EPAC: GUILLERMO - Post-Tropical

[Kingarabian]

Question,

Is CPHC using the aircraft data at all? I ask because the plane found a 996mb pressure, yet they are saying it is 990mb

Doubt it. Especially yesterday when recon found 989mb and 68kt flight level and SFMR winds to support a hurricane yet they went with 992 mb and 60kts.

It's just so funny to me that they have high tech air-force planes crossing the pacific only for them to favor Dvorak estimates as the intensity of the storms.

[Kingarabian]

Impressive outflow to the NE from Guillermo extending all the way to California.

[AbcdeerHI]

Question,

Is CPHC using the aircraft data at all? I ask because the plane found a 996mb pressure, yet they are saying it is 990mb

Doubt it. Especially yesterday when recon found 989mb and 68kt flight level and SFMR winds to support a hurricane yet they went with 992 mb and 60kts.

It's just so funny to me that they have high tech air-force planes crossing the pacific only for them to favor Dvorak estimates as the intensity of the storms.

I think this is what you are referring to?

WTPA44 PHFO 040905
TCDCP4

TROPICAL STORM GUILLERMO DISCUSSION NUMBER 22
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
1100 PM HST MON AUG 03 2015

THE LATEST INFRARED SATELLITE PRESENTATION OF GUILLERMO HAS
IMPROVED SINCE THE LAST ADVISORY...WITH PERSISTENT DEEP CONVECTION
REMAINING NEAR AND TO THE NORTHEAST OF THE LOW LEVEL CIRCULATION
CENTER. IT REMAINS EVIDENT THAT GUILLERMO IS UNDERGOING QUITE A BIT
OF WESTERLY WIND SHEAR WITH THE DEEP CONVECTION TILTING THE SYSTEM
OFF TO THE NORTHEAST...AND THIS IS SHOWN WELL BY THE LATEST
UW-CIMSS VERTICAL WIND SHEAR ANALYSIS INDICATING 20 KNOTS OF SHEAR
FROM 265 DEGREES. DESPITE THE VERTICAL WIND SHEAR PRESENT OVER THE
SYSTEM...DVORAK CLASSIFICATIONS FROM PHFO...SAB...AND JTWC CONTINUE
TO INDICATE T NUMBERS OF 3.5 OR 55 KNOTS. THE FINAL DECISION ON THE
INITIAL INTENSITY WAS BASED HEAVILY ON TIMELY DATA FROM THE U.S.
53RD WEATHER RECONNAISSANCE AIRCRAFT WHICH IS CURRENTLY SAMPLING
THE INNER CORE OF GUILLERMO. THE AIRCRAFT FOUND MAX FLIGHT LEVEL
WINDS OF 72 KNOTS...33 NM NORTHEAST OF THE CENTER OF CIRCULATION.
ADJUSTING THE FLIGHT LEVEL WINDS TO THE SURFACE YIELDS SURFACE WINDS
OF 58 MPH. ADDITIONALLY...SFMR DATA FROM THE AIRCRAFT INDICATED
SURFACE WINDS AS STRONG AS 68 KNOTS TO THE NORTHEAST OF THE CENTER.
SOME OF THE SFMR WINDS MAY HAVE BEEN RAINFALL CONTAMINATED...AND AS
A RESULT...THE INITIAL INTENSITY OF GUILLERMO UTILIZED A BLEND OF
THE FLIGHT LEVEL AND SFMR WINDS AND WAS SET AT 60 KNOTS...JUST BELOW
HURRICANE STRENGTH.

[Yellow Evan]

Question,

Is CPHC using the aircraft data at all? I ask because the plane found a 996mb pressure, yet they are saying it is 990mb

A little, but not with the pressure. Recon's big use has been helping the models handle this, not the CPHC.

[Kingarabian]

Question,

Is CPHC using the aircraft data at all? I ask because the plane found a 996mb pressure, yet they are saying it is 990mb

Doubt it. Especially yesterday when recon found 989mb and 68kt flight level and SFMR winds to support a hurricane yet they went with 992 mb and 60kts.

It's just so funny to me that they have high tech air-force planes crossing the pacific only for them to favor Dvorak estimates as the intensity of the storms.

I think this is what you are referring to?

Yes. I don't think those winds were tagged as contaminated. The 72kt winds that were found were tagged. They also sort of need to throw out Dvorak completely when recon is available.

By saying "THE FINAL DECISION ON THE
INITIAL INTENSITY WAS BASED HEAVILY ON TIMELY DATA FROM THE U.S.
53RD WEATHER RECONNAISSANCE AIRCRAFT WHICH IS CURRENTLY SAMPLING
THE INNER CORE OF GUILLERMO." means they're also giving Dvorak estimates some weight.

But again I'm an amateur, so what do I know . I appreciate all they do despite being short staffed all the time.

[Kingarabian]

Surprised here a recon mission was done on this system most models appear to be on the mark with the system tracking WNW and well N or the islands. Atm it appears this system is affected by WSW shear and the convection is ENE away from the center of circulation.

Almost all the models were showing a TS or hurricane landfall except for the GFDL (kudos). I'm glad recon came. A threat is a threat. Guillermo is supposed to be a weak TS and right now it's still a borderline hurricane.

[Yellow Evan]

Surprised here a recon mission was done on this system most models appear to be on the mark with the system tracking WNW and well N or the islands. Atm it appears this system is affected by WSW shear and the convection is ENE away from the center of circulation.

This was a threat to Hawaii early on. It's not like they have better systems to fly into.

[AbcdeerHI]

I wonder if this is temporary thing or is shear taking its toll and the lower half is being influenced by the subtropical ridge to its north.

[Kingarabian]

I wonder if this is temporary thing or is shear taking its toll and the lower half is being influenced by the subtropical ridge to its north.

Overall motion still looks 310 NWish.

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.

[Chris_in_Tampa]

Hey Chris you think this is just a wobble?

I wonder if this is temporary thing or is shear taking its toll and the lower half is being influenced by the subtropical ridge to its north.

The steering does seem to indicate more westward when weaker:

http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

The surface center each time is just a bit further south or SW of the vortex messages, but not by much. It's not decoupled.

The storm is undergoing a lot of structural changes though, so I don't really know what kind of movement it has. But it needs to be watched. It looks more like a short term movement much more westward right now. I don't think watches should be canceled.

Lets see what the next pass has.

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.

[Chris_in_Tampa]

Looking at recon better, that first pass showed an unorganized center. It might have reformed. I'll post an image.

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.

[Chris_in_Tampa]

First pass showed the winds at flight level changing directions more than once. It was not a well defined wind shift at the time.

[Chris_in_Tampa]

TROPICAL STORM GUILLERMO INTERMEDIATE ADVISORY NUMBER 24A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
200 PM HST TUE AUG 04 2015

...GUILLERMO MOVING WEST-NORTHWESTWARD EAST OF THE BIG ISLAND...


SUMMARY OF 200 PM HST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...19.9N 149.3W
ABOUT 375 MI...600 KM E OF HILO HAWAII
ABOUT 565 MI...910 KM E OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...990 MB...29.24 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* HAWAII COUNTY
* MAUI COUNTY...INCLUDING THE ISLANDS OF MAUI...MOLOKAI...LANAI AND
KAHOOLAWE

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN 36 TO 48 HOURS.

INTERESTS ELSEWHERE IN THE MAIN HAWAIIAN ISLANDS SHOULD MONITOR THE
PROGRESS OF GUILLERMO.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY THE NATIONAL WEATHER SERVICE OFFICE IN
HONOLULU HAWAII.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 PM HST...0000 UTC...THE CENTER OF TROPICAL STORM GUILLERMO
WAS LOCATED BY US AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT NEAR
LATITUDE 19.9 NORTH...LONGITUDE 149.3 WEST. GUILLERMO IS MOVING
TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/H...AND
THIS MOTION IS EXPECTED TO CONTINUE OVER THE NEXT COUPLE OF DAYS. ON
THE FORECAST TRACK...THE CENTER OF GUILLERMO IS EXPECTED TO PASS
ABOUT 230 MILES NORTHEAST OF HILO WEDNESDAY AFTERNOON...AND 200
MILES NORTHEAST OF MAUI WEDNESDAY NIGHT.

MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH...110 KM/H...WITH HIGHER
GUSTS. STEADY WEAKENING IS EXPECTED OVER THE NEXT COUPLE OF DAYS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB...29.24 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE ON THE BIG ISLAND OF
HAWAII AND THE ISLANDS OF MAUI...MOLOKAI...LANAI AND KAHOOLAWE IN
MAUI COUNTY ON WEDNESDAY INTO WEDNESDAY NIGHT.

RAINFALL...TOTAL RAINFALL AMOUNTS OF 1 TO 3 INCHES...WITH ISOLATED
MAXIMUM AMOUNTS NEAR 7 INCHES MAINLY IN HIGHER TERRAIN...ARE
POSSIBLE IN THE WATCH AREA.

SURF...SWELLS ASSOCIATED WITH TROPICAL STORM GUILLERMO WILL PRODUCE
LARGE SURF ALONG EAST FACING SHORES OF THE MAIN HAWAIIAN ISLANDS
THROUGH MUCH OF THE WEEK.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 PM HST.

$$
FORECASTER KODAMA

[Kingarabian]

Went from moving 320 degrees to 300.

So I guess the center did reform?

[Chris_in_Tampa]

[Chris_in_Tampa]

It's hard to tell if it reformed, the change in structure caused it to move temporarily that way in the short term or if that is its movement for now. They use twelve hour movement normally, so they average it out rather than go with the much more westward motion that it has been traveling short term.

[Kingarabian]

It's hard to tell if it reformed, the change in structure caused it to move temporarily that way in the short term or if that is its movement for now. They use twelve hour movement normally, so they average it out rather than go with the much more westward motion that it has been traveling short term.

Thanks for taking the time to explain.

Convection looks like it's starting to diminish but with the pressures that recon is finding, I think it's still strong enough to not be influenced by the westerly flow. Interesting for sure.

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.

[Yellow Evan]

73 knt FL and 60 knts SFMR supports 60 knts still.

[Kingarabian]

WTPA44 PHFO 050243
TCDCP4

TROPICAL STORM GUILLERMO DISCUSSION NUMBER 25
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
500 PM HST TUE AUG 04 2015

DESPITE AN INCREASINGLY RAGGED APPEARANCE ON SATELLITE IMAGES...US
AIR FORCE WEATHER RECON DATA SHOWED THAT GUILLERMO HAS BEEN ABLE TO
MAINTAIN ITS INTENSITY OVER THE PAST SIX HOURS. DROPSONDE DATA
SHOWED 60 KT IN THE NORTHWEST QUADRANT...MBL SHOWED 58 KT AND WL150
SHOWED 55 KT...ALL OF WHICH SUPPORT KEEPING GUILLERMO AT 60 KT.
RECON FIXES ALSO SHOWED THAT THE CENTER OF GUILLERMO HAS SHIFTED
WESTWARD WHICH MAY BE INDICATIVE OF THE LOW LEVEL CENTER DECOUPLING
IN THE FACE OF 34 KT OF VERTICAL SHEAR AS SHOWN IN THE CIMSS 0000
UTC ANALYSIS.

A DECOUPLING OF THE LOW LEVEL CENTER SHOULD BE INDICATIVE OF THE
START OF A WEAKENING TREND. THE OBJECTIVE AIDS SHOW THIS TREND WITH
SHIPS DISSIPATING GUILLERMO BY 72 HOURS. HWRF HOLDS THE INTENSITY UP
A LITTLE LONGER...FOR 12 HOURS...THEN BEGINS THE WEAKENING TREND.
THE FORECAST CALLS FOR A STEADY WEAKENING WITH GUILLERMO BECOMING A
TROPICAL DEPRESSION AFTER DAY 3. THIS IS CLOSE TO THE PREVIOUS
PACKAGE AND THE IVCN CONSENSUS.

THE SHORT TERM WESTWARD SHIFT HAS RESULTED IN AN ADJUSTMENT OF THE
FORECAST TRACK CLOSER TO THE MAIN HAWAIIAN ISLANDS THAN THE
PREVIOUS PACKAGE AND A BIT SLOWER AS WELL. A DECOUPLED SYSTEM WILL
RESULT IN THE CENTER OF GUILLERMO BEING STEERED MORE BY THE LOWER
LEVEL FLOW SO THE FORECAST LEANS TOWARD BAMS GUIDANCE AND IS SOUTH
OF THE GFS...ECMWF...HWRF AND THE MODEL CONSENSUS. THE TRACK CHANGE
AND THE ADJUSTMENT CLOSER TO THE MAIN HAWAIIAN ISLANDS WARRANTS
MAINTAINING THE TROPICAL STORM WATCH FOR THE BIG ISLAND AND MAUI
COUNTY. MOVEMENT AND INTENSITY TRENDS TONIGHT...WITH SUPPORTING
DATA FROM ONGOING USAF RESERVE WEATHER RECON...WILL DETERMINE THE
FUTURE STATUS OF WATCHES FOR THE STATE OF HAWAII.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 20.1N 149.7W 60 KT 70 MPH
12H 05/1200Z 20.7N 150.9W 55 KT 65 MPH
24H 06/0000Z 21.5N 152.7W 50 KT 60 MPH
36H 06/1200Z 22.1N 154.5W 45 KT 50 MPH
48H 07/0000Z 22.9N 156.5W 40 KT 45 MPH
72H 08/0000Z 24.3N 160.7W 35 KT 40 MPH
96H 09/0000Z 26.0N 165.0W 30 KT 35 MPH
120H 10/0000Z 28.0N 169.5W 25 KT 30 MPH

$$
FORECASTER KODAMA

[Chris_in_Tampa]

Multiple wind shifts.