UPDATED: 7 Sep Weather in Cayman & Tropical Report, 1 TS, 2 TD, 1 Dist.
7 Sep Fri 2018 – UPDATED
Tropical Report
Tropical Weather Outlook…Corrected
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 7 2018
Corrected status of Florence to tropical storm in first paragraph.
For the North Atlantic…Caribbean Sea and the Gulf of Mexico:
The National Hurricane Center is issuing advisories on Tropical
Storm Florence, located over the central Atlantic Ocean. The
Weather Prediction Center is issuing advisories on Tropical
Depression Gordon, located over Arkansas.
The National Hurricane Center is issuing advisories on
Tropical Cyclone Eight, located over the far eastern Atlantic.
* Formation chance through 48 hours…high…near 100 percent.
* Formation chance through 5 days…high…near 100 percent.
See also Update Tropical Cyclone Nine.
1. A trough of low pressure is producing a large area of disorganized
showers and thunderstorms over the western Atlantic Ocean.
Development, if any, of this system should be slow to occur during
the next few days before environmental conditions become
unfavorable. This system is expected to move little during the
next few days.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…20 percent.
Public Advisories on Tropical Cyclone Eight and Nine are issued
under WMO header WTNT33 KNHC and under AWIPS header MIATCPAT3.
Forecast/Advisories on Potential Tropical Cyclone Eight are issued
under WMO header WTNT23 KNHC and under AWIPS header MIATCMAT3.
Forecaster Cangialosi/Berg/Brennan
Tropical Depression Eight Discussion Number 2
NWS National Hurricane Center Miami FL AL082018
500 PM AST Fri Sep 07 2018
Satellite data and surface observations indicate that the low
pressure system located just west of the coast of Africa has
developed into a tropical depression. Conventional satellite
imagery shows a well-defined convective band has formed near the
center, and microwave satellite imagery has hinted at the formation
of an inner ring of convection. The initial intensity of 30 kt
and the central pressure of 1002 mb are based on surface
observations from ships and the west coast of Africa. The depression
currently has good cirrus outflow in all directions.
The initial motion is 275/9. During the next 3-4 days, the cyclone
should move generally west-northwestward with an increase in forward
speed on the south side of the subtropical ridge over the eastern
Atlantic. Near the end of the forecast period, a developing mid- to
upper-level trough over the central Atlantic is expected to weaken
the ridge and allow the cyclone to turn northwestward with a
decrease in forward speed. There is some spread in the guidance
late in the period, with the UKMET and the Canadian models showing
an earlier turn than the other models. The new forecast track,
which is similar to the previous track, is in best agreement with
the TVCN and HCCA consensus models.
The depression is in an environment of light to moderate easterly
vertical shear and over sea surface temperatures of 27-28C. This
should allow at least steady strengthening, and rapid strengthening
is possible based on the hints of the inner core in microwave
imagery. This portion of the intensity forecast has been increased
to the upper edge of the intensity guidance, with the cyclone
forecast to become a tropical storm in 12 h or less and a hurricane
between 48-72 h. After 72 h, the system should be over sea surface
temperatures near 26C and encountering southwesterly vertical shear
due to the aforementioned trough. This should cause at least a
gradual weakening.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 13.2N 18.6W 30 KT 35 MPH
12H 08/0600Z 13.5N 19.9W 35 KT 40 MPH
24H 08/1800Z 13.9N 21.9W 45 KT 50 MPH
36H 09/0600Z 14.4N 24.5W 55 KT 65 MPH
48H 09/1800Z 14.9N 27.5W 60 KT 70 MPH
72H 10/1800Z 16.5N 33.5W 70 KT 80 MPH
96H 11/1800Z 18.0N 38.5W 65 KT 75 MPH
120H 12/1800Z 20.5N 42.0W 60 KT 70 MPH
$$
Forecaster Beven
Tropical Depression Nine Discussion Number 1…Corrected
NWS National Hurricane Center Miami FL AL092018
500 PM AST Fri Sep 07 2018
Corrected bin number from 2 to 4
Satellite images indicate that the low pressure system over the
eastern tropical Atlantic has developed a well-defined center and
sufficient deep convection to be classified a tropical depression,
the ninth one of the 2018 Atlantic hurricane season and second one
of the day. The initial intensity is set to 30 kt based on a 2.0
Dvorak classification from TAFB and earlier ASCAT data.
The depression has not moved much today, and it has even wobbled a
bit to the east recently. This slow motion is a result of very
weak steering with broad troughing to the north and Tropical
Depression Eight to its east. Little motion is expected through
tonight, but a westward motion with a gradual increase in forward
speed is forecast thereafter as a subtropical ridge builds to the
north of the cyclone. The NHC track forecast lies closest to the
HCCA guidance and takes the system toward the Lesser Antilles by the
end of the forecast period.
The depression is experiencing some influences of easterly shear,
which is why the center is currently on the eastern edge of the
convection. Little change in intensity is expected during the next
12 to 24 hours since the cyclone is still in the developing stage
and because moderate shear is expected to continue. However, the
shear is expected to decrease to less than 10 kt in about 24 hours.
These more favorable winds aloft combined with relatively warm
waters and a fairly moist airmass should allow for steady
strengthening beginning later in the weekend. There is a large
spread in the intensity guidance, with the HWRF showing the system
becoming a major hurricane and HMON showing almost no strengthening.
The NHC intensity forecast lies a little below consensus models
since it appears that it will take some time for the system to
strengthen.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 13.6N 34.9W 30 KT 35 MPH
12H 08/0600Z 13.9N 35.2W 30 KT 35 MPH
24H 08/1800Z 14.0N 36.2W 30 KT 35 MPH
36H 09/0600Z 14.0N 37.6W 40 KT 45 MPH
48H 09/1800Z 14.0N 39.3W 50 KT 60 MPH
72H 10/1800Z 14.0N 44.0W 60 KT 70 MPH
96H 11/1800Z 14.1N 48.9W 70 KT 80 MPH
120H 12/1800Z 14.5N 54.5W 75 KT 85 MPH
$$
Forecaster Cangialosi
FLORENCE POISED TO STRENGTHEN… …THIS WEEKEND IS A GOOD TIME FOR INTERESTS ALONG THE U.S. EAST COAST TO REVIEW THEIR HURRICANE PLAN…
Tropical Storm Florence Discussion Number 34
NWS National Hurricane Center Miami FL AL062018
500 PM AST Fri Sep 07 2018
Little has changed with Florence’s structure during the day. The
low-level center is located on the southwestern side of the deep
convection due to moderate to strong southwesterly shear, and
satellite intensity estimates are essentially the same from this
morning. Therefore, the estimated maximum winds remain 55 kt.
NOAA is scheduled to conduct a research mission with the P-3
aircraft tomorrow, which should provide some useful wind data and
give us a better handle on the cyclone’s intensity.
Vertical shear is still expected to gradually decrease over the
next day or two, likely reaching values of 10 kt or less by 48
hours. During this period, Florence should become more vertically
stacked, which would allow for some reintensification, possibly back
to hurricane strength within 36-48 hours. After 48 hours, the shear
is expected to remain generally low, and oceanic heat content values
will increase significantly as Florence moves over the waters
between Bermuda and the northern Leeward Islands. This is a
classic recipe for a quick intensification trend, and Florence is
expected to become a major hurricane by days 4 and 5. The
generally skillful HCCA, Florida State Superensemble, and ICON
intensity consensus are all near 110-115 kt by day 5, and because
of this, no notable changes were required from the previous
official intensity forecast.
Florence has been moving south of due west (260 degrees) at 7 kt,
located south of a low- to mid-level ridge. The cyclone is
expected to continue moving generally westward for the next 48
hours while it remains sheared. As Florence begins to strengthen
and become vertically stacked after 48 hours, it should begin to
turn west-northwestward, steered by a deeper flow regime. By days
4 and 5, an exceptionally strong blocking ridge is forecast to
develop between Bermuda and the Northeast U.S., keeping Florence
on a west-northwestward trajectory with an increase in forward
speed by the end of the forecast period. A slight southwestward
adjustment was made to the NHC forecast to account for Florence’s
initial motion and a slight shift in the overall guidance envelope.
For most of the forecast period, the official forecast is close to
a blend of the GFS and ECMWF.
Key Messages:
1. Regardless of Florence’s eventual track, large swells are
affecting Bermuda and will begin to affect portions of the U.S. East
Coast this weekend, resulting in life-threatening surf and rip
currents.
2. The risk of other direct impacts associated with Florence along
the U.S. East Coast next week has increased. However, there is
still very large uncertainty in model forecasts of Florence’s track
beyond day 5, making it too soon to determine the exact location,
magnitude, and timing of these impacts. Interests near and along
the U.S. East Coast should monitor the progress of Florence through
the weekend and ensure they have their hurricane plans in place.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 24.8N 52.5W 55 KT 65 MPH
12H 08/0600Z 24.6N 53.5W 55 KT 65 MPH
24H 08/1800Z 24.6N 54.7W 55 KT 65 MPH
36H 09/0600Z 24.6N 55.8W 60 KT 70 MPH
48H 09/1800Z 24.8N 57.0W 70 KT 80 MPH
72H 10/1800Z 25.8N 60.9W 90 KT 105 MPH
96H 11/1800Z 27.5N 67.0W 110 KT 125 MPH
120H 12/1800Z 30.5N 73.0W 115 KT 130 MPH
$$
Forecaster Berg
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Fri Sep 7 2018
For the eastern North Pacific…east of 140 degrees west longitude:
The National Hurricane Center is issuing advisories on Hurricane
Olivia, located about 1500 miles east of Hilo, Hawaii.
1. An elongated area of low pressure located several hundred miles
south-southwest of the southern tip of Baja California peninsula
continues to produce disorganized shower and thunderstorm activity.
Environmental conditions are expected be conducive for development,
and a tropical depression is likely to form this weekend or early
next week while the system moves slowly west-northwestward away from
the coast of Mexico.
* Formation chance through 48 hours…medium…60 percent.
* Formation chance through 5 days…high…90 percent.
Forecaster Cangialosi
Global Tropics & Benefits Outlook
Weather in Cayman
SYNOPSIS
Isolated showers and possible thunder will continue across the Cayman area for the next 24 hours as the upper level trough interacts with a tropical wave over the Northwest Caribbean. Radar images show isolated showers in and around the Cayman area moving towards the northwest. The National Hurricane Center is issuing advisories on Hurricane Florence. This system poses no threat to the Cayman Islands. For further information on this storm please visit www.nhc.noaa.gov.
Humidity: 77% (DOWN from yesterday)
UV: 10.9 VERY HIGH (DOWN from yesterday)
Temperature: Today’s current temperature – See weather forecast top right of website. Yesterday: H 90.5°F L 78.0°F
Wind direction TODAY: SE 10-15 mph GC
Wind direction TONIGHT: SE 5-10 mph GC
Barometer: 1013.70 mb Steady Rain: Last month: 1.83 in Last 24 hrs 0.02 This month: 1.48 in 0 days since rain 3 rain day in September
2017 Season Total: 62.94 in 2018 Season Total: 25.48 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 September 8.2 in. Average temperature in September: 77°F to 90°F
Sea Temperature in September 84°F
MOON:
7% Waning Crescent
TIDES, SUNRISE, SUNSET, MOON RISE, MOON SET AND MOON PHASE
GRAND CAYMAN SEPTEMBER 2018 – Click to enlarge
LOCAL 5 DAY FORECAST
http://www.weather.gov.ky/portal/page?_pageid=4421,7428393&_dad=portal&_schema=PORTAL
FOR RADAR IMAGE GO TO: http://www.weather.gov.ky/portal/page/portal/nwshome/forecasthome/radar
Also see Weather In Cayman: http://www.weatherincayman.com/
Moon info and graphic:
https://www.timeanddate.com/moon/uk/georgetown
Atlantic satellite image: http://www.intellicast.com/global/satellite/infrared.aspx?region=hiatlsat
Description:
The Global Infrared Satellite image shows clouds by their temperature. Red and blue areas indicate cold (high) cloud tops. Infrared (IR) radiation is electromagnetic radiation whose wavelength is longer than that of visible light, but shorter than that of terahertz radiation and microwaves. Weather satellites equipped with scanning radiometers produce thermal or infrared images which can then enable a trained analyst to determine cloud heights and types, to calculate land and surface water temperatures, and to locate ocean surface features.
Tropical storm data and graphics from National Hurricane Center at: https://www.nhc.noaa.gov/
Weathernerds: https://www.weathernerds.org/
Mikes Weather Page: http://www.spaghettimodels.com/
