000 WTPZ43 KNHC 051455 TCDEP3 Tropical Depression Eighteen-E Discussion Number 5 NWS National Hurricane Center Miami FL EP182021 1000 AM CDT Fri Nov 05 2021 The convective structure with the depression this morning remains disheveled, with only scattered convection pulsing around the circulation without much organization. The latest subjective Dvorak satellite estimates are T2.0/30 kt from TAFB and T1.5/25 kt from SAB, while the most recent UW-CIMSS ADT estimate was T2.1/31 kt. A blend of these data support maintaining the intensity at 30 kt this advisory. Early morning visible satellite imagery suggests that the system is moving south of due west, with the latest motion estimate at 260/8 kt. As an amplified short-wave trough located over the Gulf of Mexico propagates eastward, a mid-level ridge ridge centered near the Baja California peninsula is expected to expand eastward over Mexico. This feature should dominate the steering pattern over the depression through the forecast period, leading to a general westward motion but at a gradually accelerating forward speed. Because the depression is quite shallow currently, low-level flow in association with a developing gale-force gap wind event in the Gulf of Tehuantepec may also assist the system in losing a bit more latitude over the next 24-36 hours. After 48 hours, a weakness under the ridge from an downstream disturbance may allow the depression to gain back a bit of latitude. The track guidance remains in fairly good agreement, though differences in speed are seen between the slower GFS versus the faster ECMWF guidance, and another southward shift has taken place. The official NHC track forecast is a bit further south and a touch faster compared to the previous one, following the consensus aids TVCE and HCCA. The current poor organization of the convection argues against any short-term intensity changes. While deep-layer (200-850 hPa) vertical wind shear is expected to remain low, higher mid-level shear may prevent better convective organization over the next 36-48 hours. While mid-level relative humidity is forecast to be sufficently moist, visible satellite imagery suggests stable stratocumulus inflow from the south, while the aforementioned gap wind event to the north may also contribute to a less-than-optimal thermodynamic environment. The official NHC intensity forecast now shows no intensification over the next 36 hours with only gradual intensification thereafter, favoring the more pessimistic guidance. If the latest ECMWF and LGEM guidance are correct, the depression may fail to intensify at all over the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 9.4N 92.4W 30 KT 35 MPH 12H 06/0000Z 9.2N 93.5W 30 KT 35 MPH 24H 06/1200Z 8.9N 95.4W 30 KT 35 MPH 36H 07/0000Z 8.7N 97.5W 30 KT 35 MPH 48H 07/1200Z 8.7N 99.7W 35 KT 40 MPH 60H 08/0000Z 9.2N 102.0W 40 KT 45 MPH 72H 08/1200Z 9.8N 104.4W 45 KT 50 MPH 96H 09/1200Z 10.9N 109.4W 50 KT 60 MPH 120H 10/1200Z 11.3N 114.2W 55 KT 65 MPH $$ Forecaster Papin