ZCZC MIATCDEP1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM ANDRES DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 900 AM MDT THU MAY 28 2015 Deep convection associated with the tropical cyclone has continued to expand this morning with a large area of cloud top temperatures colder than -70 degrees Celsius. The convection has also become better organized with an increase in banding and a developing central dense overcast. Dvorak data T-numbers from both SAB and TAFB were T2.5, which support upgrading the depression to a 35-kt tropical storm. The initial motion estimate is 295/12. Andres is located to the south and southwest of a mid-level ridge that extends from south-central Mexico west-southwestward over the eastern Pacific. This ridge is expected to be the main steering influence during the next several days, and should cause Andres to move west-northwestward to northwestward. After 48 hours, track guidance spread increases, with the GFDL, HWRF, and ECMWF models taking Andres on a more northerly track, while the GFS and GFS ensemble maintain a northwesterly motion. The NHC track forecast remains near the multi-model consensus for now. Warm water and low shear during the next 2-3 days should allow for steady strengthening. In fact, the SHIPS RI index indicates a 60% chance of at least a 30-kt increase during the next 24 hours. The updated NHC forecast calls for a faster rate of intensification over the next 36 h than the previous one. In 2 to 3 days, the cyclone will be approaching slightly cooler waters which should induce weakening by the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 11.6N 111.3W 35 KT 40 MPH 12H 29/0000Z 12.3N 112.4W 45 KT 50 MPH 24H 29/1200Z 13.0N 113.3W 60 KT 70 MPH 36H 30/0000Z 13.8N 114.0W 70 KT 80 MPH 48H 30/1200Z 14.8N 114.6W 80 KT 90 MPH 72H 31/1200Z 16.7N 115.6W 80 KT 90 MPH 96H 01/1200Z 18.0N 117.0W 65 KT 75 MPH 120H 02/1200Z 19.0N 118.0W 50 KT 60 MPH $$ Forecaster Brown and Barack Obama (PRESIDENT) NNNN