8 Jul Sun 2018

Tropical Report

DEPRESSION BECOMES TROPICAL STORM CHRIS… …FURTHER STRENGTHENING IS LIKELY WHILE IT MEANDERS OFF THE CAROLINA COAST

Tropical Storm Chris Discussion Number 7
NWS National Hurricane Center Miami FL AL032018
500 AM EDT Sun Jul 08 2018

An Air Force Reserve reconnaissance aircraft has been investigating
the cyclone early this morning, and found flight-level winds of 45
kt at 925 mb and believable SFMR surface winds of around 34
kt in the southeast quadrant. On this basis, the system has been
designated as Tropical Storm Chris, the 3rd named storm of the 2018
Atlantic season.

Although the winds associated with the tropical storm have increased
a little, the overall organization of Chris has not changed much
over the past few hours. The low-level center is still exposed to
the north of a broken band of deep convection and the cyclone lacks
an inner-core. Chris is located over very warm SSTs and will
remain so for the next several days. While the broad nature of the
cyclone’s circulation and some moderate shear will likely limit the
intensification rate over the next day or so, all of the intensity
guidance indicates that Chris will become a hurricane within about
72-h. By day 4, the intensity forecast is more uncertain,
and depends strongly on the timing of Chris crossing the Gulf
Stream, since the cyclone is expected to continue to intensify as
long as it remains over warm waters. Once extratropical transition
begins, weakening should occur as the wind field broadens. The new
intensity forecast is close to HCCA and IVCN through day 3, and
slightly lower beyond that, closer to the previous forecast.

The track guidance has once again made a large shift with the latest
forecast cycle. While Chris is generally expected to continue to
meander off the coast of the Carolinas for the next couple of days
before accelerating to the northeast ahead of a deep-layer trough
approaching from the northwest, the timing of this acceleration is
highly uncertain. Nearly all of the dynamical models have now
shifted to the south and west of their previous forecasts throughout
most of the forecast period. The NHC track forecast has been
adjusted in that direction, but now lies on the eastern side of the
guidance envelope, and shows a faster motion than most of the
models. Given the large run-to-run inconsistency of the guidance
over the past 24 hours, I would prefer to wait to make a more
significant change to the forecast until a more clear pattern
emerges.

The Air Force reconnaissance plane also measured winds to
gale-force about 20 miles off the coast of North Carolina. These
winds are associated with the tight pressure gradient between
Chris and high pressure over the northeastern U.S. See products
issued by the National Weather Service forecast offices for more
details.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 33.0N 75.5W 35 KT 40 MPH
12H 08/1800Z 33.0N 75.4W 40 KT 45 MPH
24H 09/0600Z 32.8N 75.3W 45 KT 50 MPH
36H 09/1800Z 32.6N 75.1W 55 KT 65 MPH
48H 10/0600Z 32.7N 74.7W 60 KT 70 MPH
72H 11/0600Z 35.2N 71.5W 70 KT 80 MPH
96H 12/0600Z 41.5N 64.0W 70 KT 80 MPH
120H 13/0600Z 49.0N 54.5W 55 KT 65 MPH…POST-TROP/EXTRATROP

$$
Forecaster Zelinsky

BERYL MOVING WEST-NORTHWESTWARD TOWARD THE LESSER ANTILLES… …RECONNAISSANCE AIRCRAFT EN ROUTE TO THE STORM

Tropical Storm Beryl Discussion Number 12
NWS National Hurricane Center Miami FL AL022018
500 AM AST Sun Jul 08 2018

A burst of deep convection developed over the eastern portion of
Beryl’s circulation just after the release of the previous
advisory. The convective burst has expanded overnight and
the earlier exposed center of the cyclone is now located near
the northwestern edge of the convective cluster. Subjective Dvorak
intensity estimates from TAFB and SAB are unchanged, and the initial
intensity remains 40 kt for this advisory. An Air Force Reserve
reconnaissance aircraft is currently en route to Beryl and should
provide a better assessment of the cyclone’s intensity this morning.

The intensity forecast reasoning is unchanged from the previous
advisory. Westerly vertical wind shear is expected to increase over
Beryl during the next 24 to 36 h, and the cyclone will be moving
into a drier mid-level environment. As a result, Beryl is expected
to weaken and degenerate into a trough of low pressure over the
eastern Caribbean Sea. However, the system will likely produce
strong gusty winds and locally heavy rainfall across the Leeward
Islands, the Virgin Islands, and Puerto Rico during the next few
days.

The tropical storm is moving quickly west-northwestward or 290/17
kt. Beryl should continue on this general heading with some
increase in forward speed as it is steered by a strong mid-level
ridge to the north. The track guidance remains in fairly good
agreement but there has been some increase in the cross track
spread at 24 and 36 h with the GFS and HWRF along the southern
edge of the guidance and the ECMWF bracketing the northern side of
the envelope. The NHC track is in the middle of the envelope,
close to the various consensus models, and in best agreement with
the HFIP corrected consensus.

Key Messages:

1. Tropical storm warnings and watches are in effect for portions
of the Lesser Antilles where Beryl is forecast to bring impacts
from wind and rainfall to some of the islands beginning late today
or tonight.

2. Although Beryl is forecast to degenerate into a trough of low
pressure over the eastern Caribbean, the system is likely to produce
strong gusty winds and locally heavy rainfall across the remainder
of the Leeward Islands, the Virgin Islands, Puerto Rico, and
Hispaniola through Tuesday.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 13.7N 56.0W 40 KT 45 MPH
12H 08/1800Z 14.7N 58.8W 40 KT 45 MPH
24H 09/0600Z 15.9N 62.7W 35 KT 40 MPH
36H 09/1800Z 17.4N 66.8W 30 KT 35 MPH
48H 10/0600Z…DISSIPATED

$$
Forecaster Brown

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sun Jul 8 2018

For the eastern North Pacific…east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Avila

Global Tropics & Benefits Outlook

Weather in Cayman

SYNOPSIS

Light to moderate east to northeasterly winds and seas are expected over the Cayman area for the next 24 hours as a ridge of high pressure lingers north of the Caribbean. A tropical wave over Jamaica will move into the Cayman area later today leading to an increase in shower activity. Radar images show a few showers in and around the Cayman area which are moving towards the west.

 

Humidity: 85%  (Same as yesterday)

UV: 11.9   EXTREME  (DOWN from yesterday)

Temperature: Today’s current temperature – Not available.  See weather forecast top right of website.  Yesterday: H 90.2°F  L 78.1°F

Wind direction TODAY: ENE 10-20 mph GC

Wind direction TONIGHT: ENE 10-15 mph GC

Barometer: 1016.70 mb  Steady  Rain:   Last month: 11.49 in    Last 24 hrs 0.14 This month:  0.16 in  0 days since rain 2 rain days in July

2017 Season Total:  62.94 in      2018 Season Total: 17.63 in

Average Yearly Rainfall 56.20 in (Note: National Weather Service 2017 Season Total – measured at Owen Roberts Airport GT – was 59.32 in)

All readings are from SOUTH SOUND.

Average rainfall in July 6.9 in.  Average temperature in July: 77°F to 90°F

Sea Temperature in July 84°F

 

Moon illumination: 28% Waning Gibbous