Tropical Depression One Advisory Number 1NWS National Hurricane Center Miami FL AL012020500 PM EDT Sat May 16 2020...TROPICAL DEPRESSION FORMS OFF THE COAST OF EAST-CENTRALFLORIDA......TROPICAL STORM WATCH ISSUED FOR A PORTION OF THE NORTH CAROLINACOAST...SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION----------------------------------------------LOCATION...28.4N 78.6WABOUT 125 MI...200 KM E OF MELBOURNE FLORIDAABOUT 505 MI...810 KM SSW OF CAPE HATTERAS NORTH CAROLINAMAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HPRESENT MOVEMENT...NNE OR 20 DEGREES AT 13 MPH...20 KM/HMINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHESWATCHES AND WARNINGS--------------------CHANGES WITH THIS ADVISORY:A Tropical Storm Watch has been issued for the North Carolina coastfrom north of Surf City to Duck, including Pamlico andAlbemarle Sounds.SUMMARY OF WATCHES AND WARNINGS IN EFFECT:A Tropical Storm Watch is in effect for...* New River Inlet to Duck NC* Pamlico and Albemarle SoundsA Tropical Storm Watch means that tropical storm conditions arepossible within the watch area, generally within 48 hours.For storm information specific to your area, including possibleinland watches and warnings, please monitor products issued by yourlocal National Weather Service forecast office.DISCUSSION AND OUTLOOK----------------------At 500 PM EDT (2100 UTC), the center of Tropical Depression One was located near latitude 28.4 North, longitude 78.6 West. Thedepression is moving toward the north-northeast near 13 mph (20km/h) and this motion should continue during the next day or so. After that time, a faster northeastward motion is expected. On the forecast track, the depression is expected to move offshore, but parallel to, the coast of Florida tonight, and then move near or east of the coast of North Carolina on Monday.Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.Gradual strengthening is forecast, and the depression is expected to become a tropical storm on Sunday.The estimated minimum central pressure based on surface observations and earlier aircraft reconnaissance data is 1008 mb (29.77 inches).HAZARDS AFFECTING LAND----------------------WIND: Tropical storm conditions are possible within the watcharea by on Monday.RAINFALL: The depression is expected to produce additional rainaccumulations of 1 to 2 inches over the central and northwestBahamas, and generally less than 1 inch over south Florida throughtonight. The depression is also expected to produce total rainaccumulations of 1 to 2 inches over coastal North Carolina Sundaynight and Monday.SURF: Swells generated by the depression are affecting portions ofthe east coast of central and northern Florida. These swells areexpected to spread northward during the next few days, and couldcause life-threatening surf and rip current conditions across muchof the U.S. southeast and mid-Atlantic coasts. Please consultproducts from your local weather office.NEXT ADVISORY-------------Next intermediate advisory at 800 PM EDT.Next complete advisory at 1100 PM EDT.$$Forecaster CangialosiTropical Depression One Discussion Number 1NWS National Hurricane Center Miami FL AL012020500 PM EDT Sat May 16 2020Satellite images, Doppler radar data, and surface observationsindicate that the low pressure system located just east of the coastof central Florida has developed sufficient organization to now beclassified as a tropical depression. The low-level center is welldefined and deep convection has persisted near the center and inbands on the east side of the circulation for the past severalhours. The cyclone is considered tropical instead of subtropicalbecause it has central deep convection and a relatively small radiusof maximum wind. The initial intensity is estimated to be 30 ktbased on data collected earlier today by the Air Force HurricaneHunters. Another aircraft is scheduled to investigate the systemthis evening.Based on satellite data and the earlier reconnaissance fixes, theinitial motion of the system is north-northeastward at 11 kt. Acontinued north-northeastward motion at about the same forward speedis expected during the next 24 hours or so, keeping the cycloneoffshore, but parallel to, the east coast of Florida. After that time,the model solutions begin to diverge and the details of the trackforecast become more complicated. The important features for thefuture track of the depression appear to be a pair of mid- toupper-level troughs currently over the central U.S. The specificamplitude, timing, and location of those troughs will ultimatelyresult in how close to the coast of North Carolina this system gets.The GFS and HWRF models are on the left side of the guidance andbring the system inland or along the coast, while the ECMWF andUKMET models show an offshore track. The NHC track forecast splitsthe difference of these solutions, and lies close to the variousconsensus models, which usually perform best. It should be notedthat forecast uncertainty is typically larger for weak systems likethis one.The system should gradually strengthen during the next couple ofdays as it remains over the Gulf Stream current and in relativelylow wind shear conditions. However, the surrounding air mass is notparticularly moist, so that and the marginally warm SSTs shouldlimit significant intensification. The NHC intensity forecast callsfor the system to become a tropical storm tonight or on Sunday withcontinued slow strengthening as it nears the North Carolina coast.Extratropical transition should occur in about 3 days, or sooner.The NHC intensity forecast generally lies roughly near the middle ofthe guidance envelope.Key Messages:1. A tropical storm watch has been issued for a portion of theNorth Carolina coast. Tropical-storm-force winds and heavy rainsare possible there on Monday.2. Dangerous coastal surf conditions and rip currents are expected to spread northward from Florida to the mid-Atlantic states during the next few days. See products from your local National WeatherService for more details.FORECAST POSITIONS AND MAX WINDSINIT 16/2100Z 28.4N 78.6W 30 KT 35 MPH12H 17/0600Z 29.7N 78.0W 35 KT 40 MPH24H 17/1800Z 31.4N 77.4W 35 KT 40 MPH36H 18/0600Z 33.0N 76.6W 40 KT 45 MPH48H 18/1800Z 35.2N 74.8W 45 KT 50 MPH60H 19/0600Z 37.1N 72.3W 50 KT 60 MPH72H 19/1800Z 38.0N 70.0W 50 KT 60 MPH...POST-TROP/EXTRATROP96H 20/1800Z 38.0N 68.5W 45 KT 50 MPH...POST-TROP/EXTRATROP120H 21/1800Z...DISSIPATED$$Forecaster Cangialosi
