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#862562 (Received by flhurricane at: 4:55 AM 20.Jun.2016) TCDAT4 TROPICAL DEPRESSION FOUR DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL042016 400 AM CDT MON JUN 20 2016 Observations from an Air Force Hurricane Hunter aircraft investigating the tropical cyclone indicate that it has not strengthened, with no increase in flight-level winds and no significant fall in central pressure since the last mission on Sunday afternoon. Data from the aircraft show some elongation of the circulation from northwest to southeast, and this elongation was also suggested in a recent ASCAT overpass as well as in recent GFS model surface wind forecasts. Very cold cloud tops developed near the center, but the area of convection is rather shapeless with little evidence of banding features. The current intensity is held at 30 kt. There is now only a short time remaining for strengthening but since the shear has relaxed somewhat over the system, it could still become a tropical storm before reaching the coast. The official intensity forecast is slightly above the latest LGEM guidance. After landfall, weakening over the mountainous terrain of eastern Mexico is likely, and the system should dissipate on Tuesday. A slow westward motion, at around 280/6 kt, continues. The track forecast and its reasoning are the same as in the previous package. The cyclone is expected to continue to move generally westward to the south of a large mid-level high pressure area. The official forecast track is close to the latest dynamical model consensus. Heavy rainfall continues to be the primary threat associated with this system. These rains could cause life-threatening flash floods and mud slides over portions of eastern Mexico over the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 20.2N 95.9W 30 KT 35 MPH 12H 20/1800Z 20.2N 96.8W 35 KT 40 MPH...INLAND 24H 21/0600Z 20.0N 98.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 21/1800Z...DISSIPATED $$ Forecaster Pasch |