Tropical Storm Lowell Forecast Discussion
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403 WTPZ42 KNHC 290851 TCDEP2 Tropical Storm Lowell Discussion Number 7 NWS National Hurricane Center Miami FL EP122026 1100 PM HST Fri Aug 28 2026 There has been little change in Lowell's organization or intensity during the past several hours. Moderate easterly vertical wind shear continues to displace the bulk of the deep convection over and west of the low-level circulation center. While an earlier scatterometer pass showed slightly lower winds, a blend of the latest objective intensity estimates and the subjective Dvorak intensity estimate from TAFB supports holding the initial intensity at 40 kt for this advisory. The cyclone continues to move slowly westward, with an initial motion of about 280/7 kt. A low- to mid-level ridge is forecast to strengthen north of the cyclone during the next couple of days, which should cause Lowell to continue westward with a gradual increase in forward speed. This general westward motion is expected to continue through the weekend and into early next week. Track forecast uncertainty increases considerably thereafter due in part to the potential influence of Tropical Storm Karina to the northeast on Lowell's steering flow. There remains considerable spread in the guidance, particularly in forward speed, with the multi-model consensus (HCCA) and Google DeepMind ensemble mean generally faster than the GFS and ECMWF solutions. In addition to the along-track spread, the cross-track spread also increases considerably by day 5. Given these differences, the latest NHC track forecast has been nudged slightly southward and reflects a blend of the previous forecast and the latest HCCA and Google DeepMind ensemble mean. The easterly vertical wind shear currently affecting Lowell is forecast to persist into the weekend, then steadily decrease by Sunday night into Monday, which should allow the cyclone to become better organized and gradually strengthen. However, the current sheared structure and nearby mid- to upper-level dry air should temper the rate of intensification in the short term. Environmental conditions are forecast to become more favorable thereafter, and a faster rate of strengthening is possible by early next week. The intensity forecast becomes more uncertain later in the period due to Lowell's potential interaction with Karina. A faster westward track would likely keep the cyclones sufficiently separated and allow Lowell to continue strengthening, while a slower solution could expose Lowell to stronger shear associated with outflow from Karina. The latest NHC intensity forecast is essentially unchanged from the previous advisory and lies near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 12.6N 134.8W 40 KT 45 MPH 12H 29/1800Z 12.8N 136.3W 45 KT 50 MPH 24H 30/0600Z 12.9N 139.0W 50 KT 60 MPH 36H 30/1800Z 13.0N 141.3W 50 KT 60 MPH 48H 31/0600Z 13.0N 143.4W 55 KT 65 MPH 60H 31/1800Z 13.1N 145.0W 65 KT 75 MPH 72H 01/0600Z 13.3N 146.8W 75 KT 85 MPH 96H 02/0600Z 13.6N 149.0W 90 KT 105 MPH 120H 03/0600Z 13.9N 151.6W 95 KT 110 MPH $$ Forecaster Gibbs