIO AND
KILO ARE BOTH CATEGORY 4 AS OF THIS ADVISORY CYCLE...A VERY RARE
OCCURRENCE INDEED FOR THE CENTRAL PACIFIC BASIN.

THE HURRICANE IS MOVING STEADILY TOWARD THE NORTHWEST...315 DEGREES
AT 8 KT...THROUGH A WEAKNESS IN THE MID-LEVEL RIDGE EAST OF HAWAII
AND TOWARD A WEAK TROUGH LOCATED TO THE NORTH OF THE NORTHWESTERN
HAWAIIAN ISLANDS. THE TRACK GUIDANCE IS IN GOOD AGREEMENT THAT THIS
GENERAL MOTION WILL CONTINUE FOR THE NEXT FEW DAYS. OUR FORECAST
TRACK IS VERY CLOSE TO THE PREVIOUS FORECAST AS WELL AS THE
CONSENSUS GUIDANCE FOR THE NEXT 24 HOURS. BEYOND 24 HOURS OUR TRACK
BENDS MORE TO THE LEFT WITH TIME IN ANTICIPATION THAT IGNACIO WILL
WEAKEN A BIT FASTER THAN THE DYNAMICAL MODELS INDICATE.

THE UW-CIMSS WIND SHEAR ANALYSIS AND CONVENTIONAL SATELLITE IMAGERY
SHOWS THAT SOUTHWESTERLY WIND SHEAR IS BEGINNING TO AFFECT IGNACIO.
HIGH CLOUDS FROM THE HURRICANE ARE STARTING TO GET PULLED TO THE
NORTHEAST. ACCORDING TO THE ANALYSIS...THE SHEAR IS NEAR 10 KT...
BUT INCREASES TO 15-20 KT TO THE NORTHWEST OF THE CYCLONE...AND
WILL INCREASE FURTHER AND BECOME QUITE STRONG AS IGNACIO APPROACHES
HAWAII. THIS WILL LEAD TO A STEADY WEAKENING TREND...DESPITE SEA
SURFACE TEMPERATURES OF 27-28C ALONG MOST OF THE FORECAST TRACK.
THE WEAKENING WILL BE GRADUAL OVER THE NEXT 24 HOURS...THEN MORE
RAPID ONCE THE SHEAR BEGINS TO IMPACT THE CORE OF THE HURRICANE.
OUR WEAKENING TREND IS NOT AS FAST AS THE SHIPS...BUT FASTER THAN
THE DYNAMIC MODELS AND IN GOOD AGREEMENT WITH THE INTENSITY
CONSENSUS.

THE RELATIVELY CLOSE PROXIMITY TO THE EXPECTED OUTER EXTENT OF THE
34 KNOT WIND RADII IN THE SOUTHWEST QUADRANT REQUIRES MAINTAINING
THE TROPICAL STORM WATCH FOR THE BIG ISLAND...AND THE ISSUANCE OF
A TROPICAL STORM WATCH FOR MAUI COUNTY AT THIS TIME.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 17.0N 147.6W 120 KT 140 MPH
12H 30/1200Z 17.9N 148.7W 115 KT 135 MPH
24H 31/0000Z 19.0N 150.0W 110 KT 125 MPH
36H 31/1200Z 20.0N 151.5W 95 KT 110 MPH
48H 01/0000Z 21.0N 153.0W 80 KT 90 MPH
72H 02/0000Z 23.0N 156.0W 70 KT 80 MPH
96H 03/0000Z 25.0N 159.0W 60 KT 70 MPH
120H 04/0000Z 27.0N 162.0W 55 KT 65 MPH

$$
FORECASTER R BALLARD

[Yellow Evan]

Good to see 1900hurricane posting on the epac-cpac you can learn from this guy.

I do like his posts, yes.

[Kingarabian]

I like everyone's posts. Appreciate all the activity on these EPAC threads!

[HURAKAN]

IJK

[Ntxw]

I like everyone's posts. Appreciate all the activity on these EPAC threads!

Ditto, and to the usual resident posters as well. The Pacific threads are more technical compared to the Atlantic threads, good for us weather geeks. But there are people who lurk as well and should be encouraged to join in.

Rbtop

[Yellow Evan]

I like everyone's posts. Appreciate all the activity on these EPAC threads!

Ditto, and to the usual resident posters as well. The Pacific threads are more technical compared to the Atlantic threads, good for us weather geeks. But there are people who lurk as well and should be encouraged to join in.

It's nice nowadays having some traffic on these threads. Years ago there'd be no one posting in these threads.

[Yellow Evan]

Eye remains quite warm

----- Current Analysis -----
Date : 30 AUG 2015 Time : 030000 UTC
Lat : 16:51:00 N Lon : 147:32:51 W


CI# /Pressure/ Vmax
6.3 / 941.0mb/122.2kt


Final T# Adj T# Raw T#
6.2 6.2 6.2

Estimated radius of max. wind based on IR : 25 km

Center Temp : +16.7C Cloud Region Temp : -65.7C

Scene Type : EYE

[Yellow Evan]

Question for you reg's who know this basin like the back of your hand, what are the realistic chances of seeing the first sub 900 in the NH within epac..cpac have these peaked or do they have more to give.

We'd need Recon. I think Linda/Rick were pretty close if not there and perhaps Marie (due to its large size).

[Kingarabian]

Question for you reg's who know this basin like the back of your hand, what are the realistic chances of seeing the first sub 900 in the NH within epac..cpac have these peaked or do they have more to give.

MAYBE Jimena if it enters the CPAC and recon decides to stick around.

[Kingarabian]

00z GFS is a bit more south. Maybe TS watches are warranted.

[Kingarabian]

Rbtop

[img]http://i60.tinypic.com/2ekr6dg.gif[img]

I know I say this a lot but Hawaii is dodging a massive bullet. This is off the charts lucky.

[Kingarabian]

145mph found. Still strengthening it seems.

[Yellow Evan]

145mph found. Still strengthening it seems.

Pressure appears to have leveled off.

[Yellow Evan]

WTPA33 PHFO 300554
TCPCP3

BULLETIN
HURRICANE IGNACIO INTERMEDIATE ADVISORY NUMBER 21A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122015
800 PM HST SAT AUG 29 2015

...MAJOR HURRICANE IGNACIO CONTINUES MOVING STEADILY NORTHWEST...


SUMMARY OF 800 PM HST...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...17.1N 147.7W
ABOUT 515 MI...830 KM ESE OF HILO HAWAII
ABOUT 725 MI...1175 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...942 MB...27.82 INCHES


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

A TROPICAL STORM WATCH HAS BEEN ISSUED FOR MAUI COUNTY.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* MAUI COUNTY...INCLUDING THE ISLANDS OF MAUI...MOLOKAI...LANAI AND
KAHOOLAWE.
* HAWAII COUNTY

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

INTERESTS ELSEWHERE IN THE MAIN HAWAIIAN ISLANDS SHOULD CONTINUE TO
CLOSELY MONITOR THE PROGRESS OF IGNACIO.


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 800 PM HST...0600 UTC...THE EYE OF HURRICANE IGNACIO WAS LOCATED
NEAR LATITUDE 17.1 NORTH...LONGITUDE 147.7 WEST. IGNACIO IS MOVING
TOWARD THE NORTHWEST NEAR 9 MPH...15 KM/H...AND THIS MOTION IS
EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST
TRACK...THE CENTER OF IGNACIO IS EXPECTED TO PASS TO THE NORTHEAST
OF THE BIG ISLAND ON MONDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 145 MPH...230 KM/H...WITH HIGHER
GUSTS. IGNACIO IS A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE WIND SCALE. LITTLE CHANGE IN INTENSITY IS EXPECTED
TONIGHT AND A WEAKENING TREND IS EXPECTED TO BEGIN ON SUNDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140
MILES...220 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 942 MB...27.82
INCHES...BASED ON LATEST AIRCRAFT RECONNAISSANCE DATA.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE ON THE BIG ISLAND OF
HAWAII STARTING LATE SUNDAY NIGHT...AND STARTING MONDAY ON MAUI.

RAINFALL...STORM TOTAL RAINFALL AMOUNTS OF 2 TO 4 INCHES...WITH
ISOLATED MAXIMUM AMOUNTS NEAR 6 INCHES MAINLY IN AREAS OF HIGHER
TERRAIN...ARE POSSIBLE IN THE WATCH AREA.

SURF...LARGE SWELLS GENERATED BY IGNACIO WILL ARRIVE ALONG EAST
AND SOUTHEAST FACING SHORES OF THE MAIN HAWAIIAN ISLANDS OVER THE
NEXT SEVERAL DAYS. RESULTANT SURF WILL BE LARGE AND POTENTIALLY
LIFE-THREATENING...ESPECIALLY ON THE BIG ISLAND LATER THIS WEEKEND
AND EARLY NEXT WEEK.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM HST.

$$
FORECASTER POWELL

[Kingarabian]

Euro more NE as well.

[Yellow Evan]

Not done yet.

----- Current Analysis -----
Date : 30 AUG 2015 Time : 060000 UTC
Lat : 17:09:09 N Lon : 147:41:26 W


CI# /Pressure/ Vmax
6.3 / 940.3mb/122.2kt


Final T# Adj T# Raw T#
6.0 5.8 5.8

Estimated radius of max. wind based on IR : 24 km

Center Temp : +17.2C Cloud Region Temp : -62.1C

Scene Type : EYE

[Extratropical94]

EP, 12, 2015083006, , BEST, 0, 171N, 1477W, 125, 942, HU

[1900hurricane]

In addition to the waning convection, the last two eye temp measurements from GOES-15 came in under 15*C. Even without recon, it's probably safe to say that Ignacio is beginning to come slowly down from peak intensity.

[Kingarabian]

Man. It had a good run.