cieldumort
(Moderator)
Wed Sep 05 2018 03:45 AM
Olivia Lounge



Above: Enhanced IR Hurricanes Norman and Olivia September 5, 2018 0715z

(Stop me if you've seen this paragraph before) An intense east Pac tropical cyclone, Olivia, looks increasingly set on a course towards the Hawaiian Islands, and thus we are now starting a thread on what could present one of the bigger tropical threats Hawaii has seen in many years, should current trends continue and model forecasts generally verify.

At the 800 PM PDT Tuesday September 4 2018 NHC Advisory, Olivia had maximum sustained winds of 125 MPH, and a minimum central pressure of 955 MB. Olivia is forecast by NHC to travel west to west-northwestward with increasing forward speed for the next several days through an area of higher shear, lower SSTs and drier air, resulting in sustained weakening, but is expected to still be a hurricane when she crosses over to CPHC's Area of Responsibility.

Our two generally most reliable global models, the ECMWF and the GFS, are continuing a trend in their longer ranges of bringing a still formidable Tropical Cyclone Olivia right into the Hawaiian archipelago on or about the middle of next week.

In the case of the ECMWF, Olivia is now depicted directly striking the Big Island as a 991 MB system on Tuesday September 12th. The GFS now has Olivia hit a little further north, striking O'ahu, which is home to Hawaii’s biggest city and capital, Honolulu, at the same intensity (991 MB) but on Wednesday September 13th.

These are model runs that are still many days out, and things could change a lot between now and then. These are not official forecasts, but are intended to provide us with information and educated best guesses. That said, the Central Pacific and Atlantic both appear to be in a phase of not only enhanced activity, but also of direct threats to land - which in Hawaii's case is especially hard to do given how small a point the islands are in the vastness of the Pacific Ocean - but, they happen to be situated roughly where a lot of the action is taking place this year. (See Lane and also 95L)


cieldumort
(Moderator)
Sun Sep 09 2018 12:30 AM
Re: Olivia Lounge

Dropsondes from Saturday made it into the new 0z model runs for Olivia, and will help bolster the accuracy in her forecast - just days away from a probable impact on the Hawaiian islands.

cieldumort
(Moderator)
Mon Sep 10 2018 03:26 AM
Re: Olivia Lounge

Olivia appears to either be holding her own tonight, or even deepening. The fourth recon mission into the tropical cyclone has found a minimum central pressure of about 981 MB.

This is still a healthy hurricane, and crossing over waters that are progressively a little warmer than yesterday.

From the latest recon vortex center fix:
Quote:

A. Time of Center Fix: 10th day of the month at 7:25:40Z
B. Center Fix Coordinates: 21.66N 146.63W
B. Center Fix Location: 721 statute miles (1,160 km) to the E (88°) from Honolulu, on the island of Oahu, HI, USA.
C. Minimum Height at Standard Level: 2,922m (9,587ft) at 700mb
D. Minimum Sea Level Pressure: 981mb (28.97 inHg)
E. Dropsonde Surface Wind at Center: From 200° at 16kts (From the SSW at 18mph)
F. Eye Character: Closed
G. Eye Shape: Elliptical (oval shaped)
G. Orientation of Major Axis in Elliptical Eye: 320° to 140° (NW to SE)
G. Length of Major Axis in Elliptical Eye: 20 nautical miles (23 statute miles)
G. Length of Minor Axis in Elliptical Eye: 16 nautical miles (18 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 75kts (86.3mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 10 nautical miles (12 statute miles) to the NE (44°) of center fix at 7:22:30Z
J. Maximum Flight Level Wind Inbound: From 144° at 85kts (From the SE at 97.8mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 12 nautical miles (14 statute miles) to the NE (44°) of center fix at 7:22:00Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 57kts (65.6mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 11 nautical miles (13 statute miles) to the SW (225°) of center fix at 7:29:00Z
N. Maximum Flight Level Wind Outbound: From 297° at 65kts (From the WNW at 74.8mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 9 nautical miles to the SW (224°) of center fix at 7:28:30Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 8°C (46°F) at a pressure alt. of 3,049m (10,003ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 15°C (59°F) at a pressure alt. of 3,048m (10,000ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 4°C (39°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 0.5 nautical miles

Remarks Section:

Maximum Flight Level Wind: 85kts (~ 97.8mph) which was observed 12 nautical miles (14 statute miles) to the NE (44°) from the flight level center at 7:22:00Z





collegemom
(Weather Hobbyist)
Wed Sep 12 2018 01:04 PM
Re: Olivia Lounge

Have we any update on Olivia? Son lives in Hana and just called to say they expect it to be there in about 30 mins.


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