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| #858123 (Received by flhurricane at: 5:01 PM 27.May.2016) TCDAT2 TROPICAL DEPRESSION TWO DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL022016 500 PM EDT FRI MAY 27 2016 An Air Force Reserve reconnaissance aircraft investigating the low pressure system located about 400 n mi southeast of Charleston, South Carolina, indicated that the system has developed a well-defined closed circulation. With this afternoon's increase in convection near the center, the system is now a tropical cyclone and advisories have been initiated. The strongest reliable SFMR surface wind measured was 30 kt, and that is the intensity set for this advisory. The initial motion estimate is 300/11 kt. A strong deep-layer ridge to the northeast of the depression is forecast to remain oriented northwest-southeast across the Carolinas through 36 hours or so, which should keep the depression moving in a general west-northwestward direction during that time. By 48 hours, however, a mid-level shortwave trough ejecting northeastward out of the south-central United States is forecast to erode the ridge, resulting in a significant weakening of the steering currents and a sharp decrease in forward speed as the cyclone is approaching the coast of South Carolina. By day 3 and beyond, the cyclone is forecast to move slowly northeastward or eastward off of the coast of North Carolina as a weakening system. The models are in good agreement on this track scenario, with only small differences in forward speed. The official track forecast is close to the consensus model TVCN and has incorporated the slightly slower speed of the ECMWF model. The depression will be moving over somewhat cooler sea surface temperatures of near 25C during the next 24 hours or so before moving over the warmer Gulfstream by 36 hours, where SSTs are 27C-28C. Over the next day or so, the cyclone will also be moving into weaker vertical wind shear conditions. The net result is expected to be slow strengthening to tropical storm status prior to landfall. The NHC intensity forecast is similar to the SHIPS model through 48 hours, and then closely follows the Decay-SHIPS model after that. FORECAST POSITIONS AND MAX WINDS INIT 27/2100Z 28.5N 74.7W 30 KT 35 MPH 12H 28/0600Z 29.5N 76.4W 35 KT 40 MPH 24H 28/1800Z 30.7N 78.3W 40 KT 45 MPH 36H 29/0600Z 32.0N 79.7W 40 KT 45 MPH 48H 29/1800Z 32.8N 80.2W 40 KT 45 MPH...INLAND 72H 30/1800Z 33.6N 78.7W 30 KT 35 MPH...OVER WATER 96H 31/1800Z 34.0N 77.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 01/1800Z 34.7N 75.6W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Stewart |