Good day everyone!
Despite taking in a large amount of dry air yesterday evening, the remnant of Dorian is firing convection once again, albeit more of a mid level feature. As of the 8:00 a.m. EDT Tropical Weather Outlook from the NHC, the probability of this remnant becoming a tropical cyclone during the next 48 hours has been lowered to LOW (20%).
I have to concur with the NHC at the moment.
One of the big factors inhibiting any regeneration is the upper level trof (trough) to the west of the remnant. This feature had been forecast to lift toward the WNW and begin to weaken about 36 hours ago, which based on previous shear forecast maps, should have provided a more conducive environment for regeneration. Current satellite loop imagery may indicate this upper feature is in fact beginning to move toward the west, away from the area of convection associated with the remnant. If this does occur, conditions MAY become a little more conducive over the next 48-72 hours.
Based on careful analysis of various satellite loop imagery channels, current wind shear map from CIMSS, and most recent vorticity maps, lower level vorticity is displaced to the WSW of the mid level convection, due to around 15-20 knots of mid level wind shear.
Analysis of the current wind shear forecast products from the GFS (Global Forecasting System) model, should the remnant survive the next 48-60 hours and enter the southern GOMEX, wind shear values could relax enough for a marginally conducive environment, and IF anything is left of this remnant, will have to be monitored.
Analysis this morning of the current mean steering layer indicates the remnant should move toward the W or on a track just north of due west today, and based on the current run of the forecast steering layers maps from the PSU e-WALL site, I expect this general motion to continue for the next 48 hours. Based on a forecast weakness in the ridge, a more northward turn could occur as shown in the 06Z Dynamic Model Guidance, albeit guidance has become pretty sparse.
CURRENT MEAN STEERING
I will continue to monitor the area of convection for the next few days, for any significant changes, as I never discount a remnant as long as convective pulses keep occurring.
Elsewhere, I will continue to monitor a small area of convection just south of the Cape Verde islands as it moves toward the west. Currently, conditions are not favorable for development from this area.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)