TROPICAL STORM DARBY TROPICAL CYCLONE UPDATE
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP052016
320 PM HST SAT JUL 23 2016
...CENTER OF DARBY MAKES LANDFALL...
The center of Tropical Storm Darby made landfall at about 200 PM
HST, or 0000 UTC, along the Kau coast on the Big Island. This is
about 10 miles east-northeast of Pahala and very close to the
location where Tropical Storm Iselle made landfall in 2014.
SUMMARY OF 200 PM HST...0000 UTC...INFORMATION
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LOCATION...19.3N 155.3W
ABOUT 35 MI...55 KM SSW OF HILO HAWAII
ABOUT 220 MI...355 KM SE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.70 INCHES
TROPICAL STORM DARBY DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016
900 AM MDT TUE JUL 12 2016
Recent microwave data indicate that the depression has a well-
defined circulation with the center located to the northeast of the
strongest convection. Subjective Dvorak intensity estimates are
T2.0 from TAFB and T3.0 from SAB, and the latest ADT estimate is
right at the tropical storm threshold. A consensus of these values
supports upgrading the depression to a tropical storm, with the
initial intensity set at 35 kt. After starting off May and June
very quietly, the eastern North Pacific season has already caught
up to where it should be climatologically in terms of named storms.
Darby appears to have turned westward with an initial motion of
270/9 kt. A subtropical ridge extending westward from northern
Mexico is expected to strengthen during the next three days, which
will steer Darby westward, or even a little south of due west,
during that time. The model fields continue to show differences in
the strength of the ridge at the end of the forecast period. The
ECMWF maintains a stronger ridge, with Darby possibly continuing a
westward motion, while the GFS erodes the ridge and allows Darby to
gain some latitude. The track model envelope has again shifted
southward on this cycle, and the updated NHC track forecast has
been nudged in that direction close to a consensus of the GFS and
ECMWF.
Darby will be moving over a warm pool of SSTs around 29.5 degrees
Celsius during the next 24 hours, and the northeasterly vertical
shear affecting the cyclone should abate a bit. Depending on
its exact track, Darby could move over the cold wake left behind by
Hurricanes Blas and Celia in a couple of days. Some shear could
also persist for a few days, therefore only steady strengthening is
expected through 72 hours. Colder water should then cause
weakening on days 4 and 5. There is still a lot of spread among
the intensity models, so for now no significant changes are being
made to the previous NHC intensity forecast. This scenario is a
little above the intensity consensus during the first three days
and then close to the consensus on days 4 and 5.
1. Numerous showers and thunderstorms are associated with a broad area
of low pressure located several hundred miles south of Manzanillo,
Mexico. This shower and thunderstorm activity has become more
organized over the last day. Environmental conditions appear
conducive for continued development of this system, and a tropical
depression is likely to form during the next couple of days while
the low moves westward to west-northwestward at about 10 mph, away
from the coast of Mexico.
* Formation chance through 48 hours...high...70 percent
* Formation chance through 5 days...high...90 percent