ATL: PHILIPPE - Post - Tropical - Discussion

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 44
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 PM AST TUE OCT 04 2011

THE STRUCTURE OF PHILIPPE HAS AGAIN CHANGED LITTLE SINCE THE LAST
ADVISORY. CONVENTIONAL AND MICROWAVE SATELLITE DATA SHOW THAT THE
LOW-LEVEL CENTER IS LOCATED NEAR THE NORTHWESTERN EDGE OF THE
CONVECTION...WITH THE MICROWAVE IMAGERY SUGGESTING A MID-LEVEL EYE
IS SOUTHEAST OF THE SURFACE CENTER. SATELLITE INTENSITY ESTIMATES
ARE 55 KT FROM TAFB AND 45 KT FROM SAB...AND...BASED ON THIS AND
THE LACK OF CHANGE IN ORGANIZATION...THE INITIAL INTENSITY REMAINS
55 KT.

PHILIPPE HAS BEGUN ITS FORECAST NORTHWARD TURN WITH THE INITIAL
MOTION NOW 300/6. THE CYCLONE IS NEAR THE WESTERN END OF THE
SUBTROPICAL RIDGE...WITH WATER VAPOR AND INFRARED IMAGERY SHOWING A
DEEP-LAYER TROUGH AND ASSOCIATED SURFACE COLD FRONT TO THE
NORTHWEST. ALL GUIDANCE AGREES THAT PHILIPPE SHOULD RECURVE ON THE
EASTERN SIDE OF THE TROUGH DURING THE NEXT 48-72 HOURS. HOWEVER...
THERE IS A SIGNIFICANT SPREAD IN THE TRACK GUIDANCE BASED ON THE
MODEL FORECASTS OF THE EVENTUAL FATE OF PHILIPPE. THE GFS...
CANADIAN...NOGAPS...GFDL...AND HWRF MODELS SHOW THE CYCLONE
REMAINING STRONG THROUGH EXTRATROPICAL TRANSITION AND FORECAST A
NORTHWARD OR EVEN WEST OF NORTH MOTION BY 120 HOURS AS PHILIPPE
MERGES WITH THE TROUGH. THE ECMWF AND UKMET SHOW A MUCH WEAKER
PHILIPPE MOVING EASTWARD AHEAD OF THE COLD FRONT THAT EVENTUALLY
ABSORBS THE TROPICAL CYCLONE. THE OFFICIAL FORECAST FOLLOWS THE
EXTRATROPICAL TRANSITION SCENARIO AND SHOWS PHILIPPE TURNING
NORTHWARD BY 120 HOURS. THE NEW FORECAST IS FASTER THAN THE
PREVIOUS FORECAST...BUT IS SLOWER THAN THE MODEL CONSENSUS.

WHILE PHILIPPE REMAINS UNDER NORTHERLY VERTICAL WIND SHEAR...
ANALYSES FROM THE SHIPS MODEL AND CIMSS AT THE UNIVERSITY OF
WISCONSIN SUGGEST THE SHEAR IS GRADUALLY DECREASING. THE DYNAMICAL
MODELS SUGGESTS THERE WILL BE A 36-48 HOUR WINDOW OF MORE FAVORABLE
CONDITIONS AS THE CYCLONE PASSES THROUGH AN UPPER-LEVEL RIDGE...AND
MOST OF THE INTENSITY GUIDANCE RESPONDS TO THIS BY FORECASTING
INTENSIFICATION. AFTER 48 HOURS...THE SHEAR SHOULD INCREASE
AGAIN...WITH EXTRATROPICAL TRANSITION FORECAST TO START AT AROUND
96 HOURS AND FINISH BY 120 HOURS. THE NEW INTENSITY FORECAST IS
UNCHANGED FROM THE PREVIOUS ADVISORY AND IS IN BEST AGREEMENT WITH
THE SHIPS AND LGEM MODELS. IT SHOULD BE NOTED THAT THE GFDL AND
HWRF MODELS FORECAST A HIGHER PEAK INTENSITY THAN SHIPS AND
LGEM...SO IT CANNOT BE RULED OUT THAT PHILIPPE COULD BE STRONGER
THAN CURRENTLY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 24.6N 60.4W 55 KT 65 MPH
12H 05/1200Z 25.3N 61.1W 55 KT 65 MPH
24H 06/0000Z 26.1N 61.5W 60 KT 70 MPH
36H 06/1200Z 27.2N 60.9W 65 KT 75 MPH
48H 07/0000Z 28.4N 59.6W 65 KT 75 MPH
72H 08/0000Z 30.5N 54.5W 60 KT 70 MPH
96H 09/0000Z 35.0N 48.0W 55 KT 65 MPH
120H 10/0000Z 40.5N 45.5W 55 KT 65 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BEVEN

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 45
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST WED OCT 05 2011

PHILIPPE CONTINUES TO HAVE A SHEARED PRESENTATION ON SATELLITE
IMAGES...ALTHOUGH THERE IS SOME EVIDENCE OF A VERY RAGGED EYE
OCCASIONALLY. DVORAK ESTIMATES ARE UNCHANGED FROM SIX HOURS
AGO...SO THE INITIAL INTENSITY WILL REMAIN 55 KT. MOST OF THE
GLOBAL MODELS SUGGEST THAT PHILIPPE WILL MOVE BENEATH AN UPPER-
LEVEL RIDGE AXIS LATER TODAY...RESULTING IN A PERIOD OF LOWER SHEAR
LASTING FOR A DAY OR SO. ALL OF THE MODELS SHOW SOME
INTENSIFICATION DURING THAT PERIOD...AND THE OFFICIAL FORECAST
FOLLOWS THAT SOLUTION...ALBEIT ON THE LOWER END OF THE GUIDANCE
SPECTRUM BELOW THE MODEL CONSENSUS. AFTER THAT TIME...
SOUTHWESTERLY SHEAR SHOULD SIGNIFICANTLY INCREASE DUE TO A LARGE
TROUGH OVER THE WESTERN ATLANTIC. USUALLY A MORE SIGNIFICANT
WEAKENING WOULD BE CALLED FOR WITH SUCH STRONG SHEAR...BUT ONLY A
MINOR DECREASE IN STRENGTH IS FORECAST DUE TO SIGNIFICANT
BAROCLINIC FORCING. EXTRATROPICAL TRANSITION IS EXPECTED BY DAY
4...AND IT IS WORTH NOTING THAT MOST OF THE GLOBAL GUIDANCE EVEN
HAVE PHILIPPE EXTRATROPICAL NEAR DAY 3 IN THE LATEST RUNS...BUT I
DID NOT WANT TO SHOW SUCH A LARGE CHANGE FROM THE PREVIOUS
FORECAST.

SOME COARSE AMSU DATA SUGGEST THAT THE TROPICAL CYCLONE IS MOVING AT
300/5...ABOUT THE SAME AS PREVIOUS. A RELATIVELY SHARP TURN TO THE
NORTH AND NORTHEAST IS LIKELY WITHIN A DAY OR SO DUE TO THE
AFOREMENTIONED TROUGH OVER THE WESTERN ATLANTIC. THIS TROUGH
SHOULD ALSO CAUSE PHILIPPE TO MOVE AT AN INCREASING PACE BY LATE
THURSDAY AS THE TROPICAL CYCLONE IS STEERED BY THE STRONGER
MID-LATITUDE FLOW. THE NEW FORECAST IS CLOSE TO THE PREVIOUS
ONE...BUT IS A BIT FASTER TO ACCOUNT FOR RECENT MODEL TRENDS. THE
EXTRATROPICAL TRANSITION APPEARS TO BE A DIFFICULT ONE TO
FORECAST...WITH THE MAIN DISAGREEMENT BEING WHETHER PHILIPPE WILL
BECOME THE MAIN NON-TROPICAL LOW OR BECOME ABSORBED INTO THE LARGER
EXTRATROPICAL CYCLONE. GIVEN THE SMALL SIZE OF PHILIPPE...THE NHC
FORECAST WILL GO WITH THE ABSORBED SCENARIO.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 24.7N 60.8W 55 KT 65 MPH
12H 05/1800Z 25.3N 61.4W 55 KT 65 MPH
24H 06/0600Z 26.5N 61.2W 60 KT 70 MPH
36H 06/1800Z 27.8N 60.1W 65 KT 75 MPH
48H 07/0600Z 28.9N 58.2W 60 KT 70 MPH
72H 08/0600Z 31.5N 52.0W 55 KT 65 MPH
96H 09/0600Z 38.0N 46.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 10/0600Z...ABSORBED

$$
FORECASTER BLAKE

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 46
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 AM AST WED OCT 05 2011

PERSISTENT PHILIPPE CONTINUES AS A SHEARED TROPICAL CYCLONE WITH
VERY COLD CLOUD TOPS AND FREQUENT LIGHTNING ON THE DOWNSHEAR...OR
SOUTHEAST...SIDE OF THE CENTER. INTENSITY ESTIMATES RANGE FROM
40 KT FROM AN 0839Z AMSU CIMSS ANALYSIS ON THE LOW END TO 55 KT
FROM THE TAFB DVORAK CURRENT INTENSITY NUMBER ON THE HIGH END. 55
KT IS RETAINED AS THE INITIAL INTENSITY...THOUGH THIS COULD BE
SLIGHTLY GENEROUS. THE 34 KT WIND RADII WAS ADJUSTED OUTWARD SOME
BASED UPON THE 0839Z AMSU CIRA SIZE ANALYSIS.

A PAIR OF MICROWAVE IMAGES FROM FNMOC JUST BEFORE SYNOPTIC TIME
ALLOWS FOR A FAIRLY ACCURATE INITIAL POSITION. BASED UPON THIS AND
THE FIRST VISIBLE IMAGES THIS MORNING THAT SUGGEST THAT THE CENTER
IS JUST TUCKED IN UNDERNEATH THE OVERCAST...AN INITIAL MOTION OF
310/5 IS ANALYZED. THE CYCLONE IS ROUNDING THE SOUTHWESTERN
PERIPHERY OF A DEEP-LAYER RIDGE AND RECURVATURE SHOULD COMMENCE
SHORTLY. THE GLOBAL AND HURRICANE REGIONAL MODELS ARE IN GOOD
AGREEMENT THAT A STRONG MID-LATITUDE TROUGH WILL TURN PHILIPPE
TOWARD THE NORTHEAST BY TOMORROW WITH INCREASING FORWARD SPEED.
THE TRACK FORECAST IS BASED UPON THE HURRICANE FORECAST IMPROVEMENT
PROGRAM MULTI-MODEL CONSENSUS AND IS NEARLY THE SAME AS THE
PREVIOUS ADVISORY.

PHILIPPE HAS A SHORT WINDOW OF OPPORTUNITY TO BECOME A HURRICANE.
THE WATER TEMPERATURES SHOULD REMAIN A WARM 28C UNDER THE TRACK OF
THE CYCLONE FOR THE NEXT TWO TO THREE DAYS. HOWEVER...THE SYSTEM
HAS ONLY ABOUT 24 HOURS OF MODERATE VERTICAL SHEAR BEFORE THE
AFOREMENTIONED TROUGH CAUSES THE SHEAR TO INCREASE DRAMATICALLY.
ADDITIONALLY...PHILIPPE IS SURROUNDED BY QUITE DRY AIR AS SHOWN IN
THE TOTAL PRECIPITABLE WATER IMAGERY...THOUGH NOT MUCH OF THAT MAY
ACTUALLY BE REACHING THE CENTER OF THE STORM. THE INTENSITY
GUIDANCE IS QUITE DIVERSE WITH LGEM AND SHIPS STATISTICAL MODELS
SHOWING LITTLE TO NO INTENSIFICATION...WHILE THE GFDL AND HWRF
DYNAMICAL MODELS ARE MUCH MORE AGGRESSIVE IN SPINNING UP THE
CYCLONE. THE INTENSITY FORECAST IS CLOSE TO THE HFIP IV15
CONSENSUS THROUGH TWO DAYS AND THEN NEAREST TO THE SHIPS MODEL
THEREAFTER...WITH LITTLE CHANGE FROM THAT INDICATED IN THE PREVIOUS
ADVISORY. EXTRATROPICAL TRANSITION IS UNANIMOUS BY ALL OF THE
DYNAMICAL GUIDANCE TO OCCUR BY 72 HOURS...WHICH IS WHEN THE
OFFICIAL FORECAST SHOWS THE TRANSITION. AN 120 HOUR POINT IS
INCLUDED HERE AS ALL OF THE GUIDANCE...WITH THE PROMINENT EXCEPTION
OF THE ECWMF WHICH KILLS OFF THE STORM AFTER 72 HOURS... CONTINUES
PHILIPPE AS AN EXTRATROPICAL SYSTEM THROUGH AT LEAST FIVE DAYS.
THE OCEAN PREDICTION CENTER PROVIDED TRACK AND INTENSITY GUIDANCE
AT DAYS FOUR AND FIVE.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 25.3N 61.3W 55 KT 65 MPH
12H 06/0000Z 26.0N 61.6W 60 KT 70 MPH
24H 06/1200Z 27.0N 60.8W 65 KT 75 MPH
36H 07/0000Z 28.2N 59.5W 60 KT 70 MPH
48H 07/1200Z 29.3N 57.0W 55 KT 65 MPH
72H 08/1200Z 34.0N 50.0W 55 KT 65 MPH
96H 09/1200Z 40.5N 45.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 10/1200Z 46.0N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
FORECASTER LANDSEA/BROWN

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 47
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 PM AST WED OCT 05 2011

THE OVERALL ORGANIZATION OF PHILIPPE HAS IMPROVED SLIGHTLY. A 1753
UTC TRMM OVERPASS SHOWS THAT THE CENTER REMAINS NEAR THE
NORTHWESTERN EDGE OF THE MAIN CONVECTIVE MASS...WITH SOME INCREASE
IN BANDING EVIDENT IN THE MICROWAVE IMAGERY. IN ADDITION...RECENT
GEOSTATIONARY IMAGERY INDICATES THAT CONVECTION HAS RECENTLY
DEVELOPED OVER THE NORTHWESTERN PORTION OF THE CIRCULATION FOR THE
FIRST TIME IN SEVERAL DAYS. HOWEVER...DVORAK SATELLITE ESTIMATES
STILL SUPPORT AN INITIAL INTENSITY OF AROUND 55 KT. IT SEEMS THAT
THE SHEAR OVER THE CYCLONE IS FINALLY DECREASING AS PREDICTED AND
PHILIPPE HAS A VERY SMALL WINDOW OF OPPORTUNITY FOR STRENGTHENING.
THE REDUCTION IN SHEAR IS EXPECTED TO BE SHORT-LIVED AS STRONG
WESTERLY UPPER-LEVEL WINDS ASSOCIATED WITH A LARGE MID-LATITUDE
TROUGH MOVING INTO THE WESTERN ATLANTIC IMPINGE UPON THE CYCLONE ON
THURSDAY. AFTER THAT...THE SHEAR IS FORECAST TO INCREASE FURTHER
AND PHILIPPE WILL ALSO BE INTERACTING WITH A FRONT IN 2 TO 3 DAYS.
THE OFFICIAL INTENSITY FORECAST IS AT OR JUST ABOVE THE STATISTICAL
GUIDANCE DURING THE NEXT COUPLE OF DAYS...BUT IS MUCH BELOW THE
MORE AGGRESSIVE HWRF AND GFDL MODELS. BY 72 HOURS...THE GLOBAL
MODELS UNANIMOUSLY SHOW PHILIPPE BECOMING EXTRATROPICAL AND SO DOES
THE OFFICIAL FORECAST.

PHILIPPE HAS TURNED NORTHWARD WITH AN INITIAL MOTION OF 360/5 KT.
THE TRACK FORECAST REASONING REMAINS UNCHANGED FROM THE PREVIOUS
ADVISORY. PHILIPPE IS EXPECTED TO TURN NORTHEASTWARD AND
ACCELERATE AHEAD OF THE AFOREMENTIONED TROUGH DURING THE NEXT
COUPLE OF DAYS. THE TRACK GUIDANCE IS IN RELATIVELY GOOD
AGREEMENT...HOWEVER THE GUIDANCE IS A LITTLE SLOWER THAN 6 HOURS AGO
IN MOVING THE EXTRATROPICAL CYCLONE NORTHEASTWARD BETWEEN DAYS 4
AND 5. AS A RESULT...THE NEW TRACK SHOWS LESS NORTHEASTWARD MOTION
THAN THE PREVIOUS ADVISORY NEAR THE END OF THE FORECAST PERIOD.

FORECAST POSITIONS AND MAX WINDS

INIT 05/2100Z 25.8N 61.3W 55 KT 65 MPH
12H 06/0600Z 26.6N 61.1W 60 KT 70 MPH
24H 06/1800Z 27.8N 59.9W 65 KT 75 MPH
36H 07/0600Z 28.8N 57.9W 60 KT 70 MPH
48H 07/1800Z 29.9N 55.2W 55 KT 65 MPH
72H 08/1800Z 35.0N 48.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 09/1800Z 41.5N 44.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 10/1800Z 45.0N 41.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BROWN

[CrazyC83]

I wonder if Philippe will set a record for highest ACE by a storm that fails to reach hurricane intensity?

[Ad Novoxium]

It's currently sitting at about 10. The record is 15.63250, set by this freak of nature:



It may happen, but it's not too likely.

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 48
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 PM AST WED OCT 05 2011

PHILIPPE HAS CHANGED LITTLE IN ORGANIZATION DURING THE PAST SEVERAL
HOURS. THE LOW-LEVEL CENTER IS LOCATED NEAR THE WESTERN EDGE OF
THE CENTRAL CONVECTION...WHILE AN OUTER CONVECTIVE BAND IS PRESENT
IN THE EASTERN SEMICIRCLE. SATELLITE INTENSITY ESTIMATES REMAIN 65
KT FROM TAFB AND 55 KT FROM SAB...SO THE INITIAL INTENSITY REMAINS
55 KT. ANALYSES FROM THE SHIPS MODEL AND CIMSS AT THE UNIVERSITY
OF WISCONSIN SHOW THAT THE VERTICAL WIND SHEAR HAS DECREASED TO
ABOUT 10 KT.

THE INITIAL MOTION IS NOW 010/6. PHILIPPE IS RECURVING TO THE EAST
OF A DEEP-LAYER TROUGH AND ASSOCIATED SURFACE COLD FRONT OVER THE
WESTERN ATLANTIC...AND THE TRACK GUIDANCE IS NOW IN GOOD AGREEMENT
THAT THE CYCLONE WILL MOVE GENERALLY NORTHEASTWARD WITH SOME
ACCELERATION DURING THE NEXT 5 DAYS. A MORE NORTHERLY MOTION MAY
OCCUR AFTER 72 HOURS AS THE CYCLONE BECOMES EXTRATROPICAL AND
MERGES WITH THE DEEP-LAYER TROUGH...AND THIS IS REFLECTED IN THE
FORECAST TRACK. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS
TRACK AND LIES IN THE MIDDLE OF THE TRACK GUIDANCE ENVELOPE.

WHILE PHILIPPE HAS NOT YET STRENGTHENED...THERE WILL BE A 12-24 HOUR
PERIOD OF LIGHT TO MODERATE SHEAR BEFORE THE CYCLONE ENCOUNTERS THE
STRONGER WESTERLIES TO THE NORTH. FOR THE MOST PART...THE
INTENSITY GUIDANCE STILL CALLS FOR PHILIPPE TO BECOME A HURRICANE
DURING THAT TIME...AND SO DOES THE INTENSITY FORECAST. AFTER 24
HOURS...INCREASING SHEAR SHOULD CAUSE A WEAKENING TREND.
EXTRATROPICAL TRANSITION SHOULD BEGIN IN ABOUT 48 HOURS AND BE
COMPLETE BY 72 HOURS. THE DYNAMICAL MODELS AGREE ON PHILIPPE
MAINTAINING GALE TO STORM INTENSITY AS AN EXTRATROPICAL LOW...AND
THIS IS REFLECTED IN THE INTENSITY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 26.4N 61.0W 55 KT 65 MPH
12H 06/1200Z 27.4N 60.4W 60 KT 70 MPH
24H 07/0000Z 28.5N 58.8W 65 KT 75 MPH
36H 07/1200Z 29.3N 56.5W 60 KT 70 MPH
48H 08/0000Z 30.8N 53.1W 55 KT 65 MPH
72H 09/0000Z 37.0N 45.5W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 10/0000Z 43.5N 41.5W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 11/0000Z 52.0N 33.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BEVEN

[bg1]

http://weather.unisys.com/hurricane/atl ... /track.gif

This storm lasted 17 days without becoming a hurricane. Philippe probably will turn extratropical after lasting 15 days, so it does not look likely that it will break any records.

[CrazyC83]

With one agency reporting T4.0 per the NHC discussion and ASCAT constantly showing an overperformance, I would have moved up to 65 kt here.

[bexar]

Philippe sure is taking a long time to reach hurricane status. What's even more weird is that the GFDL makes Philippe a Category 4 hurricane too.

[bexar]

now almost a hurricane at 60 KTs

[HenkL]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 49
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST THU OCT 06 2011

PHILIPPE HAS BECOME A LITTLE BETTER ORGANIZED DURING THE PAST
SEVERAL HOURS WITH CONVECTION INCREASING NEAR THE CENTER AND A MORE
SYMMETRIC OVERALL CLOUD PATTERN. MICROWAVE DATA FROM EARLIER ALSO
SHOW THAT A LOW-LEVEL EYE FEATURE HAS BECOME BETTER DEFINED...
THOUGH NOTHING RECENT HAS BEEN RECEIVED. A BLEND OF THE DVORAK
ESTIMATES FROM TAFB/SAB GIVES AN INITIAL INTENSITY OF 60 KT.
FURTHER INTENSIFICATION SEEMS LIKELY WITH ONLY MODERATE
SOUTHWESTERLY SHEAR AND WARM WATER CONDITIONS EXPECTED FOR THE NEXT
DAY OR SO. THUS THE OFFICIAL FORECAST CONTINUES TO SHOW PHILIPPE
ATTAINING HURRICANE STATUS LATER TODAY...WITH WEAKENING COMMENCING
BY LATE TOMORROW DUE TO INCREASING SHEAR. EXTRATROPICAL TRANSITION
WILL LIKELY START IN ABOUT 48 HOURS...AND BE COMPLETE BY DAY 3.

THE INITIAL MOTION IS NOW 030/7. PHILIPPE IS EXPECTED TO FURTHER
ACCELERATE TODAY AHEAD OF A DEEP-LAYER TROUGH AND ASSOCIATED
SURFACE COLD FRONT OVER THE WESTERN ATLANTIC. THE TRACK GUIDANCE
REMAINS IN GOOD AGREEMENT THAT THE CYCLONE WILL MOVE GENERALLY TO
THE NORTHEAST OR EAST-NORTHEAST WITH SOME ACCELERATION AS A
TROPICAL CYCLONE. THE NEW FORECAST IS BASICALLY AN UPDATE OF THE
PREVIOUS ONE THROUGH 48 HOURS. THE MODELS ARE IN MUCH POORER
AGREEMENT DURING THE EXTRATROPICAL PORTION OF THE TRACK...AND THE
OFFICIAL FORECAST IS VERY CLOSE TO GUIDANCE RECEIVED FROM THE OCEAN
PREDICTION CENTER IN THE LATER PERIODS...WHICH RESULTS IN A SLOWER
FORECAST THAN PREVIOUS.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0900Z 26.8N 60.6W 60 KT 70 MPH
12H 06/1800Z 27.8N 59.8W 65 KT 75 MPH
24H 07/0600Z 28.8N 58.1W 70 KT 80 MPH
36H 07/1800Z 29.7N 55.1W 65 KT 75 MPH
48H 08/0600Z 31.2N 51.6W 60 KT 70 MPH
72H 09/0600Z 38.0N 45.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 10/0600Z 42.0N 42.5W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 11/0600Z 49.0N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BLAKE

[dwsqos2]

06/1145 UTC 27.3N 60.4W T4.0/4.0 PHILIPPE -- Atlantic

SAB finally hit T4.0.

[brunota2003]

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

I still am not sure if my first forecast verified, Philippe may have been at 65 knots the other day before weakening during the day.

I have looked and another indicator has popped up. With shear having decreased and Philippe looking more like a borderline hurricane, I feel that RI is likely. However, I do think that if RI occurs, it should be borderline 30 to 35 knots. The indicator popped up at 11 UTC (7 am EDT), so I'm going with RI starting around 17 to 19 UTC (1 to 3 pm EDT). Going off of 60 knots (5 am advisory), that puts the intensity by 12 pm tomorrow at 90 to 95 knots...or Cat 2.

[brunota2003]

And, per BT, Philippe has become our next hurricane:

AL, 17, 2011100612, , BEST, 0, 274N, 604W, 65, 987, HU

[Macrocane]

Thouhg it's not official yet, 5 hurricanes is not that bad I think it's near average for this time of year and we're above average in terms of tropical storms and major hurricanes.

[dwsqos2]

We're above the 1968-2010 seasonal ACE average (94.5). Actually, if you use values from the ATCF directory, then the 2011 season is above the 1981-2010 seasonal ACE average (104). So, hurricane counts aside, it's fair to call this season above average.

In terms of activity it reminds me very much of the 2000 and 2001 seasons, particularly the former.

And Philippe will make hurricane number three to benefit from enhanced upper-level divergence from interaction with an upper trough (Maria, Ophelia, Philippe).

http://i55.tinypic.com/122m0xd.gif

[CrazyC83]

Could Philippe go into RI mode like Ophelia did?

[cycloneye]

HURRICANE PHILIPPE DISCUSSION NUMBER 50
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 AM AST THU OCT 06 2011

AFTER 49 PREVIOUS ADVISORIES...OVER TWELVE DAYS...PHILIPPE HAS
FINALLY BECOME A HURRICANE. A 1009Z SSM/IS MICROWAVE IMAGE
FROM FNMOC SHOWS AN EYE-LIKE FEATURE...WHILE GEOSTATIONARY
SATELLITE IMAGERY INDICATES A SYMMETRIC COLD CLOUD COVER WITH AN
EYE PERHAPS BECOMING VISIBLE. SUBJECTIVE DVORAK ESTIMATES FROM
TAFB AND SAB ARE AT 4.5 AND 4.0... RESPECTIVELY...AND THE CIMSS
ADVANCED DVORAK TECHNIQUE SPLITS THE DIFFERENCE BETWEEN THE TWO.
THE INTENSITY IS SET AT 70 KT AT ADVISORY TIME.

PHILIPPE IS BEING STEERED TOWARD THE NORTH-NORTHEAST AT ABOUT 8
KT...PRIMARILY DUE TO THE INFLUENCE OF A LARGE DEEP-LAYER
EXTRATROPICAL LOW CENTERED OVER THE CANADIAN MARITIMES. THE
MULTI-MODEL CONSENSUS IS IN VERY GOOD AGREEMENT ON AN ACCELERATION
OF PHILIPPE GENERALLY TOWARD THE NORTHEAST DURING THE NEXT FEW
DAYS. THE TRACK PREDICTION IS VERY CLOSE TO BOTH THE CONSENSUS AND
THE PREVIOUS ADVISORY.

WHILE PHILIPPE HAS REACHED HURRICANE INTENSITY...THIS PEAK WILL
LIKELY BE SHORT-LIVED. AS THE CYCLONE MOVES CLOSER TO THE
AFOREMENTIONED EXTRATROPICAL LOW...THE VERTICAL WIND SHEAR SHOULD
INCREASE DRASTICALLY WITHIN THE NEXT 24 HOURS. SO WHILE THE SEA
SURFACE TEMPERATURES REMAIN WARM UNDER THE TRACK OF PHILIPPE FOR
THE NEXT TWO DAYS OR SO...THE COMBINED EFFECT OF SHEAR AND PERHAPS
ADVECTION OF DRIER AIR INTO THE CENTER OF THE CYCLONE SHOULD LEAD
TO GRADUAL WEAKENING. THE INTENSITY FORECAST FOR THE NEXT TWO DAYS
IS BASED UPON THE LGEM AND SHIPS STATISTICAL-DYNAMICAL INTENSITY
MODELS...AS THE PURELY DYNAMICAL HURRICANE GUIDANCE APPEARS TO BE
UNREALISTICALLY IMPERVIOUS TO THE MORE HOSTILE CONDITIONS AND
CONSEQUENTLY CONTINUE TO INTENSIFY THE HURRICANE. AROUND 48
HOURS...EXTRATROPICAL TRANSITION SHOULD OCCUR AS A COLD FRONT WRAPS
AROUND THE CYCLONE. IT IS NOTED THAT THE FSU CYCLONE PHASE SPACE
ANALYSES SUGGEST THAT THE SYSTEM COULD BECOME EXTRATROPICAL AS
EARLY AS TOMORROW...THOUGH THIS WOULD APPEAR TO BE TOO QUICK A
TRANSITION.

THE EXTRATROPICAL PORTION OF THE FORECAST IS BASED PRIMARILY ON
GUIDANCE FROM THE OCEAN PREDICTION CENTER.

FORECAST POSITIONS AND MAX WINDS

INIT 06/1500Z 27.8N 60.0W 70 KT 80 MPH
12H 07/0000Z 28.6N 59.0W 70 KT 80 MPH
24H 07/1200Z 29.6N 56.7W 65 KT 75 MPH
36H 08/0000Z 31.0N 53.4W 60 KT 70 MPH
48H 08/1200Z 33.4N 49.3W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 09/1200Z 39.5N 45.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 10/1200Z 45.0N 41.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 11/1200Z 51.5N 37.5W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
FORECASTER LANDSEA/PASCH

[dwsqos2]

This will be in a much higher shear environment than Ophelia, so no nothing like that is likely.

Microwave imagery from 1245Z was quite impressive.

http://i54.tinypic.com/35auhxx.jpg

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.