WPAC: FRANCISCO - Post-Tropical

[ozonepete]

That's an illusion you sometimes get from visible.

This is what you look for if you want to see an annular Tropical Cyclone:

[euro6208]

Category 5 Super Typhoon....

WDPN33 PGTW 200300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (FRANCISCO) WARNING
NR 17//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON 26W (FRANCISCO), LOCATED APPROXIMATELY 762 NM
SOUTHEAST OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS THE SYSTEM HAS MAINTAINED A SYMMETRICAL 13-NM
EYE SURROUNDED BY A WELL DEFINED DEEP CONVECTIVE EYEWALL. THE MSI
ALSO DEPICTS A STRONG FEEDER BAND TIGHTLY WRAPPING AROUND THE
WESTERN SEMI-CIRCLE OF THE SYSTEM AS WELL AS A WEAKER BAND LOOSELY
WRAPPING AROUND THE EASTERN PERIPHERY. A 192226Z SSMIS MICROWAVE
IMAGE INDICATES THE DEEP CONVECTION WITHIN THE EYEWALL HAS SLIGHTLY
DEGRADED IN VARIOUS LOCATIONS, AND COULD BE THE RESULT OF AN EYEWALL
REPLACEMENT CYCLE (ERC). THE INITIAL POSITION IS BASED ON THE MSI
ANIMATION AND THE AFOREMENTIONED MICROWAVE IMAGE WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 140 KNOTS IS BASED ON CONGRUENT
DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW, RJTD, AND KNES. UPPER-
LEVEL ANALYSIS INDICATES A POINT SOURCE ANTICYCLONE REMAINS SLIGHTLY
DISPLACED OVER THE SYSTEM, PROVIDING HIGHLY-EFFICIENT RADIAL OUTFLOW
AND LOW (05-10 KNOT) VERTICAL WIND SHEAR (VWS). THE CYCLONE IS
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
B. THROUGH TAU 48, STY 26W IS EXPECTED TO CONTINUE ALONG ITS
CURRENT TRACK UNDER THE STEERING INFLUENCE OF THE STR. BY TAU 72, AN
EXTENSION TO THE STR IS EXPECTED TO BUILD IN AND PUSH THE TRACK OF
THE SYSTEM SLIGHTLY FURTHER WEST AS STY 26W BEGINS TO ROUND THE STR
AXIS. THOUGH FAVORABLE UPPER LEVEL CONDITIONS CONTINUE TO EXIST,
THEY ARE CURRENTLY BEING OFFSET BY ERCS AND A TONGUE OF COOL SEA
SURFACE TEMPERATURES (SSTS). FRANCISCO APPEARS TO HAVE REACHED ITS
PEAK INTENSITY AND IS FORECAST TO SUSTAIN 140 KNOTS OVER THE NEXT 12
HOURS. AFTER TAU 12, THE SYSTEM WILL SUCCOMB TO INCREASING VWS AS IT
APPROACHES THE MID-LATITUDE WESTERLIES, AS WELL AS EVEN COLDER SSTS
WHICH WILL FURTHER ERODE THE LOW LEVEL INFLOW. HOWEVER, INCREASED
POLEWARD OUTFLOW COULD POTENTIALLY OFFSET THE VWS AND HELP SUSTAIN
THE CONVECTION, THEREBY TEMPERING THE WEAKENING TREND.
C. AFTER TAU 72, STY FRANCISCO WILL BEGIN TO CREST THE STR AXIS,
ALLOWING FOR A MORE POLEWARD TRACK AND SETTING INTO A NORTHEASTWARD
RECURVATURE TOWARD JAPAN. A DECREASE IN SSTS AND FURTHER INCREASE IN
VWS WILL AMPLIFY THE WEAKENING TREND THROUGH TAU 120 AS THE SYSTEM
BEGINS EXTRA-TROPICAL TRANSITION. NUMERIC MODEL GUIDANCE REMAINS
WIDELY SPREAD IN THE EXTENDED TAUS DUE TO VARYING SOLUTIONS TO THE
ORIENTATION AND STRENGTH OF THE STR. ALL OBJECTIVE AIDS INDICATE
SOME DEGREE OF A RECURVE SCENARIO, BUT WIDELY VARY IN THE TIGHTNESS
OF THE TURN AS WELL AS TRACK SPEED. THE CURRENT FORECAST REMAINS
CLOSE TO THE MULTI-MODEL CONSENSUS AND IS BIAS TOWARDS THE ECMWF
SOLUTION. DUE TO THE HIGH UNCERTAINTY IN THE STEERING MECHANISM AT
THE EXTENDED TAUS, THE CONFIDENCE IN THE FORECAST REMAINS LOW.//
NNNN

[ozonepete]

7C core temp - a monster

Wow! You won't see that very often, for sure.

not really...those high readings are very common here and in fact Typhoon Wipha earlier this month had an 11C core temp...

I said you don't see it very often.

So you're saying you do see it very often?

[dexterlabio]

I also don't think this is annular. If you want to see an annular supertyphoon, look for STY Sanba from last year. Either way, annular or not, Francisco looks very impressive. I am not sure though if it surpassed Usagi...IMO I was more in awe by Usagi's appearance and sheer size at its peak..


And here we go again with JTWC's late upgrade to STY, IMO Francisco was a supertyphoon AND a Category 5 much earlier...

[dexterlabio]

Hey DT numbers are dropping. Just as they upgraded it to a Cat5? Looks like EWRC is taking its toll now...

[ozonepete]

I also don't think this is annular. If you want to see an annular supertyphoon, look for STY Sanba from last year. Either way, annular or not, Francisco looks very impressive. I am not sure though if it surpassed Usagi...IMO I was more in awe by Usagi's appearance and sheer size at its peak..


And here we go again with JTWC's late upgrade to STY, IMO Francisco was a supertyphoon AND a Category 5 much earlier...

Hi dex! Yeah I agree, although right now this looks to have incredibly good symmetry, I think even more than Usagi had at its best.

[phwxenthusiast]

7C core temp - a monster

isn't this the "anomaly" of the temp (in this case +7) in the core?? i read somewhere that is based near the troposphere hundreds of km away from the center.. or maybe i'm reading the graph wrong...

[ozonepete]

Hey DT numbers are dropping. Just as they upgraded it to a Cat5? Looks like EWRC is taking its toll now...

Yup, and it's beginning the recurve and may be starting to take in a little of the mid-level dry air to its northwest. You can see the CDO is getting more banded instead of solid now so I'd have to agree that this has peaked. It should start a slow weakening now.

[ozonepete]

7C core temp - a monster

isn't this the "anomaly" of the temp (in this case +7) in the core?? i read somewhere that is based near the troposphere hundreds of km away from the center.. or maybe i'm reading the graph wrong...

Yes. It's not the actual temp readings but the departure from what's expected. Although I don't know what you mean by "based near the troposphere hundreds of km away from the center" ??

[phwxenthusiast]

isn't this the "anomaly" of the temp (in this case +7) in the core?? i read somewhere that is based near the troposphere hundreds of km away from the center.. or maybe i'm reading the graph wrong...

Yes. It's not the actual temp readings but the departure from what's expected. Although I don't know what you mean by "based near the troposphere hundreds of km away from the center" ??

i just remember reading a paper many months ago on the relationship between the temp anomaly and current intensity of a cyclone... i read that the temperature anomaly is between the measurements from the AMSU on the center of the cyclone and a similar reading hundreds of km away... it's hard to explain but i hope i can find that paper again...

[Alyono]

I can say with certainty this is NOT a cat 5 any longer. Going through an EWRC and the winds have decreased. They decrease faster than Dvorak constraints allow

[Fyzn94]

I also don't think this is annular. If you want to see an annular supertyphoon, look for STY Sanba from last year. Either way, annular or not, Francisco looks very impressive. I am not sure though if it surpassed Usagi...IMO I was more in awe by Usagi's appearance and sheer size at its peak..


And here we go again with JTWC's late upgrade to STY, IMO Francisco was a supertyphoon AND a Category 5 much earlier...

Well, sure, I was hesitant in saying that it WAS annular, but it does seem pretty close if you consider that the intensity has been nearly steady for the past 12-24 hours and it's not expected to change drastically for the next day or two.

[euro6208]

I said you don't see it very often.

So you're saying you do see it very often?

yes

[mrbagyo]

the eye is filling in.

[ozonepete]

I said you don't see it very often.

So you're saying you do see it very often?

yes

No. Not temperature anomalies. I think you're thinking that's a core temp. It's not. It's the departure of AMSU from the forecast norm.

[dexterlabio]

Well, sure, I was hesitant in saying that it WAS annular, but it does seem pretty close if you consider that the intensity has been nearly steady for the past 12-24 hours and it's not expected to change drastically for the next day or two.

Yeah I agree on it being almost annular, it has very nice symmetry (made it seem to have no banding) and looks to have helped maintaining that intensity for a long time... But I don't know, IMO Sanba looks closer to being "annular" lol.

[dexterlabio]

Hi dex! Yeah I agree, although right now this looks to have incredibly good symmetry, I think even more than Usagi had at its best.

The large size and very cold cloud tops at Usagi's peak strength did it for me. But I agree Francisco has (or had) a very nice symmetry.

[ozonepete]

Yes. And you were correct earlier that this is not annular at all. I posted images of 3 annular storms before. This is not annular at all. Annular TCs have a "truck tire" or doughnut shape with a very large eye. Francisco has never had anything close to that shape.

[ozonepete]

It's now going through an ERC while recurving into the westerlies and that's going to weaken it. It's highly unlikely it will ever get back to the strength it was and should gradually weaken from here on.

[mrbagyo]

Yeah I agree on it being almost annular, it has very nice symmetry (made it seem to have no banding) and looks to have helped maintaining that intensity for a long time... But I don't know, IMO Sanba looks closer to being "annular" lol.

I actually doubt if Sanba really became annular- the eye is not that big and it doesn't have that truck tire appearance...
textbook WPAC annular typhoons are Typhoon Nestor(1997) and typhoon Longwang(2005)