21 Aug Weather in Cayman & Tropical Report, 2 Dist Atlantic, 1 Dist CS

August 21, 2017

Aug 21 Monday 2017

Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Aug 21 2017

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

1. A trough of low pressure, associated with the remnants of Harvey,
continues to produce a large area of disorganized showers and
thunderstorms over the northwestern Caribbean Sea. Some
development of this system is still possible before it reaches
the coast of Belize or the Yucatan Peninsula early Tuesday. The
disturbance is forecast to move into the Bay of Campeche early
Wednesday, where environmental conditions are expected to be more
conducive for redevelopment. Regardless of development, locally
heavy rainfall and gusty winds are likely to spread westward across
northern Nicaragua, Honduras, Belize, and the Yucatan Peninsula
during the next couple of days. The Air Force reconnaissance
aircraft mission scheduled for today has been canceled.
* Formation chance through 48 hours…medium…50 percent.
* Formation chance through 5 days…high…80 percent.

2. A trough of low pressure located near the southeastern and central
Bahamas is producing disorganized showers and thunderstorms.
Environmental conditions are expected to be unfavorable for
development of this system during the next day or so while it moves
west-northwestward at about 15 mph across the Bahamas. Conditions
could become a little more conducive for development later in the
week when the system is near Florida or the adjacent waters.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…medium…40 percent.

3. A large area of showers and thunderstorms located about 800 miles
east-northeast of the northern Leeward Islands is associated with a
surface trough that is interacting with a large upper-level low over
the central Atlantic. Upper-level winds are not conducive for
development of this system while it moves northwestward over the
central Atlantic at 10 to 15 mph.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…near 0 percent.

Forecaster Cangialosi

Hurricane Kenneth Discussion Number 12
NWS National Hurricane Center Miami FL EP132017
200 AM PDT Mon Aug 21 2017

Kenneth has continued to rapidly intensify since the previous
advisory. The satellite presentation of the hurricane is quite
impressive, as a 15-nmi wide eye has become better defined while
the cloud tops of the surrounding ring of convection has cooled.
Dvorak intensity estimates range from T5.5 (102 kt) from SAB,
T6.0 (115 kt) from TAFB, to T6.3 (122 kt) from UW/CIMSS. Using a
blend of these estimates, the initial wind speed has been increased
to 115 kt, making Kenneth a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale.

The hurricane is expected to peak in intensity very soon as it will
be moving over cooler waters and into a more stable air mass
later today. After that time, cooler sea surface temperatures and
less favorable thermodynamic conditions should cause steady
weakening. In 3 to 4 days, increasing southwesterly shear from an
upper-level trough along 140W and sub 23C SSTs should cause
Kenneth’s deep convection to dissipate, resulting in the system
becoming a post-tropical cyclone. The NHC intensity forecast is
slightly higher than the previous one at 12 and 24 h due to the
higher initial intensity. After that time, the forecast is fairly
similar to the previous advisory, and is a blend of the various
intensity aids.

The initial motion estimate is west-northwest or 300 degrees at
9 kt. The track forecast reasoning remains the same as the
previous advisory, as Kenneth is expected to turn northwestward
today, then north-northwestward on Tuesday between a mid-level ridge
to its east and a developing cut-off low to the west. Kenneth
should slow down considerably later in the period when it becomes a
vertically shallow system and is steered by the weaker low-level
flow. There is very little spread in the track guidance, and the
updated official forecast is near the middle of the guidance
envelope, and very close to the previous NHC forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 17.4N 130.0W 115 KT 130 MPH
12H 21/1800Z 18.2N 131.2W 115 KT 130 MPH
24H 22/0600Z 19.7N 132.3W 105 KT 120 MPH
36H 22/1800Z 21.3N 133.3W 85 KT 100 MPH
48H 23/0600Z 23.1N 134.1W 65 KT 75 MPH
72H 24/0600Z 26.6N 135.5W 45 KT 50 MPH
96H 25/0600Z 29.0N 136.3W 35 KT 40 MPH…POST-TROPICAL
120H 26/0600Z 30.5N 137.0W 25 KT 30 MPH…POST-TROP/REMNT LOW

$$
Forecaster Brown

Weather In Cayman

Synopsis

Not available. See Weather Forecast Top Right of Website.

Sunshine just makes the day a little better, but it can also cause sunburns. Check the UV Report below to be prepared

Humidity: 94% (DOWN from yesterday)

UV: 13.3 EXTREME (UP from yesterday)

Temperature: Today’s current temperature – See Weather Forecast Top Right of Website. Yesterday: H 91.3°F L 77.6°F

Wind direction TODAY: ESE 20-30 mph GC

Wind direction TONIGHT: SE 10-20 mph GC

Barometer: 1013:00 mb Rising slowly Rain: Last month: 6.69 in Last 24 hrs 0.79 This month: 3.46 in

12 Rain days in July 9 Rain days in Aug 0 days since rain

2016 Season Total: 20.23 in 2017 Season Total: 22.82 in

*NOTE: Official Government record of rainfall on Grand Cayman (Owen Roberts International Airport) 2016: 27.98 inches or 28.22 inches below the 30 year average rainfall of 56.20 inches. All other readings are from SOUTH SOUND.