| While they say at the moment it could be a tropical storm, they leave open the possibility for a stronger storm. "While the forecast depicts a 55-kt tropical storm moving across the islands, there could be adjustments to this forecast once Tammy's current intensity and structure become clearer, and users should be prepared for possible forecast changes." Track: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/?cone#contents Caribbean satellite: https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16§or=car&band=13&length=24 Radar composite in Eastern Carib for later: https://www.barbadosweather.org/Composite/kidbuuComposite_Lionel_displayer2.php?Product=Reflectivity&Sector=EC_Bar&Composite=Sabre&ANISP=700&MAPP=1 Tropical Storm Tammy Discussion Number 1 NWS National Hurricane Center Miami FL AL202023 500 PM AST Wed Oct 18 2023 The tropical disturbance that NHC has been monitoring for many days as it traversed the tropical Atlantic (AL94) has finally become sufficiently organized, both convectively and circulation-wise, to be designated as a tropical cyclone. The circulation still appears a bit elongated in visible satellite images, but the convective activity suggests that a well-defined center has formed. Earlier scatterometer data showed winds of 30-35 kt to the northeast of the center, and TAFB provided a Dvorak estimate of T2.5/35 kt. Therefore, advisories are being initiated on Tropical Storm Tammy, with an initial intensity of 35 kt. The initial motion is westward (275 degrees) at a fast 20 kt, but there is uncertainty in this estimate given that the center has likely just recently formed. A strong mid-level ridge to the north is forecast to keep Tammy on a westward motion, but slower, over the next 24 hours or so. After that, a deep-layer trough moving across the eastern United States is expected to push the ridge eastward, allowing Tammy to turn toward the northwest and then north into the weekend. The track models agree on this general scenario, with Tammy moving over or near the Leeward Islands Friday and Saturday. However, there are some notable differences, with some of the stronger models (e.g., HWRF and GFS) showing a turn just before Tammy reaches the islands, while the weaker models (e.g., HAFS and HMON) move the storm farther west into the northeastern Caribbean Sea. The initial NHC track forecast is between these two periphery scenarios, and is close to the ECMWF, TVCA, and HCCA solutions. After passing the Leeward Islands, Tammy is expected to accelerate northeastward over the central Atlantic ahead of the trough. Global model fields and SHIPS model diagnoses suggest that Tammy may deal with some vertical shear, and possibly some dry air in the vicinity, over the next few days. On the other hand, the storm will be moving over very warm waters of 29-30 degrees Celsius. Therefore, gradual strengthening is forecast during the next couple of days, with the NHC intensity prediction very close to the IVCN and HCCA aids. While the forecast depicts a 55-kt tropical storm moving across the islands, there could be adjustments to this forecast once Tammy's current intensity and structure become clearer, and users should be prepared for possible forecast changes. After Tammy passes the Leeward Islands, the intensity models suggest that some further intensification will be possible as it accelerates northeastward over the central Atlantic. KEY MESSAGES: 1. Tropical storm conditions are possible across portions of the Lesser Antilles beginning on Friday. Tropical storm watches are currently in effect for Barbados, Dominica, Martinique, and Guadeloupe, and additional watches or warnings will likely be required tonight or on Thursday. 2. Heavy rains from Tammy will begin to affect the northern Windward and Leeward Islands on Friday, spreading into the British and U.S. Virgin Islands and Puerto Rico over the weekend. This rainfall may produce isolated flash and urban flooding, along with isolated mudslides in areas of higher terrain. FORECAST POSITIONS AND MAX WINDS INIT 18/2100Z 13.0N 51.7W 35 KT 40 MPH 12H 19/0600Z 13.1N 53.7W 40 KT 45 MPH 24H 19/1800Z 13.5N 55.9W 50 KT 60 MPH 36H 20/0600Z 14.1N 58.2W 55 KT 65 MPH 48H 20/1800Z 15.0N 60.2W 55 KT 65 MPH 60H 21/0600Z 15.9N 61.7W 55 KT 65 MPH 72H 21/1800Z 17.5N 62.7W 55 KT 65 MPH 96H 22/1800Z 21.4N 63.4W 60 KT 70 MPH 120H 23/1800Z 26.1N 60.2W 60 KT 70 MPH $$ Forecaster Berg The latest SHIPS text model output (0Z run Thursday, 8pm Wednesday) has the storm a little weaker in the shorter term forecast and a little stronger in the longer term compared the previous run. It's stronger after 72 hours, but by then it would be pulling away from the islands. But, given they don't know well it is structured right now, the intensity over the islands it still uncertain. https://ftp.nhc.noaa.gov/atcf/stext/?C=M;O=D Look for latest file with "AL2023". (which is AL for Atlantic, then number 20 for storm number and then 23 for year) Right now at the longer ranges the GFS and Euro don't show an impact in Bermuda, but that's still a little far out to know. But for now it curves east before getting close. GFS: https://www.tropicaltidbits.com/analysis/models/?model=gfs®ion=atl&pkg=mslp_pcpn_frzn Euro: https://www.tropicaltidbits.com/analysis/models/?model=ecmwf®ion=atl&pkg=mslp_pcpn Recon is scheduled for Thursday course. I assume the NOAA mission will occur in the first one and then they added other missions. NOUS42 KNHC 171450 REPRPD WEATHER RECONNAISSANCE FLIGHTS CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL. 1050 AM EDT TUE 17 OCTOBER 2023 SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD) VALID 18/1100Z TO 19/1100Z OCTOBER 2023 TCPOD NUMBER.....23-140 I. ATLANTIC REQUIREMENTS 1. SUSPECT AREA (CENTRAL ATLANTIC - AL94) FLIGHT ONE - NOAA43 A. 19/1200Z B. NOAA3 01EEA TDR C. 19/0900Z D. 12.9N 53.3W E. 19/0945Z TO 19/1615Z F. SFC TO 10,000 FT G. TAIL DOPPLER RADAR 2. SUCCEEDING DAY OUTLOOK: A. POSSIBLE LOW-LEVEL INVEST INTO AL94 NEAR 13.5N 54.5W FOR 19/1800Z. B. TWO MORE NOAA P-3 TAIL DOPPLER RADAR MISSIONS INTO AL94 FOR 20/0000Z AND 20/1200Z. C. POSSIBLE USAF RESERVE WC-130J SYNOPTIC SURVEILLANCE MISSION AROUND AL94 FOR 20/0000Z. II. PACIFIC REQUIREMENTS 1. NEGATIVE RECONNAISSANCE REQUIREMENTS. 2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE. NOUS42 KNHC 182026 REPRPD WEATHER RECONNAISSANCE FLIGHTS CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL. 0430 PM EDT WED 18 OCTOBER 2023 SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD) VALID 19/1100Z TO 20/1100Z OCTOBER 2023 TCPOD NUMBER.....23-141 AMENDMENT I. ATLANTIC REQUIREMENTS 1. TROPICAL STORM TAMMY (CHANGED) FLIGHT ONE - TEAL 74 FLIGHT TWO - NOAA 42 A. 19/1730Z,2330Z...(ADDED) A. 20/0000Z B. AFXXX 0220A TAMMY (CHGD) B. NOAA2 0320A TAMMY (CHGD) C. 19/1500Z C. 19/2130Z D. 13.4N 55.1W D. 13.7N 56.4W E. 19/1700Z TO 19/2330Z(CHGD) E. 19/2200Z TO 20/0230Z F. SFC TO 15,000 FT F. SFC TO 15,000 FT G. FIX (CHANGED) G. TAIL DOPPLER RADAR FLIGHT THREE - TEAL 75 FLIGHT FOUR - NOAA 43 A. 20/0530Z A. 20/1200Z B. AFXXX 0420A TAMMY B. NOAA3 0520A TAMMY C. 20/0330Z C. 20/0930Z D. 14.1N 57.6W D. 14.5N 58.7W E. 20/0500Z TO 20/0830Z E. 20/1000Z TO 20/1430Z F. SFC TO 10,000 FT F. SFC TO 15,000 FT G. FIX G. TAIL DOPPLER RADAR FLIGHT FIVE - TEAL 76 A. 20/1130Z,1730Z B. AFXXX 0620A TAMMY C. 20/0930Z D. 14.5N 58.6W E. 20/1100Z TO 20/1730Z F. SFC TO 15,000 FT G. FIX 2. SUCCEEDING DAY OUTLOOK: A. CONTINUE 6-HRLY FIXES ON TAMMY. B. TWO MORE NOAA P-3 TAIL DOPPLER RADAR MISSIONS INTO TAMMY FOR 21/0000Z AND 21/1200Z, DEPARTING TBPB AT 20/2130Z AND 21/0930Z. II. PACIFIC REQUIREMENTS 1. TROPICAL STORM NORMA FLIGHT ONE - TEAL 71 A. 19/1730Z B. AFXXX 0117E NORMA C. 19/1230Z D. 17.3N 108.4W E. 19/1700Z TO 19/2030Z F. SFC TO 10,000 FT G. FIX 2. SUCCEEDING DAY OUTLOOK: FIX NORMA AT 20/1730Z. From Plan of the Day: https://www.nhc.noaa.gov/recon.php |