| NHC: https://www.nhc.noaa.gov/ 50mph as of posting. Shear is forecast to weaken it, though it is forecast to be a subtropical storm through parts of the Azores. Satellite floaters: https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL172024 https://www.ospo.noaa.gov/products/ocean/tropical/floaters/floaters.html https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al172024 Portugal's metrological service: https://www.ipma.pt/en/ I assume watches/warnings will be issued at some point soon, but that would be up to Portugal. Subtropical storms get watches and warnings too. Tropical Storm Warning: An announcement that sustained winds of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) are expected somewhere within the specified area within 36 hours in association with a tropical, subtropical, or post-tropical cyclone. Tropical Storm Watch: An announcement that sustained winds of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) are possible within the specified area within 48 hours in association with a tropical, subtropical, or post-tropical cyclone. Next names on the list: Rafael Sara Tony Valerie William Subtropical Storm Patty Discussion Number 1 NWS National Hurricane Center Miami FL AL172024 900 AM GMT Sat Nov 02 2024 The low pressure system that the NHC has been monitoring over the northern Atlantic has gradually acquired subtropical characteristics during the past 12-24 h. The low has become detached from fronts and has a shallow warm-core structure, though it remains within a cooler airmass behind a cold front over the eastern Atlantic. Despite SSTs around 21 deg C, instability aloft has allowed the system to sustain some moderate convection that wraps most of the way around its center in geostationary and passive microwave images. Since the wind field is asymmetric and the system remains co-located with an upper-level low, it seems best classified as a subtropical cyclone, which is consistent with ST2.5 classifications from TAFB. Thus, the NHC is initiating advisories on Subtropical Storm Patty. Earlier partial scatterometer data showed 35-40 kt winds in the southern semicircle, and the initial intensity is set at 45 kt since it does not appear the strongest winds were sampled by the instrument. Patty is moving east-southeastward at 105/7 kt. The track guidance is in very good agreement that Patty will move faster toward the east-southeast through early Sunday, bringing the center near or over portions of the Azores. Then, a turn toward the east and east-northeast is expected through early next week as Patty is steered by an upper-level trough. The NHC track forecast lies near the center of the guidance envelope, generally between the simple and corrected consensus aids. Little change in strength is expected today, and Patty is forecast to be a fairly short-lived subtropical cyclone. This is because westerly shear is forecast to increase over the system during the next couple of days, which will likely make it difficult for the system to sustain convection near and around its center. Due to its increasing forward speed, the strongest winds of Patty should generally remain over the southern portion of the circulation during its lifetime. Given the non-tropical origins of this system, the NHC intensity forecast leans more heavily on the GFS and ECMWF global models, which lie on the lower end of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 39.9N 34.4W 45 KT 50 MPH 12H 02/1800Z 39.1N 31.3W 45 KT 50 MPH 24H 03/0600Z 38.2N 27.3W 40 KT 45 MPH 36H 03/1800Z 38.0N 23.3W 35 KT 40 MPH...POST-TROPICAL 48H 04/0600Z 38.7N 19.1W 35 KT 40 MPH...POST-TROPICAL 60H 04/1800Z 39.8N 15.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 05/0600Z 41.3N 11.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 06/0600Z...DISSIPATED $$ Forecaster Reinhart Subtropical Storm Patty Advisory Number 1 NWS National Hurricane Center Miami FL AL172024 900 AM GMT Sat Nov 02 2024 ...SUBTROPICAL STORM PATTY FORMS OVER THE NORTHERN ATLANTIC... ...EXPECTED TO PASS NEAR OR OVER THE AZORES THIS WEEKEND... SUMMARY OF 900 AM GMT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...39.9N 34.4W ABOUT 420 MI...675 KM WNW OF THE AZORES MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...ESE OR 105 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...986 MB...29.12 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 900 AM GMT (0900 UTC), the center of Subtropical Storm Patty was located near latitude 39.9 North, longitude 34.4 West. The storm is moving toward the east-southeast near 7 mph (11 km/h). A faster east-southeastward motion is expected through tonight, followed by a turn toward the east and east-northeast on Sunday and Monday. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Little intensity change is expected today, but gradual weakening is forecast through early next week. Patty could degenerate into a post-tropical cyclone by late Sunday. Winds of 40 mph extend outward up to 205 miles (335 km) from the center. The estimated minimum central pressure is 986 mb (29.12 inches). HAZARDS AFFECTING LAND ---------------------- WIND: Tropical storm conditions are possible in portions of the Azores this weekend. See products issued by the meteorological service in the Azores for more information. RAINFALL: Patty is expected to produce rainfall amounts of 1 to 2 inches, or 25 to 50 millimeters, across the Azores through Sunday. SURF: Swells generated by Patty will affect the Azores over the next couple of days. 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 300 PM GMT. $$ Forecaster Reinhart |