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Tropical Depression TWO Forecast Discussion Number 1
2014-07-21 22:34:36| National Hurricane Center (Atlantic)
Issued at 500 PM AST MON JUL 21 2014 000 WTNT42 KNHC 212034 TCDAT2 TROPICAL DEPRESSION TWO DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL022014 500 PM AST MON JUL 21 2014 The area of low pressure in the tropical Atlantic has shown an increase in convective organization today. Despite the fact that the convection remains somewhat shallow, it has enough coverage and organization to classify the system as a tropical cyclone. An ASCAT pass around 1210 UTC was not conclusive in regards to whether the surface circulation was closed, but given the persistence of the convection, we are assuming that the circulation is closed and are initiating advisories at this time. The initial intensity of 30 kt is based on data from the ASCAT pass. The environment is marginal, at best, for development during the next couple of days, as the depression will be moving over marginal SSTs and into a region characterized by dry air and subsidence as it approaches the Caribbean Sea. Most of the global model guidance and the HWRF shows the system weakening and dissipating by 48 to 72 hours. The official forecast follows suit, but the cyclone could dissipate sooner than shown here. The SHIPS and LGEM intensity forecasts seem much too high in this scenario, and are not given much weight in the official forecast. The initial motion is quickly toward the west or 280/14 knots. The cyclone will be steered by the Atlantic subtropical ridge during its life span, and should remain on a westward to west-northwestward heading with an increase in forward speed. The NHC track forecast is close to a blend of the HWRF and the GEFS ensemble mean. Note that the global models are having a difficult time tracking the small vortex, and confidence in the details of the track forecast is lower than usual. FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 11.6N 43.8W 30 KT 35 MPH 12H 22/0600Z 11.9N 45.8W 30 KT 35 MPH 24H 22/1800Z 12.3N 48.2W 30 KT 35 MPH 36H 23/0600Z 12.8N 51.0W 30 KT 35 MPH 48H 23/1800Z 13.4N 54.2W 30 KT 35 MPH 72H 24/1800Z 15.0N 61.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 25/1800Z...DISSIPATED $$ Forecaster Brennan
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