000 WTPZ41 KNHC 312039 TCDEP1 HURRICANE ANDRES DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 200 PM PDT SUN MAY 31 2015 The satellite presentation of Andres has improved considerably since this morning. The eye has become more distinct and warmed in infrared imagery, and is now surrounded by a ring of cloud tops of about -60C to -70C. Objective and subjective Dvorak estimates have increased, and currently range from T5.5/102 kt to T6.1/117 kt. The initial intensity has been raised to 110 kt for this advisory. Beyond the observed intensity increase today, the overall intensity forecast reasoning has not changed. The cyclone will be moving over cooler waters during the forecast period, and should cross the 26C isotherm in about 36 hours, which should result in weakening. More rapid weakening forecast at 48 hours and beyond, with Andres forecast to become a remnant low in about 4 days as the shear increases over very cool SSTs. The new NHC intensity forecast is higher than the previous one through 48 hours to account for the initial intensity, and is similar after that. The official forecast is generally close to the IVCN intensity consensus. The hurricane has jogged to the left since this morning, with an initial motion of 270/07. Andres should gradually turn poleward during the next several days as a weakness develops in the subtropical ridge around 125W. There remains a fair bit of spread in the track guidance throughout the period. The UKMET and ECMWF are initially to the left of the rest of the guidance for the first 12 to 24 hours, and the NHC forecast trends towards those aids given the more westerly initial motion. Late in the period, all of the dynamical models now show a turn toward the north and northeast, but significant spread remains. Given that Andres should be sheared apart by days 4 and 5, the NHC forecast shows only a slow northward drift, in better agreement with the ECMWF and GEFS ensemble mean. The GFS remains an outlier with a track that appears to go too far to the northeast for such a weak system. Beyond 24 hours, the new NHC track is similar to or a little to the right of the previous one, adjusted for the initial position and motion, and lies a little to the left of the multi-model consensus. The initial 34-kt and 50-kt wind radii have been adjusted based on a recent ASCAT pass. Andres is only the fifth major hurricane to form in the basin in May since reliable records began in 1970. Previous May major hurricanes were Adolph (2001), Alma (2002), Bud (2012), and Amanda (2014). FORECAST POSITIONS AND MAX WINDS INIT 31/2100Z 15.3N 118.8W 110 KT 125 MPH 12H 01/0600Z 15.5N 119.7W 100 KT 115 MPH 24H 01/1800Z 16.3N 121.1W 90 KT 105 MPH 36H 02/0600Z 17.2N 122.7W 80 KT 90 MPH 48H 02/1800Z 18.2N 124.4W 65 KT 75 MPH 72H 03/1800Z 19.5N 126.5W 40 KT 45 MPH 96H 04/1800Z 20.0N 126.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 05/1800Z 20.5N 126.8W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Brennan