EPAC: JIMENA - Post-Tropical

[Kingarabian]

Would you just look at that. Guidance was just pointing at Jimena reaching the west coast and Canada and now it's Hawaii. Crazy.

[Alyono]

watch this end up missing Hawaii to the southeast afterall...

[Kingarabian]

watch this end up missing Hawaii to the southeast afterall...

Either a south west or south east miss. Heck, maybe a north west miss as well.

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[cycloneye]

HURRICANE JIMENA DISCUSSION NUMBER 33
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP132015
1100 AM HST THU SEP 03 2015

THE EYE OF JIMENA HAS BECOME INCREASINGLY CLOUD-FILLED SINCE THE
LAST ADVISORY...BUT A SMALL EYE STILL REMAINS THIS MORNING. LATEST
SUBJECTIVE AND OBJECTIVE SATELLITE-BASED DVORAK INTENSITY ESTIMATES
INDICATE LITTLE CHANGE SINCE THE PREVIOUS ADVISORY...AS SAB/JTWC/
PHFO ALL INDICATED DATA-T VALUES OF T4.5/77 KT. MEANWHILE...CURRENT
INTENSITY VALUES WERE 5.0/90 KT FROM PHFO AND JTWC...AND 5.3/97 KT
FROM UW-CIMSS ADT. BLENDING THESE ESTIMATES...WITH AN EMPHASIS ON
THE SUBJECTIVE VALUES...SUPPORTS A SLIGHT LOWERING...TO 90 KT...OF
THE INITIAL INTENSITY FOR THIS PACKAGE.

JIMENA IS EMBEDDED IN AN AREA OF NEARLY NON-EXISTENT STEERING
FLOW...WITH MID-LEVEL HIGHS CENTERED TO THE EAST...AND TO THE
DISTANT NORTH-NORTHWEST. IT IS DIFFICULT TO TELL WHICH OF THESE
FEATURES IS THE PRIMARY STEERING MECHANISM...AND IT MAY JUST BE
THAT BETA-DRIFT IS THE PRIMARY MECHANISM AT THIS TIME...AS THE
INITIAL MOTION ESTIMATE FOR THIS PACKAGE IS 320/03 KT. THE LIGHT
STEERING FLOW AND NORTHWESTWARD DRIFT IS EXPECTED TO PERSIST FOR
THE NEXT 48 HOURS OR SO. RIDGING IS THEN FORECAST TO TEMPORARILY
BUILD TO THE EAST OF THE CYCLONE...RESULTING IN A SLIGHT INCREASE IN
FORWARD SPEED TOWARD THE NORTH-NORTHWEST ON DAYS 2 THROUGH 4. TOWARD
THE END OF THE FORECAST PERIOD...JIMENA WILL BEGIN TO FEEL A STRONG
RIDGE BUILDING TO THE NORTH...AND THE FORECAST RESPONDS BY TURNING
JIMENA TOWARD THE WEST-NORTHWEST. THE UPDATED OFFICIAL FORECAST IS
VERY CLOSE TO THE PREVIOUS...BUT IS A LITTLE SLOWER AND TO THE WEST
OF THE PREVIOUS OVER THE NEXT 3 DAYS. ON DAYS 4 AND 5...THE UPDATED
TRACK FORECAST LIES ALONG THE PREVIOUS...BUT IS INDICATING A SLOWER
FORWARD SPEED. THE NEW TRACK FORECAST LIES VERY CLOSE TO THE TVCN
AND GFEX CONSENSUS GUIDANCE.

THE INTENSITY FORECAST CONTINUES TO ANTICIPATE A GRADUAL BUT STEADY
WEAKENING TREND THROUGH THE FORECAST PERIOD...PRIMARILY DUE TO THE
EFFECTS OF SOUTHWESTERLY SHEAR. MODERATE SHEAR...NEAR 10 TO 15 KT...
IS EXPECTED TO PERSIST OVER THE NEXT 24 HOURS OR SO...AFTER WHICH
TIME IT STEADILY INCREASES TO NEAR 25 KT BY DAY 3. THE FORECAST
TRACK ALSO TAKES JIMENA OVER GRADUALLY DECREASING WATER TEMPERATURES
AND OCEAN HEAT CONTENT. THE UPDATED INTENSITY FORECAST IS SIMILAR TO
THE PREVIOUS...AND VERY CLOSE TO THE IVCN CONSENSUS...BUT CONTINUES
TO BE HIGHER THAN THAT INDICATED BY SHIPS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 19.1N 144.2W 90 KT 105 MPH
12H 04/0600Z 19.4N 144.4W 85 KT 100 MPH
24H 04/1800Z 20.0N 144.8W 80 KT 90 MPH
36H 05/0600Z 20.8N 145.2W 75 KT 85 MPH
48H 05/1800Z 21.7N 145.5W 65 KT 75 MPH
72H 06/1800Z 23.9N 146.6W 60 KT 70 MPH
96H 07/1800Z 25.5N 148.0W 50 KT 60 MPH
120H 08/1800Z 26.0N 149.5W 45 KT 50 MPH

$$

FORECASTER BIRCHARD

[Alyono]

that forecast is weaker than the global models show. Leans too heavily on SHIPS guidance, IMPO. I have this maintaining 60 kts through 7 days, though there is quite a bit of uncertainty in that

[Kingarabian]

that forecast is weaker than the global models show. Leans too heavily on SHIPS guidance, IMPO. I have this maintaining 60 kts through 7 days, though there is quite a bit of uncertainty in that

Ignacio did fare well north of Hawaii considering the shear and "cooler" SST's.

[Kingarabian]

18z GFS so far is a bit more south than the 12z through 96 hours. Let's see how north or south Jimena's location will affect the track.

[Kingarabian]

18z GFS landfall on the Big Island. Similar to 12z.

[Alyono]

looks like its weakening

I wonder if the global models do not have the properly cooled SSTs after Ignacio moved through the area and due to Jimena's slow motion. May make the solutions of a track toward Hawaii utterly worthless as we may be dealing with a convectionless swirl due to the upwelled SSTs

[Yellow Evan]

looks like its weakening

I wonder if the global models do not have the properly cooled SSTs after Ignacio moved through the area and due to Jimena's slow motion. May make the solutions of a track toward Hawaii utterly worthless as we may be dealing with a convectionless swirl due to the upwelled SSTs

They should be able to detect the former (since SST's have at least partially updated) but not the latter.

The upwelled SST's should be able to recover and Ignacio has a small wind field anyhow, so only a small part of the track would moed over the slightly upwelled area.

Besides I think the main issue has been it's ERC's that made the inner core dry air prone.

[Kingarabian]

In the short term, Jimena shouldn't be tracking over Igancio up2elled water. Maybe as it nears Hawaii but that's nearly a week from now.

Just looks like dry air is hindering it.

The initialization seems about right too. Few millibars off of the CPHCs.

[Kingarabian]

The real test for it is the 27C ssts that will be ahead of it as it makes the trek north. Once and if it turns and drops south, SSTs will be really favorable. The question will be shear.

[Alyono]

27C is fine for an intense TC. However, I suspect given the slow motion, SSTs will be closer to 25C for a while

[Yellow Evan]

27C is fine for an intense TC. However, I suspect given the slow motion, SSTs will be closer to 25C for a while

There have been instances where TC's in the East Pacific have deepened over 24-25C. The most greater concern is shear.

[Kingarabian]

00z GFS same big Island/Maui landfall. Weaker.

[Kingarabian]

27C is fine for an intense TC. However, I suspect given the slow motion, SSTs will be closer to 25C for a while

There have been instances where TC's in the East Pacific have deepened over 24-25C. The most greater concern is shear.

But Jimena is not annular. I think Hawaii may be spared if Jimena pulls a Kilo. As in, the track is there but the storm isn't.

[Yellow Evan]

27C is fine for an intense TC. However, I suspect given the slow motion, SSTs will be closer to 25C for a while

There have been instances where TC's in the East Pacific have deepened over 24-25C. The most greater concern is shear.

But Jimena is not annular.

Storms can still maintain itself over 24-25C SST's under near zero shear regardless on whether it's annular. Only problem here is shear.

[Kingarabian]

Looking good.

[Kingarabian]

06z GFS much weaker and miss Hawaii to the west. In line with the 00z Euro.

[Yellow Evan]

WTPA44 PHFO 041454
TCDCP4

HURRICANE JIMENA DISCUSSION NUMBER 36
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP132015
500 AM HST FRI SEP 04 2015

JIMENA CONTINUES TO STRUGGLE IN AN INCREASINGLY HOSTILE ENVIRONMENT
EARLY THIS MORNING. THERE IS NO EYE EVIDENT...AND DEEP CONVECTION IS
CONFINED PRIMARILY IN A RELATIVELY SMALL AREA IN THE NORTHEASTERN
SEMICIRCLE OF THE INNER CORE OF THE HURRICANE ACCORDING TO 1150Z
AMSU IMAGERY. THE LATEST ESTIMATE OF ENVIRONMENTAL VERTICAL WIND
SHEAR IN THE VICINITY OF JIMENA ACCORDING TO UW-CIMSS IS 16 KT FROM
245 DEGREES AND 12 KT FROM 285 DEGREES BASED ON THE SHIPS GUIDANCE.
IN ADDITION TO SHEAR BEING A LIKELY CULPRIT IN THE DEGRADATION OF
JIMENA...WATER VAPOR IMAGERY STRONGLY SUGGESTS THAT VERY DRY IS
BEING ENTRAINED INTO THE SYSTEM. ALSO...EVEN THOUGH THE OUTFLOW
ALOFT WAS RATHER IMPRESSIVE EARLIER TONIGHT...IT NOW APPEARS TO BE
SHOWING SOME RESTRICTIONS IN THE WESTERN QUADRANT. THE MOST RECENT
SUBJECTIVE DVORAK ESTIMATES OF CURRENT INTENSITY WERE 4.5/77 KT FROM
PHFO AND JTWC...AND 4.0/65 KT FROM SAB. THE LATEST UW-CIMSS ADT
INTENSITY ESTIMATE IS 4.3/72 KT. BASED ON A BLEND OF THESE INTENSITY
ESTIMATES...WE HAVE LOWERED THE INITIAL INTENSITY TO 75 KT.

JIMENA REMAINS IN AN AREA OF WEAK STEERING...AND THE CURRENT MOTION
IS 310/04 KT. THERE IS A MID LEVEL ANTICYCLONE TO THE EAST-SOUTHEAST
OF JIMENA NEAR 16N 135W. THERE IS ALSO MID LEVEL RIDGE EXTENDING
FROM ANOTHER ANTICYCLONE NEAR 36N 155W DOWN TO 22N 153W. SINCE...
JIMENA IS SANDWICHED BETWEEN THESE FEATURES...IT APPEARS THAT
BETA-DRIFT MAY BE ONE OF THE PRIMARY STEERING MECHANISMS. THIS WEAK
STEERING WILL LIKELY CONTINUE THROUGH TONIGHT. FROM SATURDAY INTO
SUNDAY...THE WEAK STEERING PATTERN WILL PERSIST AS A MID LEVEL RIDGE
TO THE EAST BUILDS TO THE SOUTHEAST AND SOUTH OF JIMENA. THIS IS
EXPECTED TO RESULT IN A SLIGHTLY FASTER MOTION TOWARD THE
NORTH-NORTHWEST. BY MONDAY AND TUESDAY...THE MID LEVEL RIDGING TO
THE NORTH IS FORECAST TO STRENGTHEN...AND JIMENA WILL LIKELY TURN
TOWARD THE WEST. THE LATEST FORECAST IS CLOSE TO THE PREVIOUS
THROUGH 72 HOURS. THE FORECAST TRACK IS NUDGED SLIGHTLY TO THE RIGHT
COMPARED WITH THE PREVIOUS FORECAST ON DAYS 4 AND 5. THIS FORECAST
TRACK IS VERY CLOSE TO A BLEND BETWEEN THE TVCN AND GFEX CONSENSUS
GUIDANCE THROUGH DAY 4...AND THE GFEX ON DAY 5. NOTE THAT THE MODEL
SPREAD IS FAIRLY SMALL THROUGH 72 HOURS...WITH A MUCH WIDER SPREAD
ON DAYS 4 AND 5. THEREFORE...THERE REMAINS A GREAT DEAL OF
UNCERTAINTY IN THE TRACK FORECAST AS THIS SYSTEM MOVES TO A POSITION
NORTH-NORTHEAST OF THE MAIN HAWAIIAN ISLANDS.

THE LATEST INTENSITY FORECAST CONTINUES TO SHOW GRADUAL...BUT STEADY
WEAKENING. THIS IS PRIMARILY DUE TO THE EFFECTS OF MODERATE
WEST-SOUTHWEST TO WEST SHEAR DURING THE NEXT 18-24 HOURS. BEYOND 24
HOURS...THE SHEAR STEADILY INCREASES...WHILE SEA SURFACE
TEMPERATURES AND OCEAN HEAT CONTENT VALUES GRADUALLY DECREASE. THE
LATEST INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS...AND VERY
CLOSE TO THE IVCN CONSENSUS...BUT CONTINUES TO SHOW LESS WEAKENING
THAN THE LATEST SHIPS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 19.7N 145.1W 75 KT 85 MPH
12H 05/0000Z 20.2N 145.4W 70 KT 80 MPH
24H 05/1200Z 20.9N 145.8W 65 KT 75 MPH
36H 06/0000Z 22.0N 146.3W 60 KT 70 MPH
48H 06/1200Z 23.2N 147.1W 55 KT 65 MPH
72H 07/1200Z 24.9N 149.2W 50 KT 60 MPH
96H 08/1200Z 25.0N 151.0W 45 KT 50 MPH
120H 09/1200Z 25.0N 152.5W 35 KT 40 MPH

$$
FORECASTER HOUSTON