| Recon: http://hurricanecity.com/recon/ Upgrade to 125 mph might not be based on two 109 knot (125.4 mph) 10 second esitmated surface winds by SFMR in a row (1 was suspect, but no reason to doubt it), because the HDOB message this came from ended at 7:54pm EDT, not sure what time advisory came out. Further, dropsonde splashed down at 7:50:31pm EDT with 954mb and 17 knots of surface wind. NHC said this in 8pm EDT advisory: "The estimated minimum central pressure from the reconnaissance plane was 955 mb (28.20 inches)." They may have been looking at extrapolated data from the plane, where 954.4mb estimated pressure was the last ob in HDOB set ending at 7:44pm EDT. It wasn't until 7:54pm EDT HDOB set with 7:47:30pm EDT estimate of 952.5 mb. High SFMR was in the NW quadrant. They entered in SE, to center and then into NW. NW quadrant: 30s flight level: 116 knots (133.5 mph) 10s flight level: 123 knots (141.5 mph) 10s estimated surface: 109 knots (125.4 mph) ... 2 in a row (though 1 suspect) SE quadrant: 30s flight level: 115 knots (132.3 mph) 10s flight level: 118 knots (135.8 mph) 10s estimated surface: 96 knots (110.5 mph) ... 3 in a row They have yet to sample NE quadrant, so the storm could be stronger. The NHC officially says: "Little change in strength is expected during the next couple of days." But I disagree. Shear doesn't seem to be having an impact yet. SHIPS text output for 18Z: http://ftp.nhc.noaa.gov/atcf/stext/17092118AL1517_ships.txt From: http://ftp.nhc.noaa.gov/atcf/stext/ 0Z should be out shortly. 5pm NHC discussion relies too heavily on the model in the short term in my opinion: "SHIPS diagnostics indicate that southwesterly shear will be increasing over Maria during the next 12-24 hours, even though the hurricane will begin to move over an area of higher oceanic heat content. While it can't be ruled out that Maria might still strengthen a bit, the preponderance of the guidance suggests that the cyclone will only maintain its intensity for the next 12 hours and then begin a gradual decrease in strength on Friday. That trend should continue through the end of the forecast period, but Maria is expected to remain a hurricane through day 5. For now, the NHC forecast remains just above the intensity consensus, hedging toward the slower decay shown by the SHIPS model." NHC: http://www.nhc.noaa.gov/ Normal Satellite Floater: http://www.ssd.noaa.gov/PS/TROP/floaters/15L/15L_floater.html Wider Atlantic views: http://www.ssd.noaa.gov/PS/TROP/trop-atl.html GOES-16 1 minute mesoscale sector 1 floater: http://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=mesoscale_01&x=1000&y=1000&z=0&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=12&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider https://re.ssec.wisc.edu/s/fBDvs http://weather.cod.edu/satrad/exper/?parms=meso1-13-24-0-100 Hurricane Maria Intermediate Advisory Number 23A NWS National Hurricane Center Miami FL AL152017 800 PM AST Thu Sep 21 2017 ...LARGE EYE OF HURRICANE MARIA GRADUALLY APPROACHING THE TURKS AND CAICOS ISLANDS... SUMMARY OF 800 PM AST...0000 UTC...INFORMATION ---------------------------------------------- LOCATION...20.9N 70.0W ABOUT 85 MI...135 KM NNE OF PUERTO PLATA DOMINICAN REPUBLIC ABOUT 80 MI...130 KM ESE OF GRAND TURK ISLAND MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H PRESENT MOVEMENT...NW OR 315 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...955 MB...28.20 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Dominican Republic from Cabo Engano to Puerto Plata * Turks and Caicos Islands and the Southeastern Bahamas A Tropical Storm Warning is in effect for... * Dominican Republic west of Puerto Plata to the northern border of the Dominican Republic and Haiti A Tropical Storm Watch is in effect for... * Central Bahamas A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests in the Bahamas should monitor the progress of Maria. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 800 PM AST (0000 UTC), the large eye of Hurricane Maria was located near latitude 20.9 North, longitude 70.0 West. Maria is moving toward the northwest near 9 mph (15 km/h), and this general motion is expected to continue through tonight. A turn toward the north-northwest is forecast early Friday, with that motion continuing through Saturday. On the forecast track, Maria's eye will continue to pass offshore of the northern coast of the Dominican Republic this evening, and then move near or just east of the Turks and Caicos Islands and southeastern Bahamas later tonight and on Friday. Preliminary reports from an Air Force reconnaissance plane indicate that the maximum sustained winds have increased to around 125 mph (205 km/h) with higher gusts. Maria is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Little change in strength is expected during the next couple of days. Hurricane-force winds extend outward up to 70 miles (110 km) from the center, and tropical-storm-force winds extend outward up to 160 miles (260 km). The estimated minimum central pressure from the reconnaissance plane was 955 mb (28.20 inches). HAZARDS AFFECTING LAND ---------------------- WIND: Hurricane and tropical storm conditions continue across portions of the Dominican Republic. Tropical storm conditions are beginning to spread across the Turks and Caicos Islands and the southeastern Bahamas, and hurricane conditions are expected tonight or early Friday. Tropical storm conditions are possible in the central Bahamas beginning late Friday. STORM SURGE: A dangerous storm surge accompanied by large and destructive waves will raise water levels by as much as 4 to 6 feet above normal tide levels in the hurricane warning area in the Dominican Republic, and 1 to 3 ft elsewhere along the northern coasts of the Dominican Republic and Haiti. A dangerous storm surge accompanied by large and destructive waves will raise water levels by as much as 9 to 12 feet above normal tide levels within the hurricane warning area of the southeastern Bahamas and the Turks and Caicos Islands. RAINFALL: Maria is expected to produce the following rainfall accumulations through Saturday: Puerto Rico...additional 4 to 8 inches, isolated maximum storm total amounts 40 inches Northern and eastern Dominican Republic, Turks and Caicos, and Mayaguana in southeast Bahamas...8 to 16 inches, isolated 20 inches Inagua Islands, Crooked Island, and rest of southeast Bahamas...4 to 8 inches Northern Haiti...4 to 8 inches Rainfall on these islands will continue to cause life-threatening flash floods and mudslides. SURF: Swells generated by Maria are affecting Puerto Rico, the Virgin Islands, the northern coast of Hispaniola, the Turks and Caicos Islands, and the southeastern Bahamas. These swells will reach the remainder of the Bahamas tonight and should reach portions of the United States southeastern coast on Friday. 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 1100 PM AST. $$ Forecaster Avila |