EPAC: GUILLERMO - Post-Tropical

[Kingarabian]

[cycloneye]

No longer forecast to become a major cane.

[Yellow Evan]

The coldest cloud tops aren't too organized right now. It's a wait and see game at this point.

[Kingarabian]

Nudged upwards, definitely good news!

[Yellow Evan]

Well, with its weakening, chances increase that the track will shift south.

[Kingarabian]

HURRICANE GUILLERMO DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015
800 PM PDT FRI JUL 31 2015

Both microwave and conventional satellite imagery indicate that
Guillermo has not become any better organized during the past
several hours. In fact, the satellite presentation appears to have
deteriorated since earlier today with microwave data showing the
northwestern portion of the eyewall eroding. Satellite intensity
estimates from TAFB and SAB and the latest objective intensity
estimate from UW-CIMSS ADT suggest that initial intensity remains 90
kt.

Guillermo continues to move rapidly to the west-northwest, with an
initial motion estimate of 285/18 kt. Little change to this motion
is expected for the next 24 hours, with the cyclone remaining to the
south of a mid-level subtropical ridge. Beyond 24 hours to around
72 hours, a deepening mid- to upper-level trough over the central
Pacific is forecast to create a break in the subtropical ridge,
which should cause the tropical cyclone to slow down and turn more
toward the northwest. The spread in the guidance suite increases
beyond 72 hours, but most of the models maintain a general
west-northwestward motion. The new forecast track is basically an
update of the previous track through 72 hours, and is then nudged
slightly to the right or north of the previous track toward the
multi-model consensus thereafter.

The intensity forecast has become somewhat problematic. The reason
for the recent arrested development is unclear, although it might be
related to dry air entrainment into the northwestern quadrant of the
cyclone. However, there is still the opportunity for Guillermo to
strengthen a bit more during the next 12 to 24 hours, while the
system remains within a low-shear environment and over warm sea
surface temperatures. The new intensity forecast is adjusted
slightly downward to 95 kt at the 12- and 24-hour forecast times.
Thereafter, the cyclone is forecast to move into an upper-level
deformation zone between subtropical ridges to the east and west,
which is a less favorable environment. Also, sea surface
temperatures gradually cool along the forecast track. We have
followed the previous forecast trend of gradual weakening, which is
in good agreement with the latest SHIPS/LGEM and IVCN consensus
guidance. When Guillermo approaches the Hawaiian Islands, it is
expected to encounter increasing westerly shear, and the new
intensity forecast follows the previous forecast in weakening
Guillermo to tropical storm strength.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 13.2N 136.1W 90 KT 105 MPH
12H 01/1200Z 13.7N 138.5W 95 KT 110 MPH
24H 02/0000Z 14.3N 141.1W 95 KT 110 MPH
36H 02/1200Z 15.0N 143.2W 90 KT 105 MPH
48H 03/0000Z 15.8N 145.0W 80 KT 90 MPH
72H 04/0000Z 17.0N 147.5W 65 KT 75 MPH
96H 05/0000Z 19.0N 150.5W 60 KT 70 MPH
120H 06/0000Z 20.5N 153.5W 50 KT 60 MPH

$$
Forecaster Beven/Jacobson

[Yellow Evan]

Pretty much agree with most of the discussion.

Is there any confirmed evidence on how mid-level shear affects tropical cyclones?

[Kingarabian]

Not good.

[Hurricaneman]

Looks like the shear monster is taking some bites here

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[Yellow Evan]

0z GFS shows basically weakening and no change in track.

[TheStormExpert]

How come the quality of East Pacific storms has been lacking this season verses last? Many thought with a Super El Niño that the East Pacific would bomb out? Even the Central Pacific seems a little less unfavorable when compared to last season.

[Yellow Evan]

How come the quality of East Pacific storms has been lacking this season verses last? Many thought with a Super El Niño that the East Pacific would bomb out? Even the Central Pacific seems a little less unfavorable when compared to last season.

Keep in mind that as of tonight last year, we were at 10/4/2. Today we are at 10/5/3. And also keep in mind that 2014 is one of the most active years on record and those aren't always contrary to popular belief super El Ninos.

Seems to be a lot more variables in play this year for intensification than last, ill tell you that much.

[CaliforniaResident]

How come the quality of East Pacific storms has been lacking this season verses last? Many thought with a Super El Niño that the East Pacific would bomb out? Even the Central Pacific seems a little less unfavorable when compared to last season.

Like the Atlantic, the EPAC season peaks from mid August through early October. I am fully expecting potent explosion of storms around mid-August with multiple storms forming each week through mid-October. I stand by my prediction of 33/22/11 with the landfall (either Waldo or Zelda just because of the personal connections I have with those names) within 100 miles of San Diego during the first half of October (either as a strong TS or a cat 1). We will go Alpha by the end of October.

[Yellow Evan]

How come the quality of East Pacific storms has been lacking this season verses last? Many thought with a Super El Niño that the East Pacific would bomb out? Even the Central Pacific seems a little less unfavorable when compared to last season.

Like the Atlantic, the EPAC season peaks from mid August through early October. I am fully expecting potent explosion of storms around mid-August with multiple storms forming each week through mid-October. I stand by my prediction of 33/22/11 with the landfall within 100 miles of San Diego during the first half of October (either as a strong TS or a cat 1).

The EPAC's peak is from mid-July to late September. And only so many systems can form at a time. No way we're getting 23 more storms. That's more systems than the entire 2014 season.

[Kingarabian]

[Kingarabian]

00z ECMWF shifts back west for a Hawaii landfall.

[Kingarabian]

TXPZ25 KNES 010619
TCSENP

A. 09E (GUILLERMO)

B. 01/0600Z

C. 13.2N

D. 136.6W

E. THREE/GOES-W

F. T4.5/4.5/D1.0/24HRS

G. IR/EIR/SSMIS

H. REMARKS...DT=4.5 BASED ON LG EMBEDDED CENTER. PT=4.5. MET=4.5. FT
IS BASED ON DT. 01/0423Z SSMIS SHOWS WELL DEFINED EYE FEATURE.

I. ADDL POSITIONS

01/0423Z 13.1N 136.4W SSMIS


...SCHWARTZ

[Kingarabian]

HURRICANE GUILLERMO DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015
200 AM PDT SAT AUG 01 2015

Guillermo's cloud pattern has changed little in organization over
the past several hours. Convective banding features are not as
well defined as they were 24 hours ago, and the CDO lacks a circular
shape. Dvorak T-numbers remain unchanged from the previous
advisory package, so the intensity estimate is held at 90 kt.
Upper-level outflow has become restricted to the northwest of the
cyclone. The oceanic and atmospheric environment is not likely to
become more conducive for strengthening over the next couple of
days, and the numerical intensity guidance generally shows a
gradual weakening trend. Near the end of the forecast period,
global models indicate a significant increase in vertical shear
associated with strong upper-tropospheric westerlies near the
Hawaiian Islands. The official forecast is near or slightly above
the intensity model consensus and shows, as in the previous
advisory, weakening to tropical storm status in 96 hours.

Based on geostationary and microwave center fixes, in particular an
earlier SSMI/S pass from 0424Z, the motion has slowed somewhat and
is now estimated to be about 285/14 kt. Guillermo is approaching a
weakness in the zonally-oriented mid-level ridge to its north, and
this should result in further deceleration over the next couple of
days. In 3-5 days, the steering currents become less well defined
in the global models and there is a fair amount of spread in the
dynamical track predictions. The ECMWF model has been doing a bit
of a flip-flop in its last few runs, and it has shifted back the
south after shifting northward in the previous run. The official
forecast is held very close to the previous NHC track and is close
to the latest track model consensus, TVCN, which combines not only
the GFS and ECMWF solutions but also the HWRF, GFDL, and U.K. Met.
Office model forecasts.

Due to uncertainties in longer-range track predictions, it is
important for users not to focus on the exact track forecasts at 96
and 120 hours.

FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 13.4N 137.4W 90 KT 105 MPH
12H 01/1800Z 13.9N 139.6W 90 KT 105 MPH
24H 02/0600Z 14.5N 142.0W 90 KT 105 MPH
36H 02/1800Z 15.1N 144.0W 85 KT 100 MPH
48H 03/0600Z 15.8N 145.4W 75 KT 85 MPH
72H 04/0600Z 17.3N 148.0W 65 KT 75 MPH
96H 05/0600Z 19.0N 151.0W 60 KT 70 MPH
120H 06/0600Z 20.5N 154.0W 50 KT 60 MPH

$$
Forecaster Pasch

[Kingarabian]

SAB up to 5.0.

[Yellow Evan]

Code: Select all

             ----- Current Analysis -----
     Date :  01 AUG 2015    Time :   120000 UTC
      Lat :   13:32:52 N     Lon :  138:06:25 W

     
                CI# /Pressure/ Vmax
                5.0 / 967.8mb/ 90.0kt

     
             Final T#  Adj T#  Raw T#
                4.7     4.8     4.8

 Center Temp : -75.1C    Cloud Region Temp : -72.8C