ATL: PHILIPPE - Post - Tropical - Discussion

[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.

I see signs that Philippe may strengthen more than I originally guessed. I think he might even make a run for Cat 3, because RI hasn't even really started yet (off my predicted times). Peak might be closer to 100 knots.

[Macrocane]

I believe he could reach cat 2, he's really a fighter surviving the shear and dry air for 12 days and finally becoming a hurricane, good for him!

[Epsilon_Fan]

looks like he's starting to ramp up like Ophelia did... the eye is poking out. This may easily get to Cat 2, maybe low end 3 as long as conditions stay favorable for 12-24 hours

[Hurricanehink]

I agree it looks like it's ramping up. The small eye has gotten better defined over the past few hours. I think it could be upped to C2 at 5, and a major isn't out of the question (albeit rather unlikely).

[cycloneye]

Dvorak numbers go up.

06/1745 UTC 28.2N 59.6W T4.5/4.5 PHILIPPE -- Atlantic

[Macrocane]

75 kt is the intensity according to the latest advisory, even the forecasters think it's conservative I would have put the intensity at 85 kt.

[cycloneye]

HURRICANE PHILIPPE DISCUSSION NUMBER 51
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 PM AST THU OCT 06 2011

PHILIPPE HAS CONTINUED TO BECOME BETTER ORGANIZED THIS AFTERNOON AS
AN EYE IN THE VISIBLE IMAGERY HAS BECOME ESTABLISHED INSIDE A
RELATIVELY SMALL CENTRAL DENSE OVERCAST. BOTH TAFB AND SAB
SUBJECTIVE DVORAK ANALYSES GIVE A CURRENT-INTENSITY NUMBER OF
4.5...OR ABOUT 77 KT. A CIMSS AMSU ESTIMATE SUGGESTS 75 KT FROM A
1649Z POLAR-ORBITING SATELLITE PASS. THE CIMSS ADVANCED DVORAK
TECHNIQUE INDICATE A SLIGHTLY STRONGER 82 KT. A BLEND OF THESE
GIVES AN INITIAL INTENSITY OF 75 KT...WHICH MAY BE SOMEWHAT
CONSERVATIVE. A 1228Z ASCAT SCATTEROMETER PASS PROVIDED THE WIND
RADII ANALYSIS...EVEN SMALLER THAN ESTIMATED EARLIER.

PHILIPPE IS BEING STEERED TOWARD THE NORTHEAST AT ABOUT 11 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 IN THE SAME GENERAL DIRECTION DURING THE NEXT FEW DAYS.
THE MODELS INDICATE A SLOWING OF THE FORWARD SPEED AS THE CYCLONE
OCCLUDES AROUND DAYS THREE AND FOUR BEFORE ACCELERATING A FINAL
TIME IN THE FAR NORTH ATLANTIC AROUND DAY FIVE. THE TRACK
PREDICTION IS VERY CLOSE TO BOTH THE CONSENSUS AND THE PREVIOUS
ADVISORY.

THE SHARP GRADIENT OF INFRARED CLOUD TOP TEMPERATURES ALONG THE
SOUTHWESTERN FLANK OF PHILIPPE MAY BE INDICATIVE OF THE EXPECTED
INCREASE IN VERTICAL SHEAR. EVEN THOUGH PHILIPPE WILL BE PASSING
OVER A SUFFICIENTLY WARM SEA SURFACE TO SUSTAIN A TROPICAL
CYCLONE...THE COMBINATION OF STRONG VERTICAL SHEAR AND A DRY STABLE
ATMOSPHERE SHOULD LEAD TO GRADUAL WEAKENING DURING THE NEXT TWO
DAYS. THE DYNAMICAL HURRICANE MODELS HAVE BACKED OFF FROM THEIR
EARLIER INSISTENCE OF CONTINUED INTENSIFICATION. THE FORECAST IS
SLIGHTLY LOWER THAN THE INTENSITY CONSENSUS AND VERY SIMILAR TO THE
PREVIOUS ADVISORY. AROUND 36 TO 48 HOURS...EXTRATROPICAL
TRANSITION SHOULD OCCUR AS A COLD FRONT WRAPS AROUND THE CYCLONE.

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


FORECAST POSITIONS AND MAX WINDS

INIT 06/2100Z 28.7N 59.0W 75 KT 85 MPH
12H 07/0600Z 29.5N 57.7W 75 KT 85 MPH
24H 07/1800Z 30.4N 55.2W 65 KT 75 MPH
36H 08/0600Z 31.9N 51.4W 60 KT 70 MPH
48H 08/1800Z 35.3N 47.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 09/1800Z 40.5N 44.5W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 10/1800Z 45.0N 41.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 11/1800Z 54.0N 34.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
FORECASTER LANDSEA/PASCH

[brunota2003]

A true blend of those numbers equals about 77.75 knots (77, 77, 75, and 82). I think I would of gone with 80 knots.

[Cranica]

Do these fronts enhance instability in front of the front itself? Seems like all this year's storms have reacted very well to getting near fronts.

[cycloneye]

Up to 80kts.

AL, 17, 2011100700, , BEST, 0, 289N, 587W, 80, 976, HU

[bexar]

I guess they would bump Philippe to 85 KTs in the next advisory.

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.

So far the season is making up from it's dismal start. One more hurricane I think and this season would be above normal in activity

[cycloneye]

One more hurricane I think and this season would be above normal in activity

Is already above normal in the ACE front with over 100 units. One more hurricane would make the average on hurricanes of 6.

[cycloneye]

HURRICANE PHILIPPE DISCUSSION NUMBER 52
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 PM AST THU OCT 06 2011

THE CLOUD PATTERN OF PHILIPPE HAS BECOME SLIGHTLY BETTER ORGANIZED
SINCE THE LAST ADVISORY. IN RECENT HOURS...THERE HAVE BEEN
OCCASIONAL HINTS OF A WARM SPOT WITHIN A WELL-DEFINED CENTRAL DENSE
OVERCAST IN INFRARED SATELLITE IMAGERY. SUBJECTIVE DVORAK T-NUMBERS
WERE T4.5 AT 0000 UTC AND THE LATEST 3-HOUR AVERAGE ADT VALUE WAS
4.8. USING THESE DATA...THE INITIAL INTENSITY ESTIMATE IS 80 KT.
PHILIPPE APPEARS TO BE NEAR PEAK INTENSITY. GRADUAL WEAKENING IS
ANTICIPATED DURING THE NEXT 24-36 HOURS AS PHILIPPE ENCOUNTERS
INCREASING SOUTHWESTERLY SHEAR AND SLOWLY DECREASING SEA SURFACE
TEMPERATURES ALONG ITS PATH. AFTER 36 HOURS...PHILIPPE IS EXPECTED
TO CROSS THE 26C-ISOTHERM AND RECEIVE A SHOT OF BAROCLINIC ENERGY
ASSOCIATED WITH AN APPROACHING INTENSE SHORTWAVE TROUGH. THE
COMBINATION OF THESE TWO FACTORS SHOULD HASTEN EXTRATROPICAL
TRANSITION...WITH A CONSENSUS OF THE GLOBAL MODELS INDICATING THAT
THE TRANSITION PROCESS SHOULD BE COMPLETE BY ABOUT 48 HOURS. POST-
TROPICAL PHILIPPE IS EXPECTED TO REMAIN A LARGE EXTRATROPICAL
GALE/STORM SYSTEM OVER THE FAR NORTH ATLANTIC OUT TO ABOUT 5 DAYS.
THE OFFICIAL NHC INTENSITY FORECAST IS IDENTICAL TO THE PREVIOUS
ONE AND CLOSE TO THE STATISTICAL AND INTENSITY CONSENSUS AIDS
THROUGH 48 HOURS.

THE HEADING HAS TURNED TO THE RIGHT AND THE INITIAL MOTION IS
NOW ESTIMATED TO BE 050/10. THE APPROACHING TROUGH SHOULD GIVE THE
CYCLONE A KICK TOWARD THE NORTHEAST WITH INCREASING FORWARD SPEED.
AFTER PHILIPPE MERGES WITH THE TROUGH AND BECOMES AN OCCLUDED
CYCLONE...THE TRACK IS FORECAST TO BEND TOWARD THE NORTH-NORTHEAST
AND BRIEFLY DECELERATE OVER THE FAR NORTH ATLANTIC. THE TRACK
GUIDANCE REMAINS TIGHTLY CLUSTERED...AND THE NEW NHC TRACK FORECAST
IS BETWEEN THE PREVIOUS ONE AND THE GLOBAL MODEL CONSENSUS.

THE WIND RADII WERE ADJUSTED USING A JUST-RECEIVED 0042 UTC ASCAT
OVERPASS.


FORECAST POSITIONS AND MAX WINDS

INIT 07/0300Z 29.1N 58.1W 80 KT 90 MPH
12H 07/1200Z 29.9N 56.7W 75 KT 85 MPH
24H 08/0000Z 31.1N 53.3W 70 KT 80 MPH
36H 08/1200Z 33.7N 49.3W 65 KT 75 MPH
48H 09/0000Z 37.3N 46.2W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 10/0000Z 42.0N 43.4W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 11/0000Z 47.9N 38.6W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 12/0000Z 58.0N 30.1W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
FORECASTER KIMBERLAIN

[Ptarmigan]

I believe he could reach cat 2, he's really a fighter surviving the shear and dry air for 12 days and finally becoming a hurricane, good for him!

Philippe is an underdog.

[bexar]

some models still make Philippe a Cat. 3 storm.

[cycloneye]

HURRICANE PHILIPPE DISCUSSION NUMBER 53
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST FRI OCT 07 2011

SATELLITE IMAGES INDICATE THAT ALTHOUGH DEEP CONVECTION HAS
DECREASED SOME...THE OVERALL CLOUD PATTERN HAS NOT CHANGED VERY
MUCH DURING THE PAST SEVERAL HOURS. THERE IS STILL AN EYE ON
MICROWAVE DATA. SUBJECTIVE T-NUMBERS FROM TAFB AND SAB REMAIN NEAR
4.5 ON THE DVORAK SCALE...AND THE OBJECTIVE NUMBERS FROM CIMSS ARE
A LITTLE BIT HIGHER. THE INITIAL INTENSITY IS KEPT AT 80 KNOTS.
THE HURRICANE SHOULD SOON BEGIN TO GRADUALLY WEAKEN AS IT
ENCOUNTERS INCREASING SOUTHWESTERLY SHEAR AND COOLER WATERS.
PHILIPPE IS EXPECTED TO INTERACT WITH A STRONG FRONTAL SYSTEM AND
BECOME POST-TROPICAL IN 48 HOURS OR EARLIER.

PHILIPPE HAS INCREASED ITS FORWARD SPEED AND IS MOVING TOWARD THE
EAST-NORTHEAST OR 065 DEGREES AT 15 KNOTS. THE CYCLONE IS EMBEDDED
WITHIN THE MID-LATITUDE SOUTHWESTERLY FLOW...AND AS THE FRONTAL
SYSTEM APPROACHES...PHILLIPE SHOULD FURTHER INCREASE ITS FORWARD
SPEED. A TURN MORE TO THE NORTHEAST IS EXPECTED AS PHILIPPE BECOMES
AN OCCLUDED CYCLONE OR BECOMES ABSORBED BY A LARGER CYCLONE
ASSOCIATED WITH THE COLD FRONT. THE FORECAST DURING THE POST-
TROPICAL STAGE OF PHILIPPE WAS PROVIDED BY THE OCEAN PREDICTION
CENTER.


FORECAST POSITIONS AND MAX WINDS

INIT 07/0900Z 29.6N 56.3W 80 KT 90 MPH
12H 07/1800Z 30.5N 54.0W 75 KT 85 MPH
24H 08/0600Z 32.5N 50.5W 70 KT 80 MPH
36H 08/1800Z 36.0N 46.5W 65 KT 75 MPH
48H 09/0600Z 40.0N 45.5W 65 KT 75 MPH...POST-TROP/EXTRATROP
72H 10/0600Z 44.0N 41.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 11/0600Z 51.0N 36.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 12/0600Z 61.0N 30.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
FORECASTER AVILA

[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.

Well, Philippe did strengthen significantly up to an 80 knot hurricane, but "peaked" there before shear picked back up again. My forecast was off by 10 to 15 knots, but since it was on the borderline of RI, the forecast for RI busted. Just not quite a good enough environment...though I personally think he peaked out at 85 knots.

[tolakram]

Top being sheared off as I post this. That's some shear.

http://www.ssd.noaa.gov/goes/flt/t3/flash-vis.html

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 55
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 PM AST FRI OCT 07 2011

THE APPEARANCE OF PHILIPPE HAS DETERIORATED SUBSTANTIALLY DURING THE
DAY...AND THE LOW-LEVEL CENTER IS NOW COMPLETELY EXPOSED.
PRACTICALLY ALL OF THE DEEP CONVECTION IS NOW SHEARED TO THE EAST
AND NORTH OF THE CENTER. DVORAK INTENSITY ESTIMATES FROM TAFB AND
SAB HAVE DECREASED. ADDITIONALLY...A NOAA DRIFTER BUOY 41558
RECENTLY PASSED VERY NEAR THE CENTER OF THE CYCLONE AND REPORTED A
SURFACE PRESSURE OF 989 MB...WHICH ALSO SUGGESTS THAT WEAKENING IS
OCCURRING. BASED ON THIS...THE INITIAL INTENSITY HAS BEEN LOWERED
TO 60 KT. THE INTENSITY FORECAST HAS BEEN LOWERED BASED ON THE
RECENT RAPID DECLINE OF PHILIPPE. HOWEVER THE GENERAL REASONING FOR
THE INTENSITY FORECAST IS UNCHANGED...AND WEAKENING IS EXPECTED FOR
THE NEXT DAY OR SO AS PHILIPPE CONTINUES TO MOVE INTO A HOSTILE
ENVIRONMENT OF HIGH SHEAR AND DECREASING SSTS. THE STORM IS
EXPECTED TO LOSE ITS TROPICAL CHARACTERISTICS IN A DAY OR TWO AS IT
CONTINUES TO INTERACT WITH A LARGE MID-LATITUDE TROUGH AND
ASSOCIATED COLD FRONT.

PHILIPPE HAS SLOWED SLIGHTLY DURING THE DAY...AND THE ESTIMATED
FORWARD MOTION IS 070/11 KT. DESPITE THE SLOWING...AN INCREASE IN
FORWARD SPEED WITH A TURN TOWARD THE NORTHEAST IS STILL EXPECTED AS
THE CYCLONE INTERACTS WITH THE MID-LATITUDE TROUGH. THE REMNANTS OF
PHILIPPE ARE FORECAST TO BE ABSORBED BY A LARGE HIGH-LATITUDE LOW
PRESSURE SYSTEM IN ABOUT 4 DAYS. THE FORECAST TRACK AND WIND RADII
FOR THE EXTRATROPICAL PHASE OF THIS SYSTEM FOLLOW GUIDANCE PROVIDED
BY THE NCEP OCEAN PREDICTION CENTER.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 30.1N 54.2W 60 KT 70 MPH
12H 08/0600Z 31.5N 51.6W 55 KT 65 MPH
24H 08/1800Z 35.0N 47.7W 50 KT 60 MPH
36H 09/0600Z 39.0N 44.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 09/1800Z 42.5N 41.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 10/1800Z 49.5N 35.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 11/1800Z 58.0N 30.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 12/1800Z...ABSORBED

$$
FORECASTER PASCH/ZELINSKY

[cycloneye]

TROPICAL STORM PHILIPPE DISCUSSION NUMBER 56
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 PM AST FRI OCT 07 2011

PHILIPPE HAS CHANGED LITTLE IN STRUCTURE DURING THE LAST SEVERAL
HOURS. STRONG SOUTHWESTERLY SHEAR...ESTIMATED TO BE AROUND 40
KT...HAS CAUSED THE LOW-LEVEL CENTER TO BE EXPOSED TO THE SOUTHWEST
OF A PERSISTENT AREA OF DEEP CONVECTION. A BLEND OF THE LATEST
DVORAK CI- AND T-NUMBERS STILL SUPPORTS AN INITIAL WIND SPEED OF 60
KT. CONTINUED HOSTILE UPPER-LEVEL WINDS...DRIER AIR ENTRAINING INTO
THE CYCLONE...AND DECREASING SEA SURFACE TEMPERATURES SHOULD CAUSE
THE TROPICAL STORM TO WEAKEN ON SATURDAY. PHILIPPE IS FORECAST TO
BECOME AN EXTRATROPICAL CYCLONE IN 24-36 HOURS WHEN IT MERGES WITH
A COLD FRONT. GLOBAL MODELS SHOW THE EXTRATROPICAL CYCLONE BECOMING
ABSORBED INTO A MUCH LARGER LOW PRESSURE SYSTEM OVER THE
NORTHEASTERN ATLANTIC IN FOUR TO FIVE DAYS.

THE TROPICAL STORM IS ACCELERATING TO THE EAST-NORTHEAST...AND THE
LATEST INITIAL MOTION ESTIMATE IS 075/14. A TURN TO THE NORTHEAST
WITH AN ADDITIONAL INCREASE IN FORWARD SPEED IS FORECAST AS A
DEEP-LAYER TROUGH SHARPENS AS IT APPROACHES PHILIPPE. AFTER
EXTRATROPICAL TRANSITION...THE CYCLONE IS EXPECTED TO TRACK
NORTH-NORTHEASTWARD UNTIL IT DISSIPATES.

THE POST-TROPICAL PORTION OF THIS FORECAST IS VERY CLOSE TO THE
GUIDANCE PROVIDED BY THE NOAA OCEAN PREDICTION CENTER. THE 34-KT AND
50-KT WIND RADII HAVE BEEN MODIFIED BASED ON A 0022 UTC ASCAT
OVERPASS.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 30.7N 52.6W 60 KT 70 MPH
12H 08/1200Z 32.7N 49.5W 55 KT 65 MPH
24H 09/0000Z 36.6N 45.9W 50 KT 60 MPH
36H 09/1200Z 40.1N 43.2W 50 KT 60 MPH...POST-TROP/EXTRATROP
48H 10/0000Z 43.0N 40.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 11/0000Z 50.5N 34.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 12/0000Z 58.0N 29.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 13/0000Z...ABSORBED

$$
FORECASTER CANGIALOSI