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| #875243 (Received by flhurricane at: 11:07 AM 18.Sep.2016) TCDAT1 TROPICAL DEPRESSION JULIA DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112016 1100 AM EDT SUN SEP 18 2016 After an early morning burst of deep convection, strong northerly shear and dry mid-level air have significantly weakened the convection, leaving behind only shallow convection about 50-60 nmi east through southwest of the now fully exposed low-level circulation center. The initial intensity is being held at 25 kt, which could be a little conservative, based on a TAFB satellite classification of T1.5/25 kt. Julia has been drifting westward the past several hours, but a slow north-northwestward or northward motion is expected begin later today. This general motion is forecast to continue into Tuesday as a strong shortwave trough currently over the central United States moves quickly eastward, creating increasing southerly to southwesterly flow over the Carolinas. There are some notable differences between the models with the ECMWF forecasting Julia to weaken into a shallow remnant low and drift southwestward by 72 hours, whereas the remainder of the global and regional models maintain a somewhat deeper cyclone and lift it out poleward in the deeper steering flow ahead of the aforementioned shortwave trough. The NHC forecast track leans toward the model consensus and keeps Julia a little stronger and deeper, taking the cyclone northward and near the coast of North Carolina by 48 hours. However, rapid weakening is likely by 72 hours due to strong southwesterly shear, leaving Julia as a remnant low near or over the coastal regions of eastern North Carolina. The intensity forecast is a little tricky due to the rapidly decreasing shear conditions that the models are forecasting to occur during the next 24 hours or so. The current 25-30 kt of northerly vertical wind shear is expected to decrease to 10-15 kt from the southwest by Monday morning, which would support a repeat of strong convective development and spinup of the vortex, similar to what occurred overnight, especially since Julia will be moving over the warmer waters of the Gulf Stream at that time. The intensity forecast is identical to the previous advisory and remains on the low side of the guidance near the LGEM model. However, due to the possibility of the cyclone being a little stronger than forecast, the Air Force Reserve Hurricane Hunters have been tentatively tasked to investigate Julia tomorrow afternoon. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 31.8N 77.1W 25 KT 30 MPH 12H 19/0000Z 32.5N 77.3W 25 KT 30 MPH 24H 19/1200Z 33.4N 77.2W 30 KT 35 MPH 36H 20/0000Z 33.8N 77.2W 30 KT 35 MPH 48H 20/1200Z 34.2N 77.2W 30 KT 35 MPH 72H 21/1200Z 34.5N 77.1W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 22/1200Z...DISSIPATED $$ Forecaster Stewart |
