000WTNT44 KNHC 232048TCDAT4TROPICAL DEPRESSION FOUR DISCUSSION NUMBER 1NWS NATIONAL HURRICANE CENTER MIAMI FL AL042014500 PM AST SAT AUG 23 2014The Air Force Reserve Hurricane Hunter aircraft investigating thedisturbance near the southeastern Bahamas found a well-definedcirculation this afternoon. Even though the convective presentationis somewhat ragged, there is enough organization to classify thesystem as a tropical cyclone. The intensity is set to 30 kt basedon flight level wind data from the aircraft and an earlier ASCATpass, and the central pressure of 1005 mb is based on a recentsurface observation from Providenciales in the Turks and Caicos. TheSHIPS model shows light to moderate shear over the cyclone for thenext couple of days, which should allow for intensification giventhat the cyclone will be moving over waters of 29 to 30C. The NHCforecast shows slow strengthening in the first 24 to 36 hours asthe cyclone organizes. Global models show more favorable upper-level winds over the system in a couple of days, which should allowfor strengthening to a hurricane in by 3 days. The official forecastis close to the IVCN intensity consensus through the period.The initial motion estimate is a relatively uncertain 310/10 giventhe recent formation of the center. The cyclone should continuemoving northwestward and north-northwestward into a developing breakin the subtropical ridge cause by a mid/upper-level trough off theU.S. east coast. As the trough begins to lift out and steeringcurrents weaken, a slow motion is expected in 36 to 48 hours. Thenas a subtropical ridge rebuilds to the east of the cyclone later inthe period, the system is expected to turn northward and thennortheastward. However, there is significant disagreement inthe timing and sharpness of the turn in this and previous dynamicalmodel cycles. Currently the GFDL and GFS are along the westernedge of the guidance envelope showing a more westward track anda slower motion at day 5. The ECMWF, GEFS mean, and HWRF show asharper turn and a more northeastward motion by day 5 on the eastside of the guidance envelope. The NHC forecast is near the TVCAmulti-model consensus through most of the period and a little to theleft of it at day 5. Given the spread in the guidance and the recentformation of the system, confidence in the details of the trackforecast is lower than normal.FORECAST POSITIONS AND MAX WINDSINIT 23/2100Z 21.8N 72.3W 30 KT 35 MPH 12H 24/0600Z 22.9N 73.6W 35 KT 40 MPH 24H 24/1800Z 24.0N 74.4W 40 KT 45 MPH 36H 25/0600Z 24.6N 74.8W 45 KT 50 MPH 48H 25/1800Z 25.0N 75.0W 55 KT 65 MPH 72H 26/1800Z 26.5N 76.0W 65 KT 75 MPH 96H 27/1800Z 29.0N 77.5W 65 KT 75 MPH120H 28/1800Z 32.0N 76.5W 70 KT 80 MPH$$Forecaster Brennan
BULLETINTROPICAL DEPRESSION FOUR INTERMEDIATE ADVISORY NUMBER 2ANWS NATIONAL HURRICANE CENTER MIAMI FL AL042014200 AM AST SUN AUG 24 2014...DEPRESSION EXPECTED TO BECOME A TROPICAL STORM TODAY...SUMMARY OF 200 AM AST...0600 UTC...INFORMATION----------------------------------------------LOCATION...22.6N 73.0WABOUT 15 MI...25 KM N OF MAYAGUANA ISLANDABOUT 325 MI...520 KM ESE OF NASSAUMAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HPRESENT MOVEMENT...NW OR 325 DEGREES AT 9 MPH...15 KM/HMINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES