EPAC: GUILLERMO - Post-Tropical

[Yellow Evan]

Looks like it weakened more based on a new AMSU pass.

Interesting to see if recon finds a hurricane.

Convection is still quiet deep, so they might.

[Yellow Evan]

Probs around 60/986.

[Kingarabian]

00z Euro shifts east and clears Hawaii.

[Yellow Evan]

0z GFS also shifted east.

[Yellow Evan]

lol

EP, 09, 2015080306, , BEST, 0, 160N, 1450W, 70, 990, HU, 34, NEQ, 115, 100, 60, 80, 1008, 165, 20, 0, 0, E, 0, , 0, 0, GUILLERMO, D, 0, , 0, 0, 0, 0, genesis-num, 013,

[Kingarabian]

lol

EP, 09, 2015080306, , BEST, 0, 160N, 1450W, 70, 990, HU, 34, NEQ, 115, 100, 60, 80, 1008, 165, 20, 0, 0, E, 0, , 0, 0, GUILLERMO, D, 0, , 0, 0, 0, 0, genesis-num, 013,

Chris did mention that they lost an ob that contained the strongest winds after 60kts were reported.

[Yellow Evan]

lol

EP, 09, 2015080306, , BEST, 0, 160N, 1450W, 70, 990, HU, 34, NEQ, 115, 100, 60, 80, 1008, 165, 20, 0, 0, E, 0, , 0, 0, GUILLERMO, D, 0, , 0, 0, 0, 0, genesis-num, 013,

Chris did mention that they lost an ob that contained the strongest winds after 60kts were reported.

Oh, ok. 70 knts is good then, but the pressure then is probs around 985-986 mbar still,

[Kingarabian]

lol

EP, 09, 2015080306, , BEST, 0, 160N, 1450W, 70, 990, HU, 34, NEQ, 115, 100, 60, 80, 1008, 165, 20, 0, 0, E, 0, , 0, 0, GUILLERMO, D, 0, , 0, 0, 0, 0, genesis-num, 013,

Chris did mention that they lost an ob that contained the strongest winds after 60kts were reported.

Oh, ok. 70 knts is good then, but the pressure then is probs around 985-986 mbar still,

But I'd do 65kts to be safe. Looks like it will weaken some more before the next update package is out.

[Yellow Evan]

Latest pass confirms pressure of 997mbar, with slight wind, so 985 mbar is good.

Winds anywhere from 60-70 is good.

[Chris_in_Tampa]

Chris did mention that they lost an ob that contained the strongest winds after 60kts were reported.

The missing ob came in and was no higher.



First pass (NW to SE):

30s flight: 57kts
10s flight: 62kts
10s estimated surface: 55kts

Pressure: Perhaps 988mb
(992mb surface with last reported winds at 990mb being 40 knots)



Eastern quadrant, while traveling north:

10s estimated surface: 57kts



Second pass (NE to SW):

30s flight: 56kts
10s flight: 57kts
10s estimated surface: 56kts

Pressure: Perhaps 989mb
(991mb surface with wind of 22 knots)



Highest sonde surface momentary wind gust anywhere from mission (out of two sondes launched in either rainband or maximum wind band): 56 knots*
( * elevation of 66 feet, wind was not available at surface )

Higghest sonde momentary wind gust: 68 knots
(952mb level; surface in that sonde was 995mb with wind of 52 knots)


Mission over.

[Kingarabian]

12z GFS follows the European and misses Hawaii to the east.

[wxman57]

Recon could find no evidence of hurricane-force winds, but Guillermo is still classified as a hurricane because of Dvorak? That's odd. What's the point of recon, then? Looks like a 45kt TS now.

[Yellow Evan]

WTPA44 PHFO 030916
TCDCP4

HURRICANE GUILLERMO DISCUSSION NUMBER 18
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
1100 PM HST SUN AUG 02 2015

LATEST SATELLITE IMAGERY CONTINUES TO SHOW DEEP CONVECTION
STRUGGLING TO MAINTAIN ITSELF OVER THE LOW LEVEL CIRCULATION CENTER
GUILLERMO DUE TO THE INCREASING WESTERLY WIND SHEAR THE SYSTEM IS
ENCOUNTERING. THE U.S. 53RD WEATHER RECONNAISSANCE AIRCRAFT
CONFIRMED THAT THE SYSTEM IS WEAKENING WHILE SAMPLING THE INNER CORE
OF GUILLERMO THIS EVENING...WITH NO FLIGHT LEVEL OR SURFACE WINDS OF
64 KNOTS OR GREATER FOUND. THE CENTRAL PRESSURE OF THE SYSTEM HAD
RISEN TO AROUND 990 MB AS WELL. ADDITIONALLY...DVORAK
CLASSIFICATIONS WERE 4.5/77KT FROM PHFO AND JTWC AND 4.0/65 KT FROM
SAB...WHILE FINAL T NUMBERS WERE LOWER AT 3.5 TO 4.0. FOR THE
INITIAL 0600Z INTENSITY WE USED 70 KNOTS WHICH FOLLOWED CLOSELY THE
DVORAK NUMBERS...BUT AS A RESULT OF THE AIRCRAFT SAMPLING OF
GUILLERMO THE 0900Z INITIAL INTENSITY WILL BE ADJUSTED DOWNWARD TO
65 KNOTS.

THE INITIAL MOTION IS TOWARD THE WEST-NORTHWEST...OR 300 DEGREES...
AT 9 KT. A LOW LEVEL RIDGE SITS ABOUT 1500 NM TO THE NORTHWEST OF
GUILLERMO...WHILE A NORTH PACIFIC UPPER LEVEL TROUGH HAS CARVED OUT
A WEAKNESS IN THE MID TO UPPER LEVEL RIDGE JUST NORTH OF THE
HURRICANE. GUILLERMO WILL CONTINUE TO MOVE ON A SIMILAR BEARING FOR
THE NEXT FEW DAYS INTO THE WEAKNESS ALOFT...TAKING THE SYSTEM NEAR
OR POSSIBLY OVER THE HAWAIIAN ISLANDS ON WEDNESDAY AND THURSDAY.
THE TRACK FORECAST HAS BEEN CHANGED LITTLE FROM THE LAST ADVISORY
AND REMAINS NEAR A RATHER TIGHT CLUSTER OF GFS...ECMWF...AND THE
CONSENSUS MODELS. THE TIGHT CLUSTERING OF THE MODELS THEN SHOWS
INCREASING SPREAD BETWEEN 48 HOURS AND 120 HOURS...LIKELY DUE TO
THE DIFFERING INTENSITY FORECASTS BY THE VARIOUS MODELS WITH
RESPECT TO THE SYSTEM.

THE LATEST UW-CIMSS VERTICAL WIND SHEAR ANALYSIS SHOWED 8 KNOTS
FROM 290 DEGREES...WHILE THE LATEST SHIPS ANALYSIS SHOWED 16 KNOTS
FROM 285 DEGREES. THIS IS LIKELY RESPONSIBLE FOR THE POOR
SATELLITE PRESENTATION AND THE WEAKENING OF THE SYSTEM SINCE THE
PREVIOUS ADVISORY. WEAKENING IS EXPECTED TO CONTINUE THROUGH THE
FORECAST PERIOD. AS GUILLERMO CONTINUES TO MOVE INTO THE BREAK IN
THE MID TO UPPER LEVEL RIDGE...OUTFLOW WITHIN THE NORTHWEST QUADRANT
WILL BECOME FURTHER DISRUPTED AND VERTICAL WIND SHEAR WILL
CONTINUE TO SLOWLY INCREASE. THE INTENSITY FORECAST CLOSELY FOLLOWS
THE ICON...WITH SHIPS PREDICTING MORE RAPID WEAKENING BEYOND 48
HOURS. THE FORECAST AND INITIAL WIND RADII WERE ADJUSTED BASED ON
THE AIRCRAFT DATA AS WELL.

AS GUILLERMO MOVES CLOSER TO HAWAII...WATCHES MAY BE ISSUED MONDAY
OR MONDAY NIGHT FOR PORTIONS OF THE STATE. HOWEVER...IT IS STILL TOO
SOON TO DETERMINE WITH CERTAINTY WHICH ISLANDS ARE MOST LIKELY TO
EXPERIENCE THE GREATEST IMPACTS FROM GUILLERMO. IT IS ALSO IMPORTANT
TO NOTE THAT SIGNIFICANT IMPACTS CAN EXTEND WELL AWAY FROM THE
CENTER.

ANOTHER RECONNAISSANCE AIRCRAFT MISSION INTO GUILLERMO IS
SCHEDULED FOR MONDAY MORNING. THE VALUABLE DATA TRANSMITTED IN
REAL-TIME FROM THESE MISSIONS WILL HELP US TO BETTER DETERMINE THE
LOCATION...INTENSITY AND SIZE OF THE HURRICANE. IN ADDITION...THE
NOAA G-IV JET IS SCHEDULED TO CONDUCT ANOTHER SYNOPTIC SAMPLING
MISSION AROUND GUILLERMO MONDAY AFTERNOON. THIS SAMPLING SHOULD HELP
IMPROVE THE MODEL INITIALIZATION OF GUILLERMO.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 16.2N 145.4W 65 KT 75 MPH
12H 03/1800Z 16.8N 146.5W 60 KT 70 MPH
24H 04/0600Z 17.5N 148.1W 55 KT 65 MPH
36H 04/1800Z 18.1N 149.8W 50 KT 60 MPH
48H 05/0600Z 18.9N 151.5W 45 KT 50 MPH
72H 06/0600Z 20.5N 155.0W 40 KT 45 MPH
96H 07/0600Z 22.6N 158.9W 35 KT 40 MPH
120H 08/0600Z 24.5N 163.1W 30 KT 35 MPH

$$
FORECASTER JELSEMA/HOUSTON

[cycloneye]

TROPICAL STORM GUILLERMO DISCUSSION NUMBER 19
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
500 AM HST MON AUG 03 2015

LATEST INFRARED SATELLITE IMAGERY CONTINUES TO SHOW A RAGGED
APPEARANCE TO GUILLERMO...WITH DEEP CONVECTION STRUGGLING TO REMAIN
OVER THE LOW LEVEL CIRCULATION CENTER DUE TO INCREASING WESTERLY
WIND SHEAR ALOFT. THE U.S. 53RD WEATHER RECONNAISSANCE AIRCRAFT
WHILE SAMPLING THE INNER CORE OF GUILLERMO LAST EVENING...FAILED TO
FIND FLIGHT LEVEL OR SURFACE WINDS OF 64 KNOTS OR GREATER. THE MOST
RECENT DVORAK CLASSIFICATIONS WERE 4.0/65KT FROM PHFO...JTWC AND
SAB...WHILE FINAL T NUMBERS WERE LOWER AT 3.5. ADDITIONALLY...THE
ADVANCED DVORAK TECHNIQUE FROM UW-CIMSS INDICATED A CURRENT
INTENSITY T NUMBER OF 4.0 AND A FINAL T NUMBER OF 3.5. RELYING
HEAVILY ON THE FACT THAT THE AIRCRAFT FAILED TO FIND 64 KNOT WINDS
DURING THE MISSION LAST EVENING THROUGH GUILLERMO...ALONG WITH A
1220Z SSMI MICROWAVE PASS SHOWING A WELL DEFINED CIRCULATION CENTER
BUT NO THUNDERSTORMS IN THE SOUTHWEST QUADRANT...AND THE CONTINUED
RAGGED PRESENTATION IN INFRARED SATELLITE IMAGERY...THE 1500Z
INTENSITY WILL BE LOWERED SLIGHTLY TO 60 KNOTS. AS A RESULT...
GUILLERMO HAS WEAKENED TO TROPICAL STORM STATUS.

THE INITIAL POSITION OF THE SYSTEM WAS HEAVILY WEIGHTED ON A COUPLE
CENTER FIX POSITIONS FROM THE AIRCRAFT MISSION LAST EVENING ALONG
WITH EXTRAPOLATION USING INFRARED SATELLITE IMAGERY. AS A
RESULT...THE CURRENT MOTION IS TOWARD THE WEST-NORTHWEST...300
DEGREES...AT 9 KNOTS. THIS GENERAL MOTION IS EXPECTED TO CONTINUE
FOR THE NEXT COUPLE OF DAYS AS THE SYSTEM IS GUIDED BY A LARGE
SURFACE RIDGE NEARLY 1600 NM TO THE NORTHEAST OF THE MAIN HAWAIIAN
ISLANDS AND A WEAKNESS IN THE RIDGING ALOFT RUNNING ROUGHLY
SOUTHEAST TO NORTHWEST JUST TO THE NORTH OF THE SYSTEM. THE LATEST
MODEL GUIDANCE HAS SHIFTED TOWARD THE RIGHT OR NORTH OF THE
PREVIOUS FORECAST TRACK...LIKELY THE RESULT OF THE IMPROVED SAMPLING
OF THE SYSTEM BY THE NOAA G-IV AIRCRAFT ON ITS SYNOPTIC SAMPLING
MISSION SUNDAY AFTERNOON. THE SPREAD AMONGST THE MODELS HAS ALSO
INCREASED IN THE FIRST 48 HOURS OF THE FORECAST...WITH QUITE A BIT
OF SPREAD CONTINUING THROUGH THE FORECAST PERIOD. AS A RESULT...WE
HEAVILY RELIED ON A COMBINATION OF THE TVCN...GFS...AND THE HWRF
SOLUTIONS WITH A SIZEABLE WEIGHT PLACED ON THE PREVIOUS OFFICIAL
FORECAST. THE NEW OFFICIAL FORECAST TRACK SHOWS A SLIGHT SHIFT
TO THE RIGHT OR NORTH FROM THE PREVIOUS FORECAST ADVISORY.

THE LATEST UW-CIMSS VERTICAL WIND SHEAR ANALYSIS SHOWED 14 KNOTS
FROM 270 DEGREES...WHILE THE LATEST SHIPS ANALYSIS SHOWED 16 KNOTS
FROM 285 DEGREES. THIS IS LIKELY RESPONSIBLE FOR THE CONTINUED
RAGGED SATELLITE PRESENTATION AND THE WEAKENING OF THE SYSTEM SINCE
THE PREVIOUS ADVISORY. SLOW BUT STEADY WEAKENING IS EXPECTED TO
CONTINUE THROUGH THE FORECAST PERIOD. AS GUILLERMO CONTINUES TO
MOVE INTO THE WEAKNESS IN THE MID TO UPPER LEVEL RIDGE...OUTFLOW
WITHIN THE NORTHWEST QUADRANT WILL BECOME FURTHER DISRUPTED AND
VERTICAL WIND SHEAR WILL SLOWLY INCREASE. THE INTENSITY FORECAST
CLOSELY FOLLOWS THE ICON...WITH SHIPS PREDICTING MORE RAPID
WEAKENING BEYOND 48 HOURS. THE FORECAST AND INITIAL WIND RADII WERE
ADJUSTED BASED ON THE AIRCRAFT DATA LAST EVENING AND THE CURRENT
INTENSITY TRENDS OF GUILLERMO.

AS GUILLERMO MOVES CLOSER TO HAWAII...WATCHES MAY BE ISSUED LATER
TODAY OR TONIGHT FOR PORTIONS OF THE STATE. HOWEVER...IT IS STILL
TOO SOON TO DETERMINE WITH CERTAINTY WHICH ISLANDS ARE MOST LIKELY
TO EXPERIENCE THE GREATEST IMPACTS FROM GUILLERMO. IT IS ALSO
IMPORTANT TO NOTE THAT SIGNIFICANT IMPACTS CAN EXTEND WELL AWAY
FROM THE CENTER.

ANOTHER RECONNAISSANCE AIRCRAFT MISSION INTO GUILLERMO IS SCHEDULED
FOR THIS MORNING. THE VALUABLE DATA TRANSMITTED IN REAL-TIME FROM
THESE MISSIONS WILL HELP US TO BETTER DETERMINE THE LOCATION...
INTENSITY AND SIZE OF THE TROPICAL STORM. IN ADDITION...THE NOAA
G-IV JET IS SCHEDULED TO CONDUCT ANOTHER SYNOPTIC SAMPLING MISSION
AROUND GUILLERMO THIS AFTERNOON. THIS SAMPLING SHOULD HELP IMPROVE
THE MODEL INITIALIZATION AND IMPROVE THE MODEL FORECAST TRACKS FOR
GUILLERMO.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 16.6N 146.1W 60 KT 70 MPH
12H 04/0000Z 17.2N 147.2W 55 KT 65 MPH
24H 04/1200Z 17.9N 148.8W 50 KT 60 MPH
36H 05/0000Z 18.7N 150.5W 45 KT 50 MPH
48H 05/1200Z 19.6N 152.2W 45 KT 50 MPH
72H 06/1200Z 21.4N 155.9W 40 KT 45 MPH
96H 07/1200Z 23.1N 159.9W 35 KT 40 MPH
120H 08/1200Z 25.0N 164.1W 30 KT 35 MPH

$$
FORECASTER JELSEMA/HOUSTON

[Yellow Evan]

60 knts is really generous. Probs 50-55 knts.

[Yellow Evan]

Looking at recon, this is likely 50 knts.

[Yellow Evan]

12z ECMWF no threat to Hawaii at all.

[Kingarabian]

12z ECMWF no threat to Hawaii at all.

Has it turning NNW within the next 24 hours. Looks like it's still moving WNW.

[Yellow Evan]

12z ECMWF no threat to Hawaii at all.

Has it turning NNW within the next 24 hours. Looks like it's still moving WNW.

Yea. Next 24 hours will be key.

If it stays WNW, this is a Hawaii landfall storm. If it moves NW, this will brush it. If this moves NNW, it won't affect it.

[Kingarabian]

989mb found. Looks like it re-strengthened again.