EPAC : TROPICAL DEPRESSION DARBY - DISCUSSION

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 AM PDT FRI JUN 25 2010

DARBY IS A SMALL BUT INTENSE HURRICANE. SATELLITE IMAGES AND
MICROWAVE DATA REVEAL AN EYE SURROUNDED BY A RING OF VERY DEEP
CONVECTION. T-NUMBERS FROM TAFB AND SAB HAVE INCREASED TO 5.5 ON
THE DVORAK SCALE AND THE INITIAL INTENSITY HAS BEEN ADJUSTED UPWARD
TO 100 KNOTS. THE HURRICANE HAS AN OPPORTUNITY TO STRENGTHEN A
LITTLE MORE BEFORE THE UPPER-LEVEL ENVIRONMENT BECOMES UNFAVORABLE
IN A DAY OR TWO. THEREFORE...A GRADUAL WEAKENING IS INDICATED.

DARBY HAS CONTINUED TO MOVE TOWARD THE WEST-NORTHWEST OR 285 DEGREES
AT 6 KNOTS. HOWEVER...AS THE RIDGE TO THE NORTH WEAKENS AND THE
STEERING CURRENTS COLLAPSE...THE HURRICANE SHOULD BEGIN TO MEANDER
AS INDICATED IN THE OFFICIAL FORECAST. GLOBAL MODELS ARE NOT IN GOOD
AGREEMENT ON THE TRACK OF DARBY...BUT MOST OF THEM WEAKEN THE
CYCLONE AS IT BECOMES EMBEDDED WITHIN A LOW-LEVEL WESTERLY FLOW.


FORECAST POSITIONS AND MAX WINDS

INITIAL 25/1500Z 13.6N 101.2W 100 KT
12HR VT 26/0000Z 13.9N 102.0W 105 KT
24HR VT 26/1200Z 13.9N 103.2W 100 KT
36HR VT 27/0000Z 13.5N 103.5W 90 KT
48HR VT 27/1200Z 13.5N 104.0W 80 KT
72HR VT 28/1200Z 13.8N 104.0W 70 KT
96HR VT 29/1200Z 14.0N 103.3W 60 KT
120HR VT 30/1200Z 14.5N 102.5W 50 KT

$$
FORECASTER AVILA

[HURAKAN]

Looking good

[HURAKAN]

Looks amazing

[HURAKAN]

I think Darby could be stronger than 115 mph based on its organization and size

[CrazyC83]

Looks to be about 110 kt to me (pressure around 955mb).

[HURAKAN]

re-issued 18z

EP, 05, 2010062518, , BEST, 0, 135N, 1013W, 105, 963, HU

[HURAKAN]

954
WTPZ45 KNHC 252044
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
200 PM PDT FRI JUN 25 2010

DARBY REMAINS A WELL-ORGANIZED HURRICANE WITH VISIBLE IMAGERY
SHOWING A DISTINCT EYE AND AN IMPRESSIVE OUTFLOW PATTERN. DVORAK
SATELLITE CLASSIFICATIONS FROM TAFB AND SAB AT 1800 UTC WERE
T5.5...102 KT. SINCE THAT TIME...THE SYSTEM HAS BECOME BETTER
ORGANIZED WITH DEEPER CONVECTION IN THE EYEWALL. THUS...THE INITIAL
INTENSITY IS NUDGED UPWARD TO 105 KT. EASTERLY SHEAR IS FORECAST
BY ALL OF THE GLOBAL MODELS TO INCREASE OVERNIGHT WHICH SHOULD
LIMIT FUTURE STRENGTHENING. THIS SHEAR WILL LIKELY PERSIST FOR
SEVERAL DAYS AND CAUSE DARBY TO GRADUALLY WEAKEN. MOST OF THE
INTENSITY GUIDANCE IS IN REASONABLE AGREEMENT ON THIS SCENARIO...
AND THE NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ADVISORY.

THE INITIAL MOTION OF THE TROPICAL CYCLONE IS TOWARD THE
WEST-NORTHWEST OR 285/5. A MID-TROPOSPHERIC RIDGE OVER MEXICO IS
FORECAST BY ALL OF THE GLOBAL MODELS TO WEAKEN DURING THE NEXT 24
HOURS...WHICH SHOULD CAUSE DARBY TO SLOW DOWN AND BECOME NEARLY
STATIONARY. THEREAFTER...THE MODELS HAVE WILDLY DIVERGENT
SOLUTIONS...WITH THE HWRF CONTINUING A WESTWARD MOTION OF DARBY AND
THE ECMWF/UKMET SHOWING AN EASTWARD MOTION. MOST OF THIS
DISAGREEMENT IS CAUSED BY THE HANDLING OF THE SYSTEM OVER THE
NORTHWESTERN CARIBBEAN...AND WHETHER THE MUCH-SMALLER DARBY GETS
CAUGHT UP IN WESTERLY FLOW SOUTH OF MEXICO. IT IS BEST TO STAY
CLOSE TO THE MODEL CONSENSUS FOR NOW...AND THE NHC FORECAST IS
CLOSE TO THE PREVIOUS ONE...A LITTLE WEST OF THE DYNAMICAL MODEL
CONSENSUS.

DARBY IS THE EARLIEST SECOND MAJOR HURRICANE FORMATION IN THE
EASTERN PACIFIC SINCE RELIABLE RECORDS BEGAN IN 1971...ECLIPSING OF
THE PREVIOUS RECORD OF HURRICANE DANIEL ON JUNE 30 1978.


FORECAST POSITIONS AND MAX WINDS

INITIAL 25/2100Z 13.6N 101.5W 105 KT
12HR VT 26/0600Z 13.7N 102.3W 105 KT
24HR VT 26/1800Z 13.5N 103.3W 100 KT
36HR VT 27/0600Z 13.4N 103.8W 90 KT
48HR VT 27/1800Z 13.5N 104.2W 80 KT
72HR VT 28/1800Z 14.0N 103.5W 65 KT
96HR VT 29/1800Z 14.3N 102.7W 55 KT
120HR VT 30/1800Z 14.6N 102.0W 45 KT

$$
FORECASTER BLAKE

[HURAKAN]

Continues to get better

[cycloneye]

Sandy,update the ACE Pie at Talking Tropics thread to see how much more the EPAC has as of 2 PM PDT.

[KWT]

Darby looks good, nothing on the same level as the beatly Celia earlier today but it certainly has gained a major hurricane presentation, a very neat tight system thats for sure.

[Pedro Fernández]

Darby looks good, nothing on the same level as the beatly Celia earlier today but it certainly has gained a major hurricane presentation, a very neat tight system thats for sure.

I would even say that it is suffering a rapid intensification, like CELIA did... In the last satellite presentation I see DARBY better and better. I give my bet that DARBY will reach category 4.

[Pedro Fernández]

Reliable data in the last forecast discussion of the NHC about DARBY:

000
WTPZ45 KNHC 252044
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
200 PM PDT FRI JUN 25 2010

DARBY REMAINS A WELL-ORGANIZED HURRICANE WITH VISIBLE IMAGERY
SHOWING A DISTINCT EYE AND AN IMPRESSIVE OUTFLOW PATTERN. DVORAK
SATELLITE CLASSIFICATIONS FROM TAFB AND SAB AT 1800 UTC WERE
T5.5...102 KT. SINCE THAT TIME...THE SYSTEM HAS BECOME BETTER
ORGANIZED WITH DEEPER CONVECTION IN THE EYEWALL. THUS...THE INITIAL
INTENSITY IS NUDGED UPWARD TO 105 KT. EASTERLY SHEAR IS FORECAST
BY ALL OF THE GLOBAL MODELS TO INCREASE OVERNIGHT WHICH SHOULD
LIMIT FUTURE STRENGTHENING. THIS SHEAR WILL LIKELY PERSIST FOR
SEVERAL DAYS AND CAUSE DARBY TO GRADUALLY WEAKEN. MOST OF THE
INTENSITY GUIDANCE IS IN REASONABLE AGREEMENT ON THIS SCENARIO...
AND THE NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ADVISORY.

THE INITIAL MOTION OF THE TROPICAL CYCLONE IS TOWARD THE
WEST-NORTHWEST OR 285/5. A MID-TROPOSPHERIC RIDGE OVER MEXICO IS
FORECAST BY ALL OF THE GLOBAL MODELS TO WEAKEN DURING THE NEXT 24
HOURS...WHICH SHOULD CAUSE DARBY TO SLOW DOWN AND BECOME NEARLY
STATIONARY. THEREAFTER...THE MODELS HAVE WILDLY DIVERGENT
SOLUTIONS...WITH THE HWRF CONTINUING A WESTWARD MOTION OF DARBY AND
THE ECMWF/UKMET SHOWING AN EASTWARD MOTION. MOST OF THIS
DISAGREEMENT IS CAUSED BY THE HANDLING OF THE SYSTEM OVER THE
NORTHWESTERN CARIBBEAN...AND WHETHER THE MUCH-SMALLER DARBY GETS
CAUGHT UP IN WESTERLY FLOW SOUTH OF MEXICO. IT IS BEST TO STAY
CLOSE TO THE MODEL CONSENSUS FOR NOW...AND THE NHC FORECAST IS
CLOSE TO THE PREVIOUS ONE...A LITTLE WEST OF THE DYNAMICAL MODEL
CONSENSUS.

DARBY IS THE EARLIEST SECOND MAJOR HURRICANE FORMATION IN THE
EASTERN PACIFIC SINCE RELIABLE RECORDS BEGAN IN 1971...ECLIPSING OF
THE PREVIOUS RECORD OF HURRICANE DANIEL ON JUNE 30 1978.


FORECAST POSITIONS AND MAX WINDS

INITIAL 25/2100Z 13.6N 101.5W 105 KT
12HR VT 26/0600Z 13.7N 102.3W 105 KT
24HR VT 26/1800Z 13.5N 103.3W 100 KT
36HR VT 27/0600Z 13.4N 103.8W 90 KT
48HR VT 27/1800Z 13.5N 104.2W 80 KT
72HR VT 28/1800Z 14.0N 103.5W 65 KT
96HR VT 29/1800Z 14.3N 102.7W 55 KT
120HR VT 30/1800Z 14.6N 102.0W 45 KT

$$
FORECASTER BLAKE

[HURAKAN]

684
WTPZ45 KNHC 260237
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 PM PDT FRI JUN 25 2010

EVEN THOUGH DARBY HAS MAINTAINED A SMALL CENTRAL DENSE OVERCAST
DURING THE LAST SEVERAL HOURS...THE EYE TEMPERATURE HAS COOLED
AS THE EYE HAS BECOME MORE RAGGED. IN ADDITION...THE CLOUD
PATTERN HAS BECOME LESS SYMMETRIC...WITH RECENT SATELLITE IMAGES
INDICATING A SOMEWHAT ELONGATED APPEARANCE TO THE CONVECTIVE TOPS.
DVORAK SATELLITE CLASSIFICATIONS FROM TAFB AND SAB ARE 5.0/90KT AND
5.5/102 KT...RESPECTIVELY...WHILE ADVANCED OBJECTIVE DVORAK
ESTIMATES PEAKING EARLIER AROUND 5.5 HAVE BEGUN TO DECREASE. ON
THE BASIS OF RECENT TRENDS AND SLIGHTLY LOWER DVORAK INTENSITY
ESTIMATES...THE INITIAL INTENSITY IS LOWERED TO 100 KT. THE GLOBAL
MODELS CONTINUE TO INDICATE AN ABRUPT INCREASE IN EASTERLY VERTICAL
WIND SHEAR OVER DARBY WITHIN THE NEXT 6-12 HOURS...WITH THE SHEAR
POSSIBLY BECOMING RATHER STRONG AFTER 48 HOURS. THE OFFICIAL
INTENSITY FORECAST IS ADJUSTED DOWNWARD FROM THE PREVIOUS
ADVISORY...AND CLOSELY FOLLOWS THE SHIPS/LGEM INTENSITY GUIDANCE.
HOWEVER...DARBY COULD WEAKEN FASTER THAN FORECAST IF PERSISTENTLY
STRONG EASTERLY SHEAR DEVELOPS AND THE CURRENT INTENSITY FORECAST
IS OF LOW CONFIDENCE.

CENTER FIXES ARE A BIT TO THE RIGHT OF PREVIOUS ONES AND YIELD AN
INITIAL MOTION ESTIMATE OF 290/5. HOWEVER...RECENT SATELLITE
IMAGERY INDICATES THAT THE FORECAST TURN TOWARD THE WEST MAY
ALREADY BE OCCURRING. WATER VAPOR IMAGERY SHOWS DARBY ON THE
WESTERN EDGE OF MID- TO UPPER-TROPOSPHERIC RIDGING EXTENDING FROM
THE WESTERN CARIBBEAN THROUGH SOUTHERN MEXICO. MODEL GUIDANCE
INDICATES THAT THIS RIDGING WILL WEAKEN DURING THE NEXT 24 HOURS...
LEAVING DARBY IN A REGION OF WEAK ENVIRONMENTAL STEERING.
THEREAFTER...MODEL SOLUTIONS DIVERGE CONSIDERABLY...WITH ONE CAMP
OF MODELS NEARLY STALLING DARBY BEFORE MOVING IT ON A SLOW WESTWARD
TO NORTHWESTWARD COURSE. THE OTHER SET OF SOLUTIONS SHOWS THE
SMALL CYCLONE BEING DRAWN EASTWARD BY THE LARGE CIRCULATION
ASSOCIATED WITH TROPICAL DEPRESSION ONE ENTERING THE SOUTHERN GULF
OF MEXICO. THE NEW FORECAST TRACK IS ADJUSTED SLIGHTLY TO THE LEFT
AFTER 72 HOURS TO ACCOUNT FOR A SLIGHT WESTWARD SHIFT IN THE
GUIDANCE BUT NOT AS FAR WEST AS THE MULTI-MODEL CONSENSUS. GIVEN
THE DISAGREEMENT IN THE TRACK GUIDANCE...CONFIDENCE IN THE THE
OFFICIAL FORECAST IS LOW BEYOND ABOUT 48 HOURS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/0300Z 13.8N 102.2W 100 KT
12HR VT 26/1200Z 13.8N 103.0W 95 KT
24HR VT 27/0000Z 13.6N 103.7W 90 KT
36HR VT 27/1200Z 13.6N 104.2W 80 KT
48HR VT 28/0000Z 13.9N 104.3W 75 KT
72HR VT 29/0000Z 14.5N 103.0W 55 KT
96HR VT 30/0000Z 14.8N 102.6W 45 KT
120HR VT 01/0000Z 15.0N 102.5W 40 KT

$$
FORECASTER KIMBERLAIN

[Aquawind]

Serious Cane!

[Chacor]

WTPZ45 KNHC 260850
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
200 AM PDT SAT JUN 26 2010

DARBY IS AN INCREDIBLY SMALL HURRICANE. AN ASCAT PASS AROUND 0345
UTC INDICATED THAT TROPICAL STORM FORCE WINDS DO NOT EXTEND ANY
FARTHER THAN ABOUT 35 N MI FROM THE CENTER. THE HURRICANE HAD BEEN
MAINTAINING A SMALL 10-N MI WIDE EYE SURROUNDED BY DEEP
CONVECTION...WHICH SUPPORTED 0600 UTC DVORAK ESTIMATES OF T5.5 FROM
BOTH TAFB AND SAB. HOWEVER...THE EYE HAS RECENTLY BECOME
OBSCURED...AND THE MOST RECENT ADT ESTIMATE FROM UW-CIMSS IS T5.1.
THE INITIAL INTENSITY IS THEREFORE LOWERED TO 95 KT. VERTICAL
SHEAR IS EXPECTED TO INCREASE OVER DARBY OVER THE NEXT SEVERAL
DAYS...WHICH IS EXPECTED TO INDUCE GRADUAL WEAKENING. THE
WEAKENING IS EXPECTED TO BE MORE RAPID FROM 72-120 HOURS AS A
STRONG UPPER RIDGE BUILDS OVER MEXICO...CREATING FAIRLY STRONG
UPPER-LEVEL EASTERLY WINDS NEAR THE CYCLONE. THE NEW OFFICIAL
FORECAST CLOSELY FOLLOWS THE SHIPS AND LGEM INTENSITY
GUIDANCE...AND IS NOT TOO DIFFERENT FROM THE PREVIOUS ADVISORY.

DARBY HAS BEEN MOVING ALMOST WEST-SOUTHWESTWARD OVER THE PAST FEW
HOURS...AND THE INITIAL MOTION IS 260/5. THE STEERING CURRENTS
AROUND THE HURRICANE ARE STILL EXPECTED TO COLLAPSE THROUGH THE
FORECAST PERIOD...AND DARBY SHOULD BEGIN TO MOVE VERY SLOWLY
WESTWARD OVER THE NEXT 24-36 HOURS. THEREAFTER...THE CYCLONE IS
EXPECTED TO BEGIN FEELING THE INFLUENCE OF NEWLY-NAMED TROPICAL
STORM ALEX IN THE WESTERN CARIBBEAN. THE OFFICIAL FORECAST
INDICATES A SLOW NORTHEASTWARD MOTION BETWEEN DAYS 3 AND 5...BUT IT
SHOULD BE NOTED THAT THE GUIDANCE ENVELOPE IS STILL RATHER
DIVERGENT AND DARBY COULD DRIFT OR MEANDER IN PLACE FOR SEVERAL
DAYS. THE ECMWF SHOWS A QUICK NORTHEASTWARD MOTION AND BRINGS
DARBY TO THE MEXICAN COAST IN 3 DAYS...BUT THIS SOLUTION IS
DISCOUNTED AT THIS TIME.


FORECAST POSITIONS AND MAX WINDS

INITIAL 26/0900Z 13.5N 102.7W 95 KT
12HR VT 26/1800Z 13.4N 103.4W 90 KT
24HR VT 27/0600Z 13.4N 104.1W 85 KT
36HR VT 27/1800Z 13.6N 104.4W 75 KT
48HR VT 28/0600Z 13.9N 104.1W 70 KT
72HR VT 29/0600Z 14.3N 103.3W 55 KT
96HR VT 30/0600Z 14.7N 102.8W 45 KT
120HR VT 01/0600Z 15.0N 102.5W 35 KT

$$
FORECASTER BERG

[cycloneye]

000
WTPZ45 KNHC 261450
TCDEP5
HURRICANE DARBY DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 AM PDT SAT JUN 26 2010

COMPACT DARBY HAD CHANGED LITTLE THIS MORNING. ALTHOUGH THE PINHOLE
EYE HAS BECOME OBSCURED IN THE ENHANCED INFRARED IMAGERY...AN 0811
UTC AMSR-E MICROWAVE IMAGE INDICATED THAT THE EYE WAS STILL QUITE
INTACT NEAR THE SURFACE. ADDITIONALLY...A STRONG BANDING FEATURE
WAS EVIDENT OVER THE WEST AND NORTH PORTIONS OF THE SYSTEM. DVORAK
INTENSITY ESTIMATES AND AN ADVANCED OBJECTIVE DVORAK TECHNIQUE
ESTIMATE SUPPORT MAINTAINING THE ESTIMATE AT 95 KT FOR THIS
ADVISORY. EASTERLY SHEAR IS EXPECTED TO GRADUALLY INCREASE OVER
DARBY THROUGH THE FORECAST PERIOD...CAUSING THE CYCLONE TO WEAKEN.
THE OFFICIAL INTENSITY FORECAST IS BASED ON A BLEND OF THE SHIPS
MODEL AND THE LGEM...AND IS SIMILAR TO THE PREVIOUS FORECAST.

THE INITIAL MOTION IS ESTIMATED AT 260/3...WITHIN THE EASTERLY MID
TO UPPER TROPOSPHERIC STEERING FLOW OF A WEAKENING RIDGE TO THE
NORTH OF DARBY. DYNAMICAL MODELS INDICATE THAT THE AFOREMENTIONED
RIDGE WILL WEAKEN DURING THE NEXT DAY OR SO...CAUSING THE CYCLONE
TO DRIFT OR BECOME STATIONARY. BEYOND THE 36 HOUR PERIOD...AN
INCREASING WEAKNESS...POSSIBLY INFLUENCED BY TROPICAL STORM
ALEX...SHOULD INDUCE A GRADUAL NORTHEASTWARD MOTION. THIS EVENTUAL
TURN TOWARD THE NORTHEAST COULD COME MUCH LATER THAN
SUGGESTED...INDICATIVE OF A LARGE SPREAD IN THE MODELS DURING THIS
PARTICULAR PERIOD OF THE FORECAST. CONSEQUENTLY...THERE IS LOW
CONFIDENCE IN FORECAST TRACK AFTER THE 48 HOUR PERIOD. THE
OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS ONE...AND A LITTLE WEST
OF THE MULTI-MODEL CONSENSUS.



FORECAST POSITIONS AND MAX WINDS

INITIAL 26/1500Z 13.4N 102.9W 95 KT
12HR VT 27/0000Z 13.3N 103.5W 90 KT
24HR VT 27/1200Z 13.3N 104.0W 80 KT
36HR VT 28/0000Z 13.5N 104.1W 70 KT
48HR VT 28/1200Z 14.0N 103.7W 65 KT
72HR VT 29/1200Z 14.3N 103.0W 50 KT
96HR VT 30/1200Z 14.7N 102.5W 40 KT
120HR VT 01/1200Z 15.0N 102.3W 30 KT

$$
FORECASTER ROBERTS

[cycloneye]

HURRICANE DARBY DISCUSSION NUMBER 16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
200 PM PDT SAT JUN 26 2010

EARLIER THIS AFTERNOON...THE CIRCULATION CENTER OF DARBY BECAME
PARTIALLY EXPOSED TO THE EAST OF THE CENTRAL DENSE OVERCAST....
APPARENTLY DUE TO INCREASING EASTERLY SHEAR. SINCE THAT TIME...A
NEW BURST OF DEEP CONVECTION HAS DEVELOPED NEAR THE CENTER...BUT
THIS NEW CONVECTIVE ACTIVITY COULD BE TEMPORARY. DVORAK SATELLITE
CURRENT INTENSITY ESTIMATES ARE 85 KT FROM TAFB AND 95 KT FROM
SAB...BUT THEY ARE CONSTRAINED DUE TO RULES. THE CIMSS ADT AT 1745
UTC WAS 75 KT...WHICH SEEMS MUCH MORE REASONABLE SINCE SMALL...
COMPACT TROPICAL CYCLONES WEAKEN MORE RAPIDLY THAN A NORMAL
CLIMATOLOGICAL RATE. THEREFORE...THE INITIAL INTENSITY IS LOWERED
TO 75 KT. THE EASTERLY SHEAR SHOULD STRENGTHEN THROUGH THE
REMAINDER OF THE FORECAST...RESULTING IN FURTHER WEAKENING. THE
OFFICIAL INTENSITY FORECAST IS BASED ON THE SHIPS MODEL WHICH
INDICATES A QUICKER WEAKENING TREND.

THE INITIAL MOTION ESTIMATE IS A DRIFT OR 260/2...WITHIN THE
EASTERLY MID- TO UPPER-TROPOSPHERIC STEERING FLOW OF A WEAKENING
MID-LEVEL RIDGE EXTENDING WESTWARD OVER THE EASTERN TROPICAL
PACIFIC FROM MEXICO. LARGE-SCALE MODELS CONTINUE TO SUGGEST THAT
THE AFOREMENTIONED RIDGE WILL WEAKEN FURTHER DURING THE NEXT DAY OR
SO...ALLOWING DARBY TO MAINTAIN A SLOW...AND POSSIBLY ERRATIC...
WESTWARD MOTION. AFTERWARD...THE CYCLONE OR ITS REMNANTS SHOULD
GRADUALLY TURN NORTHEASTWARD AND CONTINUE ON THIS HEADING THROUGH
DAY 5. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY
WHICH CLOSELY FOLLOWS THE TVCN MULTI-MODEL CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/2100Z 13.4N 102.8W 75 KT
12HR VT 27/0600Z 13.4N 103.2W 65 KT
24HR VT 27/1800Z 13.5N 103.6W 60 KT
36HR VT 28/0600Z 13.8N 103.5W 55 KT
48HR VT 28/1800Z 14.2N 103.1W 50 KT
72HR VT 29/1800Z 14.5N 102.4W 40 KT
96HR VT 30/1800Z 14.9N 101.9W 35 KT
120HR VT 01/1800Z 15.2N 101.7W 30 KT

$$
FORECASTER ROBERTS/AVILA

[HURAKAN]

00z
EP, 05, 2010062700, , BEST, 0, 135N, 1029W, 60, 992, TS

[bahamaswx]

Alex's outflow wreaked havoc on poor old Darby.

[cycloneye]

000
WTPZ45 KNHC 270233
TCDEP5
TROPICAL STORM DARBY DISCUSSION NUMBER 17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052010
800 PM PDT SAT JUN 26 2010

ALTHOUGH THE CLOUD PATTERN ASSOCIATED WITH DARBY IN GEOSTATIONARY
SATELLITE IMAGERY REMAINS REASONABLY WELL ORGANIZED...THERE IS
EVIDENCE THAT DARBY IS BEGINNING TO UNRAVEL RATHER QUICKLY. A 2040
UTC AMSR-E OVERPASS REVEALED A PARTIALLY EXPOSED LOW-LEVEL CENTER
EAST OF A PLUME OF CONVECTION...INDICATING THAT EASTERLY VERTICAL
SHEAR IS TAKING A TOLL ON THE CYCLONE. ADDITIONALLY...THE LAST
VISIBLE IMAGES SUGGEST THAT THE LOW-LEVEL CENTER HAS SEPARATED FROM
THE MID-LEVEL CENTER...BEING DISPLACED BY NEARLY A DEGREE TO THE
NORTHWEST. DVORAK SATELLITE CLASSIFICATIONS ARE 4.0 FROM TAFB AND
SAB BUT CONTINUE TO BE CONSTRAINED BY RULES WHILE 3-HOURLY AVERAGED
UW-CIMSS AODT VALUES ARE AROUND 3.5. GIVEN THE RAPID LOSS IN
ORGANIZATION AND THE LOWER AODT VALUES...THE INITIAL INTENSITY IS
LOWERED TO 60 KT. SHIPS MODEL ANALYSES INDICATE MODERATE EASTERLY
VERTICAL WIND SHEAR OVER DARBY WHICH IS ONLY FORECAST TO BECOME
STRONGER AFTER 24 HOURS...AND SHOULD RESULT IN CONTINUED WEAKENING.
THE OFFICIAL FORECAST CLOSELY FOLLOWS THE SHIPS/LGEM INTENSITY
GUIDANCE...CALLING FOR DARBY BECOME A REMNANT LOW IN 3 DAYS...IF
NOT SOONER.

THE AFOREMENTIONED AMSR-E OVERPASS WAS HELPFUL IN DETERMINING THE
INITIAL MOTION ESTIMATE OF 270/2. DARBY IS EMBEDDED IN A WEAK
WESTERLY LOW-LEVEL FLOW ON THE PERIPHERY OF THE LARGE CIRCULATION
ASSOCIATED WITH TROPICAL STORM ALEX AND STRONGER EASTERLY FLOW
ALOFT. THE RESULTING DEEP-LAYER MEAN FLOW SHOULD CARRY THE CYCLONE
ON A SLOW WESTWARD COURSE FOR THE NEXT 12 HOURS OR SO. THEREAFTER
...AS DARBY WEAKENS FURTHER AND BECOMES A SHALLOWER CYCLONE...IT AND
EVENTUALLY ITS REMNANTS WILL BE DRAWN EAST-NORTHEASTWARD OR
NORTHEASTWARD WITHIN THE DOMINANT CIRCULATION OF ALEX...WHICH IS
FORECAST TO MOVE OVER THE EXTREME SOUTHWESTERN GULF OF MEXICO
DURING THE NEXT FEW DAYS. THE NEW FORECAST TRACK IS ADJUSTED
SHARPLY TO THE RIGHT RIGHT...BUT NOT AS FAR RIGHT AS THE
MULTI-MODEL CONSENSUS...TO ACCOUNT FOR A SIGNIFICANT EASTWARD
SHIFT IN THE MODEL GUIDANCE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/0300Z 13.5N 103.0W 60 KT
12HR VT 27/1200Z 13.5N 103.3W 45 KT
24HR VT 28/0000Z 13.7N 103.2W 40 KT
36HR VT 28/1200Z 14.0N 102.7W 35 KT
48HR VT 29/0000Z 14.4N 102.0W 30 KT
72HR VT 30/0000Z 15.0N 101.0W 25 KT...POST-TROP/REMNT LOW
96HR VT 01/0000Z...DISSIPATED

$$
FORECASTER KIMBERLAIN