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| #803540 (Received by flhurricane at: 4:55 AM 28.Sep.2015) TCDAT1 TROPICAL DEPRESSION ELEVEN DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112015 500 AM AST MON SEP 28 2015 Shortwave and enhanced BD-Curve infrared imagery show little change in the depression's cloud pattern this morning. Recently, however, a few bursts of deep convection are beginning to develop near the surface center. Subjective intensity estimates remain unchanged from the previous advisory as does the initial intensity of 30 kt. UW-CIMSS shear product and the SHIPS model both indicate 10-20 kt of northwesterly shear generated by a high amplitude upper-level ridge extending northward over the western Atlantic from the western Caribbean. Large-scale models show this upper-wind pattern persisting through day 3, which should inhibit any significant strengthening. Afterward, increasing southwesterly shear is expected to spread over the eastern seaboard and extreme western Atlantic waters in response to a deep-layer mid-latitude trough approaching from the west. Despite a rather harsh forecast upper-wind environment, the IVCN intensity consensus model shows slight strengthening to a tropical storm in 24 hours. Beyond the 96 hour period, the global models indicate either dissipation or the cyclone quickly becoming absorbed by the aforementioned baroclinic system. The official forecast is based on the IVCN consensus and indicates the cyclone merging with the frontal system in 5 days. The depression's center has been a bit difficult to find this morning, and has been moving erratically, drifting westward, or 275/2 kt. The cyclone should turn toward the west-northwest later today and continue in this general direction for a couple of days due to high pressure extending over the western Atlantic. After that time, a northward turn is forecast with an increase in forward speed around day 3 in response to the above mentioned frontal system approaching the east coast of the U.S. The NHC track forecast is nudged a little to the left of the previous forecast and sides with the TVCX multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 27.4N 68.9W 30 KT 35 MPH 12H 28/1800Z 27.6N 69.4W 30 KT 35 MPH 24H 29/0600Z 28.0N 70.0W 35 KT 40 MPH 36H 29/1800Z 28.5N 70.7W 35 KT 40 MPH 48H 30/0600Z 29.2N 71.4W 35 KT 40 MPH 72H 01/0600Z 31.2N 72.3W 35 KT 40 MPH 96H 02/0600Z 36.2N 72.5W 30 KT 35 MPH 120H 03/0600Z...ABSORBED BY FRONT $$ Forecaster Roberts |
