| NHC track: https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/?cone#contents Tropical storm warning issued for Jamaica. The NHC says it has a closed center, but not quite enough organized deep convection yet to be called a depression. Later in the forecast period when the system reaches the Gulf, the NHC says "the NHC track forecast during that time period is of notably lower confidence". The NHC is talking about shear and dry air in the Gulf which would keep it weaker. For now they think some of the hurricane models are too aggressive in their intensity forecasts in the shorter term. (HFSA and HFSB) That makes sense. I don't think those models should be given much weight until something is more developed. They often forecast a significant intensity increase that usually is too overblown. As usual, we'll have to wait and see how shear and dry air impact it when it gets to the Gulf. When we get these potential tropical cyclones we're getting them because they need to write advisories because they are close enough to landfall where they need to issue watches and warnings. It's still not fully organized yet so I consider the first forecasts to often still be more uncertain than usual. Satellite floaters: Not here yet as of posting: https://www.star.nesdis.noaa.gov/GOES/floater_index.php https://www.ospo.noaa.gov/products/ocean/tropical/floaters/floaters.html https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al182024 Recon: https://hurricanecity.com/recon/ Potential Tropical Cyclone Eighteen Discussion Number 1 NWS National Hurricane Center Miami FL AL182024 400 PM EST Sun Nov 03 2024 The Air Force Hurricane Hunters have been investigating the disturbance over the south-central Caribbean Sea and their data indicates that the system has developed a closed center. However, deep convection is not quite organized enough to designate the system a tropical depression at this time. Given the potential for development and impacts to Jamaica and the Cayman Islands during the next day or two, advisories are being issued on Potential Tropical Cyclone Eighteen. The initial motion is northeastward at 6 kt, but this is uncertain given that the system has only recently closed off. A turn to the north and then northwest is expected over the next couple of days as a mid-level ridge builds across the southwestern Atlantic and the eastern Caribbean. This motion should take the disturbance near Jamaica by late Monday and near or over the Cayman Islands and Cuba on Tuesday and Wednesday. The models are in relatively good agreement during that time period, and the official track forecast lies near the various consensus models. Once the system reaches the Gulf of Mexico by the middle of the week, the model solutions diverge due to differences in the predicted steering patterns and vertical depth of the system by that time. Therefore, the NHC track forecast during that time period is of notably lower confidence. The environmental conditions appear conducive for strengthening during the next few days, and it seems likely that the system will become a tropical storm before it reaches Jamaica and a hurricane before it reaches Cuba. However, later in the week, southwesterly vertical wind shear and intrusions of dry air should end the strengthening process and likely induce some weakening once the system reaches the Gulf of Mexico. The hurricane regional models are very aggressive, however, their intensity predictions appear overdone, at least in the short term. The NHC intensity forecast is closer to the statistical-dynamical models DSHP and LGEM and near the IVCN consensus aid. Key Messages: 1. The disturbance is expected to become a tropical storm Monday and pass near Jamaica on Monday night and Tuesday where a Tropical Storm Warning is now in effect. The system is forecast to become a hurricane by Tuesday night and there is a risk of dangerous impacts from hurricane-force winds and storm surge in the Cayman Islands and portions of Cuba. 2. Interests in the Florida Keys should closely monitor this system as tropical storm watches could be required for portions of the Florida Keys tonight or early Monday. 3. The system is forecast to approach the northern Gulf Coast as a tropical storm later this week, but given uncertainties in the long-range forecast, it is too soon to determine what, if any, impacts could occur. Residents in this area should regularly monitor updates to the forecast. 4. The system will bring areas of heavy rain across portions of the western Caribbean, including Jamaica and the southern and western portions of Cuba through mid-week. Flooding could occur over portions of Jamaica and Cuba, with mudslides possible. Heavy rainfall could then spread northward into Florida and adjacent areas of the Southeast United States during the middle to late portions of the week. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 13.0N 77.1W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 04/0600Z 14.3N 77.1W 35 KT 40 MPH...TROPICAL CYCLONE 24H 04/1800Z 16.0N 77.7W 40 KT 45 MPH 36H 05/0600Z 17.7N 78.6W 50 KT 60 MPH 48H 05/1800Z 19.6N 80.4W 60 KT 70 MPH 60H 06/0600Z 21.5N 82.6W 70 KT 80 MPH 72H 06/1800Z 23.3N 84.5W 65 KT 75 MPH 96H 07/1800Z 25.4N 86.6W 60 KT 70 MPH 120H 08/1800Z 26.9N 88.6W 50 KT 60 MPH $$ Forecaster Cangialosi Potential Tropical Cyclone Eighteen Advisory Number 1 NWS National Hurricane Center Miami FL AL182024 400 PM EST Sun Nov 03 2024 ...DISTURBANCE FORECAST TO STRENGTHEN AS IT MOVES ACROSS THE WESTERN CARIBBEAN... ...HURRICANE WATCH ISSUED FOR THE CAYMAN ISLANDS AND TROPICAL STORM WARNING ISSUED FOR JAMAICA... SUMMARY OF 400 PM EST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...13.0N 77.1W ABOUT 345 MI...555 KM S OF KINGSTON JAMAICA ABOUT 515 MI...825 KM SSE OF GRAND CAYMAN MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...NE OR 45 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of the Cayman Islands has issued a Hurricane Watch for Grand Cayman, Little Cayman and Cayman Brac. The government of Jamaica has issued a Tropical Storm Warning for the island of Jamaica. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Watch is in effect for... * Cayman Islands A Tropical Storm Warning is in effect for... * Jamaica A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 24-36 hours. Interests in Cuba and the Florida Keys should closely monitor this system. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 400 PM EST (2100 UTC), the disturbance was centered near latitude 13.0 North, longitude 77.1 West. The system is moving toward the northeast near 7 mph (11 km/h). A turn to the north and then northwest is expected over the next few days. On the forecast track, the system is expected to move near Jamaica by late Monday and near or over the Cayman Islands Tuesday and Wednesday. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. This system is expected to become a tropical depression tonight and steady strengthening is forecast. * Formation chance through 48 hours...high...near 100 percent. * Formation chance through 7 days...high...near 100 percent. The estimated minimum central pressure based on data from the Air Force Hurricane Hurricane is 1004 mb (29.65 inches). HAZARDS AFFECTING LAND ---------------------- WIND: Hurricane conditions are possible in the Cayman Islands on Tuesday. Tropical storm conditions are expected in Jamaica by late Monday. RAINFALL: Heavy rainfall will impact areas of the western Caribbean with the heaviest rainfall occurring over Jamaica and southern Cuba through mid-week. Rainfall totals between 3 to 6 inches with locally up to 9 inches are expected. Flooding could occur over portions of Jamaica and Cuba, with mudslides possible. Heavy rainfall will spread north into Florida and adjacent areas of the Southeast United States mid to late week. STORM SURGE: Minor coastal flooding is possible in Jamaica on Monday and the Cayman Islands on Tuesday. SURF: Swells generated by the system are expected to affect much of the western Caribbean during the next few days. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 700 PM EST. Next complete advisory at 1000 PM EST. $$ Forecaster Cangialosi GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs®ion=watl&pkg=mslp_pcpn Euro: https://www.tropicaltidbits.com/analysis/models/?model=ecmwf®ion=watl&pkg=mslp_pcpn Ensemble members are more tightly clustered to western Cuba and then spread out. GFS and Euro aren't as far apart as they were, but still a considerable difference later on in the forecast. GFS Ensemble Members: https://www.tropicaltidbits.com/analysis/models/?model=gfs-ens®ion=watl&pkg=lowlocs Euro Ensemble Members: https://www.tropicaltidbits.com/analysis/models/?model=eps®ion=watl&pkg=lowlocs Even though the water is cooler than it was, it can still certainly support a hurricane. It'll be up to that shear and dry air to determine how much. Often more time over water is worse, but maybe if it heads to the northern Gulf coast it could potentially have more of a chance to weaken if shear is forecast to possibly be high. I wish the SHIPS intensity text output had coordinates all the way out. (https://ftp.nhc.noaa.gov/atcf/stext/?C=M;O=D) After 120 hours it has shear 30 knots or more, but I don't know the path from that. I can't assume that the path in the ATCF system matches that. But with that kind of shear, it weakens it from a hurricane to a tropical storm. We'll just have to see. At least the waters are not record temperatures any longer, so that's a nice positive. |