Good evening everyone!
Tropical Disturbance INVEST 92L remains over the Yucatan Peninsula this evening. However, based on careful analysis of RGB and Shortwave IR2 satellite loop imagery, I am relocating the center of the disturbance a little further north and west of the 18Z ATCF FTP information, which placed the center near 19.3N…88.3W. I hold it near 20.7N…89.2W, which is kind of supported by the 925 mb vorticity map
The disturbance is moving to the WNW, and I expect this motion to continue tonight, with a turn more to the NW tomorrow. Currently, the NHC has a 50% (medium) probability of this becoming a tropical cyclone during the next 48 hours, and a 60% (high) chance in the next 5 days.
At the moment, the area is under 15-20 knots of shear, as the upper level anticyclone is just west of the circulation. Based on the possible relocation of the LLC, and current run of the GFS wind shear forecast products, INVEST 92L may encounter a little more favorable environment than forecast earlier today, with a weak upper level anticyclone forecast over the central GOMEX in about 18 hours. This is now forecast to remain right before whatever may become of the disturbance, makes it ashore on the Gulf Coast. The GFS and FIM models still show an open wave, while the CMC has a depression coming ashore. Given the possible center relocation, I expect the center to be over the water again in about 12 hours or less…so if these conditions do materialize, there is the slim chance the CMC may be correct.
Based on current and forecast steering, I’m to the right of the 18Z Dynamic Model guidance TVCN track. I do prefer the track of the FIM model, in that any center will still be over E. LA, however with the weather to the right of track. Regardless of development or not, winds of 35 to possibly 40 mph may be experienced along the AL/FL Panhandle border in about 48-50 hours. Residents in these areas may experience flooding due to accumulated rainfall totals 120 hours into the forecast period.
I will continue to monitor INVEST 92L for any significant changes.
Tropical Storm Erin continues to move toward a weakness in the ridge. As of the 5:00 p.m. EDT advisory from the NHC, the following was available:
5:00 PM AST Thu Aug 15
Location: 15.0°N 27.5°W
Moving: WNW at 14 mph
Min pressure: 1006 mb/29.71 in
Max sustained: 40 mph
Satellite loop imagery shows almost a NW motion, and convection was just SW of the LLC.
Erin is currently under favorable upper level winds,and should remain in favorable conditions for the next 72 hours, based on the wind shear forecast. However, the NHC forecast still calls for her to move into a more stable environment, which would preclude strengthening. Based on current and forecast steering maps, and satellite loop imagery, I prefer the southern portion of the guidance package, however I am somewhat north of the NHC official track.
I will continue to monitor Erin as she approaches just north of the Lesser Antilles, to see if any significant environmental changes occur.
I will have another update in the a.m.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)