Tropical Storm Watch issued for Grand Cayman and Jamaica -UPDATED 8:00EDT
UPDATE
NOAA HURRICANE HUNTERS INVESTIGATING THE DISTURBANCE
Potential Tropical Cyclone Fifteen Discussion Number 3 NWS National Hurricane Center Miami FL AL152022 500 AM EDT Mon Oct 31 2022 The system has changed little in organization overnight. Deep convection is not very extensive at this time and convective banding features are rather limited, as evidenced by a Dvorak classification of T1.0 from TAFB. Thus, the disturbance still lacks sufficient organized convection to be classified as a tropical cyclone. Observations from an Air Force Hurricane Hunter aircraft and scatterometer data indicate that the circulation is somewhat elongated from south to north, and the maximum winds are 30-35 kt. Satellite images show that the broad center is located just to the west of the main area of deep convection. The disturbance continues moving generally westward, or around 270/10 kt. A mid-level anticyclone to the north of the system should maintain a westward to west-northwestward track for the next 48 hours or so. Then, as the high shifts westward, the system is forecast to turn west-southwestward when it nears the coast of Belize or eastern Yucatan. The official track forecast is close to the model consensus and not much different from the previous NHC prediction. It should be noted, however, that the the forecast track could undergo some additional adjustments until the circulation center becomes better defined. It is expected that the system will acquire sufficient convective organization to make the transition to a tropical cyclone in 12 hours or so. During the next couple of days, the system/tropical cyclone will be traversing very warm waters and moving through a fairly moist air mass. Also, the upper-level winds are forecast by the global models to become increasingly anticyclonic which should enhance the outflow over the area. Therefore strengthening appears likely and the official forecast continues to call for hurricane status before landfall in Belize or the eastern Yucatan Peninsula. This is near or above the latest intensity consensus guidance. Key Messages: 1. Tropical storm conditions are possible within the Tropical Storm Watch areas beginning today for Jamaica and on Tuesday for Grand Cayman Island. 2. Interests along the coast of Central America, especially near Belize and the Yucatan Peninsula of Mexico, should monitor the progress of this system. Additional watches and warnings will likely be required early this week. FORECAST POSITIONS AND MAX WINDS INIT 31/0900Z 15.8N 76.1W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 31/1800Z 16.1N 77.5W 40 KT 45 MPH...TROPICAL CYCLONE 24H 01/0600Z 16.4N 79.7W 45 KT 50 MPH 36H 01/1800Z 16.8N 82.2W 50 KT 60 MPH 48H 02/0600Z 17.2N 84.7W 60 KT 70 MPH 60H 02/1800Z 17.4N 86.8W 70 KT 80 MPH 72H 03/0600Z 17.2N 88.6W 70 KT 80 MPH...INLAND 96H 04/0600Z 16.0N 92.0W 30 KT 35 MPH...INLAND 120H 05/0600Z...DISSIPATED $$ Forecaster Pasch
Original Story Oct 30 2022
The National Hurricane Center today Sunday (30) has issued a Tropical Storm Watch for Grand Cayman and Jamaica as a system continues to organise over the Caribbean Sea.
Reports from NOAA and Air Force Reserve Hurricane Hunter aircraft today has shown increased organization of the system, which was producing winds of 35-40 mph to the north of its centre/
It has been given a 90% chance of developing into a tropical depression in the next 48 hours, according to the 5 p.m. Sunday outlook.
The system is forecast to move west-northwest at 10 to 15 mph over the central and northwestern Caribbean. In addition to Grand Cayman and Jamaica, heavy rain is possible in the Virgin Islands, Puerto Rico, Haiti and Dominican Republic.
From The National Hurricane Center
Potential Tropical Cyclone Fifteen Discussion Number 1 NWS National Hurricane Center Miami FL AL152022 500 PM EDT Sun Oct 30 2022 This morning we were fortunate to have concurrent NOAA and Air Force Reserve Hurricane Hunter missions, which provided a wealth of flight-level, Tail Doppler Radar, and dropsonde data over the system in the central Caribbean Sea. The data indicated that a well-defined, while somewhat broad, circulation had formed with a minimum pressure of 1005 mb. A combination of SFMR winds and surface dropsonde data also suggested that the system had 35-kt winds in its northern semicircle. With that said, the satellite presentation of the system currently lacks sufficient convective organization to be considered a tropical cyclone. However, given the well-defined center and tropical-storm-force winds, there is significant risk for tropical storm conditions in the near future in portions of Jamaica and Grand Cayman Island. With the expectation that this system will likely become a tropical storm soon, advisories have been initiated on Potential Tropical Cyclone Fifteen. The estimated motion of the disturbance is off to the west-northwest at 290/9 kt. This general motion is forecast to continue for the next day or so, as an expansive mid-level ridge is currently centered north of the system and expected to move westward with the cyclone. Toward the end of the forecast period, the ridge may nose further westward as a deep-layer trough becomes established well to the the northeast, which could result in a south of due west motion when the system approaches the coast of Belize. Landfall is expected between the 72- and 96-hour forecast points. The initial NHC track forecast is roughly a blend of the latest GFS and ECMWF guidance, which is also quite close to the HCCA and TCVA consensus aids. Based on the current structure, it may take a bit longer for the convection to become sufficently organized to allow the formation of a tropical cyclone, but this is forecast to occur at some point tonight, likely during the typical diurnal maximum. After deep convection become better established, environmental conditions appear to be conducive for further intensification, especially in the 24-48 hour period when the vertical wind shear is expected to be lowest (5-15 kt) as the system traverses 29-30 C sea-surface temperatures. Mid-level relative humidity is quite low (55-60 percent), but given the relatively low shear, this may act to keep the system's structure small with a constricted radius of maximum winds. The initial intensity forecast after 24 hours closely follows the latest HCCA and ICON intensity guidance, making the system a Category 1 hurricane in 60-72 hours. The system should weaken quickly over land and is forecast to dissipate before day 5. Based on the latest forecast, the government of Jamaica has issued a Tropical Storm Watch for Jamaica, and the government in the Cayman Islands has issued a Tropical Storm Watch for Grand Cayman Island. Key Messages: 1. Tropical storm conditions are possible within the Tropical Storm Watch areas beginning Monday for Jamaica and on Tuesday for Grand Cayman Island. 2. Interests along the coast of Central America, especially near Belize, should monitor the progress of this system. Additional watches and warnings will likely be required early this week. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 15.7N 73.6W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 31/0600Z 16.0N 74.9W 35 KT 40 MPH...TROPICAL CYCLONE 24H 31/1800Z 16.3N 76.6W 40 KT 45 MPH 36H 01/0600Z 16.7N 78.8W 50 KT 60 MPH 48H 01/1800Z 17.2N 81.3W 60 KT 70 MPH 60H 02/0600Z 17.5N 83.6W 65 KT 75 MPH 72H 02/1800Z 17.4N 85.7W 70 KT 80 MPH 96H 03/1800Z 16.4N 89.5W 35 KT 40 MPH...INLAND 120H 04/1800Z...DISSIPATED $$ Forecaster Papin/Cangialosi