EPAC: DALILA - Post-Tropical

[greenkat]

I spy with my little eye... Dalila's eye!

[Hurricane_Luis]

Hurricane Dalila has an eye and what a good looking storm.

[Kingarabian]

The GFS was depicting a stronger storm and moving it west... The ECMWF had a weakening storm beginning to drift south. The NHC followed the GFS for the entirity of this storm until last advisory where they began to lean towards the ECMWF's side... Do they switch back?

[tolakram]

Live visible loop: http://wwwghcc.msfc.nasa.gov/cgi-bin/ge ... umframes=9

[Kingarabian]

[brunota2003]

Looking at that image, it looks closer to 70 or 75 knots. Usually the eye isn't that well defined and doesn't start appearing on visible images at 65 kts.

[cycloneye]

HURRICANE DALILA DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
200 PM PDT TUE JUL 02 2013

A COUPLE OF MICROWAVE IMAGES...RECEIVED SHORTLY AFTER THE RELEASE OF
THE 1500 UTC ADVISORY...SHOWED THAT THE INNER-CORE STRUCTURE OF
DALILA BECAME SUBSTANTIALLY BETTER DEFINED DURING THE MORNING
HOURS. IN PARTICULAR...1335 UTC WINDSAT MICROWAVE IMAGE SHOWED THAT
THAT AN EYE HAD DEVELOPED. THAT PASS ALSO INDICATED THAT THE
CENTER OF DALILA WAS NORTH OF THE PREVIOUSLY ESTIMATED POSITION. A
RAGGED EYE-LIKE FEATURE IS STILL PRESENT IN VISIBLE IMAGERY AND THE
OVERALL CLOUD PATTERN HAS BECOME FAIRLY SYMMETRIC. THE INITIAL
INTENSITY IS SET TO 65 KT...BASED ON A BLEND OF MICROWAVE-ADJUSTED
OBJECTIVE DVORAK INTENSITY ESTIMATES FROM UW-CIMSS AND SUBJECTIVE
DVORAK ESTIMATES FROM TAFB AND SAB. THERE HAS BEEN A LARGE UPWARD
SHIFT IN THE STATISTICAL AND DYNAMICAL INTENSITY GUIDANCE. THE
OFFICIAL INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD...ALTHOUGH IT
NOW LIES ON THE LOWER END OF THE GUIDANCE RANGE. DALILA IS STILL
FORECAST TO BECOME A REMNANT LOW BY 120 HOURS AS IT MOVES INTO A
DRIER ENVIRONMENT AND OVER COOLER WATERS.

ALTHOUGH THE CENTER HAS BEEN EASIER TO LOCATE...THE TROPICAL CYCLONE
IS STILL MOVING VERY SLOWLY AND THE INITIAL MOTION IS RATHER
UNCERTAIN. IN THE SHORT RANGE...A DEEP-LAYER RIDGE LOCATED TO THE
NORTH OF DALILA IS STILL EXPECTED TO IMPART A TURN TOWARD THE
WEST-SOUTHWEST WITHIN THE NEXT 24 HOURS. THERE REMAINS A VERY
LARGE SPREAD IN THE GUIDANCE AFTER THAT...AND THE GFS AND ECMWF
HAVE NOT COME INTO BETTER AGREEMENT. THE GFS STILL SHOWS A
GENERALLY WESTWARD-MOVING STRONG CYCLONE...WHILE THE ECMWF
FORECASTS A SOUTHWARD-MOVING WEAK LOW. GIVEN THE CURRENT STATE OF
DALILA...MORE CREDENCE IS BEING GIVEN TO THE FORMER SCENARIO.

FORECAST POSITIONS AND MAX WINDS

INIT 02/2100Z 18.4N 107.2W 65 KT 75 MPH
12H 03/0600Z 18.3N 107.5W 70 KT 80 MPH
24H 03/1800Z 18.0N 108.1W 65 KT 75 MPH
36H 04/0600Z 17.7N 108.9W 65 KT 75 MPH
48H 04/1800Z 17.5N 109.8W 60 KT 70 MPH
72H 05/1800Z 17.5N 111.5W 60 KT 70 MPH
96H 06/1800Z 18.0N 113.5W 40 KT 45 MPH
120H 07/1800Z 18.5N 116.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
FORECASTER PASCH/ZELINSKY

[Kingarabian]

Unique looking hurricane IMO.

[Yellow Evan]

Dalila may not be done intensifying. Good looking hurricane.

[greenkat]

Maybe Dalila will take the opportunity to RI that Cosme lost due to its sheer size.

[TropicalAnalystwx13]

Dalila's intensification phases seem to be aided solely by diurnal changes now. During diurnal minimum, the storm weakens...as of the latest microwave pass, Dalila has lost its eye. During diurnal maximum, it quickly rebuilds a core...it became a hurricane this morning and intensified quite substantially yesterday at that time.

Because of its southwest trek, it will be over waters in excess of 26C for a few more *days*. The problem is that mid-level dry air will only become worse of an issue, and the storm is now being sheared at 15-20 knots.

[cycloneye]

HURRICANE DALILA DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
800 PM PDT TUE JUL 02 2013

THE CLOUD PATTERN OF DALILA HAS CHANGED LITTLE IN ORGANIZATION
DURING THE LAST SEVERAL HOURS...WITH THE CYCLONE STILL MAINTAINING A
SMALL AND FAIRLY SYMMETRIC CDO. A 0016 UTC SSMI/S PASS DID...
HOWEVER...SHOW A SLIGHT DEGRADATION OF THE INNER CORE...WITH THE
EYEWALL OPEN TO THE EAST. THE MID-LEVEL CENTER ALSO WAS DISPLACED
NORTHWEST OF THE LOW-LEVEL CENTER...SUGGESTING THAT SOUTHEASTERLY
SHEAR IS STILL AFFECTING THE CYCLONE. THE INITIAL INTENSITY IS KEPT
AT 65 KT IN AGREEMENT WITH A TAFB DVORAK INTENSITY ESTIMATE OF
T4.0/65 KT.

THE STATISTICAL MODEL GUIDANCE SHOWS DALILA CHANGING LITTLE IN
STRENGTH DURING THE NEXT 2-3 DAYS...EVEN THOUGH THE HURRICANE
SHOULD BE PASSING OVER RELATIVELY WARM WATERS. THE MAIN OBSTACLE TO
ANY FURTHER STRENGTHENING IS LIKELY RELATED TO MODERATE EAST-
SOUTHEASTERLY TO SOUTHEASTERLY WIND SHEAR FORECAST TO PREVAIL OVER
THE CYCLONE. THE ECMWF SHOWS DALILA QUICKLY WEAKENING AS A RESULT
OF THE ENTRAINMENT OF A LAYER OF DRY AIR TO THE WEST OF DALILA. IT
IS DIFFICULT...HOWEVER...TO IMAGINE THIS SCENARIO...GIVEN THAT THE
UPPER-LEVEL FLOW IS FROM THE EAST. THE NHC INTENSITY FORECAST
CONTINUES TO LEAN ON THE GFS-BASED MODEL GUIDANCE AND IS NEAR A
BLEND OF THE SHIPS/LGEM THROUGH 72 HOURS...AND THEN NEAR THE
MULTI-MODEL INTENSITY CONSENSUS AIDS BEYOND THAT TIME.

DALILA IS NOT MOVING MUCH. A LONG-TERM AVERAGE OF SATELLITE FIXES
YIELDS A HIGHLY UNCERTAIN INITIAL MOTION ESTIMATE OF 270/02.
HOWEVER...RECENT MICROWAVE FIXES SUGGEST THAT A WEST-SOUTHWESTWARD
TO SOUTHWESTWARD DRIFT MAY HAVE COMMENCED. A MID-LEVEL TROUGH ACROSS
NORTHERN MEXICO HAS TEMPORARILY WEAKENED THE SUBTROPICAL RIDGE AND
CREATED A WEAK STEERING ENVIRONMENT OVER THE CYCLONE. HOWEVER...THE
STRONG HEAT RIDGE OVER THE WESTERN UNITED STATES IS FORECAST TO MOVE
SOUTHEASTWARD DURING THE NEXT COUPLE OF DAYS...WHICH SHOULD CAUSE
DALILA TO TURN SOUTH OF WEST WITH SOME MINOR INCREASE IN FORWARD
SPEED. THE TRACK GUIDANCE REMAINS DIVERSE...WITH THE ECMWF STILL
FORECASTING A WEAK CYCLONE MOVING SOUTHWARD AND DISSIPATING. THE
GFS CONTINUES TO SHOW A STRONGER SYSTEM MOVING ON A MORE WESTERLY
TRACK. THE NEW NHC TRACK FORECAST CONTINUES TO WEIGH THE GFS
SOLUTION MORE...AND IS BETWEEN THE PREVIOUS FORECAST AND THE
MULTI-MODEL CONSENSUS TVCE THROUGH 72 HOURS...AND CLOSER TO THE GFS
LATE IN THE PERIOD.

FORECAST POSITIONS AND MAX WINDS

INIT 03/0300Z 18.3N 107.3W 65 KT 75 MPH
12H 03/1200Z 18.1N 107.6W 65 KT 75 MPH
24H 04/0000Z 17.7N 108.2W 65 KT 75 MPH
36H 04/1200Z 17.4N 108.9W 65 KT 75 MPH
48H 05/0000Z 17.4N 109.9W 60 KT 70 MPH
72H 06/0000Z 17.6N 111.9W 55 KT 65 MPH
96H 07/0000Z 18.0N 114.0W 40 KT 45 MPH
120H 08/0000Z 18.5N 116.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER KIMBERLAIN

[Yellow Evan]

Wonder if Dalila will re-intensify tomorrow. This is sorta like Boris 08.

[cycloneye]

HURRICANE DALILA DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
200 AM PDT WED JUL 03 2013

EARLIER MICROWAVE IMAGERY SUGGESTED THAT THE CORE CONVECTION OF
DALILA HAD AGAIN BECOME SOMEWHAT DISORGANIZED...POSSIBLY DUE TO
SHEAR INDICATED BY CIRRUS CLOUDS MOVING INTO THE CYCLONE FROM THE
EAST. HOWEVER...THE CLOUD TOP TEMPERATURES REMAIN PERSISTENTLY
NEAR OR COLDER THAN -80C...AND THE SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB HAVE NOT CHANGED DURING THE PAST 12 HOURS. THE
INITIAL INTENSITY THUS REMAINS 65 KT...ALTHOUGH IT IS POSSIBLE THAT
THIS IS GENEROUS.

THE INITIAL MOTION IS AN UNCERTAIN 225/2. THERE IS LITTLE CHANGE IN
EITHER THE TRACK FORECAST PHILOSOPHY OR THE MODEL GUIDANCE SINCE
THE LAST ADVISORY. A STRONG DEEP-LAYER RIDGE OVER THE WESTERN
UNITED STATES SHOULD BUILD SOUTHEASTWARD DURING THE NEXT SEVERAL
DAYS AS A TROPICAL DISTURBANCE SOUTH OF EASTERN MEXICO MOVES TOWARD
DALILA. THIS EVOLUTION SHOULD CAUSE THE CYCLONE TO MOVE GENERALLY
WEST-SOUTHWESTWARD FOR 36 HOURS OR SO...FOLLOWED BY A WESTWARD
MOTION. THE GUIDANCE BECOMES QUITE DIVERSE AFTER 72 HOURS...WITH
FORECAST TRACKS SPREAD BETWEEN A SOUTHWESTWARD MOTION AND A
NORTHWESTWARD MOTION. THIS PORTION OF THE TRACK WILL SHOW A
GENERAL WEST-NORTHWESTWARD MOTION NEAR THE CENTER OF THE GUIDANCE
ENVELOPE. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK.

THE ECMWF...UKMET...AND CANADIAN MODELS FORECAST DALILA TO DISSIPATE
COMPLETELY DURING THE NEXT 3-5 DAYS...WHILE THE GFS AND NAVGEM
MODEL SHOW IT SURVIVING AS A TROPICAL CYCLONE OR LOW PRESSURE AREA
FOR 5 DAYS. THE DISSIPATION SCENARIO IS SUPPORTED BY DRY AIR SEEN
NEAR THE CYCLONE IN MICROWAVE DATA...WHILE THE SURVIVAL SCENARIO IS
SUPPORTED BY WARM SEA SURFACE TEMPERATURES DURING THE FIRST 3 DAYS
OF THE NEW FORECAST TRACK. THE INTENSITY FORECAST GOES WITH THE
SURVIVAL SCENARIO...CALLING FOR DALILA TO MAINTAIN HURRICANE
STRENGTH FOR 24 HOURS WITH GRADUAL WEAKENING THEREAFTER. THE
INTENSITY FORECAST HAS BEEN TWEAKED SLIGHTLY TO MATCH THE INTENSITY
CONSENSUS FORECAST.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 18.1N 107.5W 65 KT 75 MPH
12H 03/1800Z 17.8N 107.9W 65 KT 75 MPH
24H 04/0600Z 17.4N 108.7W 65 KT 75 MPH
36H 04/1800Z 17.2N 109.6W 60 KT 70 MPH
48H 05/0600Z 17.2N 110.7W 55 KT 65 MPH
72H 06/0600Z 17.5N 113.0W 50 KT 60 MPH
96H 07/0600Z 18.0N 115.0W 40 KT 45 MPH
120H 08/0600Z 18.5N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER BEVEN

[Yellow Evan]

000
WTPZ44 KNHC 031442
TCDEP4

HURRICANE DALILA DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
800 AM PDT WED JUL 03 2013

DALILA APPEARS TO HAVE UNDERGONE ANOTHER STRUCTURAL
TRANSFORMATION...AND A 0935 UTC MICROWAVE IMAGE FROM TRMM INDICATED
THAT THE INNER-CORE HAD BECOME A LITTLE BETTER ORGANIZED. A
CONSENSUS OF OBJECTIVE AND SUBJECTIVE DVORAK INTENSITY ESTIMATES AT
1200 UTC IS ABOUT 70 KT...HOWEVER THE CLOUD TOPS HAVE WARMED A
LITTLE SINCE THEN...SO THE INITIAL INTENSITY HAS BEEN HELD AT 65
KT. THE INTENSITY GUIDANCE HAS NOT CHANGED MUCH...AND SUGGESTS
THAT DALILA WILL REMAIN NEAR HURRICANE INTENSITY FOR THE FIRST 48
HOURS. AFTER THAT...STEADY WEAKENING IS EXPECTED WHILE DALILA
MOVES INTO AN AREA OF COLDER WATER AND STRONGER SHEAR...AS
INDICATED BY THE SHIPS DIAGNOSTIC OUTPUT. DALILA IS STILL EXPECTED
TO BECOME A REMNANT LOW BY THE END OF THE FORECAST PERIOD.

THE CENTER OF DALILA REMAINS DIFFICULT TO FIND...HOWEVER
EXTRAPOLATING THE POSITION OF THE CENTER OF THE CYCLONE AS
INDICATED ON THE AFOREMENTIONED TRMM PASS YIELDS AN ESTIMATED
MOTION OF 240/3. DALILA SHOULD CONTINUE TO MOVE SLOWLY TO THE
WEST-SOUTHWEST FOR THE NEXT 36 HOURS OR SO...BEFORE TURNING TO THE
WEST AND EVENTUALLY WEST-NORTHWEST WHILE THE DEEP-LAYER RIDGE TO
ITS NORTH PROPAGATES EASTWARD. THE DYNAMICAL TRACK GUIDANCE STILL
VARIES GREATLY ON HOW QUICKLY DALILA WILL TURN TO THE
WEST-NORTHWEST. THE OFFICIAL TRACK FORECAST IS VERY NEAR THAT OF
THE GFS...WHICH HAS BEEN A GOOD PERFORMER FOR THIS STORM THUS FAR.

FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 17.8N 108.0W 65 KT 75 MPH
12H 04/0000Z 17.6N 108.5W 65 KT 75 MPH
24H 04/1200Z 17.2N 109.5W 65 KT 75 MPH
36H 05/0000Z 17.1N 110.6W 60 KT 70 MPH
48H 05/1200Z 17.1N 111.7W 60 KT 70 MPH
72H 06/1200Z 17.5N 114.0W 50 KT 60 MPH
96H 07/1200Z 18.5N 116.5W 40 KT 45 MPH
120H 08/1200Z 19.0N 119.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER PASCH/ZELINSKY

[HurricaneBelle]

THE CENTER OF DALILA REMAINS DIFFICULT TO FIND

How often do you hear this in reference to a hurricane?

[tolakram]

Looking at the latest floater loop: http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

It appears to be falling apart, and fast.

[Extratropical94]

18Z Best Track suggests a downgrade to TS at next advisory:

EP, 04, 2013070318, , BEST, 0, 175N, 1080W, 60, 991, TS

[cycloneye]

Downgraded to Tropical Storm

TROPICAL STORM DALILA DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
200 PM PDT WED JUL 03 2013

CLOUD TOPS HAVE BEEN WARMING RECENTLY...AND THE CDO HAS TAKEN ON A
PATTERN THAT IS MORE INDICATIVE OF EASTERLY VERTICAL WIND SHEAR.
OBJECTIVE DVORAK INTENSITY ESTIMATES HAVE BEEN DECREASING FOR THE
PAST SEVERAL HOURS...AND SUBJECTIVE DATA T-NUMBERS HAVE ALSO
DECREASED. BASED ON THE DVORAK ESTIMATES...DALILA HAS BEEN
DOWNGRADED TO A 60-KT TROPICAL STORM. THERE HAS BEEN VERY LITTLE
CHANGE IN THE INTENSITY GUIDANCE. ALTHOUGH THE DYNAMICAL MODELS
INDICATE THAT THE INTENSITY COULD FLUCTUATE DURING THE NEXT 48
HOURS...ALL OF THE MODELS GENERALLY FORECAST A SLOW WEAKENING TREND.
THE INTENSITY FORECAST HAS BEEN ADJUSTED DOWNWARD A LITTLE TO
ACCOUNT FOR THE NEW INITIAL INTENSITY...AND STILL SHOWS DALILA
GRADUALLY WEAKENING TO A REMNANT LOW BY THE END OF THE FORECAST
PERIOD.

ALTHOUGH THE LOW-LEVEL CENTER IS STILL OBSCURED...A COUPLE OF
MICROWAVE PASSES SUGGEST THAT IT IS DISPLACED SLIGHTLY TO THE
NORTHEAST OF THE CENTER OF THE CDO. THE TROPICAL STORM HAS BEEN
DRIFTING SOUTHWESTWARD DURING THE DAY...AND THE INITIAL MOTION
ESTIMATE IS 230/3. DALILA IS BEING STEERED BY A LARGE DEEP-LAYER
RIDGE TO THE NORTH-NORTHWEST. A TURN TOWARD THE WEST...AND
EVENTUALLY THE NORTH-NORTHWEST...IS EXPECTED AS THE RIDGE
PROPAGATES EASTWARD. THE MODEL GUIDANCE STILL DOES NOT AGREE ON
HOW QUICKLY THIS TURN WILL OCCUR...AND THERE IS A LOT OF SPREAD AT
3-5 DAYS. THE OFFICIAL TRACK FORECAST HAS BEEN SHIFTED A LITTLE TO
THE SOUTH...BUT REMAINS NEAR THE FSSE AND GFS MODEL PREDICTIONS.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 17.4N 108.1W 60 KT 70 MPH
12H 04/0600Z 17.1N 108.9W 55 KT 65 MPH
24H 04/1800Z 16.8N 109.9W 55 KT 65 MPH
36H 05/0600Z 16.8N 111.0W 55 KT 65 MPH
48H 05/1800Z 16.9N 112.1W 55 KT 65 MPH
72H 06/1800Z 17.6N 114.7W 45 KT 50 MPH
96H 07/1800Z 18.0N 117.0W 35 KT 40 MPH
120H 08/1800Z 18.5N 120.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
FORECASTER PASCH/ZELINSKY

[jaguarjace]

Latest Floater:

JUL 3 1400 UTC - JUL 3 2100 UTC Floater Loops:
>WATER VAPOR Enhancement
>RGB Enhancement
>RAINBOW Enhancement
>RBTOP Enhancement