Tropical Storm Alvin Discussion Number 13
Wiki-Hurricanes Forecast Center
2:00 PM PDT Fri Jun 28 2019
Alvin has rapidly weakened today. Conventional satellite imagery shows deep convection restricted to the northern half of the storm's low-level circulation due to ever-increasing southerly wind shear. Widespread low-level clouds indicate that Alvin is embedded within a dry environment, and ocean temperatures have fallen under 24C. A series of ASCAT passes around 17z indicated that the storm's maximum sustained winds had fallen to around 40kt. Precedent with Alvin would be to set the initial intensity to 45kt given its small radius of maximum winds. However, given its rapid degradation in appearance and the environment it is currently embedded within, I have elected to take ASCAT at face value and set the intensity to 40kt.
There is not much left to discuss in term of Alvin's future. The culmination of unfavorable factors should continue to cause rapid weakening, and Alvin is expected to become a remnant low in 36 hours; this could feasibly occur sooner. Dissipation is expected in 48 hours. Alvin has continued on its west-northwest track, but a turn toward the west is expected within the next day as it loses vertical depth and is steered by low-level easterly trade winds.
FORECAST MAX WINDS
INIT 28/2100Z 40 KT 45 MPH
12H 29/0600Z 35 KT 40 MPH
24H 29/1800Z 30 KT 35 MPH
36H 30/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW