Estelle still a tropical storm at 5 AM HST

[cycloneye]

Tropical Storm Estelle Discussion Number 10


Statement as of 5:00 am HST on August 21, 2004



Estelle continues to slowly organize beneath a cold central dense
overcast. Satellite intensity estimates are now 65 kt from phfo
but have increased the initial intensity to 60 kt due to consensus
of 12z fixes being more conservative.

The initial motion is 297/9...slightly more northwesterly and a tad
slower than previous estimates. Estelle continues to progress west
northwestward on the south side of the subtropical ridge...perhaps
now feeling a bit of the more southerly windflow at higher levels
around the east side of troughing now over the Hawaiian islands.
Synoptic-scale models indicate the surface ridge should strengthen
and build westward during the forecast period...but keep the upper
level trough over the islands. The result is increasing shear from
the south and as a result...after initially strengthening Estelle
to minimal hurricane force within the next 12 hours...then have
storm weakening beyond 36 hours...and then taking a more west
southwesterly track under the influence of the lower level trade
winds and more in line with the later periods of the BAM-medium and
BAM-shallow.

The dynamical forecast models are in fair agreement through 48 hr
and then somewhat diverge...with the UKMET bringing the storm
farther north toward the islands and GFDL calling for a generally
westward motion. The NOGAPS and GFS are in line with the forecast
west-southwestward motion. The official track remains close to the
previous forecast and closer to the GFDL in general...taking the
storm toward the west and west southwest as Estelle weakens beyond
36 hours.

Estelle is quite comapct...with a well-organized central core. This
would be favorable for rapid intensification were the storm not
moving from 27c sea surface temperatures to 25-26c in 24 hr...and
the vertical shear is forecast to increase as Estelle approaches
the aforementioned upper-level trough currently along 151w. Given
these limiting factors...the intensity forecast calls for 12 hr of
strengthening...followed by gradual weakening beyond 36 hours. The
intensity forecast is stronger than either the ships or GFDL models
and is in best agreement with shifor-5.

Forecaster Farrell

forecast positions and Max winds

initial 21/1500z 15.1n 141.3w 60 kt
12hr VT 22/0000z 15.6n 142.5w 65 kt
24hr VT 22/1200z 16.2n 144.3w 65 kt
36hr VT 23/0000z 16.8n 146.1w 65 kt
48hr VT 23/1200z 17.3n 148.0w 60 kt
72hr VT 24/1200z 17.6n 151.9w 50 kt
96hr VT 25/1200z 17.2n 156.2w 40 kt
120hr VT 26/1200z 16.5n 160.7w 35 kt


They went with the conservative side and not classify it a a hurricane despite it's great appeareance at sat pics looking like a cane.

[Derek Ortt]

All of the available data shows that this has become a hurricane. They can call it a storm for now, but $1,000 says that best-track makes this a cane at 1200 UTC; thus, its a cane now

[cycloneye]

Yeah Derek I agree with you that it is a minimal hurricane at best 75 mph instead of 70 mph.

[B-Bear]

Yeah Derek I agree with you that it is a minimal hurricane at best 75 mph instead of 70 mph.

Okay, help me out here. I promise I'm not trying to be a smart-ass.

I thought this would be a typhoon and not a hurricane because it was in the Pacific???

[cycloneye]

They name hurricanes Typhoons in the western pacific basin but in the eastern and central pacific they are called hurricanes but essentially they are the same.

[B-Bear]

They name hurricanes Typhoons in the western pacific basin but in the eastern and central pacific they are called hurricanes but essentially they are the same.

Interesting. So where is the cut-off line where they stop calling them hurricanes and start calling them typhoons?

[OklahomaWeather]

I believe it's 180E.

[cycloneye]

The international dateline 180E.

[B-Bear]

Gotcha. Now I know. Thanks.

[Matthew5]

Wind shear of 20 to 30 knots is starting to distroy the western Quad of this storm. Expect this system to start weaking.

[Derek Ortt]

the SE quad is exposed. I do not see the w quad being destroyed, but instead the E quad

[Matthew5]

Derek on the western side the outflow is shooting to the north instead of outwards to the west. Wind shear maps show 20 to 30 knot shear just to the north in west of the system. All together it would not take much for this to make a landfall on Hawaii!

[caribepr]

This from a friend of mine who has lived on the southwestern corner of the big island for the last 30 years. I emailed him this morning in light of this thread. I thought his take on it was interesting enough to share.

"could be. we seldom pay attention. the Mountains of Mauna Loa and Mauna Kea provide their own, independent weather system, and shove huricanes away from us, back out to sea. then they circle back and hit Maui, Oahu and / or Kauai. don't think there is a recorded hurricane hit on this island. we have had 2 tornadoes, one last year. ran down some trees on the Jimmy Stewart Ranch. we have had a couple, maybe three, head our way this year. provided some refreshing rain, keeping things green."

[PurdueWx80]

This from a friend of mine who has lived on the southwestern corner of the big island for the last 30 years. I emailed him this morning in light of this thread. I thought his take on it was interesting enough to share.

"could be. we seldom pay attention. the Mountains of Mauna Loa and Mauna Kea provide their own, independent weather system, and shove huricanes away from us, back out to sea. then they circle back and hit Maui, Oahu and / or Kauai. don't think there is a recorded hurricane hit on this island. we have had 2 tornadoes, one last year. ran down some trees on the Jimmy Stewart Ranch. we have had a couple, maybe three, head our way this year. provided some refreshing rain, keeping things green."

The mountains do provide some interesting convergence patterns that can steer a storm around them. However, that said, horrible tropical storms have devastated that island. A couple of years ago a TS combined with another low and extremely high moisture converged on the volcanoes/mountains from the southeast. Some rain stations reported more than a meter of rain, with it coming down as hard as 100 mm/hr. Washed all sorts of homes and land away, including a GPS sensor used for both geological and meteorological purposes.