Tropical Storm FLOSSIE (CPAC): Discussions, Analysis and Ima

[Derek Ortt]

the intensity models and my brain both need to be recalibrated. Conditions this favorable and yet neither forecast significant intensification?

[Coredesat]

Took long enough, but there's good reason - Flossie's a major:

000
WTPZ44 KNHC 110850
TCDEP4
HURRICANE FLOSSIE DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092007
200 AM PDT SAT AUG 11 2007

FLOSSIE HAS UNDERGONE RAPID INTENSIFICATION OVERNIGHT. INFRARED
SATELLITE IMAGERY INDICATES THAT THE HURRICANE HAS A 15 N MI-WIDE
CLEAR EYE EMBEDDED IN DEEP CONVECTION WITH CLOUD TOPS AROUND -75C.
DVORAK INTENSITY ESTIMATES FROM BOTH TAFB AND SAB ARE T5.5/102
KT...AND 6-HR AVERAGED ADT ESTIMATES FROM CIMSS ARE RUNNING AROUND
102 KT AS WELL. BASED ON THIS INFORMATION...THE INITIAL INTENSITY
HAS BEEN RAISED TO 100 KT...AND FLOSSIE IS NOW A CATEGORY THREE
HURRICANE ON THE SAFFIR/SIMPSON HURRICANE SCALE.

FOR THE NEXT 36 TO 48 HOURS...THE SHEAR IS EXPECTED TO BE LESS THAN
10 KT AND SSTS SHOULD REMAIN ABOVE 26C. WITH THAT SAID...SOME
FURTHER STRENGTHENING IS ANTICIPATED...POSSIBLY EVEN MORE THAN
FORECAST...HOWEVER BOTH THE SHIPS AND FSSE INTENSITY GUIDANCE PEAK
FLOSSIE AROUND 100 KT. AFTER TWO OR SO DAYS...THE CYCLONE SHOULD
ENCOUNTER COOLER WATERS AND AN INCREASE IN VERTICAL SHEAR. THE
IMPACT OF THE INCREASING SHEAR IN THE LATER PERIODS OF THE FORECAST
VARIES FROM EACH OF THE MODELS...AND THE OFFICIAL INTENSITY FORECAST
IS A BLEND OF THE SHIPS AND FSSE WHICH HAVE A MORE ACCURATE
INITIALIZATION.

FLOSSIE CONTINUES TO BE STEERED WESTWARD...270/12...UNDER THE
INFLUENCE OF A STRONG RIDGE TO THE NORTH. THE OVERALL MODEL
GUIDANCE IS IN GOOD AGREEMENT THAT THE CYCLONE WILL MOVE TOWARD THE
WEST OR WEST-NORTHWEST FOR THE NEXT TWO OR THREE DAYS. THEREAFTER
THE MODELS DIVERGE...THE NOGAPS AND GFDL SOLUTIONS TAKE A STRONGER
SYSTEM TO THE NORTHWEST WHILE THE UKMET...GFS...AND HWRF GUIDANCE
MAINTAIN A MORE WESTWARD TRACK SOUTH OF THE HAWAIIAN ISLANDS AS A
RESULT OF A MORE WEAKENED SYSTEM. THE OFFICIAL TRACK FORECAST
ESSENTIALLY SPLITS THE DIFFERENCE AND IS CLOSE TO THE PREVIOUS
FORECAST AS WELL AS THE FSSE MODEL.

THIS IS THE LAST ADVISORY ON FLOSSIE FROM THE NATIONAL HURRICANE
CENTER. FUTURE ADVISORIES WILL BE ISSUED BY THE CENTRAL PACIFIC
HURRICANE CENTER IN HONOLULU HAWAII.


FORECAST POSITIONS AND MAX WINDS

INITIAL 11/0900Z 12.6N 139.3W 100 KT
12HR VT 11/1800Z 12.9N 141.1W 105 KT
24HR VT 12/0600Z 13.3N 143.4W 105 KT
36HR VT 12/1800Z 13.8N 145.6W 95 KT
48HR VT 13/0600Z 14.4N 148.0W 85 KT
72HR VT 14/0600Z 15.5N 152.5W 70 KT
96HR VT 15/0600Z 17.0N 156.0W 60 KT
120HR VT 16/0600Z 18.5N 159.0W 45 KT

[Matt-hurricanewatcher]

Since this is the Eastern pacific I will just post.


This thing is now at least 100 knots. Both Cimss and t numbers show 5.5. Very clear eye has developed with reds half circled around. This thing is kicking backside big time. I expect this could get to cat4, with the fact that the shear is moving westward with it at least 8-10 lat away. Which gives it a chance to have a strong outflow channel. This puppy could bomb into a cat4 115-125 knots....Everything else is how much Tchp and if this set up can hold for it. The best shot at Hawaii this has is if it go's westward or west-northwestward intill 147 west, fellowed by a curve northwestward shot from the south into the Big island. This could be a cat2 if it doe's that. Gfdl doe's something close, but just about 3-4 degrees east of what I'm talking about.

I also feel this will not weaken like the Nhc. I think this will stay south of cool water up to around 145 west,,,then will be strong enough that once it reachs it the curve I'm talking about will happen. I think this has a fair chance of becoming a cat4 by 2pm pst tomarrow. Already a perfect eye is forming, also its almost clear.

[Matt-hurricanewatcher]

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.

6(8am) 12.8/140.5 110 knots
12(2pm) 13.2/141.5 115 knots
24(2am) 14.2/144.5 115 knots
36(2pm) 14.8/146 95 knots
48(2am) 17.8/153 85 knots
72(11pm) 19/155.5 70 knots

[Chacor]

[Matt-hurricanewatcher]

http://cimss.ssec.wisc.edu/tropic/real- ... 9dlm1.html

Strong subtropical high pressure to its north at all levels. I expect this to pick up a little speed durning the next 24 hours...Fellowed by a slow weaking of the subtropical ridge.

[benny]

the intensity models and my brain both need to be recalibrated. Conditions this favorable and yet neither forecast significant intensification?

interesting storm-- over 27ish waters and it makes major hurricane. the SSTs are slowly decreasing beneath it soon, so i don't expect much more strengthening. It looks like one of those doughnut hurricanes now. It may keep a nice structure for a day or two until the shear increases. I still don't think this will be a big deal for Hawaii, save some enhanced rain and surf.

[Aquawind]

Looks very good in IR this morning. Shrinking eye and not as lopsided in deep convection anymore.

[Derek Ortt]

Isabel became a cat 5 over 26-27C waters

At the Mark DeMaria seminar at NHC on Thursday, he discussed annular hurricanes in a part of it and they tend to form over cool water. He was also speculating that Flossie would become an annular cane. Props to him

[Derek Ortt]

what is the backup NRL site?

[Thunder44]

what is the backup NRL site?

http://tcweb.fnmoc.navy.mil/tc-bin/tc_home.cgi

[Derek Ortt]

the intensity models are even more useless than normal. They have this as a cat 1 by this afternoon, which si why they have it so weak at lanbdfall or closest approach

[clfenwi]

Both SSD and TAFB estimated the intensity at 115 knots, which is what the models were initialized with.

Code: Select all

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1302 UTC SAT AUG 11 2007
 
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
 
EAST PACIFIC OBJECTIVE AIDS FOR
 
TROPICAL CYCLONE FLOSSIE (EP092007) 20070811 1200 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        070811  1200   070812  0000   070812  1200   070813  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    12.7N 139.7W   13.0N 141.8W   12.9N 143.7W   13.2N 145.9W
BAMD    12.7N 139.7W   12.9N 142.3W   13.1N 144.7W   13.4N 146.9W
BAMM    12.7N 139.7W   12.9N 142.0W   12.9N 144.2W   13.1N 146.3W
LBAR    12.7N 139.7W   13.0N 141.8W   13.8N 144.1W   14.6N 146.0W
SHIP       115KTS         125KTS         118KTS         106KTS
DSHP       115KTS         125KTS         118KTS         106KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        070813  1200   070814  1200   070815  1200   070816  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    13.8N 148.2W   15.4N 152.0W   16.9N 155.4W   18.2N 158.9W
BAMD    13.8N 149.2W   15.5N 153.0W   17.7N 154.7W   20.8N 154.5W
BAMM    13.6N 148.2W   14.9N 151.7W   16.3N 154.2W   17.6N 156.5W
LBAR    15.8N 147.6W   18.1N 150.1W   20.4N 151.3W   23.0N 150.9W
SHIP        94KTS          68KTS          53KTS          38KTS
DSHP        94KTS          68KTS          53KTS          38KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  12.7N LONCUR = 139.7W DIRCUR = 270DEG SPDCUR =  10KT
LATM12 =  12.6N LONM12 = 137.7W DIRM12 = 270DEG SPDM12 =  10KT
LATM24 =  12.6N LONM24 = 135.4W
WNDCUR =  115KT RMAXWD =   15NM WNDM12 =   75KT
CENPRS =  950MB OUTPRS = 1010MB OUTRAD =  175NM SDEPTH =   D
RD34NE =   75NM RD34SE =   60NM RD34SW =   60NM RD34NW =  75NM

[Derek Ortt]

very important note:

ALL of the interpolated intensity models are showing a very strong hurricane at landfall or closest approach, which SHIPS is on drugs or something as nearly all of its intensity change is SST related, giving it a low bias due to the structure

Now, if we can just get the phantom storm watchers to venture over here to see what a real USA threat is...

[Chacor]

000
WTPZ64 KNHC 111205
TCUEP4
HURRICANE FLOSSIE TROPICAL CYCLONE UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092007
500 AM PDT SAT AUG 11 2007

AS OF 500 AM PDT...1200 UTC...THE CENTER OF HURRICANE FLOSSIE HAS
NOT YET CROSSED 140 DEGREES WEST LONGITUDE INTO THE CENTRAL PACIFIC
HURRICANE BASIN. THEREFORE...THE NEXT ADVISORY WILL AGAIN BE
ISSUED BY THE NATIONAL HURRICANE CENTER IN MIAMI FLORIDA.

$$
FORECASTER KNABB

[windstorm99]

I dont see heading for hawaii it looks like it might start moving WNW but i think it will stay south of the island in my opinion.Also conditions closer to the island are less favorable for tropical cyclone development.

[Scorpion]

How is this occuring in a La Nina/neutral year?

[Blown Away]

[img]http://www.wunderground.com/tropical/tracking/ep200709_sat.html#a_topad[/img]

Nice looking storm.

[Derek Ortt]

they tend to approach from the east in neutral/la nina years and from the SW in el nino

[Chacor]

By the way - this is still in the EPac, someone please change the topic.