EPAC: GUILLERMO - Post-Tropical

[Kingarabian]

We have hurricane Guillermo.




000
WTPZ44 KNHC 310832
TCDEP4

HURRICANE GUILLERMO DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015
200 AM PDT FRI JUL 31 2015

Guillermo's cloud pattern has continued to become better organized,
with well-defined convective banding and a fairly symmetric
upper-level outflow pattern. A recent GMI microwave image showed a
nearly closed low-level eyewall. The current intensity is set to 70
kt, based on a blend of subjective and objective Dvorak estimates.
This makes Guillermo the fifth hurricane of the 2015 eastern North
Pacific season. Given that the hurricane should be moving over warm
waters, and in a moist mid-level environment with moderate shear,
further strengthening is likely. The official intensity forecast
is near or above the latest model consensus. Since the SHIPS-RI
index still indicates a significant probability of rapid
intensification over the next 24 hours, the NHC forecast could be
conservative. There is considerable uncertainty in the intensity
forecast beyond 48-72 hours, since Guillermo could encounter
stronger shear, depending mainly on how far north the cyclone moves
late in the forecast period.

Based on geostationary and microwave center fixes, the initial
motion is west-northwestward or 300/14 kt. A mid-tropospheric
ridge to the north of the tropical cyclone should maintain the
west-northwestward motion for the next several days. In 48-72
hours, Guillermo should encounter a weakness in the ridge which
will likely cause some slowing of forward speed. However most of
the guidance does not show much of a turn to the right in response
to this weakness. The official track forecast is close to a
consensus of the latest GFS and ECMWF solutions, with the former
model to the north of the latter near the end of the period. This
is similar to the previous NHC track.

FORECAST POSITIONS AND MAX WINDS

INIT 31/0900Z 11.5N 130.6W 70 KT 80 MPH
12H 31/1800Z 12.1N 132.8W 80 KT 90 MPH
24H 01/0600Z 12.7N 135.7W 90 KT 105 MPH
36H 01/1800Z 13.3N 138.4W 95 KT 110 MPH
48H 02/0600Z 14.1N 140.6W 95 KT 110 MPH
72H 03/0600Z 15.5N 144.0W 80 KT 90 MPH
96H 04/0600Z 16.5N 146.5W 70 KT 80 MPH
120H 05/0600Z 17.5N 150.0W 55 KT 65 MPH

$$
Forecaster Pasch

[Kingarabian]

Buzzsaw.

Code: Select all

     UW - CIMSS                     
              ADVANCED DVORAK TECHNIQUE       
                  ADT-Version 8.2.1               
         Tropical Cyclone Intensity Algorithm       

             ----- Current Analysis -----
     Date :  31 JUL 2015    Time :   073000 UTC
      Lat :   11:48:32 N     Lon :  130:44:41 W

     
                CI# /Pressure/ Vmax
                4.4 / 982.0mb/ 74.6kt

     
             Final T#  Adj T#  Raw T#
                4.4     4.4     4.1

 Center Temp : -72.6C    Cloud Region Temp : -69.0C

 Scene Type : UNIFORM CDO CLOUD REGION w/ MW EYE

[Kingarabian]

06z GFS stronger, back to a hurricane as it bears down on Hawaii.
Grazes the islands as a hurricane.

It's interesting how it has Guillermo at 990mb approaching Hawaii but strengthens it as it skirts the islands.

[hawaiigirl]

Can anyone tell me when Oahu will be feeling the storm? And Maui? Jeesh, im supposed to fly to Maui for a wedding on Aug 6th.

[tatertawt24]

It looks really good! The shape is classic.

[srainhoutx]

Can anyone tell me when Oahu will be feeling the storm? And Maui? Jeesh, im supposed to fly to Maui for a wedding on Aug 6th.

From The Weather Prediction Center:

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
649 AM EDT Fri Jul 31 2015

Valid 00Z Sat Aug 01 2015 - 00Z Sat Aug 08 2015

Quiet pattern for the next few days as upper ridging drifts
westward through the weekend. Early next week the remnants of TD
8E is forecast to drift west southwestward between 11-15N south of
the islands. However, part of its moisture will overspread the
eastern islands -- and an increase in rainfall is likely,
especially in windward locations of the Big Island.

The next system on its heels is Tropical Cyclone Guillermo. The
latest National Hurricane Center (NHC) track takes it east of the
big island with a motion in its general direction. Individual
ECMWF and GFS runs show timing changes and north-south differences
on the track. More ECMWF ensembles show a track south of the big
island, in contrast with the 00-06z GFS showing a track north of
the islands next Wed-Thu, 05-06 Aug. A track at or south of the
islands would induce a heavy rainfall threat, so the system will
be watched closely. See the latest advisories from the NHC for the
official track and intensity forecasts and resultant impacts.

Petersen

[SouthDadeFish]

The current RI phase is probably over after seeing recent microwave passes. Nonetheless the storm intensified by 35 knots in the past 24 hours. As Alyono pointed out, there is some factor that isn't quite apparent that disrupted the inner core. Mid-level shear is a good guess. The CIMSS shear analysis shows the shear is westerly, with mid-level shear near 15-20 knots near the the core. This shear direction matches the convective asymmetry seen in the core.

[SouthDadeFish]

Of course just as I post RI may be finishing, the convective pattern on IR satellite continues to improve. We'll see.

[Yellow Evan]

Generally, there are two phases of RI. One from development to high-end TS/low-end Cat 1 status and another once it mixes out dry air and the eye clearly. We've passed Phase 1, so no it needs to get its core ready.

[cycloneye]

80kts.

09E GUILLERMO 150731 1200 12.1N 132.0W EPAC 80 975

[Yellow Evan]

TXPZ25 KNES 311225
TCSENP

A. 09E (GUILLERMO)

B. 31/1200Z

C. 12.1N

D. 132.0W

E. THREE/GOES-W

F. T4.5/4.5/D1.0/06HRS

G. IR/EIR/SWIR

H. REMARKS...SYSTEM HAS DEVELOPED RAPIDLY OVER THE PAST 6HRS WITH A MED
GRAY EYE EMBEDDED IN LIGHT GRAY WITH SURROUNDING BLACK RING. MET=4.0 ON
RAPID CURVE BUT PAT ALSO 4.5. AND FT AND CI CHANGE OF 2.0 OVER 24HRS. FT
IS BASED ON DT.

I. ADDL POSITIONS

NIL


...SWANSON

[Yellow Evan]

Eye not closed yet

[Yellow Evan]

Mid-shear doesn't look that bad.

[cycloneye]

Forecast to become a major.

HURRICANE GUILLERMO DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015
800 AM PDT FRI JUL 31 2015

The satellite presentation has improved during the past several
hours. The eye, however, is not completely closed on microwave
imagery at this time. There are several cyclonically curved
convective bands around the center, and the outflow is symmetric.
Both objective and subjective Dvorak numbers have continued to
increase, and the average of these numbers leads to an initial
intensity of 80 kt.

The current environment of low shear and warm ocean is quite
favorable for Guillermo to intensity further, and the NHC forecast
brings the winds up to 100 kt in about 24 hours. This forecast is a
little bit higher than the SHIPS guidance, but follows the
upward trend of the consensus. Beyond two days, the hurricane will
encounter a less favorable shear environment as Guillermo approaches
the prevailing upper-level westerlies. By the end of the forecast
period, when Guillermo is expected to be nearing the Hawaiian
Islands, the cyclone should have weakened to a tropical storm.

The hurricane is racing west-northwestward or 285 degrees at about
15 kt. The cyclone will likely continue on this track and speed for
the next day or two while embedded within a layer of deep easterlies
to the south of the subtropical ridge. After 48 hours, the hurricane
is expected to slow down as it approaches the southwestern edge of
the subtropical ridge. By then, the presence of weaker steering
currents makes the track forecast uncertain, and even more uncertain
as the cyclone approaches the Hawaiian islands in about five days.
The NHC forecast is consistent with the solution provided by global
models. The forecast is also near the consensus, but heavily
weighted on the GFS and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 31/1500Z 12.4N 132.7W 80 KT 90 MPH
12H 01/0000Z 13.0N 134.9W 90 KT 105 MPH
24H 01/1200Z 13.6N 137.8W 100 KT 115 MPH
36H 02/0000Z 14.3N 140.4W 100 KT 115 MPH
48H 02/1200Z 15.0N 142.4W 90 KT 105 MPH
72H 03/1200Z 16.3N 145.4W 70 KT 80 MPH
96H 04/1200Z 17.5N 148.3W 60 KT 70 MPH
120H 05/1200Z 18.5N 152.0W 50 KT 60 MPH

$$
Forecaster Avila

[Yellow Evan]

000
NOUS42 KNHC 311424
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT FRI 31 JULY 2015
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 01/1100Z TO 02/1100Z AUGUST 2015
TCPOD NUMBER.....15-066

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK:
A. FIX HURRICANE GUILLERMO AT 02/1800Z AND 03/0600Z.
B. A G-IV SYNOPTIC SURVEILLANCE FLIGHT AROUND
GUILLERMO FOR 03/0000Z.
3. ADDITIONAL DAY OUTLOOK:
A. FIX GUILLERMO AT 03/1800Z AND BEGIN 6-HRLY FIXES
AT 04/0600Z.
B. A G-IV FLIGHT FOR 04/0000Z.
$$
JWP

[Yellow Evan]

Might be inheriting a crap ton of dry air.

[Kingarabian]

[Alyono]

One thing I remember from 1997, there were no Hawaii threats from the east that year. Everything got sheared.

Ironically, some of the greatest threats from the EAST have come during strong la niña years. 1999 had Dora, 2007 had Flossie. Both were very powerful hurricanes that narrowly missed to the south. Not entirely sure why this is the case

[Alyono]

MU shows this having peaked now and this weakens from here on out

still not seeing that much of a Hawaii threat, unless ALL models are dead flat wrong

[Kingarabian]