000 WTPZ41 KNHC 190232 TCDEP1 TROPICAL STORM KARINA DISCUSSION NUMBER 25 NWS NATIONAL HURRICANE CENTER MIAMI FL EP112014 800 PM PDT MON AUG 18 2014 Karina has continued to become better organized over the past few hours. A convective cloud band wraps about 80 percent around the circulation, and the Dvorak data T-number from TAFB is now 3.5 which corresponds to an intensity estimate of 55 kt. The vertical shear over the storm has decreased and is forecast to stay low for another 24-36 hours. Upper-level outflow has also increased over the tropical cyclone. Therefore, Karina has an opportunity to intensify some more and it could become a hurricane tomorrow as indicated by the official forecast. Later in the forecast period, east- northeasterly shear is predicted to increase, which should cause gradual weakening. The official intensity forecast is close to the SHIPS model guidance through 36 hours, and close to the intensity model consensus thereafter. The forward motion continues to slow and is now around 255/7 kt. A mid-level ridge to the north of Karina should push the tropical cyclone a little farther west over the next day or two. However the westward steering is likely to end in a couple of days as Karina becomes more influenced by the large circulation of Tropical Storm Lowell passing to its northeast. By late in the forecast period, a broad area of southwesterly low-level flow associated with Lowell should start drawing Karina toward the northeast. The official forecast takes the storm farther northeast late in the period than the previous one, but not as much as some of our better track guidance. The new NHC track forecast is in good agreement with latest Florida State University Superensemble prediction. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 15.9N 133.6W 55 KT 65 MPH 12H 19/1200Z 15.9N 134.3W 60 KT 70 MPH 24H 20/0000Z 15.9N 135.3W 65 KT 75 MPH 36H 20/1200Z 15.9N 136.0W 65 KT 75 MPH 48H 21/0000Z 16.0N 136.5W 60 KT 70 MPH 72H 22/0000Z 16.0N 136.5W 50 KT 60 MPH 96H 23/0000Z 16.6N 135.8W 45 KT 50 MPH 120H 24/0000Z 17.5N 134.5W 45 KT 50 MPH $$ Forecaster Pasch