Official Discussion issued by the National Hurricane Center
Gordon (AL072024) DATA RELEASED: 9/16/2024 9:00:00 PM UTC
Copy of official data Tropical Depression Gordon Discussion Number 22 NWS National Hurricane Center Miami FL AL072024 500 PM AST Mon Sep 16 2024 Gordon is producing only a few sporadic bursts of deep convection, mainly over the southern and eastern portion of its circulation. The vertical wind shear does not appear to be very strong at this time, as evidenced by the relatively slow motions of the cirrus clouds over the system. Since the cyclone is situated over a warm ocean, the suppression of convection is probably due to a stable air mass and/or dry air. The advisory intensity is held at 30 kt in accordance with an objective estimate of 32 kt from UW-CIMSS and a subjective Dvorak Current Intensity number of 30 kt from TAFB. Gordon continues to move slowly westward with a current motion estimate of 270/5 kt. A high pressure area that was north of the system over the past couple of days is shifting westward, and being replaced by a mid-level trough within the next day or two. Also, there is a frontal cyclone located about 10 degrees to the north of Gordon. This feature, along with the trough, should cause the tropical cyclone to turn northward and north-northeastward during the next couple of days. Although Gordon is expected to at least briefly interact with the frontal wave, the global model guidance indicates that it will retain its identity and move farther north-northeastward over the Atlantic during the forecast period. The official forecast is shifted a little more to the east of the previous NHC prediction and is close to the corrected model consensus, HCCA. Output from the statistical-dynamical SHIPS models shows some increase in the low- to mid-level relative humidity and also suggests some increase in instability during the forecast period. The SHIPS output also shows generally low to moderate vertical shear for the next few days. The official forecast shows some restrengthening after 48 hours, but not as much of an intensity increase as called for by the SHIPS/LGEM predictions. FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 19.0N 48.5W 30 KT 35 MPH 12H 17/0600Z 19.2N 49.0W 30 KT 35 MPH 24H 17/1800Z 19.7N 49.1W 30 KT 35 MPH 36H 18/0600Z 20.3N 48.8W 30 KT 35 MPH 48H 18/1800Z 21.3N 48.3W 30 KT 35 MPH 60H 19/0600Z 22.8N 47.6W 35 KT 40 MPH 72H 19/1800Z 24.6N 46.5W 40 KT 45 MPH 96H 20/1800Z 27.0N 44.5W 45 KT 50 MPH 120H 21/1800Z 29.0N 43.5W 50 KT 60 MPH $$ Forecaster Pasch |