EPAC : TROPICAL DEPRESSION CELIA - DISCUSSION

[Kingarabian]

Im wondering, why did Celia go down?

[HURAKAN]

Im wondering, why did Celia go down?

Lost its eye

[cycloneye]

TCDEP4
HURRICANE CELIA DISCUSSION NUMBER 21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010
200 AM PDT THU JUN 24 2010

CELIA APPEARS TO BE GOING THROUGH YET ANOTHER RE-STRENGTHENING PHASE
BASED ON A SIGNIFICANT INCREASE IN THE AREAL COVERAGE OF COLD CLOUD
TOPS IN THE CENTRAL DENSE OVERCAST FEATURE. DEEP CONVECTION
...WITH SOME TOPS AS COLD AS -86C...HAS DEVELOPED IN THE PREVIOUSLY
CONVECTION-VOID WESTERN SEMICIRCLE. SATELLITE INTENSITY ESTIMATES
ARE T5.5/102 KT FROM TAFB AND T5.0/90 KT FROM SAB USING THE
EMBEDDED CENTER TECHNIQUE. SINCE THE 06Z FIXES...DEEP CONVECTION
HAS CONTINUED TO EXPAND IN ALL QUADRANTS AND UPPER-LEVEL OUTFLOW
HAS ALSO BECOME MORE SYMMETRICAL. HOWEVER...I WOULD PREFER TO SEE
AN EYE APPEAR IN INFRARED IMAGERY BEFORE BRINGING CELIA BACK UP TO
MAJOR HURRICANE STATUS. THE OFFICIAL INTENSITY OF 95 KT IS A BLEND
OF THE TWO DVORAK SATELLITE INTENSITY ESTIMATES.

THE INITIAL MOTION ESTIMATE IS 285/11. THERE IS NO CHANGE TO THE
PREVIOUS FORECAST TRACK REASONING. FOR THE NEXT 3-4 DAYS...CELIA IS
EXPECTED TO MOVE IN A GENERAL WEST-NORTHWESTWARD DIRECTION TOWARD A
DEVELOPING WEAKNESS IN THE DEEP-LAYER RIDGE TO THE NORTH OF THE
CYCLONE. BY DAYS 4 AND 5...THE MID- TO UPPER-LEVEL TROUGH THAT
WEAKENS THE RIDGE IS FORECAST TO LIFT OUT TO THE NORTHEAST AND
ALLOW THE RIDGE TO BUILD BACK WESTWARD TO THE NORTH OF THE
HURRICANE...WHICH SHOULD FORCE CELIA ON A MORE WESTWARD TRACK. THE
OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND IS
ALONG THE LEFT SIDE OF THE GUIDANCE ENVELOPE.

A 24/0215Z SSMI-S WATER VAPOR IMAGE INDICATED A NARROW BAND OF DRY
AIR HAD BEEN DRAWN INTO THE WESTERN SEMICIRCLE...WHICH LIKELY LED
TO THE EARLIER EROSION OF CONVECTION IN THAT PART OF THE STORM.
HOWEVER...BASED ON THE RECENT RE-DEVELOPMENT OF CENTRAL DEEP
CONVECTION...IT WOULD SEEM THAT THE DRY AIR HAS BEEN MIXED OUT.
CELIA IS EXPECTED TO REMAIN OVER 28C OR WARMER SSTS AND IN A LOW
WIND SHEAR ENVIRONMENT FOR THE NEXT 24 HOURS...WHICH WOULD FAVOR
SOME ADDITIONAL STRENGTHENING TO OCCUR. THE PROXIMITY TO DRY AIR
JUST TO THE WEST OF THE CYCLONE...HOWEVER...COULD RESULT IN
ADDITIONAL FLUCTUATIONS IN INTENSITY DURING THAT PERIOD WHICH CAN
NOT BE SPECIFICALLY FORECAST. BY 48 HOURS...CELIA WILL BEGIN TO
MOVE OVER COOLER WATER AROUND 25C...WHICH SHOULD INDUCE SLOW BUT
STEADY WEAKENING FOR THE REMAINDER OF THE PERIOD. THE INTENSITY
FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY THROUGH 24 HOURS...
AND AFTERWARD CLOSELY FOLLOWS THE DOWNWARD TREND OF THE SHIPS AND
LGEM INTENSITY MODELS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 24/0900Z 12.6N 112.8W 95 KT
12HR VT 24/1800Z 13.0N 114.6W 100 KT
24HR VT 25/0600Z 13.7N 117.0W 100 KT
36HR VT 25/1800Z 14.4N 119.1W 95 KT
48HR VT 26/0600Z 15.1N 120.9W 85 KT
72HR VT 27/0600Z 16.2N 123.9W 60 KT
96HR VT 28/0600Z 16.5N 125.5W 50 KT
120HR VT 29/0600Z 16.5N 126.5W 35 KT

$$
FORECASTER STEWART

[Chacor]

Quite a storm, strengthening, weakening, strengthening, weakening, strengthening again...

[brunota2003]

She has some impressive tops on her right now...-80C per the IR loop legend.

[cycloneye]

Celia is a major once again.

EP, 04, 2010062412, , BEST, 0, 123N, 1133W, 100, 963, HU

[HURAKAN]

24/1200 UTC 12.3N 113.3W T5.5/5.5 CELIA -- East Pacific

100 knots

[cycloneye]

WTPZ44 KNHC 241435
TCDEP4
HURRICANE CELIA DISCUSSION NUMBER 22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010
800 AM PDT THU JUN 24 2010

THE EYE OF CELIA HAS ONCE AGAIN BECOME VISIBLE ON SATELLITE IMAGERY
BEGINNING AROUND 1200 UTC. IN ADDITION...THE CONVECTIVE PATTERN HAS
BECOME SIGNIFICANTLY MORE SYMMETRIC OVERNIGHT...WITH CLOUD TOPS
COLDER THAN -80 C IN THE EYEWALL. DVORAK T-NUMBERS FROM TAFB AND
SAB ARE 4.5/77 KT AND 5.5/102 KT. BASED ON THE SAB CLASSIFICATION
AND THE CONTINUED INCREASE IN ORGANIZATION OF THE CLOUD PATTERN
SINCE 1200 UTC...CELIA IS ONCE AGAIN UPGRADED TO MAJOR HURRICANE
STATUS...WITH THE INITIAL INTENSITY SET AT 100 KT...AND THIS COULD
BE CONSERVATIVE.

NONE OF THE INTENSITY GUIDANCE SHOWS ANY STRENGTHENING OF
CELIA...AND THIS APPEARS SOMEWHAT UNREALISTIC GIVEN THE VERY
FAVORABLE UPPER-LEVEL WIND PATTERN AND RELATIVELY WARM WATERS THAT
CELIA IS OVER AT THE MOMENT. HOWEVER...ANY INTENSIFICATION SHOULD
BE IN THE SHORT TERM AS SEA SURFACE TEMPERATURES DECREASE TO NEAR
26-27 C ALONG THE FOR CAST TRACK IN ABOUT 24 HOURS AND THEN
STEADILY COOL BEYOND THAT. IN ADDITION...THE ATMOSPHERIC
ENVIRONMENT IS FORECAST TO BECOME INCREASINGLY STABLE ALONG THE
EXPECTED TRACK. THE NEW NHC OFFICIAL INTENSITY FORECAST IS NUDGED
UPWARD AND IS ABOVE ALL OF THE GUIDANCE IN THE NEXT 12-24
HOURS...ALLOWING FOR SOME ADDITIONAL STRENGTHENING.
THEREAFTER...THE LESS FAVORABLE THERMODYNAMIC ENVIRONMENT SHOULD
CAUSE WEAKENING AND THE OFFICIAL FORECAST REMAINS NEAR THE PREVIOUS
ADVISORY...AND IN GOOD AGREEMENT WITH THE LGEM MODEL.

THE INITIAL MOTION ESTIMATE IS 275/11...AND THE EYE OF CELIA LIES A
LITTLE TO THE SOUTH OF THE PREVIOUS FORECAST TRACK. OVERALL...THERE
REMAINS LITTLE CHANGE TO THE TRACK FORECAST FORECAST REASONING.
CELIA IS EXPECTED TO TRACK WEST-NORTHWESTWARD FOR THE NEXT FEW DAYS
AS A LARGE-SCALE MID- TO UPPER-LEVEL TROUGH OFFSHORE OF THE UNITED
STATES WEST COAST ERODES THE MID-LEVEL RIDGE TO THE NORTH OF THE
HURRICANE. THE TROUGH IS EXPECTED TO LIFT OUT EARLY NEXT WEEK WITH
WEAK MID-LEVEL RIDGING BUILDING IN ITS WAKE. THIS PATTERN...
COMBINED WITH CELIA BECOMING A SHALLOWER SYSTEM BY THEN...SHOULD
ALLOW THE CYCLONE TO TURN BACK TOWARD THE WEST LATE IN THE FORECAST
PERIOD. THE NEW NHC OFFICIAL FORECAST IS SHIFTED A LITTLE SOUTH OF
THE PREVIOUS ONE IN THE SHORT-TERM TO ACCOUNT FOR THE INITIAL
MOTION...AND IS OTHERWISE AN UPDATE OF THE PREVIOUS ONE.


FORECAST POSITIONS AND MAX WINDS

INITIAL 24/1500Z 12.5N 113.9W 100 KT
12HR VT 25/0000Z 12.9N 115.7W 110 KT
24HR VT 25/1200Z 13.6N 117.9W 105 KT
36HR VT 26/0000Z 14.4N 119.8W 95 KT
48HR VT 26/1200Z 15.2N 121.4W 85 KT
72HR VT 27/1200Z 16.0N 124.0W 60 KT
96HR VT 28/1200Z 16.5N 125.5W 50 KT
120HR VT 29/1200Z 16.5N 126.5W 35 KT

$$
FORECASTER CANGIALOSI/PASCH

[srainhoutx]

[KWT]

Looks very close to being annular to me right now, just needs perhaps a slightly more defined eye.

[Hurricane Andrew]

I don;t think it is annular. BUT, I do think this will reach cat 4.

[srainhoutx]

I don;t think it is annular. BUT, I do think this will reach cat 4.

May want to look again. Lack of spiral banding is a big clue for an often mistaken annular cyclone. This one fits rather nicely for a true annular system. Should look very impressive once the eye feature is exposed from the cirrus shield.

[KWT]

Its not quite there yet but give it another 12hrs and it may well be close enough to Annular to get called Annular, I'd suspect the NHC will mention about it.

[Hurricane Andrew]

You are right. One cat 4 celia comin' up.

[tolakram]

Will be interesting to discover if the strange weakening was related to some kind of structure change that moved Celia toward being annular. Seems like EPAC has one of these every other year.

[CrazyC83]

Will be interesting to discover if the strange weakening was related to some kind of structure change that moved Celia toward being annular. Seems like EPAC has one of these every other year.

Maybe a couple of ERC's did the weakening trends.

[Chacor]

## ANNULAR HURRICANE INDEX (AHI) EP042010 CELIA 06/24/10 12 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=6 NFAIL=1 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
## ANNULAR INDEX RAN NORMALLY

Meets six of the seven criteria to be called annular. But it's not annular yet, one more criterion.

[clfenwi]

Its not quite there yet but give it another 12hrs and it may well be close enough to Annular to get called Annular, I'd suspect the NHC will mention about it.

The only thing keeping the Annular Hurricane Index from being triggered is SSTs. What's being reported to SHIPS is 28.9°. The high end of the threshold is 28.6°. If things go according to forecast/analysis, Celia will be in waters cooler than that within 12 hours, so your suspicion may be spot on.

[HURAKAN]

Looking very good

[HURAKAN]

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