ATL: PHILIPPE - Post - Tropical - Discussion

[cycloneye]

TROPICAL DEPRESSION SEVENTEEN DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
500 AM AST SAT SEP 24 2011

THE SMALL AREA OF LOW PRESSURE SEVERAL HUNDRED MILES SOUTH OF THE
CAPE VERDE ISLANDS HAS DEVELOPED ENOUGH ORGANIZED CONVECTION TO BE
CONSIDERED A TROPICAL CYCLONE. MICROWAVE DATA FROM TRMM AND AMSR-E
OVER THE PAST FEW HOURS SHOWED DISTINCT CURVED BANDS...AND EARLY
MORNING VISIBLE IMAGES SUGGEST THAT THE CENTER IS WELL EMBEDDED
WITHIN THE CLOUD CANOPY. AN EARLIER ASCAT PASS INDICATED THAT THE
SYSTEM WAS CLOSED...AND HAD WINDS OF ABOUT 30 KT...SO THAT WILL BE
THE INITIAL INTENSITY. ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR STRENGTHENING FOR THE NEXT COUPLE OF DAYS WHILE THE
DEPRESSION IS OVER WARM WATERS WITH LIGHT SHEAR. AFTER THAT TIME...
THE CYCLONE COULD WEAKEN SOMEWHAT DUE TO INCREASING SOUTHWESTERLY
SHEAR FROM A LARGE UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC
OCEAN AND DECREASING SSTS. THE NHC INTENSITY FORECAST IS ON THE
CONSERVATIVE SIDE OF THE GUIDANCE ENVELOPE...BUT FOLLOWS THE TREND
OF THE LGEM MODEL.

BEST ESTIMATE OF THE INITIAL MOTION IS 280/12. A MID-LEVEL RIDGE TO
THE NORTH OF THE DEPRESSION IS FORECAST TO WEAKEN...WHICH SHOULD
CAUSE THE CYCLONE TO GRADUALLY TURN TOWARD THE WEST-NORTHWEST AND
NORTHWEST OVER THE NEXT FEW DAYS. SOME OF THE GUIDANCE TURNS THE
SYSTEM MORE TOWARD THE NORTH BY THE END OF THE FORECAST PERIOD DUE
TO A STRONG MID-LATITUDE TROUGH. FOR NOW...MOST OF THE RELIABLE
GLOBAL MODELS SHOW THE TROUGH STAYING FAR ENOUGH AWAY FROM THE
DEPRESSION TO AVOID RECURVATURE...AND THE NHC FORECAST IS ON THE
LEFT SIDE OF THE GUIDANCE ENVELOPE AND NOT TOO FAR FROM THE ECMWF
MODEL.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 10.7N 25.2W 30 KT 35 MPH
12H 24/1800Z 11.1N 27.2W 35 KT 40 MPH
24H 25/0600Z 11.8N 29.3W 40 KT 45 MPH
36H 25/1800Z 12.7N 31.4W 50 KT 60 MPH
48H 26/0600Z 13.7N 33.1W 60 KT 70 MPH
72H 27/0600Z 16.0N 35.5W 60 KT 70 MPH
96H 28/0600Z 18.0N 37.5W 55 KT 65 MPH
120H 29/0600Z 20.0N 39.5W 50 KT 60 MPH

$$
FORECASTER BLAKE

[bg1]

I take back what I said yesterday about the intensity models being a joke. For once this season they may be too low (very favorable environment, storm's pressure gradient).

[HurrMark]

As unbelievable as it sounds...if Seventeen becomes Phillippe (which is pretty likely), and we squeeze Rina out in the next six days, we will be caught up with 2005. This season (and last season) are clear examples about it doesn't matter how many storms for...it's where they go and what intensity they are...

[cycloneye]

12z Best Track

Still a TD.

AL, 17, 2011092412, , BEST, 0, 108N, 260W, 30, 1006, TD

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[Gustywind]

24/1145 UTC 10.7N 26.2W T1.5/1.5 17L

[brunota2003]

CI # and ADT final T # both have TD 17 at 2.5...or 40 mph. ADT adjusted has it at 2.8

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 24 SEP 2011 Time : 124500 UTC
Lat : 10:51:02 N Lon : 26:02:05 W


CI# /Pressure/ Vmax
2.5 /1011.0mb/ 35.0kt


Final T# Adj T# Raw T#
2.5 2.8 3.2

Center Temp : +4.9C Cloud Region Temp : -29.0C

Scene Type : SHEAR (0.15^ TO DG)

Positioning Method : FORECAST INTERPOLATION

[cycloneye]

11 AM EDT

TROPICAL DEPRESSION SEVENTEEN DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011
1100 AM EDT SAT SEP 24 2011

AFTER AN EARLIER INCREASE IN DEEP CONVECTION AND BANDING
FEATURES...THE CONVECTIVE ORGANIZATION OF THE DEPRESSION HAS
DECREASED A LITTLE SINCE THE 12Z FIXES. INTENSITY ESTIMATES ARE
T2.8/41 KT FROM UW-CIMSS ADT...T2.5/35 KT FROM TAFB...AND T1.5/25
KT FROM SAB. HOWEVER...THE CURVED BAND TO THE NORTH OF CENTER HAS
FRACTURED AND DEGENERATED AND THE ADT ESTIMATES ARE BASED ON AN
UNREPRESENTATIVE SHEAR PATTERN. AS A RESULT...THE INITIAL INTENSITY
WILL REMAIN AT 30 KT FOR THIS ADVISORY...WHICH IS CONSISTENT WITH
SEVERAL 30-KT WIND VECTORS NOTED IN A 1058Z ASCAT OVERPASS.

THE INITIAL MOTION ESTIMATE IS 285/14. THE CYCLONE IS EXPECTED TO
MOVE IN A GENERAL WEST-NORTHWESTWARD MOTION FOR THE NEXT 3 DAYS OR
SO UNDER THE INFLUENCE OF A STRONG SUBTROPICAL RIDGE ORIENTED
EAST-WEST ALONG 20N LATITUDE. HOWEVER...BY 72 HOURS A BREAK IN THE
RIDGE IS FORECAST TO DEVELOP BETWEEN 40-45W LONGITUDE AS A BROAD
LOW PRESSURE TROUGH DIGS SOUTHEASTWARD OVER THE EASTERN ATLANTIC.
THIS SHOULD RESULT IN THE CYCLONE SLOWING DOWN AND TURNING TOWARD
THE NORTHWEST INTO THE WEAKNESS. THE OFFICIAL FORECAST IS JUST AN
EXTENSION OF THE PREVIOUS ADVISORY TRACK AND LIES CLOSE TO THE
CONSENSUS MODELS TVCN AND TVCA.

ENVIRONMENTAL CONDITIONS WILL BE MAXIMIZED DURING THE NEXT 48 HOURS
OR SO FOR INTENSIFICATION TO OCCUR OVER THE NEXT COUPLE OF DAYS.
AFTER THAT...VERTICAL SHEAR IS EXPECTED TO INCREASE...ALBEIT TO
ONLY ABOUT 15 KT...FROM THE SOUTHWEST AHEAD OF THE AFOREMENTIONED
MID/UPPER-LEVEL TROUGH. THIS IS EXPECTED TO RESULT IN A SLOWER RATE
OF INTENSIFICATION. THE OFFICIAL INTENSITY FORECAST REMAINS ON THE
CONSERVATIVE SIDE OF THE INTENSITY GUIDANCE ENVELOPE AND FOLLOWS A
BLEND OF THE SHIPS AND LGEM MODELS.

FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 11.0N 26.7W 30 KT 35 MPH
12H 25/0000Z 11.4N 28.3W 35 KT 40 MPH
24H 25/1200Z 12.2N 30.5W 40 KT 45 MPH
36H 26/0000Z 13.2N 32.3W 50 KT 60 MPH
48H 26/1200Z 14.2N 33.8W 60 KT 70 MPH
72H 27/1200Z 16.4N 36.1W 60 KT 70 MPH
96H 28/1200Z 18.4N 38.1W 55 KT 65 MPH
120H 29/1200Z 20.5N 39.5W 50 KT 60 MPH

$$
FORECASTER STEWART

[HurricaneWarning92]

So.. Im guessing the same trough that is picking Ophelia up, will most definitely pick TD17 up as well... If it hadnt been for those troughs, i think the U.S. specially the east coast would have been blasted quite a few times already.

[lilybeth]

What a difference a week makes. There wasn't anything much out there and now we have three pockets of activity in the ATL and Hilary spinning by Mexico.

[bg1]

As unbelievable as it sounds...if Seventeen becomes Phillippe (which is pretty likely), and we squeeze Rina out in the next six days, we will be caught up with 2005. This season (and last season) are clear examples about it doesn't matter how many storms for...it's where they go and what intensity they are...

Good points. I was going to comment about 05's rate versus this year's. Also, about this time that year, wasn't there also a lull before the 9 total depressions in October?

Back on topic, does anyone think this could RI into a major hurricane before the shear picks up?

[tobol.7uno]

Here are the 8am runs on 17...

[tobol.7uno]

Looks like this is the only thing interesting in the Atlantic. Has a chance to make it big.

[Gustywind]

24/1745 UTC 10.9N 27.5W T2.0/2.0 17L

[Nimbus]

As long as Tiger Woods the east coast trough keeps working those wedge shots north and out to sea we should be OK. No sign of the east coast trough pattern changing yet is there?

[cycloneye]

18z Best Track

Hello Philippe

AL, 17, 2011092418, , BEST, 0, 110N, 274W, 35, 1006, TS

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[cycloneye]

Code: Select all

WHXX01 KWBC 241855
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1855 UTC SAT SEP 24 2011
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
ATLANTIC OBJECTIVE AIDS FOR
 
TROPICAL CYCLONE SEVENTEEN (AL172011) 20110924 1800 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        110924  1800   110925  0600   110925  1800   110926  0600
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    11.0N  27.4W   11.6N  29.8W   12.6N  31.9W   13.7N  33.9W
BAMD    11.0N  27.4W   11.5N  29.5W   12.2N  31.3W   13.3N  32.8W
BAMM    11.0N  27.4W   11.5N  29.7W   12.4N  31.7W   13.5N  33.6W
LBAR    11.0N  27.4W   11.5N  29.7W   12.3N  32.1W   13.5N  34.3W
SHIP        35KTS          44KTS          53KTS          61KTS
DSHP        35KTS          44KTS          53KTS          61KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        110926  1800   110927  1800   110928  1800   110929  1800
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    15.0N  35.7W   17.5N  38.5W   20.2N  40.7W   23.1N  41.3W
BAMD    14.7N  34.0W   18.3N  35.8W   22.4N  37.0W   26.6N  34.0W
BAMM    14.9N  35.2W   17.9N  37.5W   21.5N  39.2W   25.1N  38.3W
LBAR    15.0N  36.2W   19.7N  37.8W   25.6N  36.2W   29.6N  27.4W
SHIP        64KTS          65KTS          60KTS          57KTS
DSHP        64KTS          65KTS          60KTS          57KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  11.0N LONCUR =  27.4W DIRCUR = 280DEG SPDCUR =  14KT
LATM12 =  10.5N LONM12 =  24.6W DIRM12 = 281DEG SPDM12 =  14KT
LATM24 =   9.9N LONM24 =  21.8W
WNDCUR =   35KT RMAXWD =   40NM WNDM12 =   30KT
CENPRS = 1006MB OUTPRS = 1011MB OUTRAD =  180NM SDEPTH =   M
RD34NE =   40NM RD34SE =    0NM RD34SW =    0NM RD34NW =  40NM


[OURAGAN]

As usual,nhc and the models want to send it to the north too quickly,i think it is moving westward.

[OURAGAN]

I see the center may be at 10N / 28W

[tobol.7uno]

One of the more impressive storms we have seen in the Atlantic basin this year.

[CrazyC83]

Could this be a Fred or Julia that bombs out of nowhere?