| Record setting season, in terms of named storms, continues. Forecast to become a major hurricane before landfall in Central America. Track: https://www.nhc.noaa.gov/refresh/graphics_at1+shtml/?cone#contents Satellite: https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL312020 https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al312020 Tropical Storm Iota Discussion Number 2 NWS National Hurricane Center Miami FL AL312020 400 PM EST Fri Nov 13 2020 Banding features over the eastern and southeastern portions of the cyclone's circulation have increased since this morning, and the overall organization of the system continues to quickly improve. Earlier ASCAT data indicated that there was a fairly large area of light winds near the center, and that the low-level center was displaced to the northwest of the mid-level center seen in visible satellite imagery. Since the system is still in its formative stage, the low-level center may reform closer to the mid-level feature, and the advisory position is a compromise between the low- and mid-level circulations. The earlier ASCAT data indicated peak winds of around 30 kt with several higher rain-inflated vectors. Based on the continued increase in organization, and Dvorak T-numbers of T2.5 from both TAFB and SAB, the initial intensity is raised to 35 kt. Iota becomes the 30th named storm of the recording-breaking 2020 hurricane season. The environment ahead of Iota appears to be quite conducive for intensification. The system will be moving over warm waters, in a moist atmosphere, and within an area of very low vertical wind shear. As a result, steady to rapid strengthening appears likely over the next few days. The NHC intensity forecast calls for Iota to reach hurricane status within 36 h, and now calls for the system to be a major hurricane when it approaches the coast of Central America. The NHC intensity foreast is in good agreement with the HFIP corrected consensus model, and the 70-kt increase in intensity over the next 72 hours is supported by the SHIPS Rapid Intensification Index that shows a nearly 60 percent chance of a 65 kt increase in intensity during that time period. The tropical storm has not moved very much today, and the initial motion estimate is a somewhat uncertain 255/3 kt. A strong mid-level ridge that extends across Florida and the western Atlantic is forecast to slide eastward over the next few days causing the cyclone to move faster toward the west or west-northwestward. The track guidance has come into a bit better agreement this afternoon, with only the HWRF showing a track farther north over the northwestern Caribbean Sea. The latest consensus aids were very close to the previous official forecast, and no significant adjustments to the earlier track forecast were required. Key Messages: 1. Iota is expected to strengthen and be a major hurricane when it approaches the coast of Central America. There is a risk of dangerous wind, storm surge, and rainfall impacts across portions of Nicaragua and Honduras beginning Sunday night or early Monday. Hurricane Watches will likely be issued for a portion of this area tonight or early Saturday. 2. Through Wednesday morning, heavy rainfall from Iota may lead to life-threatening flash flooding and river flooding across portions of Haiti, Jamaica and Central America. Flooding and landslides from heavy rainfall could be significant across Central America given recovery efforts underway after Hurricane Eta. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 13.8N 74.3W 35 KT 40 MPH 12H 14/0600Z 13.7N 75.1W 45 KT 50 MPH 24H 14/1800Z 13.7N 76.2W 55 KT 65 MPH 36H 15/0600Z 13.9N 77.5W 70 KT 80 MPH 48H 15/1800Z 14.2N 79.3W 85 KT 100 MPH 60H 16/0600Z 14.6N 81.2W 95 KT 110 MPH 72H 16/1800Z 15.0N 82.8W 105 KT 120 MPH 96H 17/1800Z 15.2N 85.5W 50 KT 60 MPH...INLAND 120H 18/1800Z 14.7N 88.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown Tropical Storm Iota Advisory Number 2 NWS National Hurricane Center Miami FL AL312020 400 PM EST Fri Nov 13 2020 ...DEPRESSION STRENGTHENS INTO TROPICAL STORM IOTA.. ...RISK OF DANGEROUS WINDS, STORM SURGE, AND RAINFALL IMPACTS IN CENTRAL AMERICA BEGINNING SUNDAY NIGHT OR MONDAY... SUMMARY OF 400 PM EST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...13.8N 74.3W ABOUT 335 MI...540 KM SSE OF KINGSTON JAMAICA MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...WSW OR 255 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warning in effect. Interests in Nicaragua and Honduras should monitor the progress of this system. A Hurricane Watch may be required for a portion of that area tonight or early Saturday. DISCUSSION AND OUTLOOK ---------------------- At 400 PM EST (2100 UTC), the center of Tropical Storm Iota was located near latitude 13.8 North, longitude 74.3 West. Iota is moving toward the west-southwest near 3 mph (6 km/h), and this motion is expected to continue through early Saturday. A westward to west-northwestward motion at a slightly faster forward speed is expected to begin by late Saturday and continue through Monday. On the forecast track, Iota will move across the central Caribbean Sea during the next day or so, and approach the coasts of Nicaragua and northeastern Honduras late Sunday and Monday. Maximum sustained winds have increased to near 40 mph (65 km/h) with higher gusts. Steady to rapid strengthening is likely over the weekend, and the system is forecast to be a major hurricane when it approaches Central America. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 1006 mb (29.71 inches). HAZARDS AFFECTING LAND ---------------------- Rainfall: Through Wednesday morning, Iota is expected to produce 4 to 8 inches of rain, with local 12 inch totals, across portions of northern Colombia, Panama and Costa Rica. Across Jamaica and southern Haiti, 2 to 4 inches are expected, with local amounts up to 6 inches. Across remaining sections of Central America, the system has the potential to produce 20 to 30 inches of rain with a focus across northern Nicaragua and Honduras. This rainfall would lead to significant, life-threatening flash flooding and river flooding, along with landslides in areas of higher terrain. SURF: Swells generated by Iota will begin affecting portions of the coast of Colombia, and the southern coasts of Hispaniola and Jamaica during the next day or so. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 1000 PM EST. $$ Forecaster Brown |